Complete Works of Machining Technology Foundation! The interview questions are coming

How much do you know about the processing technology after so long? Let’s review it together today.
1. What are the three methods of workpiece clamping?

{1. clamping in fixture; 2. direct alignment clamp; 3. scribed alignment clamp}

2. What are the contents of the process system?

{Machine Tools, Workpieces, Fixtures, Tools}

3. Composition of Machining Process?

{Rough, Semi-Finish, Finish, Ultra-Finish}

4. How to classify benchmarks?

Design Benchmark 2. Process Benchmark: Procedure, Measurement, Assembly, Location: (Original, Additional): (Rough Benchmark, Precise Benchmark)] ____________

What does the processing accuracy include?

{1. Dimension accuracy 2. Shape accuracy 3. Position accuracy}

5. What are the original errors in the process of processing?

{Principle error, Positioning error, Adjustment error, Tool error, Fixture error, Machine spindle rotation error, Machine tool guide error, Machine tool transmission error, Mechanical deformation of process system, Thermal deformation of process system, Tool wear, Measurement error, Error caused by residual stress of workpiece}

6. The influence of stiffness of process system on machining accuracy (machine tool deformation, workpiece deformation)?

{1. Workpiece shape error caused by change of position of cutting force action point 2. Machining error caused by change of cutting force size 3. Machining error caused by clamping force and gravity 4. Effect 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 mainly includes relative displacement errors of tool and workpiece in error sensitive direction caused by the guide 2. Radial circular runout of spindle, axial circular runout and tilt angle swing}

8. What is the phenomenon of “error duplication”? What is the error mapping coefficient? What measures can be taken to reduce error reproduction?

Because of the change of the error and deformation of the process system, the part of the blank error is reflected in the workpiece. Measures include increasing the number of cutters, increasing the stiffness of the process system, reducing the feed and improving the precision of the blank.

9. Error analysis of machine tool transmission chain? Measures to reduce transmission error of transmission chain?

Error analysis: that is to say, the angle error of the end element of the transmission chain is measured by the angle error

Measures: 1. The smaller the number of transmission chains, the shorter the transmission chains, and the smaller the_, the higher the accuracy. 2. The smaller the transmission ratio I, especially the smaller the transmission ratio at both ends. 3. Because the error of the end parts in the transmission parts has the greatest impact, it should be as accurate as possible. 4. Using correction device}

10. How to classify machining errors? Which errors belong to constant errors? Which errors belong to variable system errors? Which errors belong to random errors

Systematic Error: (Constant Systematic Error Variable Systematic Error) Random Error

Constant System Errors: Machining Principle Errors, Manufacturing Errors of Machine Tools, Tools, Fixtures, Stress and Deformation of Process Systems, etc.

Variable system error: wear of props; thermal deformation error of tools, fixtures, machine tools before thermal balance

Random error: copy of blank error, positioning error, tightening error, error of multiple adjustments, deformation error caused by residual stress}

11. What are the ways to ensure and improve the processing accuracy?

Error Prevention Technology: Rationally Using Advanced Technology and Equipment to Reduce the Initial Error Transfer, the Initial Error Transfer, the Initial Error Homogenization and the Initial Error Homogenization

2. Error Compensation Technology: On-line Inspection of the Error Factor in Active Control of Automatic Matching of Couple Parts

12. What are the contents of machined surface geometry?

{Geometric roughness, surface waviness, texture direction, surface defects}

13. What are the physical and chemical properties of surface materials?

Cryogenic Hardening of Surface Metal 2. Metallographic Deformation of Surface Metal 3. Residual Stress of Surface Metal}

14. Trial analysis of factors affecting the surface roughness of cutting?

Roughness value is determined by: the main factor of the height of the cutting residual area: the secondary factor of the feed rate of the main deviation angle and the vice-deviation angle of the tool tip arc radius: the increase of cutting speed, the appropriate choice of cutting fluid, the appropriate increase of the rake angle of the tool, and the improvement of the grinding quality of the tool.)

15. Trial analysis of factors affecting surface roughness in grinding?

Geometric factors: the influence of grinding parameters on surface roughness 2. The influence of grinding wheel size and grinding wheel dressing on surface roughness 2. The influence of physical factors: plastic deformation of surface metal: the choice of grinding parameters for grinding wheel}

16. Try to analyze the factors affecting the cold work hardening of the machined surface.

{The influence of cutting parameters on tool geometry and material properties}

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 phase transformation temperature of quenched steel, but has exceeded the transformation temperature of martensite, the martensite on the surface of the workpiece will be transformed into a tempered structure with lower hardness for quenching. If the temperature in the grinding zone exceeds the transformation temperature, coupled with the cooling effect of coolant, the surface metal will have a secondary quenching martensite structure with hardness higher than the original martensite. In his lower layer, annealing of tempered structure with hardness lower than that of original tempered martensite occurs because of slower cooling. If the temperature in the grinding zone exceeds the phase transformation temperature and there is no coolant in the grinding process, annealing structure will appear on the surface metal and the hardness of the surface metal will decrease sharply.

18. Prevention and Control of Machining Vibration

Eliminating or weakening the conditions for vibration in machining; improving the dynamic characteristics of the process system and improving the stability of the process system