1. What are the three methods of workpiece clamping?
{1. Clamping in the fixture; 2. Directly aligning the fixture; 3. Marking to align the fixture}
2. What does the process system include? {Machine tools, workpieces, fixtures, cutting tools}
3. What are the components of the machining process? {Rough machining, semi precision machining, precision machining, ultra precision machining}
4. How are benchmarks classified? {1. Design benchmark 2. Process benchmark: Process, measurement, assembly, positioning: (original, additional): (rough benchmark, precision benchmark)} What content does machining accuracy include? {1. Dimensional accuracy 2. Shape accuracy 3. Position accuracy}
5. What are the original errors that occur during the processing? {Principle error, positioning error, adjustment error, tool error, fixture error, spindle rotation error of machine tool, guide rail guidance error of machine tool, transmission error of machine tool, force deformation of process system, thermal deformation of process system, tool wear, measurement error, errors caused by residual stress of workpiece.}
6. How does the stiffness of the process system affect machining accuracy (machine tool deformation, workpiece deformation)? 1. Shape error of the workpiece caused by changes in the position of the cutting force application point 2. Processing error caused by changes in the magnitude of cutting force 3. Processing error caused by clamping force and gravity 4. Influence of transmission force and inertia force on machining accuracy
7. What are the guiding errors and spindle rotation errors of machine tool guides? 1. The guide rail mainly includes the relative displacement error between the tool and the workpiece in the error sensitive direction caused by the guide rail. 2. The radial circular runout, axial circular runout, and inclination angle oscillation of the main shaft
8. What is the phenomenon of "error reflection"? What is the error reflection coefficient? What measures are taken to reduce error remapping? {Due to changes in the deformation caused by errors in the process system, some of the errors in the blank are reflected on the workpiece. Measures include increasing the number of tool passes, increasing the stiffness of the process system, reducing the feed rate, and improving the accuracy of the blank}
9. Error analysis of machine tool transmission chain transmission? Measures to reduce transmission chain errors? Error analysis: that is, using the angle error of the end components of the transmission chain Δφ To measure measures: 1. The fewer the number of transmission chains, the shorter the transmission chain, Δφ The smaller it is, the higher the accuracy The smaller the transmission ratio i, especially the transmission ratio at the beginning and end, the more accurate it should be as much as possible. 3. Due to the greatest impact of error on the end part of the transmission component, it should be made as accurate as possible. 4. Use a calibration device}
10. How to classify processing errors? What errors belong to constant value errors? What errors belong to variable system errors? Which errors belong to random errors

What are the ways to ensure and improve machining accuracy? 1. Error prevention technology: Reasonably using advanced processes and equipment to directly reduce the transfer of original errors. 2. Error compensation technology: online detection of automatic grinding of even parts. Actively controlling the error factors that play a decisive role in determining the original error
12. What does the geometric morphology of the machined surface include? {Geometric roughness, surface waviness, texture direction, surface defects}
13. What are the physical and chemical properties of surface layer materials? {1. Cold work hardening of surface layer metal 2. Metallographic deformation of surface layer metal 3. Residual stress of surface layer metal}
14. Analyze the factors that affect the surface roughness of cutting machining? {The roughness value is determined by: the height of the cutting residual area. The main factor is the radius of the tool tip arc, the main deviation angle, the secondary deviation angle, and the feed rate. The secondary factor is the increase in cutting speed. The appropriate selection of cutting fluid increases the leading angle of the tool to improve the grinding quality of the tool.}
15. Analyze the factors that affect the surface roughness of grinding machining? {1. Geometric factors: The influence of grinding amount on surface roughness. 2. The influence of grinding wheel particle size and grinding wheel dressing on surface roughness. 2. The influence of physical factors: Plastic deformation of surface layer metal: Selection of grinding amount and grinding wheel}
16. Analyze the factors that affect the cold work hardening of cutting surfaces? The influence of cutting parameters on the geometric shape of cutting tools and the performance of machining materials
17. What is grinding tempering burn? What is grinding quenching burn? What is grinding annealing burn? {Tempering: If the temperature in the grinding zone does not exceed the transformation temperature of the quenched steel, but has exceeded the transformation temperature of martensite, the martensite on the surface metal of the workpiece will be transformed into a lower hardness tempered structure. Quenching: If the temperature in the grinding zone exceeds the transformation temperature, combined with the cooling effect of the coolant, the surface metal will form a secondary quenched martensite structure, with a higher hardness than the original martensite. In its lower layer, due to slow cooling, it will appear Annealing of tempered microstructure with lower hardness than the original tempered martensite: If the temperature in the grinding area exceeds the phase transition temperature and there is no coolant during the grinding process, the surface metal will exhibit annealed microstructure, and the hardness of the surface metal will sharply decrease
