Mar 25, 2020
What are the three methods of workpiece clamping?
1. Clamp in the fixture;
2. Directly find the correct clamping;
3. Straighten the alignment clamp
What does a process system include?
Machine tools, workpieces, fixtures, tools
What is the composition of the machining process?
Roughing, semi-finishing, finishing, super finishing
How are benchmarks classified?
What does the machining accuracy include?
1. dimensional accuracy 2. shape accuracy 3. position accuracy
What are the original errors that occur during processing?
Principle error, positioning error, adjustment error, tool error, fixture error, machine tool spindle rotation error, machine tool guide error, machine tool transmission error, process system force deformation, process system thermal deformation, tool wear, measurement error, workpiece residual stress caused Error
How does the stiffness of the process system affect machining accuracy (machine tool deformation, workpiece deformation)?
1. The workpiece shape error caused by the change of the position of the cutting force application point 2. The machining error caused by the change of the cutting force 3. The machining error caused by the clamping force and gravity 4. The influence of the driving force and inertia force on the machining accuracy
How are processing errors classified? Which errors are constant errors? Which errors are variable-valued systematic errors? Which errors are random errors
System error: (constant system error, variable value system error) random error
Constant value system error: Machining error caused by machining principle error, machine tool, tool, fixture manufacturing error, force deformation of process system, etc.
Variable value system error: wear of props; tool, fixture, machine tool, etc. have thermal deformation error before thermal equilibrium
Random errors: copying of blank errors, positioning errors, tightening errors, multiple adjustment errors, deformation errors caused by residual stress
What are the ways to ensure and improve machining accuracy?
1. Error prevention technology: reasonable use of advanced technology and equipment to directly reduce the original error, transfer the original error, even the original error, equalize the original error
2. Error compensation technology: on-line detection, automatic matching of parts, active control of the determinant error factors
What does the machining surface geometry look like?
Geometric roughness, surface waviness, texture direction, surface defects
What are the physical and chemical properties of the surface layer material?
1. Cold work hardening of surface metal
2. Metallographic deformation of surface layer metal
3. Residual stress of surface layer metal
Try to analyze the factors that affect the roughness of the cutting surface?
The roughness value is determined by the height of the cutting residual area. The main factor: the cutting edge arc radius, the main declination angle, and the sub-angle deflection feed amount. Quality
Try to analyze the factors that affect the surface roughness of the grinding process?
1. Geometric factors: the effect of grinding amount on surface roughness
2.Effect of grinding wheel size and dressing on surface roughness
3. The influence of physical factors: plastic deformation of the surface metal: the amount of grinding