đồ án thiết kế hệ thống cơ khí thiết bị tự động đề tài thiết kế hệ thống phân loại sản phẩm

CHAPTER 2:BASIC COMPONENTS OF THE SYSTEM2.1 ConveyorFigure 2.1 Conveyor model in real life The main characteristics of conveyors for purposes of classification are the type of traction a

ĐẠI HỌC BÁCH KHOA HÀ NỘI

TRƯỜNG CƠ KHÍ KHOA CTTT CƠ ĐIỆN TỬ

Sinh viên thực hiện: Nguyễn Duy Tùng Anh - 20195759

Giảng viên hướng dẫn: Trịnh Đồng Tính

Hà Nội, tháng 4 năm 2023

TRƯỜNG ĐẠI HỌC BÁCH KHOA HÀ NỘI SME.EDU –Mẫu 6.a

ĐỒ ÁN MÔN HỌC: THIẾT KẾ HỆ THỐNG CƠ KHÍ Mã HP: ME3066

Thời gian thực hiện: 15 tuần; Mã đề: VCK01-19 Ngày giao nhiệm vụ: 10/04/2023; Ngày hoàn thành://2023

Họ và tên sv: Nguyễn Duy Tùng Anh MSSV: 20195759 Mã lớp:729127

I Nhiệm vụ thiết kế: Thiết kế hệ thống phân loại sản phẩm

II Số liệu cho trước:

1 Hệ thống cấp phôi tự động

2 Nguồn lực cấp phôi và đẩy phôi: Khí nén

3 Nguồn lực quay băng tải: Động cơ điện

4 Bộ truyền ngoài: Xích

5 Thông số hình học phôi:

 Hình lập phương : h1= 3cm, h2= 4cm, h3= 5cm

6 Trọng lượng phôi: Q min = 0.5 kg; Q max = 6.5 kg

7 Năng suất làm việc : N = 20 sp/ph

III Nội dung thực hiện:

1 Phân tích nguyên lý và thông số kỹ thuật

- Tổng quan về hệ thống

- Nguyên lý hoạt động

- Phân tích tính chất, đặc điểm của phôi/sản phẩm để lựa chọn phương pháp cấp phôi phù hợp

- Xác định các thành phần cơ bản và thông số/yêu cầu kỹ thuật của hệ thống

2 Tính toán và thiết kế

- Thiết kế các mô đun chức năng của hệ thống:

+ Mô đun cấp phôi tự động

+ Mô đun băng tải

+ Mô đun phân loại: pít tông khí nén, van từ, sensor,

3 Thiết kế chi tiết và xây dựng bản vẽ lắp

- Xây dựng bản vẽ lắp 2D/3D

- Xây dựng các bản vẽ chế tạo các chi tiết chính

4 Mô phỏng nguyên lý hoạt động (động học)

Đề số Năng suấtlàm việc Trọng lượng phôi Kích thước hình học phôi (cm)

Today, due to the constant development of technology, the need of a fast and

convenient application in industries is necessary Automation is a practical

solution which helps increase the speed, accuracy and reduce labor price

In the era of industrialization and modernization of Vietnam, the automatic control

