Fabrication of mililing holder deformation measurement model

At the same time, whenmechanical processing in general and milling in particular always create vibration and noise.Most of the time, to reduce vibration and noise, machine operators ofte

GENERAL

The urgency of the subject

Today, when the production level is highly automated, when the fields of modern technology are combined to form a new higher technology such as mechanical, electrical, electronic, information organization materials processing science has made new developments, for example, material processing in the production of computer-controlled combinations CAD/CAM/CNC has brought economic efficiency and improved get part surface quality.

With the advancement of science and technology, the explosion of information makes high technology become an era revolution with modern milling machines, combination machines, and program-controlled machines But any technological option, a structural plan, a process automation plan or a work organization plan must be evaluated from the point of view of economic efficiency and product quality products.

The surface quality of the part is affected by factors: technology system, external factors, materials, cooling is probably a topic that is not easy when technology is increasingly changing Significant changes in both tools, machines and processing materials, so this is a topic that probably requires a lot of effort and ink to study it Talking about the quality of machining, it is impossible not to mention the surface gloss of the part and the roughness is the criterion to evaluate this Up to now, there have been quite a few studies on the influence of cutting methods, cutting parameters, technology systems on surface roughness during machining on universal machines as well as CNC machines However, studying the effect of damping tool shank (a new technology in cutting machining) on the surface gloss of details has not been studied, because this technology has not been popularized in Vietnam Vietnam, so its investigation is very necessary because the surface gloss of mechanical details is increasingly demanding, so the use of damping technology in the future is certain.

Also, when machining in general and machining in particular, it always creates loud vibrations and noises Mostly to reduce this vibration and noise, the machine operator often chooses the method of reducing the machining process parameters: spindle speed (rpm), Vc: cutting speed (m/min), fz : tooth feed amount (mm/tooth), t: depth of cut (mm) Reducing the parameters in such a process negatively affects the machining productivity Therefore, this study will help to provide solutions to solve vibration recovery while ensuring process parameters, maintaining productivity by applying tools with damping ability in the machining process mechanical.

Stemming from such a need, the research team chose the topic: "FABRICATION OFMILLING HOLDER DEFORMATION MEASUREMENT MODEL".

Target research

- An overview of technology in metal cutting machining.

- Fabrication and measurement of models on damping milling holders and conventional milling holders with different diameters and tool lengths.

- Provide measurement results, analyze and comment based on the change of value variables for each measurement, write reports.

Research object and scope

There are many factors that affect milling holders vibration ( machine, workpiece,tool, cutting mode ) However, this topic only focuses on creating a model for measuring tool holders in dynamic state The vibration object impacts the knife holder to generate vibrations and measure them with a sensor to give vibration results That is, the research hypothesis given here is that the factors of machinery, parts, and raw materials are considered to ensure the vibrations conditions.

Due to limited time and equipment, the scope of the study is as follows:

- Standard parts purchased online Non-standard parts are based on working conditions to design in 3D, 2D and then hire precision machining.

- The test is conducted on the damper BAP 300R C20-20-150 (AODEBO brand) and the 300R C10-10-120 normal knife

- Focus on researching the ability to create vibrations, parameters related to the cutting process.

Research methods

- Gather all relevant theoretical bases, information about the model to be implemented.

- Measure the material of the C45 steel tool.

- Use manufactured damping end mills (BAP 300R C20-20- 2L160-1135 19E13) and usually 300R C10-10-120 to measure through sensor and PLC programming.

- The model was tested at Ho Chi Minh City University of Technology and Education.

- Make a table of results and graphs for each measurement case Make comments and conclusions.

THEORETICAL BASIS

Basis of metal cutting theory

2.1.1 Characteristics and role of cutting and cutting.

There are numerous other ways to cut metal nowadays, including casting, forging, rolling, welding, but these techniques generally result in crude products with poor accuracy and shine.

Machining by metal cutting is required to carry out in order to increase the gloss and precision of the products in accordance with the technical requirements.

By removing the metal layer in the form of chips from an original workpiece, metal cutting is a technological procedure that produces mechanical products with the shape and size of the surface shine in accordance with the technical criteria.

Machining is done in a temperature-controlled environment (both before and after the heat treatment operation) Compared to welding, casting, forging, and hot stamping, it provides a greater gloss and degree of accuracy.

Turning, milling, planing, drilling, boring, boring, broaching, and grinding are the fundamental metal cutting techniques.

The workload for mechanical machining is made up of 30% cutting operations currently and may increase in the future.

A technological system is the collective name for the set of tools needed to execute the cutting task, which consists of the following: machine, fixture, cutting tool, and workpiece.

The machine is in charge of supplying the required energy for the cutting operation.

During the part-machining process, the jigsaw is in charge of establishing and maintaining the precise relative position between the tool, the machine, and the work piece.

It is the tool's responsibility to directly remove the "extra metal" layer from the component, and the machine's energy is given by the relative motions.

The work item itself serves as the cutting process's target The work piece shows the full effects of the cutting process.

The trajectory of the relative motion between the tool and the component varies depending on the kind of metal cutting machine Three different motions exist:

Primary Motion The fundamental action of the cutter as it passes through the cutting tool or work piece (primary cutting motion) Rotation, round-trip translation, or a mix of both are possible.

The rotation of the workpiece in the chuck is the primary movement while turning When milling, drilling, and grinding, the milling cutter, drill, and grinding wheel travel in a circular motion; when planning and cutting, the tool moves in a reciprocating and up-and- down action

Tool motion is the primary movement that constitutes the cutting process and refers to the movement of the tool or workpiece.

The feed movement may be constant or sporadic Typically, this movement is done in a direction that is opposite to the primary movement, notably:

The feed movement is the tool table's cutting-related horizontal and vertical movement during rotating.

When milling, the table containing the workpiece moves horizontally, vertically, and vertically.

When grinding, the table moves horizontally (or vertically), and the tool head moves up and down.

When the table or the grinding wheel's axis is reciprocating in a transverse (vertical) direction.

The downward movement of the drill bit while drilling.

Extra motion: This refers to motions like forward and backward movement that do not directly produce the chip (without cutting into the workpiece).

Figure 2.2:Basic movement of tool when milling [12]

Two quantities are used to describe the primary motion:

- The relative displacement of a point on the workpiece surface and the cutting edge per unit of time, or the relative displacement of the cutting edge and the workpiece as a whole.

- The number of revolutions (or double strokes) in one-time unit.

2.1.3 Tool movement and amount of tool running.

It is the relative distance of the cutting edges relative to the part in the direction of the tool feed movement after a unit time, after one revolution of the workpiece or after a double stroke The feed rate can be the circular feed rate, the minute feed rate, etc.

When turning, the feed rate S is the amount of tool displacement in the toolpath along the machined surface by one revolution of the workpiece (mm/rev).

When planing and cutting the feed amount S is the displacement of the tool or table after a double stroke of the table (or tool)

For multi-blade tools such as milling cutters, it is possible to calculate the feed rate after one tooth (mm/tooth), the feed amount after one revolution of the tool (mm/rev), the feed amount after one minute of tool operation (mm/min).

2.1.4 Secondary motion and cutting depth.

Is the depth of metal removed after a cut (or the distance between two adjacent machinable and unmachined surfaces measured perpendicular to the toolpath).

=> The set of factors of cutting speed V, depth of cut t, feed amount S is called cutting mode

Milling technology theory basis

Milling is a metal work method using cutters with multiple blades The main movement is the spinning movement of the knife, the movement of the knife is the vertical, vertical, and vertical movement performed by the machine table Cutting speed when milling is calculated according to the formula: v = π.D.n 1000 (m/min)(2.2)

D – diameter of the milling holder [mm] n - number of revolutions of the tool [rev/min].

The feed rate for milling is determined by one of three factors:

- The amount of tooth feed (Sz) is the displacement of the part during the time one tooth (1 cutting edge) of the milling cutter enters the metal, the unit is mm/gear.

- The feed rate is the displacement of the part when the milling cutter rotates one revolution, denoted by Sv and has a single velocity of mm/rev.

- The minute feed rate is the displacement of the part after a time of one minute, denoted by

Sm and the unit is mm/min.

Thus, the relationship between the above feed rates is as follows:

Sm = Sv.n = Sz.Z.n (mm/min) (2.3) With:

Z - number of teeth (number of cutting edges) of the milling cutter. n - number of revolutions of the tool in one minute.

Milling can be done in two ways:

- Forward milling is when the forward direction of the workpiece coincides with the direction of the tool rotation.

- Reverse milling is the direction of movement of the workpiece against the rotation of the tool

Figure 2.4:Reverse milling During forward milling, the thickness of the cutting part varies from amax to zero The milling cutter exerts pressure on the workpiece to the machine table Does not cause slippage when feeding, so the surface gloss is better than reverse milling The collision between the tool and the large part Suitable for finishing In reverse milling, the cutting process is less prone to impact, machine and tool damage is less, suitable for rough milling. The advantage of reverse milling is that the cutting length increases from amin = 0 to amax, so the cutting force increases slowly, avoiding impact, the force acting in the forward direction has the effect of stimulating between the nut and the lead screw of the table does not produce vibration does not cause vibration.

