Does CNC Machining Graphite Damage the Milling Cutters?

In mold manufacturing, because most technicians lack CNC machining experience in graphite, they think that graphite is not easy to mill and it is very costly. Is this true?

In fact, compared with copper, graphite material has good machining performance and lower cutting resistance. Its milling efficiency is about 2 to 3 times that of copper. Pay attention to the following aspects in the milling process.

As I wrote before in the article “What Is the Best End Mill for Graphite?“, it is best to use diamond-coated end mills for graphite machining. In addition to the choice of tool material and tool coating, we already know the answer, what other aspects should be paid attention to?

First of all, tool wear is the most important problem in graphite electrode machining. The amount of wear not only affects the cost of tool wear, processing time, and processing quality, but also affects the surface quality of the workpiece material processed by the electrode EDM, which is an important parameter for optimizing high-speed processing. The main tool wear areas for graphite electrode material processing are the rake face and the flank face. On the rake face, the impact contact between the tool and the broken chip area produces impact abrasive wear, and the chips sliding along the tool surface produce sliding friction and wear. Several factors affecting tool wear are as follows.

Choosing a proper geometric angle for graphite tools helps reduce the vibration of the milling tool. Conversely, graphite workpieces are not easy to chip.

  • Rake angle, when using negative rake angle to process graphite, the cutting edge strength of the tool is better, and the performance of impact and friction resistance is good. With the decrease of the absolute value of the negative rake angle, the wear area of the flank face does not change much, but the overall trend is decreasing. When a positive rake angle is used for machining, as the rake angle increases, the strength of the cutting edge of the tool is weakened, which in turn leads to increased flank wear.
  • Clearance angle, if the clearance angle increases, the cutting edge strength of the tool will decrease, and the wear area of the flank surface will gradually increase. After the tool clearance angle is too large, the cutting vibration is strengthened.
  • The helix angle. When the helix angle is small, the length of the graphite workpiece simultaneously cut into the graphite workpiece on the same cutting edge is the longest, the cutting resistance is the largest, and the cutting tool bears the largest cutting impact force, so the tool wear, milling force and cutting vibration are the largest. When the helix angle is large, the direction of the milling force deviates from the surface of the workpiece to a large extent, and the cutting impact caused by the graphite material is intensified due to the collapse of the graphite material, so the tool wear, milling force and cutting vibration also increase.

Therefore, the influence of tool angle changes on tool wear, milling force and cutting vibration is a combination of rake angle, clearance angle and helix angle, so comprehensive consideration should be given to these angles when choosing them.

A good graphite processing tool should have a smooth graphite powder chip flute, long service life, deep engraving processing, and saving processing costs. You deserve to have this good milling cutter for processing graphite, as long as you find the right supplier-Our.

Write a Comment