Definition: Injection molding is the process of heating granular feedstock to a certain temperature to make it fluid, then cooling it by injection into the mold cavity to obtain the required shape of the part.
Core: Because of the variety of metal powder and the different content of various feedstock ingredients, the setting of parameters is very important in the process of injection moulding, and the errors in operation will result in the defects of the products. The excellent injection ability requires the technical staff of the company to prepare for the injection moulding process simulation, parameter determination and tool selection, so as to ensure the uniformity of injection.
Definition: The process of removing the binder component by placing the green part in a special container.
Technology: It mainly includes three systems: wax based system (flux de-binding), plastic based system (catalytic de-binding) and thermal de-binding system. Plastic based system (catalytic de-binding) is mainly used in the industry. Its core advantage is that it does not need condiments, the process is simple, and the disadvantage is that the price of imported feedstock is high, and the raw materials could not be fine-tuned.
Core: De-binding process directly affects the residual amount of binder in the green part. If the de-binding treatment is not enough, there will be too much residual binder. When a large number of binders are decomposed and gasified at high temperature sintering, the product will easily burst. If the de-binding process is excessive, it may cause adverse consequences such as metal oxidation and structural deformation of the product. Therefore, the selection of de-binding process and the control of process parameters are particularly important.
Definition: Parts after de-binding are placed in high temperature and high pressure furnace, and slowly heated under the protection of gas to remove residual adhesives. After the adhesives are completely removed, parts are heated at high temperature, and the voids between particles disappear due to particle fusion, and eventually parts are directionally contracted to their design size and transformed into a compact solid.
Core: Due to the existence of voids between particles, the shrinkage of parts will occur during sintering. Different materials have different shrinkage rates in the sintering process, generally at 15%-18%. Therefore, the shrinkage rate can be controlled by controlling sintering time, temperature and other parameters.
Definition: Inspection content includes dimension inspection, appearance inspection, deformation inspection, etc. Common defects are concave, multi-material, notch, door panel defect, crush, etc.
Core: At present, the MIM industry has not realized batch automatic detection. The core reason is that iteration speed of downstream demand is too fast. If using automatic detection equipment, the frequency of replacement or parameter adjustment will be too high.
Union Precision advantages
【Apply to injection / de-binding / sintering】
- DOE was used to test the standard process and confirm the optimum process parameters.
- Stable production, cavity-by-cavity flow, high quality traceability
- Through independent research and development, the standard injection moulding, de-binding and sintering are automated to further improve efficiency.
【Apply to post treatment】
- Automation of in-house manufacturing process and ultimately connection automation realized through single process automation
- Processes with environmental protection requirements are outsourced.
- Reduce the in-house processes such as CNC which is with excess capacity in the industry
【Apply to inspection】
- The R&D team independently develops CCD equipment and uses machines instead of manpower for inspection to improve the efficiency and stabilize the yield.
- According to the characteristics of the product, the general equipment are designed in advance to facilitate mass production.