The disadvantage is that at the first time when the new tooth is cut, the cutting thickness amin = 0, so there is a slippage between the cutting edge and the machined surface, making the surface smoothness poor and causing the tool to wear quickly Therefore, reverse milling is only used for roughing.

The advantage of forward milling is that there is no slippage when the new cutting edge enters the cutting edge and the blade thickness varies from amax to amine Therefore, the tool has less wear and the tool life increases, and the surface is smooth.

The disadvantage is that when cutting, there are bumps, fragile tool, great vibrations The cutting force in the feed direction makes the alignment between the lead screw and the nut on the machine table intermittent

If we cut with small cutting thickness, the small impact force affects the vibration insignificant.

Unlike turning tools, milling cutters have a lot of cutting edges, these cutting edges can be built into the tool body, can be made separately called chamfer teeth The cutting edge is arranged on the cylinder face, the end face or both the cylinder face and the end face. Depending on the shape, position of the cutting edge and structure, milling cutters are divided into the following types:

Figure 2.7:Disk-type milling cutter

Figure 2.8:End milling Cylindrical milling cutters are tools where the cutting edge is arranged on the cylindrical face of the tool There are two types of cylindrical milling cutters, straight tooth milling cutters and inclined tooth milling cutters Straight tooth milling cutters are milling cutters where the direction of the main cutting edge is parallel to the tool axis Inclined tooth milling cutters have a main cutting edge that is made with the tool axis at a certain angle.

- Face end mills are milling cutters whose cutting edge is arranged on the face of the tool.The end face milling cutter can be solid tooth or joined tooth.

- End mills can have from 2 to 8 cutting edges.

There are also profile mills, keyway end mills, and modular tooth roller mills for gear processing.

Milling cutters should have a back angle α from 10 to 200 and a cutting angle from 60 to

900 When milling soft materials it is recommended to choose a large α angle and a smaller cutting angle δ.

Milling can machine many different types of surfaces, but below we will only study two types of surfaces: flat and keyed surfaces Particularly, gear milling will be studied in the next chapter (gear machining chapter).

The machined planes on the milling machine are the horizontal planes, the vertical planes and the inclined planes When machining these types of planes, cylindrical end mills, end mills, end mills or disc mills can be used In large series production, end mills are used more than cylindrical milling cutters for the following reasons:

Figure 2.9:Technological capabilities of milling cutters

- Allows the use of large-diameter knives, which can cut a large width plane, so the productivity is high.

- The tool mandrel does not need to be long, so the rigidity of the tool shaft is better, allowing to improve the cutting mode.

- Many cutting edges are in contact with the workpiece, so the cutting process is smoother.

- Allows multiple tools to be used to machine multiple surfaces at the same time.

- Easy to manufacture all kinds of toothed tools.

Grooved or small tread surfaces are usually machined with disc or end mills.

Keyway and keyway often require high machining accuracy to ensure the fitting properties of the keyed or keyed joint.

Depending on the key type, the keyway can be machined with a three-sided disc milling cutter or using an end mill.

When milling a keyshaft, a three-sided disc milling cutter can be used by milling the two sides with two disc milling cutters, and then using a key cylinder milling cutter Key hubs are also often machined with profile mills.

Vibration during cutting

2.3.1 Overview of vibration in cutting.

Vibration is a common phenomenon in nature and in engineering because all objects of mass and elasticity can vibrate in response to an excitation force The machine tool is an elastic system, so in the process of machining external forces and cutting forces acting on the system will cause the system to vibrate In fact, there is no metal cutting process where the technological system does not vibrate Vibration is an accompanying phenomenon in the metalworking process Under certain specific conditions this vibration can grow strong in the processing process, thereby worsening the economic indicators and product quality. Specifically, vibration can cause the following consequences:

- Do not allow the full capacity of the machine or the cutting capacity of the tool to be used.

- Causes rapid wear of the main parts of the machine, reducing the accuracy of the machine.

- Increases the risk of mechanical damage to the cutting tool's blade.

- Mechanical destruction of cutting tools (fracture of multi-edged tool teeth) or some machine parts.

- Reduced geometric accuracy of workpieces as well as surface gloss surface, especially for finishing operations.

- Make noise to the working environment.

2.3.2 Types of vibration and causes of vibration.

Vibrations during cutting generally include the following types:

Forced vibration occurs when an external force excites the dynamics impact on the technological system: machine - cutting tools - workpieces.

- Noise from the outside is transmitted through the machine foundation.

- Noise inside the technology system due to:

+ Improperly fabricated or worn actuators cause impact during articulation.

+ Bearings, especially main bearings, are worn.

+ The slip rings are worn.

+ Dynamic loads arising when speeding up or when braking parts with high volume.

- Due to the shear force variation when cutting intermittent surfaces or due to impact of knife teeth when entering the cutting during machining.

+ The technology system will vibrate with the frequency of the excitation force The amplitude of the vibration depends on the amplitude of the excitation force and on the dynamic stiffness of the technological system.

+ If the variable excitation force has a period and the excitation frequency is approximately equal to the natural frequency of the system, the vibration will appear with a very large amplitude.

It is the phenomenon of resonance.

- For pulsed excitation force, the system vibrates with natural frequency and vibration amplitude will gradually decrease.

- The case of forced vibration occurs due to the changing and specific cutting force especially when cutting discontinuous surfaces, the vibration frequency is usually suitable for rotational frequency of the main axle or the rotational frequency of the cutting tool. Forced vibration reduces machining quality especially at finishing materials It has the greatest effect when the excitation frequency is close to the natural frequency of the system. During milling, forced vibration can lead to unstable when the tool rotation speed is large enough to make the cutting input frequency of the knife tooth is exactly equal to the natural frequency of the system This frequency is determined by the formula: f = n.Z 60 Hz (1-1) Most forced vibrations can be reduced or eliminated by a way to remove the source of the excitation or change the excitation frequency for periodic excitations such that its frequency is not close to that of specific to a particular system:

- Eliminate errors in machine transmission.

- Dynamic balance of rotating parts.

- Choose the correct spindle rotation speed and number of teeth.

Private vibrations in the machine system - cutting tools - workpieces or in some nodes of the system is the vibration generated by the impact, for example when the clutch is closed, when the tool starts to cut Most of the effect of the private vibration during the cutting process is negligible Because it is a very fast damping oscillation It only makes sense when it is related to determining the characteristics of the oscillation process to serve the research of a certain vibration phenomenon in the cutting process.

Self-excited vibrations are vibrations generated by the cutting process itself Self-excited vibrations are generated during cutting due to the following reasons:

- Variation of shear force which is due to variation of cutting speed, sectional section or variation of information Geometric number of the knife.

- Due to the formation and destruction of the stye.

- The modify in the composition of the workpiece material.

- Due to the regenerative effect.

- Due to site binding (Non-regenerative self-excited vibration).

- Increasing the cutting speed, the amplitude of oscillation increases (in the area prone to tool distortion), after the amplitude of oscillation reaches a certain maximum value, the cutting speed increases, the amplitude of oscillation decreases.

- When the cutting depth increases, the vibration amplitude increases because the increased cutting force affects the technology system.

- The influence of geometrical parameters, the most significant is the angle φ, the angle φ increases the vibration decreases, (Py force = PN.cosφ, is the shear force that affects the vibration the most).

- When processing cast iron, cutting out chips, the cutting force changes much, so the vibration increases As for the cutting of flexible materials, when the condition for forming the stye is large, the vibration increases.

- In addition, the vibration is also greatly influenced by the technology system The more rigid the system, the less vibrations.

- In fact, it is necessary to choose a reasonable cutting mode, and at the same time increase the rigidity of the machine - tool - jigsaw system - details and use some other specialized vibration reduction tools.

- As mentioned above about vibration, there are many things to discuss, many factors to consider However, the topic here is considering the influence of the damping milling cutter, so we consider the other factors to be stable, we only consider the tool holder, and the damping toolholder comes into play when we are milling The disadvantageous position is that the tool holder needs to be set long, in the following we will look at how the effect of different tool lengths on the machining quality and how vibration can be reduced.

- A few cases involve the tool itself, the tool holder device, the length and diameter of the holder, and the cutting parameters and many other factors as discussed above.

2.3.4.1 Group of measures related to machine structure.

- Improve the rigidity of the machine.

- Ensuring the rigidity of the machine foundation including solutions to install the machine with damping effect.

- Selecting the optimal working position of important machine parts such as sliding table, knife table.

- Change the spindle rotation speed accordingly to reduce the regenerative effect.

- Improve the damping ability of the machine.

