So here comes the question, what is the small problem? In fact, it is a simple automatic CNC lathe to drill the center hole.
Not much to say, enter the topic. Just yesterday, I was free to go to the workshop to chat with the new employees. There happened to be an employee who was drilling the center hole with a CNC lathe. Since he had drilled a lot before, there were no problems such as whether or not the parameters were set correctly. However, suddenly with a crisp sound, the center drilled into it, after stopping the bed. We discussed this small issue together, and hope it will help him in the future.
First, what exactly is a fully automatic CNC lathe center drill? what is the purpose?
The center drill is a prefabricated precision positioning for hole processing, which guides the twist drill to perform hole processing to reduce errors. It is used for machining center holes on the end faces of shafts and other parts.
Second, is there a classification for center drills?
The common center holes are type A and type B. The A-type center hole has only a 60° taper hole. In addition to the 60° taper hole in the B-type center hole, there is also a 120° taper at the outer end, also called a protective taper, to protect the outer edge of the 60° taper from being damaged. Type A and Type B center holes are processed on a lathe or special machine tool with corresponding center drills.
Third, the key point is here. What are the reasons for the center drilling?
1. There is a convex head on the end of the workpiece of the automatic CNC lathe.
When the end face is processed, the center of the turning tool is not aligned, or it is high or low, resulting in a little protruding head in the center of the end face. When the center drill enters the end face, the core tip is on the convex head, and the center drill bit will be broken if it is slightly deviated.
2. The center of the center drill is deviated from the center of the workpiece.
This reason is mainly caused by the inconsistency between the center of the lathe tailstock and the center of the spindle. If the workpiece is not concentric, the center drill will be eccentric, which will easily break the center drill.
3. No lubricant is added.
When drilling the center hole, no lubricating fluid will be added, which will cause the chips to be poorly discharged in the center hole, jam the center drill, and cause breakage. Therefore, when drilling the center hole, it is necessary to add some water-based or oily lubricating fluid, which can not only remove chips smoothly, but also increase the smoothness of the center hole.
4. Improper selection of cutting parameters.
Improper selection of cutting parameters will also cause the center drill to break. Generally, the center hole is drilled by hand cranking the tail shaft to feed the knife. Because the drawing is faster when hand cranking, the feed rate is fast, uneven, and if it is not discharged in time, it will squeeze and break easily.
5. The quality problem of the center drill of the fully automatic CNC lathe
When machining, you must choose a good-quality center drill, so that not only the processed product can be beautiful, but also the production efficiency can be greatly improved.
Generally speaking, there are several reasons for the fracture of the center drill. It’s also very important that you must pay attention to concentration and not be affected by the outside world when you work.
