What are the difficulties in the processing of medical device parts

In the new wave of world economic integration, the accelerated transfer of global manufacturing to mainland China has become the general trend. China will gradually develop into a world-class manufacturing base. "The global general machinery, automobile, aerospace, energy, medical, rail transit, mold machine tools, and other industries are inseparable from tool equipment." From the perspective of future development trends, the global tool market is expected to grow by 3% to 5% in the next five years. At this rate of growth, we are still firmly in the top spot in the world. From the perspective of the supply of domestic knives, domestic knives occupy the mainstream position, reaching 65%.

The medical device industry is showing a dynamic growth trend, and medical device manufacturers are also looking for better turning centers and tools to enhance their competitive advantage, which has also become an important channel for the growth of the tool industry.

In the face of the epidemic in 2022, the medical device industry shows a dynamic growth trend. Difficult materials, complex workpiece shapes, and frequent small batch production put forward higher requirements for the processing of medical devices. So what problems will exist when processing medical device parts?

The medical device industry puts forward new requirements for professional precision cutting tools.

Difficult-to-machine materials, complex workpiece shapes, and frequent small batch production place high demands on tools for machining specialized medical devices. Products such as implants and prosthetics play an important role in successful surgical procedures, helping surgeons achieve the best possible medical outcome. The tools used to process medical devices determine the quality of medical devices to a large extent.

1. Titanium alloy material that is difficult to process：

90% of the implanted components of medical devices are made of ti6al-4v titanium alloy, which comes from lightweight, high strength, and high biocompatibility. Titanium alloy 6Al-4V has become the most commonly used material for medical implanted devices. Titanium alloy 6Al-4V is usually used in the manufacture of the hip joint, bone screw, knee joint, bone plate, implant tooth, and spinal connecting element. Titanium alloy has the characteristics of work hardening. In the machining process, the shear angle is large, the chip produced is thin, and a relatively small contact area is formed on the tool. In addition, the high cutting force in the machining process, combined with the friction during chip flow, will comprehensively lead to excessive local cutting heat of the tool. The thermal conductivity of titanium alloy is poor, so the cutting head can not be transmitted quickly. Therefore, a large amount of cutting heat is concentrated on the cutting edge and tool surface. High cutting force and cutting heat will comprehensively cause crescent depression and rapid tool failure.

2. Reliable and compact machine tool fixture：

Medical device 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, such as the replacement parts of bones and joints. Due to the poor cutting performance of the processed material, the blank is usually bar material - which means that a large amount of metal needs to be removed. Therefore, some parts are cast into the shape close to the finished product, but this also increases the trouble - the need to make complex and expensive fixtures. Another factor that increases the complexity of machining is the narrow tolerance range.

Medical device parts have high requirements for workpiece materials, processing accuracy, and surface finish, which requires the high reliability of the processing system. Thus, it puts forward high requirements for machine tools, fixtures, cutting tools, CAM software, and so on. Workpieces are usually processed on advanced medical device processing equipment such as Swiss automatic lathe, multi-spindle machine tool, and rotary worktable. Most of these machine tools are characterized by very small size and compact structure.

3. Stable and efficient cutting tools：

Generally speaking, the medical device industry is different from other machining industries in three aspects:

First, the requirements for machine tools are relatively high. Advanced medical device processing equipment such as Swiss automatic lathe, multi-spindle machine tool, and rotary worktable are completely different from the usual processing centers and lathes. Their size is very small, and their structure is very compact. To meet such requirements, the structure of the tool also needs a special design, the size of the tool is also required to be very small, and the rigidity of the tool should be ensured at the same time.

Second, it requires high processing efficiency. For medical devices, the most important thing is the processing efficiency, that is, the processing beat. It is required to replace the blade in the shortest time.

Third, the workpiece itself is very different from other mechanical parts. Medical devices implanted into the human body first require a very good surface finish, high precision, and no deviation, which requires the cutter to meet high processing requirements from the design of blade structure to the design of blade coating. In addition, it also includes the repeated positioning accuracy of the blade, which can not ignore the requirements of high quality while ensuring the improvement of efficiency.