- Use orientation measures so that the cutting force perpendicular to the direction of the machine has the greatest dynamic flexibility.

2.3.4.2 Group of measures related to workpieces and machining tools.

Using supports increases the rigidity of the work piece.

- Reduce the weight of the workpiece.

- Use a knife with damping effect Reduce the weight of the cutting tool.

- Choose a knife with a small radius.

- Choose a good anti-corrosion material.

- If the length of the overhanging part is 4xD to 6xD, choose a carbide toolholder.

- If the length is longer than 6xD, select “Dampers”.

- Select insert with sharp cutting angle.

- Choose a tool with a tip radius smaller than the depth of cut.

2.3.4.3 Measures related to the cutting process.

- Select processing materials with appropriate specific cutting force.

- Increase the back angle of the knife.

- Try to use a knife with an angle first.

- Limiting the cutting length of the cutting mesh Increase the value of the feed amount Use very low or very high cutting speeds to avoid stable minima.

- For cutting tools with many cutting edges, it is recommended to use tools with uneven tooth pitch.

2.3.4.4 The problem of fixing and clamping the knife holder.

For the damper shank and normal shank, it is important to take care not to clamp on the damper part of the bar.

Vibration measuring equipment (sensor)

The TcAs DynaLogger is designed to identify failure mode symptoms or defects in machinery and equipment in general according to ISO 20816 In addition, with triaxial spectra and contact temperature sensor, the TCAs is able to monitor unusual equipment and structures such as suspensions, servers, pipes and valves Additionally, the solution has an online platform, with no need for local installation, with several tools that assist in data analysis and allow for constant monitoring of asset health.

The TcAs DynaLogger has two monitoring modes: spectral/waveform and telemetry Band configurable telemetry monitoring includes several metrics such as acceleration, velocity, and displacement in RMS, peak, peak to peak, and crest factor, as well as skewness, kurtosis, and contact temperature In spectral monitoring, different tools can be used: spectrum, waveform (linear, circular and orbital), frequency filters, cepstrum, spectral envelope (demodulation), autocorrelation and multi-metrics.

- One of the smallest sensors on the market.

- Long battery life Easy mounting.

- High spectral resolution up to 91200 spectral lines.

- More than 40 telemetry metrics that can be applied in different frequency bands up to 2.5 kHz (under development).

- Monitoring of rotating machines in general according to ISO 20816.

- Machine structures: chassis, suspensions and springs, rails, etc.

- Pulleys and roller bearing housing

- Bearings (more advanced defects - stage 3 or 4)

Initial figures

- Requires the geometrical shape of the model to be designed and fabricated

- Standard parts such as: belt, motor, bearing, pulleys, bolts and nuts

- Diameter of milling cutter: Dc% mm, Dcmm or Dc mm.

- Milling tool holder: BAP 300R C20-20-150 (AODEBO brand), BAP 300R C10-10-120.

- Initial materials: Particle impact damping, an overview of metal working and milling technology, characteristics of the milling process and working conditions of the milling holder shank Related articles.

FABRICATION OF MILLING HOLDER DEFORMATION

Model 3D

In general, machining operations can be classified based on the nature of tool-work engagement into two distinct catego- ries; namely intermittent engagement as in milling operation and continuous engagement as in grinding, turning, boring, etc Vibration is an undesirable phenomenon in any machining operation, as it results in poor surface finish, increased form deviation, reduced material removal rate, increased tool wear, and higher noise level It also affects instantaneous depth of cut, feed-rate, shear angle, and cutting force Vibrations in machining process can be classified into forced and self- excited vibrations Forced vibration, for example, occurs due to unbalances in forces arising from rotating members and/ or due to interrupted cutting as in milling Tobias and Fishwick are the earlier researchers to investigate the self-excited vibration in machining under orthogonal cutting conditions The previous cut resulted in a wavy surface and the dynami- cally varying chip thickness in the subsequent pass in the machining was shown to produce regenerative effect Sweeney and Tobias explained that self-excited vibration, referred to as chatter, is due to the interaction between dynamic characteristics of both machine tool structure and process Koenigsberger and Tlusty also analyzed the machine-tool chatter and explained that the regenerative and the mode- coupling mechanisms are the major contributors for chatter Among the two, former has a severe influence on the stability of the machining process Altintas and Weck presented a review of research work on chatter in metal cutting and grinding A recent review of 174 research papers on chatter in machining process by Quintana and Ciurana brings out comphrehensively the research work carried out upto 2011 Most of the researchers investigating the vibration effect in interrupted cutting have considered the milling operation and studied dynamic stability of the process Many of the studies involve establishing stability diagram experimentally and the results are used for confirming the theoretically predicted stability The stability diagrams thus obtained are useful to identify chatter-free zones for safe operations Bayly et al and Insperger et al. Have attempted to develop analytical methods to predict stability in intermittent cutting like milling.

Merdol and Altintas have developed a virtual simulation system incorporating vibration prediction model It is identified that process damping has an effect on the dynamic stability and hence the effect of cutting parameters and cutting geometry on process damping has also been studied Patel et al Also developed an analytical model and brought out the influence of helix-angle on the stability of milling process Wan et al. Proposed a unified stability prediction method with multiple delays and showed that feed per tooth has great effect in the presence of cutter run-out Tunỗ and Budak have shown that process conditions and tool geometry can be appropriately selected to enhance proces damping and hence the chatter stability Compeán et al Have proposed a milling tool with variable pitch, helix, and rake angles for high performance milling.

In case of continuous cutting also, chatter-free machining conditions must be identified for the machining operations like turning, boring, etc Takasu et al brought out the effect of small amplitude vibration on surface roughness obtained in diamond turning and suggested the methods to improve the surface finish Rivin and Kang modeled the work piece and cutting tool system in turning and suggested a method to improve the system stability by improving the dynamic stiffness of the tool Lin and Hu proposed a vibration reduction system which would be triggered to suppress the vibration when chatter occurs. Vela-Martínez et al developed a compliance model for turning operation by introducing interaction between work piece and cutting tool as lumped mass system The effect of the dynamics of cutting tool on the stability of process was investigated Moradi et al Modeled orthogonal turning process as a single degree model and proposed control strategies to suppress regenerative chatter Otto and Radons have proposed an approach involving spindle speed variation for chatter suppression in turning operation.

The boring operations are used for enlarging or finishing predrilled holes in cast, forged, or extruded components Rivin et al Modeled the cantilever boring bar and suggested methods to improve its dynamic performance Li et al Investigated chatter phenomenon in rotating-bar boring operations and showed that the stability limits of the system is shifted to the higher values, by changing the speed about the nominal speed at certain frequency Moradi et al Modeled boring bar as Euler-Bernoulli cantilever beam and suggested a design of tuneable vibration absorber The proposed method was analyzed for the chatter stability in boring process Subsequently, Åkesson et al focused on changing clamping to change the dynamic properties of boring bar The active mechanism provides continuously adjustable dynamic parameters based on feedback signals from the machining process Inasaki et al reported in their paper the details of an active method applied to plunge grinding by Weck and Brecher, RWTH Aachen University, Ger- many, in the same year In this method, a peizo-electric actuator attached to the spindle-housing is activated using a feedback signal from the acceleration sensor and the vibrations are suppressed. Monnin et al Have proposed an active system for milling operation consisting of a peizo- electric stack mounted at the front-end of the machine spindle The signal is to be obtained from an accelerometer and feedback to the peizo-electric stack through a control circuit.

On-line methods of adjusting the damping characteristics are easier to implement and comparatively less expensive Tewani et al Implemented a dynamic absorber having a force-generating piezo-electric actuator to reduce chatter in boring operation They demonstrated that amplitude of vibration could be reduced during the experimental trials. However, the constructional details were not included in their paper Wang and Fei used a specially designed sleeve for boring bar with a provision to accomodate electro-rhelogical fluid and damping characteristics is varied by changing the voltage applied to the fluid. Tarng et al Used a tunable vibration absorber with piezoelectric inertia actuator for turning operation Very early passive damper is the one designed by F.W Lanchester in 1910 for suppressing crankshaft vibration in automobile engine Hahn has adapted Lanchester’s concept of using rubber-like material as damping-medium to suit machining applications. Subsequently, Hahn patented a boring bar having a hollow-construction, fitted inside with a cantilever carrying a mass at the free-end and filled with viscous fluid Such visco-elastic material and viscous fluid used in the dampers are known to perform well in room temperatures, but performance of these dampers deteriorates with temperature and time. Ema and Marui developed a different design that uses a freely moving mass inside a cavity located at the free-end of the boring bar Such a single-mass impact damper with proper clearance inside the cavity of the boring bar is effective in chatter control.

