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In recent years, CNC machined parts used in the medical device industry have shown a dynamic growth trend. Medical device manufacturers are also constantly looking for better turning centers and good tools to enhance their competitive advantage in the industry.

Ⅰ. CNC machining and difficult-to-machine materials

Difficult-to-machine titanium alloy materials 90% of medical device implant components are made of Ti6Al4V titanium alloy due to its light weight, high strength and high biocompatibility. Due to these properties, titanium alloy 6AL-4V has become the most commonly used material for medical implants. Titanium alloy 6AL-4V is commonly used in the production of hip joints, bone screws, knee joints, bone plates, dental implants and spinal connection components. One of the characteristics of titanium alloys is CNC work hardening. During CNC machining, the shear angle is large, the chips produced are thin, and the contact area formed on the tool is relatively small.

In addition, the high cutting force during the process, coupled with the friction during chip flow, will cause the local cutting heat of the tool to be too high. However, titanium alloys have poor thermal conductivity, resulting in the heat generated not being conducted well. As a result, a large amount of cutting heat is concentrated on the cutting edge and tool surface. High cutting forces and cutting heat will combine to cause crater wear and rapid tool failure. These factors lead to poor product quality and heavy tool wear, which are issues that companies have to consider.

Titanium alloys have better elastic properties than steel because their elastic modulus is relatively low. Therefore, in order to ensure small rebound of the workpiece, excessive cutting force should be avoided. Thin-walled parts often have a tendency to deform under tool pressure and can also suffer from chatter, friction and even tolerance issues.

Therefore, the key to solving these problems is to ensure the rigidity of the entire system. Using sharp cutting edges and correct tool geometry is essential! In addition, titanium alloys have a tendency to chemically react and alloy with cutting tools at high temperatures, and their chips tend to be welded to the cutting tool surface. These are all factors to consider!

Reliable and compact machine tool fixtures, medical device processing equipment, difficult-to-machine materials (such as titanium alloys or stainless steel) and small complex parts with high precision requirements, such as CNC processing of bone and joint replacement parts are quite complex.

Due to the poor cutting properties of CNC-machined materials, bar stock is often used as a blank—which means a lot of metal needs to be removed. Some parts are also cast to a near-finished shape, but this comes with the added hassle of creating complex and expensive fixtures.

Another factor that increases the complexity of CNC machining is the narrow tolerance range. Medical device parts have very high requirements for materials, processing accuracy, and surface finish, as well as high reliability requirements for the processing system. Therefore, extremely high requirements are placed on machine tools, fixtures, cutting tools, software, etc.

Workpieces are usually processed on internationally advanced medical equipment processing equipment such as Swiss automatic lathes, multi-axis machine tools, and turntables. The main features of these machine tools are their very small size and compact structure.

The characteristics and requirements of medical device parts processing have undoubtedly promoted the development of CNC processing technology and solutions to improve the competitiveness and production efficiency of small and medium-sized enterprises in processing CNC processing of medical equipment.

Ⅱ. The difference between the medical device industry and other mechanical CNC processing industries lies in three points:

1. The requirements for machine tools are relatively high. Swiss automatic lathes, multi-axis machine tools, turntables and other advanced medical device processing equipment are completely different from common CNC machining centers and lathes. They are very compact in structure and very small in size.

In order to meet these requirements, the structure of the tool also needs to be specially designed, the size of the tool is also required to be small, and the rigidity of the tool must be ensured.

2. High requirements for CNC machining efficiency. For medical equipment, the most important thing is CNC processing efficiency, that is, processing speed, which requires that the blade can be replaced in the shortest time.

3. CNC processing

In itself, it is very different from other mechanical parts. Medical devices implanted into the human body first require very good surface finish, very high precision, and no deviation. This has strict requirements on the blade structure of the knife and the coating of the blade.

In addition, there are strict requirements for the accuracy of repeated positioning of the blade, so as to ensure the improvement of efficiency without neglecting high quality!