用注入成形工艺做成最小的骨头置换物

用注入成形工艺做成最小的骨头置换物
       利用微金属粉末注入成形，研究者现在能制成微小的埋植剂像镫骨，镫骨是人耳中最小的骨头，一般用生物相容性材料如，钛制成。
      “我们制成纤小的听小骨的精密复制品，用极细的金属粉末注入成形能使我们复制出这些组织。”来自德国不来梅Fraunhofer制造工艺和实用材料研究所（IFAM）的Philipp Imgrund解释道，迄今为止，这种小金属部件产品还应用蚀刻或碾磨技术，这些一直是种非常复杂并耗时的工艺过程，并且并不适用于许多金属，虽然有金属注入成形（micro－MIM）,科学家们能够混合或改造不同类型的材料，这在相当长的一段时间里用不锈钢制做小部件成为可能，现在，研究能够不使用组织相容性材料，如，钛，钛合金来制造这些微笑精细的部件。在一个调控装置系列中，研究者制出300多个5.4mg重0.3mm厚的微小部件，“我们现在装备上马了micro－MIM的系列产品” Imgrund强调道“以镫骨为例，我们证明了这一工序的极限和可行性。”
      在注入成形微小部件之前，研究人员将一种有机黏合剂与微金属粉末混合，于是这种混合物就能像处理塑料制品一样在注入成形机上进行处理，随后，黏合剂被排出随之混合物就烧结成一个高密度物质。Imgrund解释说：“我们改进粉末和黏合剂使之与注入成形和烧结工艺过程相配，我们的目标是――获得可再生的高品质，不管是为了制成非常复杂的微小组织还是为了完备这些组织所要求的其他功能。”
来源于：德国弗劳恩霍夫应用研究促进协会

Bones: Smallest Substitutes with Injection Molding
     By means of micro metal powder injection molding, researchers can now produce tiny implants like the stirrup, a small bone in the human ear, from biocompatible materials such as titanium.
   “We make exact copies of this delicate ossicle. Injection molding with very fine metal powder enables us to replicate these tiny structures,” explains Philipp Imgrund of the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research IFAM in Bremen. Until now, the production of tiny metal parts using techniques such as etching or milling has been a very complex and time-consuming process, and not suitable for many types of metal. With micro metal powder injection molding (micro-MIM), however, the scientists are able to combine and shape different types of material. It has been possible for a long time to produce tiny parts from stainless steel. Now the researchers are in a position to make such small, delicate components out of biocompatible materials such as titanium and titanium alloys. In a pilot series, the researchers manufactured 300 miniature parts with a weight of 5.4 milligrams each and a wall thickness of only 0.3 millimeters. “We are now ready to start series production with the micro-MIM process,” Imgrund stresses. “Using the stirrup as an example, we are demonstrating the limits and possibilities of the process and of the new materials.”

     Before injection-molding miniature parts, the researchers mix the fine metal powder with an organic binding agent. The mixture can then be processed on an injection molding machine in the same way as a plastic. Following this, the binding agent is expelled from the component, which is then sintered to a high density. “We vary the powder and binding agent and are developing suitable injection-molding and sintering processes. Our objective is to achieve reproducibly high quality for very complex micro-components and to equip these components with additional functions as required,” explains Imgrund.

  Source: Fraunhofer-Gesellschaft