18. Prevention and Control of Mechanical Processing Vibration {Eliminating or Weakening the Conditions for Generating Mechanical Processing Vibration; Improving the Dynamic Characteristics of the Process System and Enhancing the Stability of the Process System Using Various Vibration Reduction Devices}
19. Briefly describe the main differences and application scenarios of mechanical processing process cards, process cards, and process cards. {Process card: Single piece small batch production using ordinary processing methods; Mechanical processing process card: Medium batch production process card: Large quantity production type requires strict and meticulous organization of work}
*20. Rough benchmark selection principle? Principle of selecting precise benchmarks? {Coarse benchmark: 1. The principle of ensuring mutual position requirements; 2. The principle of ensuring reasonable distribution of machining allowances on the machining surface; 3. The principle of facilitating workpiece clamping; 4. The principle of generally not reusing coarse benchmarks. Precision benchmark: 1. The principle of overlapping benchmarks; 2. The principle of unified benchmarks; 3. The principle of mutual benchmarks; 4. The principle of self benchmarks; 5. The principle of easy clamping.}
21. What are the principles for arranging the process sequence? {1. Process the reference surface first before processing other surfaces; 2. In half cases, process the surface first before processing the hole; 3. Process the main surface first before processing the secondary surface; 4. Arrange the rough machining process first, and then arrange the fine machining process}
22. How to divide the processing stages? What are the benefits of dividing processing stages?
{Processing stage division: 1. Rough machining stage, semi precision machining stage, precision machining stage, and precision finishing stage can ensure sufficient time to eliminate thermal deformation and residual stress generated by rough machining, so as to improve subsequent processing accuracy. In addition, when defects are found in the rough machining stage, there is no need to proceed to the next processing stage to avoid waste. In addition, equipment can be used reasonably, and low precision machine tools can be used for rough machining Precision machining machines are specifically designed for precision machining to maintain the precision level of precision machines; Reasonably arranging human resources, high-tech workers specializing in precision and ultra precision machining, is very important for ensuring product quality and improving process level
23. What are the factors that affect process margin? {1. Dimensional tolerance Ta of the previous process; 2. Surface roughness Ry and surface defect depth Ha generated by the previous process; 3. Space error left by the previous process}
24. What are the components of the working hour quota? {T quota=T single piece time+t quasi final time/n number of pieces}
25. What are the process ways to improve productivity? {1. Shorten the basic time; 2. Reduce the overlap between auxiliary time and basic time; 3. Reduce the time for arranging work sites; 4. Reduce preparation and completion time}
26. What are the main contents of the assembly process regulations? 1. Analyze product drawings, divide assembly units, determine assembly methods; 2. Draft assembly sequences, divide assembly processes; 3. Calculate assembly time quotas; 4. Determine assembly technical requirements, quality inspection methods, and inspection tools for each process; 5. Determine the transportation method of assembly components and the required equipment and tools; 6. Select and design the tools, fixtures, and special equipment required in the assembly process
27. What should be considered for the assembly process of machine structures? 1. The machine structure should be able to be divided into independent assembly units; 2. Reduce repair and mechanical processing during assembly; 3. The machine structure should be easy to assemble and disassemble
28. What does assembly accuracy generally include? {1. Mutual position accuracy; 2. Mutual motion accuracy; 3. Mutual fit accuracy}
29. What issues should be noted when searching for assembly dimension chains? 1. The assembly dimension chain should be simplified as necessary; 2. The "one piece, one ring" composed of the assembly dimension chain; 3. The "directionality" of the assembly dimension chain should be supervised according to different directions when there are assembly accuracy requirements in different positions and directions within the same assembly structure
What are the methods to ensure assembly accuracy? How are the applications of various methods? {1. Exchange method; 2. Selection method; 3. Repair method; 4. Adjustment method}
31. Composition and function of machine tool fixtures? Machine tool fixture is a device used to clamp workpieces on a machine tool. Its function is to ensure that the workpiece has a correct position relative to the machine tool and the tool, and to maintain this position during the machining process. The components include: 1. Positioning element or device. 2. Tool guide element or device. 3. Clamping element or device. 4. Connecting element. 5. Clamping specific components. 6. Other components or devices. Main functions: 1. Ensure machining quality. 2. Improve production efficiency. 3. Expand the range of machine tool technology. 4 Reduce the labor intensity of workers to ensure production safety
