This paper proposes the effect of various toolpath methods for semi-finish operation on the machining time when milling 3D surfaces. An optimal selection of toolpath can cause remaking in the advance of time.
ISSN: 1859-2171 TNU Journal of Science and Technology 192(16): 67 - 71 INFLUENCE OF TOOL PATH STRATEGIES ON MACHINING TIME USING THE BALL NOSE TOOL WHEN MILLING 3D SURFACES Nhu Nguyet Vu* , Minh Tuan Ngo, Thuan Nguyen University of Technology - TNU ABSTRACT In machining flexible surfaces, machining processing costs can be reduced by several factors such as removed material workpieces, the choice of suitable cutting tools, optimal coolant and saving machining time This paper proposes the effect of various toolpath methods for semi-finish operation on the machining time when milling 3D surfaces An optimal selection of toolpath can cause remaking in the advance of time The analysis and comparison of different toolpath strategies in 3D milling are investigated in order to choose the best strategies in different situations The NX software, known as computer- aided manufacturing software, was used to evaluate the different toolpath strategies of three-axis milling The experimental results clearly show the influence of the cutter path strategies on machining times and selecting the optimal strategy was based on a CAM software Keywords: Tool path strategy, machining time, three- axis milling, 3D surface, CAM software Received: 29/8/2018; Revised: 13/10/2018; Approved: 28/12/2018 ẢNH HƯỞNG CỦA PHƯƠNG PHÁP CHẠY DAO ĐẾN THỜI GIAN GIA CÔNG KHI PHAY BỀ MẶT 3D SỬ DỤNG DAO PHAY ĐẦU CẦU Vũ Như Nguyệt*, Ngô Minh Tuấn, Nguyễn Thuận Trường Đại học Kỹ thuật Cơng nghiệp - ĐH Thái Ngun TĨM TẮT Trong gia cơng bề mặt phức tạp, chi phí q trình gia cơng giảm vài cách lượng vật liệu phôi hớt đi, lựa chọn dụng cụ cắt phù hợp, tiết kiệm dung dịch làm mát hay giảm thời gian gia công máy công cụ Bài báo đề cập đến hướng nghiên cứu ảnh hưởng số kiểu chạy dao phay bán tinh bề mặt 3D đến thời gian gia cơng Việc chọn đường chạy dao tối ưu dẫn đến lợi ích định cho thời gian gia cơng Sự phân tích so sánh phương pháp chạy dao khác phay mặt cong đánh giá để chọn cách thức chạy dao tốt nghiên cứu Phần mềm NX, biết phần mềm trợ giúp cho trình gia công máy công cụ, chọn để sử dụng mô so sánh khác kiểu đường chạy dao lập trình phay trục Kết thí nghiệm rõ ảnh hưởng cách thức chạy dao đến thời gian gia công việc chọn phương pháp gia công tối ưu phần mềm CAM Từ khóa: Phương thức chạy dao, thời gian gia công, phay trục, mặt cong 3D, phần mềm CAM Ngày nhận bài: 21/9/2018; Hoàn thiện: 27/10/2018; Duyệt dăng: 28/12/2018 (*) Corresponding author: vunhunguyet@tnut.edu.vn; Tel 0985960902 http://jst.tnu.edu.vn; Email: jst@tnu.edu.vn 67 Vu Nhu Nguyet et al TNU Journal of Science and Technology INTRODUCTION In the milling processes using the CAD/CAM technology, the selection tool path strategy extremely affects the quality of machine parts and the machining time By using a CAM software, the tool path and the way removing the material in the milling process can be simulated Afterwards, having the verified accuracy as well as the efficiency of the operations, the CNC program is exported by input of the milling machine to produce the parts without confronting any problem of any kind This, indeed, is another privilege of using computers in the production process, i.e., reducing machine time as well as reducing the production costs The less the machining time, the cost of products decreases much In recent years, several studies have been conducted in optimizing the machining time parameters and the tool path strategies In 2016, Mebrahitom A studied the optimizing the tool path strategies and machining parameters for milling operations of a rectangular cavities [1] In 2017, Bagci analysed the effect of tool path strategies on dynamic tool deflection, cutting forces, machining time, effective cutter diameter, cutter/workpiece engagement area, instantaneous material removal rate and machining errors in rough machining of a sculptured surface [2] Adriano Fagali de Souza focused on improvements on the choice of milling strategy in machining research and application [3] Analysis of programming and simulations of manufacturing process in CNC milling machine applying through Mastercam software (CAD/CAM) were proposed by P V Savalia and Prof M M Chandrala [4] The effects of cutter orientation used to machine curvature surface of thin aluminum parts (7075) with a 3-axis ball end-milling were investigated to improve geometric accuracy, surface integrity, and the most 68 192(16): 67 - 71 optimal range of machining forces by B Jabbaripour [5] A computation scheme that generates optimized tool path for five-axis flank milling of ruled surface was studied by Ping-Han Wu [6] H Perez proposed a machining strategy providing a