of production and product processing has been increased This results in the

forming of flexible production systems, allowing a high degree of automation for

small and medium batch production on the basis of CNC machines and

industrial robots Automation is also utilized in the product category system,

which is an important stage affecting the quality of commercial goods

The project " Designing an automatic product classification system " was

conducted in order to reinforce students' knowledge and at the same time help

them recognize the connection between the theoretical knowledge and the

practical applications and use The topic has many important applications in

fields such as product transportation, counting and classification With this

automation system labor and production cost can be reduced

Given the broad range of general knowledge, there are multiple areas of

knowledge that I have not mastered despite having consulted technical documents

Hence, when implementing the project " DESIGN OF MECHANICAL

ELECTRICAL SYSTEMS ", it is unavoidable that limitations and shortcomings

exist We look forward to receiving constructive advice and the support of

lecturers and peers

We sincerely thank the lecturers in the Department of Technology mechanical

and especially …, who has enthusiastically guided, created favorable conditions

and given us valuable knowledge for the completion of this subject project

Thank you sincerely

TABLE OF CONTENTS

FIGURE LIST 6

CHAPTER 1: 7

OVERVIEW OF THE PRODUCT CLASSIFICATION SYSTEM 7

1.1 Definition and Application 7

1.2 Working principle 7

CHAPTER 2: 8

BASIC COMPONENTS OF THE SYSTEM 8

2.1 Conveyor 8

2.3 Piston 14

2.4 Sensor 15

2.5 Motor 16

2.5.1 Definition 17

2.5.2 Working Principle 17

CHAPTER 3: 18

CALCULATION AND DESIGN OF THE SYSTEM COMPONENT 18

3.1 Conveyor system 19

3.1.1 Calculate the parameters of the conveyor geometric and kinetics 19 3.1.2 Calculate the tensile force 21

3.1.3 Choose the roller (Active/Passive) 23

3.1.4 Test strength of the belt 27

3.1.5 Choose the motor 27

3.1.6 Choose the external transmission 30

3.2 Choose automatic work-piece feeding system 35

3.3 Pneumatic system and cylinder calculation 36

3.3.1 Introduction of compressed air system and components 36

3.3.2 Calculate the piston 38

3.3.3 Calculate the air compressor 39

3.4 Choose sensor 41

CHAPTER 4: 43

DESIGNING SYSTEM MODEL ON SOFTWARE 43

4.1 Overview of SOLIDWORKS software 43

4.2 Basic components of the system 44

4.2.1 Main frame 44

4.2.2 Conveyor belt 45

4.2.3 Feeding box 45

4.2.4 Roller 45

4.2.5 Chain transmission 46

4.3 Model of product 47

FIGURE LIST

Figure 2.1 Conveyor model in real life 8

Figure 2.2 Belt conveyor 9

Figure 2.3 Chute conveyor 10

Figure 2.4 Gravity conveyor 10

Figure 2.5 Powered roller conveyor 11

Figure 2.6 Bucket conveyor 11

Figure 2.7 Ball transfer conveyor 12

Figure 2.8 Slat conveyor 12

Figure 2.9 Train conveyor 13

Figure 2.10 Trolley conveyor 13

Figure 2.11 Structure of the piston 15

Figure 2.12 How sensor works 16

Figure 2.13 Types of motor 16

Figure 3.1 Length of conveyor, distance between products 19

Figure 3.2 Forces acting on conveyor 22

Figure 3.3 Active roller 23

Figure 3.4 Forces acting on roller 24

Figure 3.5 Moment chart Oy 25

Figure 3.6 Moment chart Ox 26

Figure 3.7 TAILI-MINHMOTOR Speed control motor 29

Figure 3.8 Forces acting on piston 38

Figure 3.9 DSNU piston catalog 39

Figure 3.10 Piston’s journey 39

Figure 3.11 Air compressor Wing TW-OF750-25l -1HP 40

Figure 3.12 Infrared sensor E18-D80NK 41

Figure 4.1 Main frame 44

Figure 4.2 Conveyor belt 45

Figure 4.3 Feeder 45

Figure 4.4 Roller 46

Figure 4.5 Chain transmission 46

Figure 4.6 Large Sprocket 47

Figure 4.7 Small Sprocket 47

Figure 4.8 Model 48

CHAPTER 1:

OVERVIEW OF THE PRODUCT CLASSIFICATION SYSTEM

1.1 Definition and Application

A product classification system is an automatic or semi-automatic control system

which categories products with similar feature for packaging or discarding flawed

products

These types of systems include for example:

 Based on the control method: automatic or semi-automatic systems, without or

with human participation to a certain extent, controlled by PLC and microprocessor.

 By color: the color sensor will recognize the color and convert it to electrical

signal and then through an ADC converter to the processor.