The general literature on structural vibration also deals with both active and passive methods of damping In an early paper, Panossian suggested a novel passive method referred to as non-obstructive particle damping for suppressing structural vibrations It used a small cavity appropriately positioned inside the structure and filled with particles The energy dissipation because of collision between the particles and the particles with the cavity wall led to damping Friend and Kinra applied the particle damping method on cantilever beam and showed 50 % improvement in damping capacity with a very small weight penalty Later, Marhadi and Kinra [18] extended particle impact damping (PID) method to cover different materials and established its effectiveness The char- acterization of particle damping has also been attempted by Mao et al Using discrete element method which simu- lates the behavior of granular materials in three-dimension Different modeling and simulation approaches have been used by Xu et al And Bai et al for prediction of the damping effect and to have better insight and understanding of PID Novelty of the present work is in the application of PID concept in the design of special boring bar for suppression of chatter PID can also be considered as a derivative of single mass damper used to attenuate vibration in structural ele- ments Hence, the present work provides a basis for an important application in the manufacturing industry, particularly in the metal cutting industry A specially designed boring bar with PID is developed in the present work Its damping characteristics are evaluated for different sizes and volume fractions of spherical steel particles using impact and shaker tests, and the results are included Unlike structural applications, demands are more stringent in metal cutting applications, as improvement in the final product quality must be demonstrated with PID boring bar The surface topography reveals macro- and micro-geometrical deviations present on the surfaces. Therefore, the bored hole is investigated in terms of chatter marks, surface roughness, and roundness.

Figure 3.2:Schematic diagram of boring bar with particles filled in a cavity [11]

Figure 3.1: Schematic diagram of the impact test set-up for boring bar [11]

Figure 3.3:Response signals from impact test: a time domain, b frequency Domain [11]

Figure 3.4:Shaker excitation test on boring bar [11]

Figure 3.5:Signals measured during shaker test (excitation frequency, 660 Hz; particle size, 3.17 mm, and volume fraction, 30 %) a Excitation signal (i) time domain, (ii) frequency domain; b response signal (i) time domain, (ii) frequency domain [11]

=> From experiments, research on inventions and articles on vibration as above, my team based on that idea to fabricate: “FABRICATION OF MILLING HOLDERDEFORMATION MEASUREMENT MODEL”

Figure 3.9:PLC circuit to control Figure 3.10:PLC programming softwareGXDeveloper stepper motor

Standard parts such as: milling tool holder, SKF 6204 bearing, large pulley diameter, small pulley, belt 3M thickness 10mm length 444mm, motor, sensor, milling tool 300R- C10-10-120, collet, rubber feet, bolts, nuts, hexagons of all kinds

Non-standard parts such as: base plate, retaining plate, ribs, V block, tool holder plate,turnplate, axis, keys, motor flange, motor jig, vibrating rod, vibrating rod clamp plate.

Parts of PLC control circuit stepper motor: driver, FX3U PLC board, 24V 5A source,2K Ohm resistor, 3-color electric wire, USB cable, electrical panel, power connection wire.

Operating principle

Operation based on PLC programming software to control stepper motor The variables we need to change such as: rotational speed, which depends on the rotational speed of the turnplate through changing the pulse frequency, changing the time for the motor to stop or rotate continuously, the length of the vibrating rod depends on the diameter and length of the milling tool, change the milling tool holder length.

When the motor rotates through the belt pulling the rotating turnplate, causing the rods to impact the milling tool holder Install the sensor on the milling tool holder Under this impact, the sensor will receive a vibration signal and output a waveform graph From the results of that waveform graph, we can compare through two values of PP and RMS to determine the level of vibration, as well as phenomena such as collision, eccentricity, wear,distortion, etc.

Standard parts

- Calculation to choose stepper motor:

Determine the load: light impact load for rotating purposes, with W=1kg

Calculation and choosing of gear ratio Based on the diameter of large pulley D1Rmm and small pulley D2m, we can calculate the gear ratio as follows: U= D1/D2R/16=3.25 Pulley D1 torque: T1=(à x W x D1/2)/η1=0.2x1x26=5.2N.mm

Therefor we can give larger stepper motor is the most reasonable

- Specifications: 60 series 2-phase high torque mixed type stepper motor with 1.8° step (HSTM60-1.8-S-88-8-2)

Table 3.1:Specifications of the motor

Application control DA2404MD, DC2405M

Couple de positionnement (gf-cm) 1

Figure 3.11:Technical information of the motor [13]

Material: Manganese steel grade SL32-ER32-100

- Tightening nut, good steel, strong clamping force.

-The product can reduce the use of extension tools, reduce costs and increase efficiency. -The product can realize the automation of CNC machine drilling and tapping, and the tool change is convenient and fast.

-Preparation for grinding the outer diameter and other parts eliminates the amount of unbalance and increases the stability when cutting.

– Speed limit: 20,000 rpm Figure 3.13:SKF 6204 bearing

- Pulley 3M50 50 teeth type BF 11mm wide belt 20mm shaft is a transmission mechanism for motors, grinding machines, mini cutters Making accessories for saws, homemade drills, making transmissions for 775, 795 engines

- Pulley 3M50 50 teeth type BF 11mm wide belt 20mm shaft widely used in machine tools, home textile, printing, food packaging, electric wire and cable, instrumentation, petrochemical, tobacco, telecommunications and other industries in the belt drive structure Specifications:

- Suitable for standard 3M belts (12mm version)

- Pulley transmits 8mm axis movement.

- Pulley Axis 8mm - 20 teeth 10 belts are used with 10mm

-Pulley outer ring size may be different due to measurement error, the outer ring is calculated as the largest ring (not the diameter of the inner thread), but the number of teeth is still correct as the product name and description.

- Diameter of axis hole: 8mm

- Pulley type: 2GT/GT2 Figure 3.15:Small pulley

- Pulley Shaft 8mm - 20 teeth 10 belts are used together with 10mm belts

- Pulley 3M-444 10mm wide belt (also known as timing belt) is a belt with a transmission mechanism for the engine, grinding machine, mini cutter Bulley 444 can also be used as an accessory for a homemade saw, as a transmission With 3mm pitch used to combine with pulley to transmit motion, 777 motor, 795 motor

- This pulley is often used in industry,

- Belt width: 10mm (suitable for pulley 11mm version)

- Type: BAP milling, right angle master milling

- Rolling: 45HRC to 55HRC active material

- Control mode: CNC milling machine

- Material: Environmentally safe rubber, RoHS standard

3.3.10 Bolts, nuts, hexagons of all kinds.

+ Input with optical isolation, high speed.

+ Built-in over-current and over-voltage measurement.

DC+: Connect to a power source from 9 – 40VDC

DC- : Negative (-) voltage of the source

A+ and A -: Connect to the winding pair of stepper motor

B+ and B- : Connect to the remaining windings of the motor

PUL+: Speed control pulse (+5V) signal from BOB for M6600

PUL-: Speed control pulse (-) signal from BOB for M6600

DIR+: Reverse pulse supply signal (+5V) from BOB for M6600

DIR-: Reverse pulse supply signal (-) from BOB for M6600

ENA+ and ENA -: when giving signal to this pair, the motor will no longer have holding and rotating torque

A common positive (+) signal or a common negative (-) signal can be connected

PUL-: Speed control pulse (-) signal from BOB for M6600DIR+: Reverse pulse supply signal (+5V) from BOB for M6600

Figure 3.20:Amperage settingFigure 3.21:Install micro step for driver

3.3.12 PLC Board Mitsubishi FX3U-14MT-6AD-2DA.

- 8 NPN inputs, 6 NPN Transistor outputs, 6 analog inputs (3 0-10V inputs and 3 0-20mA inputs), 2 analog outputs (0-10V)

- X0-X5 is high speed pulse input, get 3 AB encoders, default is 12K, can request 100K

- Y0-Y1 is a high speed pulse output that can be up to 100K

- There is memory area to maintain when power failure.

- 105% overload protection —150% rated capacity, automatic recovery

- Automatic short circuit protection function

- Overvoltage protection 105% —150% of rated voltage

Figure 3.23:PLC Board Mitsubishi FX3U-14MT-6AD-2DA

- Specification: Resistor plug 4 color rings.

3.3.15 Core 3 color power cord 0.5mm 2

- Converts a standard 9-pin serial port to a USB port.

- It uses power directly from USB no need for additional power adapter.

- Very easy to use and connect.

- Transfer buffer: 120 bytes for high data transfer rate.

- Support remote wake-up and power management.

- RS232 DB9 serial interface support.

Fabrication non-standard parts

3.4.1.1 Creat workpiece: workpiece is cut from steel plate with size 446-206-50mm

Figure 3.27:Creat workpiece for base plate

Figure 3.28:Marking of machined surfaces

No Name of operation Face Locate

Table 3.2: Machining processes of the base plate

- Machining option: We find that the above part is the most optimized in terms of the order of operations because of the simple part If you make another option, only change the positioning standards.