cutting mode for the tool during a particular machining operation, determining the axial and radial depth of cut and the recommended trajectories for the cutting tool [7] It can be seen that, several studies have been investigated to study the tool path strategies However, influence of tool path strategies on machining time using the ball nose tool when milling 3D surfaces has not yet been reported This paper presents the effect of various milling strategies for semi- finish ball end milling computermouse surface on the machining time SIMULATION CUTTING OPERATIONS WITH DIFFERENT TOOL PATH TYPES IN A CAD/CAM SOFTWARE The models and drawings created by the designer have to undergo other processes to get to the finished product Fig.1 shows the flow chart of the design and manufacturing process using a CAD/CAM software Figure Design and manufacturing process using a CAD/CAM software http://jst.tnu.edu.vn; Email: jst@tnu.edu.vn Vu Nhu Nguyet et al TNU Journal of Science and Technology The process widely and commonly used to generate program codes for CNC machines to mill the component This technological development reduces the amount of human intervention in creating CNC codes After analyzing the geometry part, parent group objects are created to store manufacturing information such as tool data, feed rates, and tolerances, etc The data is specified in the parent group object in inherited by operations that are listed under that particular parent group object Usually, there are four types of parent group objects, such as geometry, method, program and tool Before choosing operation types, numerous items must be taken into consideration for achieving the desired output In this work, the computer mouse surface is a complex surface and is designed on NX software as shown in figure After creating the machining environment, the tool paths are created and generated for the cover housing Most of the CAM systems would provide for different area clearance options in which the user can choose considering the type of geometry In NX software, there are types of tool path strategies, such as the follow part, follow periphery, trochoidal, zig and zig zag The follow part is the most optimal strategy where the tool path manipulates depending on the part geometry If there are cores and cavities in the part, the software will intelligently consider them to remove the materials in an optimal way This kind of treatment is widely used for roughing operations The follow periphery takes the path which depends on upon the periphery profile For example, the outer periphery of our part is rectangular So the tool path will be generated such that it gradually cuts the material from outside to inside with the step over value This option is mostly used for projections and cores rather than cavities The profile takes the cut only along the profile of the part geometry It is used for semifinishing or finishing operations In the trochoidal method, the cutter is huge and is http://jst.tnu.edu.vn; Email: jst@tnu.edu.vn 192(16): 67 - 71 used for removing a large amount of material The bulk of material is removed by gradual trochoidal movements The depth of cut will be very high for this strategy Figure The computer mouse surface model in NX software Figure The tool path strategies for the semifinish milling process in NX software a) Follow part b) Zigzag c)Follow periphery d) Zig 69 Vu Nhu Nguyet et al TNU Journal of Science and Technology The zig takes a linear path in only one direction of flow In the zig zag method, the tool takes a zigzag path at every level of depth It decreases machining time by reducing amount of air cutting time (idle running) The climb and conventional cuts alternate These tool path types were used in this research In this research, the free-form model was designed, and the machining operation was created in NX software as shown in figure In this figure, the machining operations were designed with four tool path types in order to analyze the influence of the tool path strategies on machining time ANALYSIS RESULTS After conducting simulation for different tool path types, the values of the machining time and the length of the NC program were calculated and recorded Table shows numerical values of the parameters for each of these strategies in the experimental tests Table The numerical values of the parameters for each of these strategies in the experimental tests PVD when milling computer mouse surface C45 workpieces material Experimental conditions were presented in table The figure of actual operation of semi- finish mouse computer surface milling in Lab (Figure 5) Figure The machining time and the length of NC codes for the semi- finish milling process in NX software The experiment was performed in the Laboratory of Thai Nguyen University of Technology Table Experimental