 According to the weight, shape and size.

1.2 Working principle

Based on sensors to classify types of products (cylinder and cube, its

height)

 Basic technical requirements of functional clusters in the system:

+ Conveyor speed is sufficient to achieve working productivity and engine with

enough capacity for stable operation of the transmission system

+ The system of pushing work pieces with compressed air has low latency to

avoid affecting the product classification sensor

CHAPTER 2:

BASIC COMPONENTS OF THE SYSTEM

2.1 Conveyor

Figure 2.1 Conveyor model in real life

The main characteristics of conveyors for purposes of classification are the type

of traction and the load-carrying elements A distinction is made between

conveyors with belt, chain, and cable drive elements and conveyors without a

drive element (gravitational, inertial, and screw conveyors) Conveyors with drive

elements can be differentiated by type of load-carrying elements into belt, apron,

cradle, flight, and bucket types Such conveyors are characterized by movement of

the load together with the working element The thrust is transmitted either by the

load-carrying element or by an element that pushes or pulls the material along a

fixed trough, tube, or bed In conveyors without a drive element the movement

of the load is usually separate from the movement of the working elements, which

revolve in roller and screw conveyors or perform reciprocating motion in, for

example, inertial conveyors Conveyors may have a machine drive (most often

electric; sometimes pneumatic), or the load may be moved by the force of gravity

(gravitational conveyors)

Advantages of conveyor belt:

- Simple structure, durable, capable of transporting separately and individually

in horizontal, inclined or a combination of horizontal and inclined

- The investment capital is not very large, can be automated, simple operation,

easy maintenance, reliable work, high productivity and energy consumption

compared to other transport machines is not very large

Types of conveyor belts on the market today

When designing a conveyor system to transport products to a sorting location, you

can choose from the following types of conveyors:

2.1 Belt Conveyor

Figure 2.2 Belt conveyor

This is probably what you picture when you think of a conveyor They are simple

devices—a moving belt turned by pulleys—but are very useful A motor is used to

turn the pulleys, thus moving the belt

Chute Conveyor

Figure 2.3 Chute conveyor

Picture a slide for your packages Chute conveyors are metal slides used to

transport packages down to a lower level of your warehouse They are cheap but

using them can increase the odds of packages bumping into each other and getting

damaged

Gravity Roller Conveyor

Figure 2.4 Gravity roller conveyor

Instead of a belt, this device uses cylindrical rollers It is built at a slight decline so

parts slide downward on their own

Powered Roller Conveyor

Figure 2.5 Powered roller conveyor

This is like a gravity roller conveyor except a chain or belt is used to make the

rollers turn on their own, so they don’t have to be built on a decline Sometimes

they can even go uphill

Bucket Conveyor

Figure 2.6 Bucket conveyor

Grain elevators, which we discussed here, fall under this category Bucket

conveyor systems are used to move material vertically, by scooping it with a series

of buckets attached to a belt, chain, or cable The conveyor moves the buckets

upward, scooping up the material, and carrying it to the top before dumping it out

Ball Transfer Conveyor

Figure 2.7 Ball transfer conveyor

This type of conveyor system is described as: “Ball Transfer tables or conveyors

use a series of mounted ball casters to allow for unpowered, multi-directional

conveyance of the product.” Essentially, imagine rows of metal balls on a table

that can turn and rotate in any direction This allows material to be pushed in

different directions (as opposed to rollers which can only go forwards and back)

Slat Conveyor

Figure 2.8 Slat conveyor

“A slat conveyor is basically a two-strand chain conveyor with slats connected

to the chain and a guiding system for the slats This creates a smooth surface to

which tooling details or fixtures can be mounted to hold parts in the desired

position.”