Figure 3.29: Machining processes of the base plate

Positioning:The part is positioned with 3 degrees of freedom, 3 degrees of freedom on the bottom surface is a slab

Choose machine: Choose a vertical milling machine 6H12 with a capacity of 7kW n = 30 ÷

1500, 18 levels (Table 19 - Page 232 - Machining cutting mode)

Distance from axis or tool head face to platform 30 – 400 ( mm)

Number of tooling running levels 18

Tooling running limit (mm/ min):

Choose tooling: choose the face milling cutter with a piece of wind steel.

Tool diameter: D= 250 mm ; Number of teeth: Z= 26 ; Material: T15k6

Measuring instruments: 125mm long caliper, 0.02 accuracy

Figure 3.30:Mounting diagrams of operations 1

Table 3.3:Machine specifications of operations 1

Steps:This operation is divided into two steps:

Look up the cutting mode

- Rough tooling running rate: Sz = 0.13 (mm/tooth) ( Table 5-125 page 113 – ST2 )

- Cutting speed Vb = 36.5 m/min (Table 5-120, page 109 – ST2) This value corresponds to the depth of cutting t mm.

The adjustment coefficient depends on the hardness of steels K1=1

The adjustment factor depends on tool life cycle K2=1

The correction factor depends on the grade of a hard alloy K3=1

The adjustment factor depends on the machined surface K4=1

The adjustment factor depends on themilling width K5=1.13

The correction factor depends on the main tilt angle K6=1

- So the calculation speed: Vt=Vb*K1*K2*K3*K4*K5*K6 = 41,2 (m/min)

- Number of revolutions calculated:� � = 1000∗� �∗� � = 1000∗36,5 �∗250 = 52,5(rpm)

Machine 6H12 has nmin0; nmax00, number of speed levels m, find work multiples: φ m−1 = φ 18−1 = φ 17 = n n max min = 1500 30 = 50 The corresponding φ 17 value 50.65 is close to 50 respectively (Table 4.7, page 58,

On the other hand:φ x = n n t min = 46,5 30 = 1,75 The correspondingφ = 1,26to us has a valueφ 2 = 1,58 close to 1.75

- So the number of revolutions according to the machine is: nm = 30 * 1,58 = 47,4rpm

- Thus, the actual cutting speed is:� �� = �∗�∗� 1000 � = �∗250∗47,4 1000 = 37,2 ��

- Minute tooling running rate: Sph= Sz* Z * n = 0,13 * 26 * 47,4 = 160 mm/min

Choose machine running speed: Sph = 145mm/min (Table5-123, page 111, ST2)

Cutting mode when rough milling: t = Z = 5,5 mm ; Sph= 145 mm/min nmG,4rpm

- The feed rate t0= 0,13mm/tooth (Table5-125, page 113, ST2)

- Cutting speed V b = 42,5 m/min: Cutting speed with depth of cutting t= 3

In there: K1 = 1: The correction factor depends on the hardness of the steel.

K2 = 1: The coefficient depending on tool life cycle

K3 = 1: The correction factor depends on the grade of the hard alloy.

K4 = 1: The adjustment factor depends on the machined surface

K5 = 1.13: The adjustment factor depends on milling width.

K6 = 1: The correction factor depends on the main tilt angle.

- Number of revolutions calculated:� � = 1000∗� �∗� � = 1000∗48 �∗250 = 61(rpm)

- Looking up table 4.7 we have φ 3 = 2 (Table 4.7 - page 58 - CNCTM project manual)

- So the number of revolutions according to the machine is: nm0*2 = 60 rpm, choose 60 rpm

- Actual cutting speed is:� �� = �∗�∗� 1000 � = �∗250∗60 1000 = 47m/min

- The minute tooling running rate is: Sph= Sz* Z * n =0,13* 26 * 60 = 202,8 mm/min

Choose the feed rate of the machine: Sph = 151 mm/min

Choose machine feed rate: Sph = 145 mm/min (Table5-123, page 111, ST2)

Cutting mode when fine milling: t = Z = 0.5 mm nm` rpm Sph = 145 mm/min

 Operation 2: Side C and opposite face milling

Positioning:The part is positioned 5 degrees of freedom,

- 3 degrees of freedom on that face is the slab

- 2 pivot pins restricting 2 degrees of freedom on the raw face.

Choose machine: Choose 6H82 horizontal milling machine with parameters (Table 4.5, page 49, CNCTM project manual)

Wattage of the main axis, (kW) 7

Tool choose: choose a three-tooth disc milling cutter mount a piece of wind steel With D 250, B, d = 50, Z = 26 (Table 4.84, page 369, ST1)

- Tool life: 180 minutes (Table 5-72, page 155, ST2)

- Measuring instruments: 125mm long caliper, 0.02 accuracy

- Rough tooling running rate: Sz=0.13 (mm/tooth) (Table 5-170 page 153 – ST2)

- Cutting speed Vb = 32 m/min (Table 5-171, page 154, ST2)

The adjustment coefficient depends on the group and mechanical properties of steel K1=1 The adjustment factor depends on tool life cycle K2=1

The adjustment factor depends on the machining type K3=1 (rough)

So the calculation speed: Vt=Vb*K1*K2*K3= 32(m/min)

- Number of revolutions calculated:n t = 1000∗V π∗D t = 1000∗32 π∗250 = 40,7(rpm)

Machine 6H12 has nmin= 30; nmax= 1500, number of speed levels m, find work multiples:φ m−1 = φ 18−1 = φ 17 = n n max min = 1500 30 = 50 The corresponding φ 17 value 50.65 is close to 50 respectively (Table 4.7 - page 58 -

On the other hand:φ x = n n t min = 40,7 30 = 1,36 Corresponding φ = 1,26 to us has a value close to 1.36

- So the number of revolutions according to the machine is: nm0*1,58 G,4 rpm

- Thus, the actual cutting speed is:��= �∗�∗� 1000 � = �∗250∗47,4 1000 = 37,2m/min

The minute tooling running rate is: Sph= Sz* Z * n =0,13 * 26 * 47,40 mm/min

The feed rate of the machine is: Sm= 30 ÷ 1500mm/min, choose Sph= 177 mm/min.

- Cutting wattage when rough milling:

The cutting power is: 1.6 kW

Comparison: Nc= 3 kW < Nm = 7 * 0,75 = 5,25 kW

- Fine tooling running rate: Sz=0.1 (mm/tooth) (Table 5-170 page 153 – ST2)

- Cutting speed: Vb = 34 m/min (Table 5-171, page 154, ST2)

The adjustment factor depends on the machining type K3=0.8 (fine)

So the calculation speed Vt=Vb*K1*K2*K3= 27.2 (m/min)

- Number of revolutions calculated:nt = 1000∗V π∗D t = 1000∗27,2 π∗250 = 34,6(rpm)

Calculate by machine:φ x = n n t min = 34,6 30 = 1,15 Looking at table 4.7, we have φ = 1.26 which is close to 1.15 (Table 4.7 - page 58 -

- So the number of revolutions according to the machine is: nm= 30*1,26 = 37,8 rpm

- Actual cutting speed is:v tt = π∗D∗n 1000 m = π∗250∗37,8 1000 = 29,7m/min

- The minute tooling running rate is: Sph= Sz* Z * n =0,1* 26 * 29,7 =77mm/min

The tooling running rate of the machine is: Sm= 30 ÷ 1500 mm/min, choose 88 mm/min.

 Operation 3: Side D and opposite face milling

Positioning:The part is positioned 5 degrees of freedom:

- 2 pivot pins restricting 2 degrees of freedom on the fine face

Choose machine: choose 6H82 horizontal milling machine with parameters (Table 4.5, page 49, CNCTM project manual)

Wattage of the main axis, kW 7

Choose tooling: choose a three-tooth disc milling cutter mount a piece of wind steel With

Tool life: 180 minutes (Table 5-72, page 155, ST2)

 Operation 4: Drilling, boring, reaming hole E ỉ24

- The slab to position on the bottom surface, limiting 3 degrees of freedom.

- 2 pins against face D to control 2 degrees of freedom.

- 1 pin against face C to control 1 degree of freedom.

Choose machine: choose 2H55 drilling machine with parameters (Table 3.1, page 46, CNC project manual)

Limit tool running (mm/rev) 0,056-2,5

- Drilling the hole with size: ỉ22

- Boring to expand the hole: ỉ23.8

Look up the cutting mode and calculate the operation time:

Look up cutting mode when drilling

- Tooling running rate: S = 0.27 mm/rev (Table 5-87, page 84, ST2)

- Cutting speed: (Table 5-96, page 83, ST2), we have Vb= 32m/min With the velocity correction factor K1 = 1: The actual durability age is chosen equal to the nominal endurance age.