conditions Cutting tool Design of cutting tool Tool diameter d (mm) Flute (s) Helix angle λ (◦) Angle of rake γ (◦) Coating The results are also shown in figure Regarding the simulated machining times, the shortest machining time belonged to the follow periphery strategy was 881 seconds because this can be found in the lowest movements of toward the safe level in Z direction and tool’s idle movement The longest machining time, that is 218943 seconds with the zig strategy because of too many the non-cutting motions of the cutting tool EXPERIMENTAL WORKS In this experimental study, the applied milling tool was a ball nose mill The tool had a diameter of mm and two insert flutes made from micro carbide and coated multi-layered 70 192(16): 67 - 71 Workpiece material Hardness (HRC) Binder Machine tool Table Right/Left Table Longitudinal Spindle Taper Maximum Speed Number of Tools Travel (X Axis) Travel (Y Axis) Travel (Z Axis) P3202- WXM25 Ball nose mill mm 15 −14 Carbide with multilayered PVD C45 40 - 42 0,42% C; );15 % Si; 0,5% Mn; 0,025% P; 0,025% S; 0,2% Cr Mazak VCS 530C 1300 mm / 51.180 in 550 mm / 21.650 in 40 12000 rpm 30 1050 mm / 41.34 in 530 mm / 20.87 in 510 mm / 20.08 in http://jst.tnu.edu.vn; Email: jst@tnu.edu.vn Vu Nhu Nguyet et al TNU Journal of Science and Technology Table Cutting parameters and machining time Tool path strategies Zig Zigzag Follow periphery Follow part Pick feed (mm) Machining time 0.05 0.05 1h21'15" 56'09" The experimental work shows that the machining time when milling using follow periphery tool path strategy is the smallest prepared with three different methods, it is mean that the optimal strategy for each geometry model was selected based on simulation in a CAM software ACKNOWLEDGMENT 160 160 Feed per tooth (mm/ tooth) 0.02 0.02 160 0.02 0.05 55'39" 160 0.02 0.05 1h21'13'' Cutting speed (m/ min) 192(16): 67 - 71 The work described in this paper has been supported by Thai Nguyen University of Technology for ĐH2016-TN02-09 project REFERENCES a) b) Figure Some images of experiment a) Mazak VCS 530C b) The part after miling CONCLUSION This study investigated and compared the effect of three- axis tool path strategies on the free-form surface as the simulation of machining operation in NX software Several remarks can be outlined as follows: - The optimal tool path strategy for computermouse surface is the follow periphery method in three- axis milling aided by using NX software because the length of NC code is the smallest compared with others - The simulation shows that the machining time is speedy at the convex surface for the semi- finish milling when choosing the follow periphery method of the toolpath http://jst.tnu.edu.vn; Email: jst@tnu.edu.vn Mebrahitom A., Rizuan D., M Azmir and M Nassif (2016), “Effect of High-speed Milling tool path strategies on the surface roughness of Stavax ESR mold insert machining, 114, pp 012006 Bagci, Eyup; Yüncüoğlu, Ercüment U, (2017) The Effects of Milling Strategies on Forces, Material Removal Rate, Tool Deflection, and Surface Errors for the Rough Machining of Complex Surfaces, Vol 63 Issue 11, p643-656 14p Adriano Fagali de Souza, Ernesto Berkenbrock, Anselmo Eduardo Diniz, Alessandro Roger Rodrigues, 2015 Influences of the tool path strategy on the machining force when milling free form geometries with a ballend cutting tool Journal of the Brazilian Society of Mechanical Sciences and Engineering, Volume 37, Issue 2, pp 675–687 P V Savalia , Prof M M Chandrala, 2017 Generating Point Cloud Data by Using CMM for Surface Modeling and Select Proper Cutting Method to Optimize Total Machining Time Themed Section: Engineering and Technology, Volume 3, Issue 2, Print ISSN: 2395-1990,| Online ISSN : 2394-4099, p826- 832 Toh C A study of the effects of cutter path strategies and orientations in milling Journal of Materials Processing Technology 2004 Oct; 152(3), pp 346–356 Wu, P.H., Y.W Li, C.H Chu, 2008 Optimized tool path generation based on dynamic programming for five-axis flank milling of rule surface Machine Tools and Manufacture., 48(11), pp 1224-1233 Perez H, Diez E, Perez J, Vizan A Analysis of machining strategies for peripheral milling Procedia Engineering 2013 Sep; 63, pp 573-581 71 ... cutting tool [7] It can be seen that, several studies have been investigated to study the tool path strategies However, influence of tool path strategies on machining time using the ball nose tool when. .. figure, the machining operations were designed with four tool path types in order to analyze the influence of the tool path strategies on machining time ANALYSIS RESULTS After conducting simulation... optimizing the machining time parameters and the tool path strategies In 2016, Mebrahitom A studied the optimizing the tool path strategies and machining parameters for milling operations of a rectangular