xiehe model

10 knowledge that CNC machining needs to master

CNC processing manufacturers introduce 10 knowledge that CNC processing needs to master.

1. Influence on cutting temperature: cutting speed, feed rate, tool retraction amount;

Influence on cutting force: retraction amount, feed amount, cutting speed;

Influence on tool durability: cutting speed, feed speed, and retraction amount.

2. When the amount of knife return doubles, the cutting force doubles;

When the feed rate is doubled, the cutting force will increase by about 70%;

When the cutting speed doubles, the cutting force gradually decreases;

In other words, if G99 is used, the cutting speed will increase, but the cutting force will not change much.

3. The cutting force can be judged according to the iron filings, and whether the cutting temperature is within the normal range.

4. When the actual measured value X and the diameter Y of the drawing are greater than 0.8, the turning tool with a concave arc in the car and a secondary deflection angle of 52 degrees (that is, the blades we commonly use are turning tools with a main deflection angle of 35 degrees and 93 degrees) will be turned from the car The R on the top may wipe the knife at the starting point.

5. The temperature represented by the color of iron filings:

White is less than 200 degrees

Yellow 220-240 degrees

Dark blue 290 degrees

Blue 320-350 degrees

Purplish black greater than 500 degrees

Red is greater than 800 degrees

6. The external thread is generally 1.3P, and the internal thread is 1.08P.

7. Thread speed S1200/thread pitch*safety factor (generally 0.8).

8. Manual tool nose R compensation formula: chamfering from bottom to top: Z=R*(1-tan(a/2))X=R(1-tan(a/2))*tan(a) from top And the bottom chamfer can be changed from a minus sign to a plus sign.

9. For every 0.05 increase in feed rate, reduce the speed by 50-80 rpm. This is because lower speed means less tool wear and a slower increase in cutting force, which compensates for the increase in cutting force caused by increased feed.

10. The influence of cutting speed and cutting force on the cutting tool is very important. The relationship between cutting speed and cutting force: the faster the cutting speed, the feed remains constant, and the cutting force decreases slowly. The higher it is, when the cutting force and internal stress are too high for the blade to bear, it will fall into an avalanche (of course, there are also reasons for the decrease in stress and hardness due to temperature changes).