Analysis of Difficulties in Processing of Medical Parts and Devices

90% of medical machining parts and equipment implants are made of Ti6Al-4V titanium alloy, which is derived from light weight, high strength and high biocompatibility. Titanium alloy 6AL-4V has become a commonly used material for medical implant equipment. Titanium alloy 6AL-4V is usually used in the production of hip joints, bone screws, knee joints, bone plates, dental implants, and spine connection components. Titanium alloy has the characteristics of work hardening, the cutting angle is large in the processing process, and the chips produced are thin. A relatively small contact area is formed on the surface.

1. Titanium alloy materials that are difficult to process for medical parts

The high speed laser cutting force during the machining process, combined with the frictional force during chip flow, will comprehensively lead to excessive local cutting heat of the tool. The poor thermal conductivity of titanium alloys prevents the cutting heat from being conducted quickly. As a result, a large amount of cutting heat is concentrated on the cutting edge and the tool surface. High cutting force and cutting heat will comprehensively cause crescent craters and cause rapid tool failure.

The relatively low modulus of elasticity makes titanium alloys more elastic than steel. Therefore, excessive cutting force should be avoided to ensure that the rebound of the workpiece is small. Thin-walled parts have a tendency to deform under tool pressure, causing chatter, friction and even tolerance problems. The key to solving the problem is to ensure the rigidity of the entire system. It is very necessary to use tools with sharp cutting edges and correct geometric shapes. In addition, machining titanium alloys have a tendency to chemically react and alloy with cutting tools at high temperatures, and their chips have a tendency to be welded to the surface of the tool.

2. Reliable and compact machine tool fixture

Medical equipment processing equipment needs to be able to process small and complex parts made of difficult-to-process materials (such as titanium alloy or stainless steel) with high accuracy requirements. For example, processing bone and joint replacement parts is quite complicated. Due to the poor cutting performance of the material being processed, the blank is usually a bar stock-which means that a large amount of metal needs to be removed. As a result, some parts are cast into a shape close to the finished product, but this also adds to the trouble-the need to manufacture complex and expensive fixtures. Another factor that increases processing complexity is the narrow tolerance range.

Medical equipment parts and components have high requirements for material, processing accuracy, and surface finish, which requires high reliability of the processing system. Therefore, extremely high requirements are placed on machine tools, fixtures, cutting tools, and CAM software. Workpieces are usually processed on advanced medical equipment processing equipment such as Swiss automatic lathes, multi-spindle machine tools and rotary tables. These machine tools are mostly characterized by very small size and very compact structure.

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