K2=1.1: The adjustment difference depends on the state of the steel (cold)

K3=1: The adjustment difference depends on hole depth (choose 3D)

K4=1: The adjustment difference depends on the grade of the drill bit material

- Calculation speed: Vt= 32*1*1,1*1*1 = 35,2mm/min

- Number of rounds to calculate:� � = 1000∗� �∗� � = 1000∗35,2 �∗22 = 509(rpm)

Choose the number of revolutions according to the machine, first find work multiples: φ m−1 = φ 21−1 = φ 20 = n n max min = 2000 20 = 100 Corresponding toφ 20 = 101,61 (closer to 100) can be scaled upφ= 1,26

(Table 4.7 - page 58 - Manual of CNCTM project)

On the other hands:φ x = n n t min= 509 20 = 25,45 According to table 4.7 in columnφ= 1,26 is close to 25.45 hasφ 14 = 25,28

- So the number of revolutions of the machine: nm= nmin* 40 = 20*25,28 = 506 rpm

The actual speed is: � �� = �∗�∗� 1000 � = �∗22∗506 1000 = 35 �/min.

Look up cutting mode when boring

- Cutting speed: (Table 5-105, page 96, ST2), we have Vb= 22 m/min With correction factors K1 = 1, K2 = 1.18 , K3 = 1, K4=1

- Calculate by machine:φ x = n n t min= 323 20 ,15 Looking up table 4.7, we have φ 12 = 16,64 which is close to 16.15 (Table 4.7 - page 58 - CNCTM project manual)

- So the number of revolutions of the machine: nm=nmin * 16,64 = 20 * 16,64 = 333rpm The actual speed is: �� = �∗�∗� 1000 � =�∗23,85∗333

Look up cutting mode when reaming

- Cutting speed: (Table 5-114, page 106, ST2), we have Vb= 9.2 m/min With a constant velocity correction factor of 1.

- Calculation speed: Vt=Vb =9,2 m/min.

- Number of revolutions calculated:�� = 1000∗� �∗� � = 1000∗9,2 �∗24 2 (m/min)

- Calculate by machine:φ x = n n t min= 122 20 = 6,1 Looking at table 4.7, we have φ 8 =3,32 which is close to 6.1 (Table 4.7 - page 58 - CNCTM project manual)

- So the number of revolutions of the machine: nm=nmin * 6,32 = 20*6,32 = 126,4rpm.

The actual speed is: v tt = π∗D∗n 1000 m = π∗24∗126,4 1000 = 9.53 m/min

Positioning:Restricted to 6 degrees of freedom

- The face A controls 3 degrees of freedom

- Short hole pivot pin ỉ24 controls 2 degrees of freedom

- D pin controls 1 degree of freedom

Choosing a machine:Choose a vertical milling machine 6H12 with a capacity of 4kw n0 ÷ 1500, 18 levels ( Table 19 - page 232 - Machining cutting mode )

Choosing a tool: choose the face milling cutter with a piece of wind steel.

Tool diameter: D= 250 mm ; Number of teeth: Z= 26 ; Material: T15k6 ( Table 4-93, Page

Look up cutting mode:Same as operations 1

 Operation 6: Hole with shoulder milling F ỉ47

Table 3.7: Machine specifications of operations 5

- The slab A controls 3 degrees of freedom

- Pin D controls 1 degree of freedom

Choosing machine:CNC milling machine

Choosing tool: tool diameter: d= 25 mm; length: L2mm; Number of teeth: Z= 5 ;

Material: Wind Steel (Table 4-74, Page 363 - ST1)

Measuring instruments: 125mm long caliper, 0.02 accuracy.

Look up the cutting mode:

- Rough tooling running rate: Sz= 0,09 ( mm/tooth ) ( Table 5-153 page 138 – ST2 )

- Cutting speed Vb = 23 m/min (Table 5-154, page 138 – ST2) This value corresponds to the depth of cutting t mm.

The adjustment coefficient depends on the mechanical properties of steel: K1=1 The adjustment factor depends on tool life cycle: K2=1

- So the calculation speed: Vt=Vb*K1*K2 = 23 (m/min)

- Number of revolutions calculated:� � = 1000∗� �∗� � = 1000∗23 �∗25 = 292,8(rpm)

- The minute tooling running rate: Sph= Sz* Z * n = 0,12 * 3 * 292,87 5,4 mm/min Fine milling

- Fine tooling running rate: Sz = 0.09 ( mm/tooth ) ( Table 5-153 page 138 – ST2 )

- Number of revolutions calculated:�� = 1000∗� �∗� � = 1000∗23 �∗25 = 292,8(rpm)

- The minute tooling running rate: Sph= Sz* Z * n = 0,12 * 3 * 292,87 5,4 mm/min

 Operation 7: Drilling and taro 4 holes G M8

Positioning:Controls 6 degrees of freedom

- Short hole pivot pin ỉ24 control 2 degrees of freedom

Choosing a machine:choose a need drilling machine 2H55 with parameters (Table 3.1, page 46, CNCTM project manual)

Look up cutting mode when drilling:

- Cutting speed: (Table 5-86, page 83, ST2), we have Vb = 55m/min With the velocity

Table 3.8:Machine specifications of operations 7 correction factor

K1 = 1: The actual durability age is chosen equal to the nominal endurance age. K2=1.1: The adjustment difference depends on the state of the steel (cold)

K3=0.6: The adjustment difference depends on hole depth (choose 8D)

- Calculation speed: Vt U*1*1,1*0.6*1 = 36.3 mm/min

- Number of rounds to calculate:� � = 1000∗� �∗� � = 1000∗36,3 �∗7,8 = 1481(rpm)

Choose the number of revolutions according to the machine, first find work multiples: φ m−1 = φ 21−1 = φ 20 =n max n min 00

20 = 100 Corresponding toφ 20 = 101,6 (closer to 100) can be scaled upφ= 1,26

On the other hands:φ x = n n t min = 1481 20 = 74,05 According to table 4.7 in columnφ= 1,26 is close to 74.05 hasφ 19 = 80,64

- So the number of revolutions of the machine: nm= nmin *80,64 = 20*80,64 =1613rpm

The actual speed is: �� = �∗�∗� 1000 � = �∗7,8∗1613 1000 = 39,5m/min

 Operation 8: Drilling and taro 4 holes H M5

- The slab controls 3 degrees of freedom mode

Choosing machine: choose a need drilling machine 2H55 with parameters (Table 3.1, page

- Cutting speed: (Table 5-86, page 83, ST2), we have Vb = 55m/min With the velocity correction factor

K3=0.85: The adjustment difference depends on the depth of the hole (choose 3D) K4=1: The adjustment difference depends on the grade of the drill bit material

- Calculation speed: Vt U*1*1.1*0.85*1 = 51.4 mm/min

- Number of rounds to calculate:n t = 1000∗V π∗D t = 1000∗51,4 π∗4,8 = 3409(rpm)

Choose the number of revolutions according to the machine, first find work multipliers: φ m−1 = φ 21−1 = φ 20 =n max n min 00

On the other hands:φ x = n n t min = 3409 20 = 170,45 According to table 4.7 in columnφ= 1,26 is close to 170.45 yesφ 20 = 101,61

- So the number of revolutions of the machine: nm= nmin*101,61 = 20*101,61 = 2032 rpm

The actual speed is:vtt = π∗D∗n 1000 m = π∗4,8∗2000 1000 = 30,2 m/min

 Operation 9: Drilling and taro 4 holes L M6

Choosing machine:choose a need drilling machine 2H55 with parameters (Table 3.1, page

- Number of rounds to calculate:�� = 1000∗� �∗� � = 1000∗51,4 �∗5,8 = 2820(rpm)

Choose the number of revolutions according to the machine, first find work multipliers: φ m−1 = φ 21−1 = φ 20 =nmax n min 00

On the other hands:φ x = n n t min = 2820 20 = 141 According to table 4.7 in columnφ= 1,26 is close to 170.45 yesφ 20 = 101,61

The actual speed is:� �� = �∗�∗� 1000 � = �∗5,8∗2000 1000 = 36,4 m/min

3.4.2.1 Creating workpiece: After look up the machining residue in Table 3-96, page 253 –ST2, we choose the workpiece is cut from steel plate with size 260x190x40mm

Figure 3.39:Creating workpiece for retaining plate

Figure 3.40:Marking of machined surfaces for retaining plate

Item No Name of operation Face Locate

Drilling, boring 6 holes E,F ỉ9 and hole with shoulder G ỉ14

Figure 3.41: Machining processes for retaining plate

Table 3.11: Machining processes of retaining plate

Similar to base plate parts

 Operation 5: Drilling, boring, 6 holes ỉ24 and 4 holes ỉ9

Look up the cutting mode and calculate the operation time

- Calculation speed: Vt = 32*1*1,1*1*1 = 55 mm/min

- Number of rounds to calculate:�� = 1000∗� �∗� � = 1000∗55 �∗8,8 = 1989 (rpm)

Choose the number of revolutions according to the machine, first find work multipliers: φ m−1 = φ 21−1 = φ 20 =nmax nmin 00

On the other hands:φ x = n n t min = 1989 20 = 99,45 According to table 4.7 in columnφ= 1,26 is close to 99.45 has φ 20 = 101,61

- So the number of revolutions of the machine: nm= nmin *101,61 = 20*101,61 = 2032 Choosing 2000 rpm

The actual speed is: � �� = �∗�∗� 1000 � = �∗8,8∗2000 1000 = 55,29 �/min

Look up cutting mode when reaming:

- Cutting speed: (Table 5-113, page 105, ST2), we have Vb= 13 m/min With a constant velocity correction factor of 1.