Chain Conveyor

Figure 2.9 Chain conveyor

These are exactly what they sound like Instead of having rollers or a belt, they

have moving chains to carry products They are usually low to the ground and are

used to carry larger items

Trolley Conveyor

Figure 2.10 Trolley conveyor

There is a whole family of conveyors that carry their load beneath them instead of

on top of them Sometimes the load is hung from an overhead beam and pushed

along Other times they are motorized Sometimes, as with the Power- and-Free

Conveyor, they have two tracks—one motorized and one not motorized.

Because the conveyor is used in the system to transport products, in this project

I have chosen a belt conveyor for the following reasons:

- Conveyor load is not too large.

- The mechanical structure is not too complicated.

- Easy to design and manufacture.

However, this type of conveyor also has some disadvantages such as: the accuracy

when transporting is not high, sometimes the conveyor belts operate unstable due

to many factors: environmental temperature affects rollers, friction of the belt

drops through

2.2 Piston

A piston is a component of reciprocating engines, reciprocating pumps, gas

compressors, hydraulic cylinders and pneumatic cylinders, among other similar

mechanisms It is the moving component that is contained by a cylinder and is

made gas-tight by piston rings In an engine, its purpose is to transfer force from

expanding gas in the cylinder to the crank shaft via a piston rod and/or connecting

rod In a pump, the function is reversed and force is transferred from the

crankshaft to the piston for the purpose of compressing or ejecting the

fluid in the cylinder In some engines, the piston also acts as a valve by covering

and uncovering ports in the cylinder

The piston is usually cylindrical, divided into 3 parts including the pavilion,

head and body:

- In the piston nails, there are 3 types of convex, concave and equal Each piston

peak receives high temperature gas pressure The piston head section has oil ring

grooves and cement rings when used for mounting in the device The grape

holes at the top of the oil capacity are opened into the bottom of the trench to

perform the task of supplying and escaping The number of ring slots depends on

the engine type On the piston body, there are horizontal holes, performing the

task of guiding the piston to move in the cylinder to transmit the force to rotate the

crankshaft when linked with the transmission rod to perform the function of

mounting the piston connecting pin and the transmission rod The body of a diesel

engine's piston is usually longer than the piston body of a gasoline engine and the

base usually has an additional 1-2 rings of oil ring In order to facilitate the air

conditioning when working from the carburetor to the engine crankcase, the piston

body of the two-stroke engine does not have a gas cylinder with a bottom hole or a

defect

Working principle of the piston:

- The piston base is compressed at a certain temperature and pressure, the piston

operates automatically through the compressed air supply Thanks to the

difference between the pressure at the outside school and the pressure level in

the piston act to supply the piston The source of compressed air is the energy

that helps the piston work Pistons can go all the way, requiring gas in the piston

to be discharged When there is a type of pneumatic electronic valve in the

piston that causes the air to expand, the compressed air is converted into kinetic

energy In the piston cavity, air will be compressed when supplying gas to the

piston Energy is generated and transformation is performed This amount of gas

generates work that helps the device work while taking up the space inside the

piston, causing the piston to move Therefore, depending on the performance of

the device, the piston operates in a variety of methods to regulate intermediate

stops At the same time control the amount of expansion or retraction of the

piston rod

Figure 2.11 Structure of a piston

2.3 Sensor

In general, sensor is known as a Detector A sensor is an electronic equipment that is

used to detect and observe the physical activities and pass the notification/signal to other

electrical control devices In other words, a sensor is an electronic device that can

transform energy from one form to another form So, it is also called a

Transducer The main function of the sensor is to identify and communicate with

physical quantities such as temperature, heat, pressure, distance, moisture, gas, and so

on And it provides output in the form of electrical signal to connected control systems.

Figure 2.12 How sensor works

According to the principle of the sensor there are:

- Electronic and ion sensors

According to the nature of the power source:

- Generator sensor

- Parameter sensor

According to the measuring method:

- Direct variable sensor

- Compensation sensor

2.4 Motor

Figure 2.13 Motor

2.5.1 Definition

Electric motors in general and DC motors in particular are rotating electromagnetic

devices, working according to the electromagnetic principle, when placed in a magnetic

field by a conductor and allowing current to flow through the conductor to make the coil

move An electric motor converts electrical energy into mechanical energy.

