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How to control the milling effect of high hardness materials in CNC machining?

Mar 26,21

How to control the milling effect of high hardness materials in CNC machining?

Milling high hardness materials is usually used to process hardened workpiece by CBN solid tool, CBN cutter head or ceramic tool, which is also often called hard cutting. The new technology of hard cutting can be used to cut hardened steel, gray iron, nodular iron, powder metallurgy and special materials. Of course, there are also some materials such as bronze that are not suitable for hard cutting. Hard cutting technology can also be used for turning, surface processing, tapping thread, milling, slotting, profiling, turning cone and other operations. Steel materials with hardness more than 56hrc or strength more than RM > 2000n/mm2 are generally referred to as hard cutting.
The success of hard milling usually involves many factors,
Hard milling steel - 63 Rockwell hardness, 6000 rpm, 100 in / min, 0.012 per pass (slope).

The first important factor to consider in hard milling is the structure of your machine tool. Therefore, in order to achieve the ideal hard milling effect, we need a very strong machine with high vibration reduction capability.
Hard milling CNC machines need to be rigid by granite machines or polymer concrete and cast steel structures.

Generally speaking, machines built from polymer concrete have the buffering capacity of many machines made of cast iron. At the same time, it is important to have CNC controller which can handle the dynamic requirements of constant and fast acceleration and deceleration!

The solid granite processing platform makes it a rigid hard milling machine.
The next thing to say is the clamping of the spindle and the tool. These are two very different things, but they are closely related to their use.

First you need a rigid rotor! If your spindle is beating, the world's most concentric and best handle will only help you. That is, combining the high-speed spindle with the best tool will produce unexpected results.
HSK series tool handles are one of the most popular tool handles in hard milling because their interface with the spindle improves rigidity and concentricity.

Hard milling spindle and tool holder shall be selected according to rigidity and low runout. In the process, we found that HSK tool clamping system is very effective!

Of course, we can't forget the tool itself. We have also done some research and found that many mold manufacturers have customized specific tools for hard milling. But we can't trust these parameters too much. Most of these mold manufacturers have experts who can help select materials and specific processing tools, and we can make full use of these services, save our time and increase efficiency. At the same time, the cutting tools selected in hard milling applications must be coated to withstand the high heat and high friction associated with these materials.

And, these tools are probably not cheap! So if you ask your boss for a purchase and you buy a milling cutter at a high price, you can give him so many advantages to justify the purchase. In addition, if you need to buy two, you can ask for four. In this way, when he asked for only two, he would feel like he had saved a sum of money for the company.
The edge radius of hard milling tool such as 8mm4 edge end milling cutter is 0.5mm, and the coating thickness is 0.5mm, which can show excellent cutting performance and durability.

Back to the topic. CAD / CAM software is the last problem (not true, it will never be missing). Programming software is one of the most important factors in hard milling, which can control the load on the tool. You want the cutting tool to be loaded without impact, which means cycloid milling is sequential or dynamic as is usually said. The principle behind the dynamic milling associated with hard milling is that your tool can easily and permanently engage the material. There is no sharp jump, no steady force. Most of the major CAD / CAM packages now have some form of dynamic milling.
Effective hard milling procedures need to understand the characteristics of CAD / CAM software

Just as you use these tools and strategies in a mechanical workshop, garage, or anywhere else, knowledge is power. We need to learn constantly to acquire higher processing skills.