- Calculation speed: Vt=Vb = 13 m/min

- Number of revolutions calculated:�� = 1000∗� �∗� � = 1000∗13 �∗9 E9,8 (m/min)

Calculate by machine:φ x = n n t min = 459,8 20 = 23 Looking at table 4.7, we have φ 14 %,28 which is close to 23 (Table 4.7 - page 58 -

- So the number of revolutions of the machine: nm=nmin * 25,28 = 20*25,28= 505,6 rpm. The actual speed is: � �� = �∗�∗� 1000 � = �∗9∗505,6 1000 = 14,3 �/min

 Operation 6: Hole with shuolder milling ỉ14

Positioning:Controls to 6 degrees of freedom

Choosing a machine:CNC milling machine

Choosing tool:Cylindrical end mills tool

Tool diameter: d= 10 mm; length: Lrmm; Number of teeth: Z= 5; Material: Wind Steel (Table 4-74, Page 363 - ST1)

Measuring instruments:125mm long caliper, 0.02 accuracy

- Rough tooling running rate: Sz= 0.035 ( mm/tooth ) ( Table 5-153 page 138 – ST2 )

- Cutting speed Vb = 34 m/min (Table 5-154, page 138 – ST2) This value corresponds to the depth of cutting: t mm.

The adjustment coefficient depends on the mechanical properties of steel K1=1 The adjustment factor depends on tool life cycle K2=1

- Number of revolutions calculated:�� = 1000∗� �∗� � = 1000∗34 �∗10 = 1082(rpm)

- The minute tooling running rate: Sph = Sz * Z * n = 0.035 * 5 * 1082 = 189.35 mm/min

- Fine tooling running rate: Sz= 0.035 (mm/tooth) ( Table 5-153 page 138 – ST2 )

- So the calculation speed Vt=Vb*K1*K2 = 34 (m/min)

3.4.3.1 Creat workpiece: After look up the machining residue in Table 3-96, page 253 – ST2, we choose the workpiece is cut from steel plate with size 107x87x18mm

Figure 3.44:Creat workpiece for the motor flange

Figure 3.45:Marking of machined surfaces for the motor flange

Table 3.13:Machining processes of the motor flange

 Operation 2: Side C and opporite face milling

 Operation 3: Side D and opporite face milling

Figure 3.46: Machining processes for the motor flange

- 2 pins face C controls 2 degrees of freedom

- 1 pin face D controls 1 degree of freedom

Choosing a tool:Tool diameter: d= 25 mm; length: L2mm; Number of teeth: Z= 5 ; Material: Wind Steel (Table 4-74, Page 363 - ST1)

- Rough tooling running rate: Sz = 0.09 ( mm/tooth ) ( Table 5-153 page 138 – ST2 )

- The minute tooling running rate: Sph = Sz * Z * n = 0.12 * 3 * 292.87 5.4 mm/min

Figure 3.47: Mounting diagrams of operations 5

- 3 degrees of freedom on the bottom face is an slab

- Short cylindrical pin with 2 degrees of freedom in hole ỉ30

- Short cylindrical pin positioned 1 degree of freedom on the face D

Choosing machine:Choosing a vertical milling machine 6H12 with a capacity of 7 kw n 30 ÷ 1500, 18 levels ( Table 19 - page 232 - Machining cutting mode )

Choosing a tool:choosing the cylindrical shank keyway milling cutter.

Tool diameter: d= 6 mm; length: LRmm; Number of teeth: Z= 4 ; Material: Wind Steel (Table 4-74, Page 363 - ST1)

Look up the cutting mode and calculate the machining time

- Rough tooling running rate: Sz = 0.018 (mm/tooth) (Table 5-153 page 138 – ST2 )

- Cutting speed Vb = 35 m/min ( Table 5-155 page 139 – ST2 ).

The adjustment factors equal to 1

- So the calculation speed Vt=Vb= 35 (m/min)

Machine 6H12 has nmin0; nmax00, number of speed levels m, find work multiples: φ m−1 = φ 18−1 = φ 17 =n max n min 00

30 = 50 The correspondingφ 17 value 50.65 is close to 50 respectivelyφ = 1,26(Table 4.7, page 58, CNCTM project manual)

On the other hand:φ x = n n t min = 1856 30 = 61,86 Correspondingφ = 1,26to us has a value φ 18 = 64 close to 61.68

- So the number of revolutions according to the machine is: nm = 30 * 64 20 rpm

The rotation speed is too large, so we choose nm=320 rpm

- Thus, the actual cutting speed is:��= �∗�∗� 1000 � = �∗6∗320 1000 = 6m/min

Figure 3.49:Creat workpiece for the tool holder plate

Figure 3.50: Marking of machined surfaces for the tool holder

Figure 3.51:Machining processes for the tool holder

Table 3.15:Machining processes for the tool holder

3.4.4.3 Operation design: Similar to base plate parts

3.4.5.1 Creat workpiece: After looking up the machining residue in table 3-96, page 253 - ST1, we can choose the workpiece cut from steel plate with the size as below.

Figure 3.52:Creat workpiece for ribs

Figure 3.53:Marking of machined surfaces for ribs

- Step 2: Fine milling Drilling, taro 2 holes9

 Operation 2: Face milling B, drilling and boring 2 holes ỉ9

Figure 3.54:Machining processes for ribs

Table 3.16:Machining processes for ribs

Positioning:The part is positioned with 3 degrees of freedom on face A as an slab

Choosing a machine:Choose a vertical milling machine 6H12 with a capacity of 7kW n 30 ÷ 1500, 18 levels ( Table 19 - page 232 - Machining cutting mode )

Choosing a tool: choose a face milling cutter with a piece of wind steel.

Tool diameter: D= 100 mm ; Number of teeth: Z ; Material: T15k6

- Rough tooling running rate Sz = 0.13 ( mm/tooth ) ( Table 5-125 page 113 – ST2 )

- Cutting speed Vb = 28.2 m/min (Table 5-120, page 109 – ST2) This value corresponds to the depth of cutting t=5 mm.

The adjustment coefficient depends on the hardness of steel K1=1

The correction factor depends on the grade of hard alloy K3=1

The adjustment factor depends on milling width K5=1.13

- So the calculation speed Vt=Vb*K1*K2*K3*K4*K5*K6 = 31.9 (m/min)

Machine 6H12 has nmin0; nmax00, number of speed levels m, find work multiples: φ m−1 = φ 18−1 = φ 17 = n n max min = 1500 30 = 50 The corresponding φ 17 value 50.65 is close to 50 respectivelyφ = 1,26(Table 4.7, page 58, CNCTM project manual)

On the other hand:φ x = n n t min = 101,5 30 = 3,385 Correspondingφ = 1,26to ta has a valueφ 5 = 3,16close to3,385

- So the number of revolutions according to the machine is: nm = 30 * 3,16 = 94,8 rpm

- Thus, the actual cutting speed is:� �� = �∗�∗� 1000 � = �∗100∗94,8 1000 = 29,78m/min

- The minute tooling running rate: Sph = Sz * Z * n = 0.13 * 10 * 94.8 = 123.2 mm/min Cutting mode when rough milling: t = Z = 3.5 mm ; Sph = 123.2 mm/min

- The feed rate t0 = 0.13 mm/tooth (Table 5-125, page 113, ST2)

- Cutting speed Vb= 31.6 m/pℎ: Cutting speed with depth of cutting t= 1.5

K1 = 1: The correction factor depends on the hardness of the steel.

K2 = 1: Coefficient depending on tool life cycle

K4 = 0.8: The adjustment factor depends on the machined surface

- Number of revolutions calculated:�� = 1000∗� �∗� � = 1000∗28,6 �∗100 = 91(rpm)

Calculate by machine:φ x = n n t min = 91 30 = 3 Looking up table 4.7 we have φ 5 = 3,16 (Table 4.7 - page 58 - CNCTM project manual)

- So the number of revolutions according to the machine is: nm= 30 * 3,16 = 94,8 rpm

- Actual cutting speed is:� �� = �∗�∗� 1000 � = �∗100∗94,8 1000 = 29,78m/min

- The minute tooling running rate is: Sph = Sz * Z * n = 0.13 * 10 * 94.8 = 123.2 mm/min Cutting mode when fine milling: t = Z = 0.5 mm nm.8 rpm Sph = 123.2mm/min

3.4.6.1 Creat workpiece: After looking up the machining excess in Table 3-96, page 253 – ST1, we choose the workpiece cut from sheet steel with the size as shown.