32. How are machine tool fixtures classified according to their usage range? {1. Universal fixture 2. Special fixture 3. Adjustable fixture and group fixture 4. Combination fixture and random fixture}
33. What are the commonly used positioning components for workpiece positioning in a plane? And analyze the situation of eliminating degrees of freedom. {The workpiece is positioned in a plane. Common positioning components include 1. fixed support 2. adjustable support 3. self positioning support 4. auxiliary support}
34. What are the commonly used positioning components for workpiece positioning with cylindrical holes? And analyze the situation of eliminating degrees of freedom. {The workpiece is positioned with a cylindrical hole. Common positioning components include 1 spindle and 2 positioning pins}
35. What are the commonly used positioning components for locating the outer circular surface of the workpiece? And analyze the situation of eliminating degrees of freedom. {Surface positioning on the outer circular surface of the workpiece. Common positioning components include V-shaped blocks}
36. How to design two pins when the workpiece is positioned with one side and two pins? 1. Determine the center distance dimension and tolerance between the two pins. 2. Determine the diameter and tolerance of the cylindrical pin. 3. Determine the width, diameter, and tolerance of the diamond pin
37. What are the two aspects of positioning error? What are the methods for calculating positioning errors?
{Two aspects of positioning error: 1. Positioning error caused by inaccurate production of positioning components on the workpiece positioning surface or fixture is called benchmark position error. 2. Positioning error caused by non coincidence of the workpiece's process benchmark and positioning benchmark is called benchmark non coincidence error.}
38. Basic requirements for the design of workpiece clamping devices. 1. During the clamping process, the correct position obtained during workpiece positioning should be maintained. 2. The clamping force should be appropriate, and the clamping mechanism should ensure that the workpiece does not become loose or vibrate during the processing, while avoiding inappropriate deformation and surface damage. The clamping mechanism should generally have a self-locking effect. 3. The clamping device should be easy to operate, labor-saving, and safe. 4. The complexity and automation level of the clamping device should be consistent with the production batch and production method Corresponding. The structural design should strive for simplicity, compactness, and use standardized components as much as possible
39. What are the three elements for determining clamping force? What are the principles for selecting the direction and point of application of clamping force? The selection of clamping force direction in the direction of magnitude should generally follow the following principles: 1. The direction of clamping force should be conducive to the accurate positioning of the workpiece without damaging the positioning. Therefore, it is generally required that the main clamping force should be perpendicular to the positioning surface. 2. The direction of clamping force should be as consistent as possible with the direction of the workpiece with high stiffness to reduce clamping deformation of the workpiece. 3. The direction of clamping force should be as close as possible to the cutting force and the direction of workpiece gravity To reduce the required clamping force, the general principle for selecting the clamping force application point is as follows: 1. The clamping force application point should be directly facing the supporting surface formed by the supporting element to ensure that the positioning of the workpiece that has been obtained remains unchanged. 2. The clamping force application point should be located in a rigid part to reduce the clamping deformation of the workpiece. 3. The clamping force application point should be as close as possible to the machining surface to reduce the flipping moment caused by the cutting force on the workpiece
What are the commonly used clamping mechanisms? Focus on analyzing and mastering the wedge clamping mechanism. {1. Wedge clamping structure 2. Spiral clamping structure 3. Eccentric clamping structure 4. Hinge clamping structure 5. Centering clamping structure 6. Linkage clamping structure}
How to classify drilling dies based on their structural characteristics? How to classify drill sleeves based on their structural characteristics? What are the specific connection methods between drilling templates and clamps? According to the common structural characteristics of drilling dies: 1. Fixed drilling dies 2. Rotary drilling dies 3. Flip drilling dies 4. Cover plate drilling dies 5. Sliding column drilling dies Classification of drilling die structural characteristics: 2. 1. Fixed drilling dies 2. Exchangeable drilling dies 3. Quick change drilling dies 4. Special drilling die drilling dies with clamp specific connection method: 3. Fixed hinge separation suspension type}
42. What are the characteristics of machine tool clamps in machining centers? 1. Simplification of functions 2. Complete positioning 3. Open structure 4. Quick readjustment