First, the surface roughness of ordinary high-speed precision machining
lathes does not meet the requirements. What are the reasons?
1. Problem analysis: I often see some novice lathe operators, when finishing small shaft or small hole parts, the speed has reached the limit speed of the machine tool. However, for technical reasons, the processing size is not directly in place, only a few threads or a dozen threads are in place. At this time, the tool is in the state of finishing. The results reached the size, but the surface roughness was poor.
2. The reason is that the alloy knife does not cut into the meat as smoothly as the kitchen knife in the process of processing. It cuts off the iron filings with a little squeeze. When the allowance is sufficient, it will be "cut off" smoothly due to the toughness of the material and the surface will become smooth. But once the allowance is too small, small iron filings by the effect of extrusion can not be removed smoothly, and the surface of the workpiece will be "picked".
3. Solution: The allowance reserved for finishing shall not be less than 0.35mm, otherwise the workpiece surface will be damaged due to insufficient deformation of iron filings. Improving the method of mastering dimensional accuracy becomes the key to solving this kind of problem!
Two. What is the reason for the excessive resistance in CNC metal processing and drilling? What's the reason for not drilling?
1. The chisel is too wide! The transverse edge at the drilling core is an important factor that directly affects the resistance of drilling. Generally, THE WIDTH OF THE TRANSVERSE BLADE CAN BE TRIMMED TO 1/3- 1/5 of THE ORIGINAL BEFORE it can be CUT INTO THE workpiece.
2. The back horn is too big! Many novice lathe workers are always afraid that the drill bit is not sharp enough, so the back of the drill bit is very inclined! The drill bit didn't work as smoothly as it was supposed to. Especially in the moment of cutting and reaming, it is easy to produce edge collapse, produce huge noise, and affect the image of the lathe. In addition, if the rear Angle is too large, it will produce a lot of vibration, which will cause serious vibration of the drill bit in the process of machining. For small and long bits, it is more likely to appear inexplicable fracture. Therefore, the rear Angle should not be too large. Generally, 6-8 degrees is appropriate, back shape as far as possible not to grind straight shape. Grinding into arc use better, and more durable.
3, chisel edge near the front corner to artificial amplification! The front Angle is ground close to the bit edge to reduce drilling resistance, making the cutting light and labor-saving.
4. The drill blade is asymmetrical and the center is offset! After roughening the drill tip, first correct the transverse edge to make the transverse edge shorter, which is more conducive to observing whether the drill core is centered.
Three, the turning tool keeps falling blade, how to solve this?
1. Problem analysis: After being turned by the turning tool, the iron filings pass through the front of the turning tool and curl and break along the shape of the front of the turning tool. Therefore, the shape of the turning tool front directly affects the deformation of iron filings.
2. If you carefully observe the deformation of the iron filings, it will be found that after the iron filings are cut, bending deformation will occur before the turning tool. As the iron filings pass through the chip chute, they begin to bend upward and then move toward the front of the turn!
3. Continuous iron filings usually begin to bend forward a long way after they have passed through the chip chute. However, after hitting the edge of the chip chute, the broken iron filings begin to violently flip forward, then strike the lower part of the tool and break! So, the key to breaking iron filings is how to force them over the edge of the chip chute and start folding forward!
4. Solution: Grind the cutting edge of the CNC machining workpiece to a position lower than the groove edge to form a high and low step shape. The curvature of the steps is minimized, creating a "chip block" that is close to a right Angle.
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