1. What are the three methods of workpiece clamping?
{1. Clamping in the fixture;2. Go straight to the suit clip;3. Underline and find the formal folder}
2. What does the processing system include?
{machine tool, workpiece, fixture, tool}
3, the composition of the machining process?
{roughing, semi-finishing, finishing, superfinishing}
4. How to classify the benchmark?
2. Process reference: process, measurement, assembly, positioning: (original, additional) : (rough reference, fine reference)}
What does machining accuracy include?
{1. Dimensional accuracy 2. Shape accuracy 3. Position accuracy}
5. What are the original errors in processing?
{principle error · positioning error · adjustment error · tool error · fixture error · spindle rotary error · guide error · machine tool transmission error · process system stress deformation · process system heat deformation · tool wear · measurement error · error caused by residual stress of the workpiece}
6. Influence of process system stiffness on machining accuracy (machine tool deformation, workpiece deformation)?
{1. Workpiece shape error caused by variation of cutting force position; 2. Machining error caused by variation of cutting force; 3. Machining error caused by clamping force and gravity; 4.
7, machine guide error and spindle rotation error include what?
{1. The guide mainly includes the relative displacement error between the tool and the workpiece in the error sensitive direction caused by the guide.
8. What is the phenomenon of "error mapping"?What is the error mapping coefficient? What measures are in place to reduce error replications?
Due to the change of process system error and deformation, the blank error part is reflected on the workpiece. Measures: increase the number of cutting, increase the process system stiffness, reduce the feed, improve the blank precision
9. Machine tool transmission chain transmission error analysis?Measures to reduce chain transmission errors?
{error analysis: it is using the element at the end of the transmission chain Δ phi Angle error measure
Measures: 1. The less quantity of transmission chain and transmission chain is short, the smaller Δ phi, the precision is higher (2) the smaller the transmission ratio I, especially at the end of the first small on both ends of the transmission ratio, (3) because of the influence of transmission error of the end in a biggest, therefore should make it as accurate as possible 4. Use correction device}
10. How to classify machining errors? What errors are constant errors? What errors are variational systematic errors? Which errors are random errors
{systematic error :(constant systematic error variable systematic error) random error
Constant systematic error: machining error caused by machining principle error, manufacturing error of machine tool, tool, and fixture, stress deformation of the processing system, etc
The systematic error of variable value: wear of props; Tools, fixtures, machine tools, etc. Obtain thermal deformation error before the thermal balance
Random error: a copy of blank error, positioning error, tightening error, multiple adjustment error, deformation error caused by residual stress
11. What are the ways to ensure and improve machining accuracy?
{1. Error prevention technology: rationally adopt advanced technology and equipment, directly reduce original error, transfer original error, average inferior original error, and homogenize original error
2. Error compensation technology: online detection, automatic grinding of the couple, positive control of decisive error factors}
12. What does surface geometry include?
{geometric roughness, surface waviness, texture direction, surface defects}
13. What are the physical and chemical properties of surface materials?
{1. Cold hardening of surface metal 2. Metallographic deformation of surface metal 3. Residual stress of surface metal}
14. Try to analyze the factors affecting the surface roughness in cutting.
{Roughness value by Height of cutting residual area main factor: radius of tooltip main deflection Angle auxiliary deflection Angle feed Secondary factor: increase of cutting speed Appropriate selection of cutting fluid appropriate increase of cutting tool front Angle to improve the grinding quality of the tool
15. Try to analyze the factors affecting the surface roughness of grinding.
{1. Geometric factors: influence of grinding amount on surface roughness; 2. Influence of grinding wheel grain size and grinding wheel dressing on surface roughness; 2.
16. Try to analyze the factors affecting the cold hardening of cutting surfaces.
{the influence of cutting parameters on the Influence of tool geometry on the influence of machining Material properties}
17. What is grinding temper burn? What is a grinding quenching burn? What is grinding annealing burn?
{tempering: if the grinding zone temperature does not exceed the phase transition temperature of hardened steel, but exceeds the martensitic transformation temperature, the surface of metal martensite will translate into lower hardness, quenching tempering organization if grinding zone temperature over the phase change temperature, and cooling liquid cooling, can appear on the surface of the metal secondary quenching martensite structure, hardness is higher than the original martensite;In his lower layer, due to the slow cooling, tempering microstructure annealing with a hardness lower than the original tempering martensite appears: if the temperature of grinding zone exceeds the phase transition temperature and there is no coolant during grinding, surface metal will appear annealed microstructure and surface metal hardness will drop sharply.
Prevention and control of machining vibration
{Eliminate or weaken the conditions that produce machining vibration; To improve the dynamic characteristics of the processing system to improve the stability of the processing system using a variety of vibration elimination and reduction devices
19. Briefly describe the main differences and application occasions of the machining process card, process card, and process card.
{process card: Single small batch machining process card: medium batch machining Process card: a large number of mass production type requires strict and meticulous organization work}
20. Rough benchmark selection principle?Fine benchmark selection principle?
{Coarse datum: 1. Principle of ensuring mutual position requirements; 2.2. Principle of ensuring reasonable distribution of machining allowance on machining surface;3. Principle of facilitating workpiece clamping;4. The principle of fine datum generally not to be reused: 1. The principle of coincidence of datum; 2.2. Uniform benchmark principle;3. Mutual benchmark principle;4. Self-benchmarking principle;5. Principle of easy clamping
21. What are the principles of process sequencing?
{1. First process the base level, then process other surfaces;2. In half of the cases, the surface is processed first and the hole is processed later;3. The primary surface is processed first, and the second surface is processed later;4. First, arrange a rough machining process, then arrange the finishing process.
22. How to divide the processing stage? What are the advantages of dividing the processing stage?
1. Rough machining stage · semi-finishing stage · Precision finishing stage · Precision finishing stage can ensure sufficient time to eliminate thermal deformation and residual stress caused by rough machining, so as to improve subsequent machining accuracy. In addition, in the rough machining stage found blank defects do not have to carry out the next processing stage of processing, to avoid waste. In addition, the equipment can be reasonably used. Low-precision machine tools are used for rough machining and precision machine tools are specially used for finishing to maintain the precision level of precision machine tools.