Figure 3.56:Creat workpiece for V block

Figure 3.57: Marking of machined surfaces for V blocks

Table 3.18: Machining processes of V blocks

Figure 3.58: Machining processes of V blocks

3.4.7.1 Creat workpiece: After look up the machining excess, we choose the workpiece cut from steel plate with the size as shown.

Facing Turning and drilling holes

Figure 3.59: Creat workpiece for axis ỉ20

Figure 3.60:Marking of machined surfaces for axis ỉ20

Table 3.19:Machining processes of axis ỉ20

Figure 3.61:Machining processes of axis ỉ20

Figure 3.62:Creat workpiece for the turnplate

Figure 3.63:Marking of machined surfaces for the turnplate

Face milling, drilling, boring, reaming 20

5 Milling 6 grooves F and drilling, taro 12 holes

Figure 3.64:Machining processes of turnplate

Table 3.20:Machining processes of turnplate

Machining keys: Cutting wire to size as drawing (See appendixs)

Machining vibration rod: Cutting wire to size as drawing (See appendixs)

Machining vibration rod clamp plate: Cutting wire and drilling 2 holes to size as drawing (See appendixs)

Machining vibration rod clamp plate: Cutting wire and drilling

2 holes slot to size as drawing (See appendixs)

Figure 3.67:Vibration rod clamp plate

Assembly and testing

The model is assembled and tested according to the following steps:

- Step 1:Read and understand assembly and disassembly drawings (See figure 3.6 and 3.7)

- Step 2: Check the appearance, the quantity of parts, measure all the dimensions of each part according to the machining drawings (See details in the drawing volume)

- Step 3: Proceed to assemble standard and non-standard parts together according to the designed drawings.(See figure 3.6 and 3.7)

- Step 4:Connect the PLC circuit according to the diagram below and program the PLC on

GX Developer software to control the stepper motor to rotate (See more figure 3.10)

- Step 5:Check the model overview again after complete assembly

- Step 6: Testing on different holders milling We can change the variable as follows: rotation speed through pulse frequency, tool holder length, vibrating rod length Give results and reviews (See detailed results of chapter 4).

Figure 3.69:Connection diagram of stepper motor and PLC

APPLICATION IN DEFORMED MEASUREMEN

Introduce value for vibration comparison of experimental results

In this research, the results were compared when changing 3 parameters: pulse frequency, milling cutter length, and rod length in contact with the milling tool Based on the results obtained after measuring, we can set up a table of experimental results With the knife holder: BAP 300R C10-10-120

L: Length of milling cutter (mm)

L1: Length of vibrating rod (mm)

To compare two waveform histograms, you can use both PP (peak-to-peak) and RMS (root mean square) values, depending on your purposes.

PP value: is the difference between the highest peak value and the lowest peak value of the vibration The PP value indicates the maximum amplitude of the vibration, as well as its oscillation in one cycle You can compare the PP value of two waveform graphs to determine the degree of vibration fluctuations, as well as phenomena such as collisions, eccentricities, and more.

RMS value: is the mean squared value of vibration, calculated by taking the square root of the sum of the squares of the vibration values divided by the number of values The RMS value indicates the effective intensity level of the vibration, as well as its equilibrium over a cycle You can compare the RMS value of two waveform graphs to determine the intensity level of the vibration, as well as phenomena such as wear, noise, and more.

Some examples of how to compare two waveform histograms using PP and RMS values:

If you want to compare the vibrations of two camcorders with the same rotational speed, you can compare the PP values of the two waveform graphs to see which has greater vibration and which has more stable vibration.

If you want to compare the vibrations of two cameras with different rotational speeds, you can compare the RMS values of the two waveform charts to see which has stronger vibrations and which has weaker vibrations.

Analyzing and reviewing on experimental results

Figure 4.1.Effect of rotational speed (12kHZ) Figure 4.2.Effect of rotational speed (8kHZ)

Figure 4.3.Effect of tool holder length (94mm) Figure 4.4 Effect of tool holder length

Figure 4.5 Effect of rod length vibrating impact

(45.5mm) Figure 4.6.Effect of rod length vibrating impact (46.3mm) 4.2.1 Case 1: Change the pulse frequency

(Hz) L L1 PP (V) PP (A) PP (D) RMS

Table 4.1:Experimental cases of frequency change according to X

Table 4.2:Experimental cases of frequency change according to Y

4.2.2 Case 2: Change the length of milling cutter

Table 4.4:Experimental cases of length of milling cutter change according to X

Table 4.3:Experimental cases of frequency change according to Z

Figure 4.7:Graph PP and RMP for the case 1

Table 4.5:Experimental cases of length of milling cutter change according to Y

Table 4.6:Experimental cases of length of milling cutter change according to Z

4.2.3 Case 3: Change the length of vibrating rod

Table 4.7:Experimental cases with length of vibration rod change according to X

Table 4.8: Experimental cases with length of vibration rod change according to Y

Table 4.9: Experimental cases with length of vibration rod change according to Z

The graph shows the damping oscillation:

Figure 4.11:Damper knife holder ỉ20-154mm

Figure 4.12:Damper knife holder with core ỉ20-154mm

Case 1: See tables 4.1, 4.2, 4.3 and figure 4.1 when changing the pulse frequency to increase gradually and keep the tool length and vibrating rod length the same, we see that the PP value of the vibration level in the X, Y, Z direction is almost gradually decreasing, this shows the phenomenon like collision touch, eccentricity, etc the less.

Case 2, 3: See tables 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 and figures 4.2, 4.3 when changing the tool length and the length of the vibrating bar increasing gradually and keeping the pulse frequency unchanged, we see that the PP value of the vibration level in the X, Y, Z directions is almost increasing, this represents a phenomenon similar to a collision . inductive, eccentric, etc the bigger it is.

=> Therefor we see that: the vibration of the tool holder depends on the tool length and the impact rod length The longer it is, the greater the vibration level Therefore, we need to adjust the tool accordingly to make the machining more accurate.

CONCLUSION AND DEVELOPMENT DIRECTION

Conclusion

Through the process of implementing the graduation project, the team has completed the requirements set out and summarized in this report in the correct format with full form and content, including the urgency, objectives, tasks, overview of the topic In general, the content of the graduation project has completed the following main issues:

- Apply knowledge of mathematics, science and engineering, and social sciences demonstrated in computating, designing, and fabricating model.

- Perform/analyze/synthesize/evaluate is demonstrated in model testing.

- The problem of designing or fabricating a system, component, or process that meets a given requirement with realistic constraints is demonstrated in “FABRICATION OF MILLING HOLDER DEFORMATION MEASUREMENT MODEL”

- The ability to improve and develop is demonstrated in deformation measurement model of this milling holder.

- Ability to use technical tools, specialized software is demonstrated in designing, machining, testing and assembling models.

- After the implementation of this topic, the obtained results can be applied in measuring the vibration of different milling holders.

In the end, the process of implementing the project has achieved the following specific products: the deformation measurement model of milling holders, topic explanatory report, give results of vibration measurement of milling holders.

mm, and volume fraction, 30 %) a Excitation signal (i) time domain, (ii) frequency domain; b response signal (i) time domain, (ii) frequency domain [11]

=> From experiments, research on inventions and articles on vibration as above, my team based on that idea to fabricate: “FABRICATION OF MILLING HOLDERDEFORMATION MEASUREMENT MODEL”

Figure 3.9:PLC circuit to control Figure 3.10:PLC programming softwareGXDeveloper stepper motor

Standard parts such as: milling tool holder, SKF 6204 bearing, large pulley diameter, small pulley, belt 3M thickness 10mm length 444mm, motor, sensor, milling tool 300R- C10-10-120, collet, rubber feet, bolts, nuts, hexagons of all kinds

Non-standard parts such as: base plate, retaining plate, ribs, V block, tool holder plate,turnplate, axis, keys, motor flange, motor jig, vibrating rod, vibrating rod clamp plate.

Parts of PLC control circuit stepper motor: driver, FX3U PLC board, 24V 5A source, 2K Ohm resistor, 3-color electric wire, USB cable, electrical panel, power connection wire.

Operation based on PLC programming software to control stepper motor The variables we need to change such as: rotational speed, which depends on the rotational speed of the turnplate through changing the pulse frequency, changing the time for the motor to stop or rotate continuously, the length of the vibrating rod depends on the diameter and length of the milling tool, change the milling tool holder length.

When the motor rotates through the belt pulling the rotating turnplate, causing the rods to impact the milling tool holder Install the sensor on the milling tool holder Under this impact, the sensor will receive a vibration signal and output a waveform graph From the results of that waveform graph, we can compare through two values of PP and RMS to determine the level of vibration, as well as phenomena such as collision, eccentricity, wear, distortion, etc.