In 2012, China's medical device market is expected to grow by 17%, including medical equipment growth of 13%, medical supplies increased by 25%; Shangpu Consulting released "2011 China medical device industry analysis and development prospects report". It is estimated that by 2015, entire medical instrument and equipment market in China will double to $53.7 billion. Compound growth rate of China's medical device industry will remain at 20% to 30%.
Faced with increasingly serious phenomenon of industrial homogenization, differentiation and refinement of industrial chain came into being. Such as: Beijing Changhang Precision Casting Technology Co., Ltd. is a manufacturer specializing in production of cobalt chrome molybdenum implant equipment casting base. Its invented production process can make comprehensive mechanical performance of products far better than similar products in Europe and America; Shanghai Geometry Precision Machinery Manufacturing Co., Ltd. integrates Shanghai Science and Technology Resources, and its invented special manufacturing system can efficiently produce metal ball heads with better precision than hips of international multinational companies at a lower cost than their peers. Xi'an Western Superconducting Materials Technology Co., Ltd. achieves breakthroughs in quality of Ti6Al4V raw materials commonly used in implanted devices by means of high-tech means. Its ultra-low gap Ti6Al4VELI alloy bars are exported to hundreds of tons per year in Europe. Differentiation and refinement of industrial chain is crucial to improving quality of implanted devices.

 

It is gratifying to note that although orthopedic implant products of multinational companies still have significant advantages in domestic market, these advantages have begun to weaken. From perspective of evolution of market share, share of domestic orthopedic implanted medical equipment continues to rise. It is expected that domestic orthopedic implanted medical equipment may occupy 70% to 80% of domestic market in the future.
Molds and high precision machining are very important in manufacture of surgical instruments and orthopedic materials. It is generally said that production of medical devices almost always involves molds. Precision mold and ultra-precision molds for polymer composite molding, bio-life engineering, and medical device parts production play an important role in manufacture of medical devices. Level of molds will determine level of quality of medical device products. It is hoped that medical device manufacturers, molds and precision processing enterprises will further deepen mutual understanding and collaboration. In particular, medical device manufacturers should take initiative to understand status of China's mold industry development, new products and technologies in mold field, broaden development ideas of new products in medical device manufacturers industry and application of practical molds, become a window for medical device industry to understand relevant medical injection molding companies and products, and promote common development of two industries.

Selection of molds is very strict, because medical injection molding are all finished in clean room. First, mold materials need stainless steel materials, and need to do matching surface treatment, such as vacuum heat treatment, PVD coating, laser heat treatment and so on. Plastic materials of medical device products often have medical grade PP, PVC, ABS, PSU, POM, PA, etc., which have high strength, are corrosive, have wear resistance and high transparency, etc. Requirements for medical injection molding are relatively high as precision mold. Commonly used mold steels are imported S136, 2316, S136H, NAK80, etc., to meet high corrosion resistance and high polishability. Because of large number of cavities and large batch size of medical injection molding for medical consumables, hardness and wear resistance of injection molding materials are very high. Hardness of commonly used medical injection molding steel is suitable around HRC48-56. It can ensure strength of mold and good polishing performance.

 

There are many different design requirements for mold forming structures. There are many transparent parts for medical consumable products. Products should choose hot runners as much as possible to reduce trace of fusion. When using cold runners, soft PVC should minimize size of runners; Device products are small in size and large in volume. Therefore, automatic unloading and shearing gates should be used to ensure production efficiency and quality; disposable medical device products have many transparent tubular parts. Pay attention to feeding position of gate and Z-fixing method of dynamic model during design to avoid improper selection of gate position and core fixing method, resulting in uneven material flow during injection molding, which causes core to be elastically deformed, product is uneven or not filled, wall thickness is uneven. Extension tube shape product should pay attention to adopt appropriate exhaust method. Inlet port runner should open overflow well according to molding condition of product to avoid difficulty of molding product due to closed gas. Mold cooling system should adopt multiple sets of separate cooling water channels to reasonably control dynamic mold temperature to control deformation of product. In addition, many medical device products involve problem of push-and-seal sealing. Core of mold forming should be designed to straighten body and not to design draft angle, and to ensure that mold release is normal without strain, so that design cooling should be uniform and provide a higher mold temperature, core surface needs to be treated, and special requirements are required on demolding method to ensure quality and precision of product after injection.
Manufacturing precision of medical injection molding is high as precision mold, because products are in contact with blood and liquid medicine entering human body. Injection molding products related to medical equipment are definitely not allowed to have existence of burr, and many of them are directly matched by plastic parts to achieve sealing and pressure resistance effect, multi-cavity product compatibility requirements. So processing precision of mold core is extremely high, and machining precision of some cores is less than 0.005mm. Surface of mold core is required to ensure that Ra value is 0.20 or more. These precisions have basically reached high manufacturing precision of imported precision equipment. Protection and special handling are required on polishing process of mold.
In general, there is not much difference in structure between medical injection molding and traditional mold, which is mainly reflected in control of processing technology and processing precision. Use environment of medical injection molding is relatively harsh.