2.5.2 Working Principle

The stator of a DC motor is usually one or more pairs of permanent magnets, or

electromagnets, the rotor has windings and is connected to a DC power source, another

important part of a DC motor is rectifier, it is responsible for changing the direction of

current while the rotation of the rotor is continuous Usually this part consists of a

commutator and a set of brushes in contact with the commutator.

If the shaft of a DC motor is pulled by an external force, the motor will act as a

DC generator, and generate an induced Electromotive force (EMF) During

normal operation, the rotor when rotating will generate a voltage called

counter-EMF (Ccounter-EMF), because it opposes the external voltage applied to the motor This

electromotive force is similar to that generated when the motor is used as a

generator (like when we connect a load resistor to the motor output, and pull the

motor shaft by an external torque) Thus, the voltage applied to the motor consists

of two components: the electromotive force, and the voltage drop caused by the

internal resistance of the armature windings

CHAPTER 3: CALCULATION AND DESIGN OF THE SYSTEM COMPONENT

*Overview of transmission system:

With: 1 Motor, 2 Clutch, 3 Gearbox, 4 Chain drive, 5 Conveyor

Electric motors usually have high rotation speed So the rotation from the motor will be reduced through the gearbox, then reduced again through the chaindrive and transmit to the conveyor in order to reach optimal working speed

For my project, I choose motor with built in gear box, focus on designing the chain drive system and the conveyor

3.1 Conveyor system

- Input parameters

+ Geometrical parameters of products:

Cubes: h1=3 (cm) h2=4 (cm) h3=5 (cm)

+ Weight of block: Qmin = 0.5kg Qmax = 6.5 kg

+ Working capacity: N = 20 block/min

+ Source of power: Electrical motor

Figure 3.1 Length of conveyor, distance between products

3.1.1 Calculate the parameters of the conveyor geometric and kinetics

- Find L:

• L = d + (n-1) Y

Where: n is the number of product on the conveyer at 1 time (n=4)

d is the diameter of products (d=0.05m)

Y is the distance between the center of 2 products (choose Y=0.3m)

=> L = 0.05 + (4 - 1).0.3 = 0.95(m) Choose L=1.3m

- Find W:

- Y v > 2(M+W ) v

1

With: Y is the distance between the center 2 products (choose Y=0.3m)

v is the speed of the conveyor

v1 is the speed of the pistons (choose FESTO brand)

M is the distance from product’s edge to the conveyor’s edge (choose M=0)

- Time to object go over the conveyor:

Choose DSNU-20-200, v1=0.5(m/s) at Qmax = 6.5 kg

=> 0.3

0.1083>

2 (0+W )

0.5 => W<0.69(m)Width of the conveyor should also longer than the diameter of product

 Frame structure: Shaped aluminum

I choose PVC conveyor belt because of these advantages:Wear and scratch resistant, Broad range in types, Easy the rework, Price friendly, Easy to clean, Oil and grease resistant

3.1.2 Calculate tensile force

- Analysis forces applied on the conveyor belt

Primary tensile force:

+ Friction force between surface of belt and roller made by weight of blocks andbelt

+Initial belt tension

Tension at point S1 => S4:S i = S i−1 + W i−1 /i

With: W i−1 /i is the drag force from point (i-1) to point (i).

-Band drag force is the force transmitted from the guide drum to the belt

F = S3 – S0 = ΣW i−1 /i = 2.86 + 0.06S0 + 0.172 + 89.55 = 0.06S0 + 92.58 (N)

So to determine the drag force F we need to know the value of S0 The force S0 can be determined from the condition of sufficient frictional force to transmit force at the path:

S3 ≤ S0.efα

F = S3 - S0 ≤ S0.(efα - 1)

With: α: angle of embrace of the tape on tang , α =π

f: coefficient of friction between the tape and the tang (0.2 ~ 0.4) Choose f = 0.4