Sintered spline hub for magnetic clutch of automotive air-conditioning compressor for DELPH* AUTOMOTIVE

Key point:Spline, Copper infiltration, Electrophoresis

We received this inquiry in July, 2014. We got two types of hubs from our client and there are different design of flange with same dimension of spline. After our evaluation and trial quotation, the client decided to visit our sintered factory at Yangzhou city, Jiangsu province on August 18th. During the visit, our client checked our equipments, the process of production for this product, QC team, QC procedure, and how we control the tolerance of spline and shrinkage rate in the sintering. After the first time visit, our client finally decide to place the order and start to making the mould for trial samples in 23rd, August. In the process of trial samples, it occurred many unanticipated technical difficulties. 1. Because the dimension will shrink in the copper infiltration of sintering, so we need to figure a range of change out for the real product with the tolerance of drawing. It means the dimension of mould is different from dimension of drawing. After the two times of samples, it occurred the difference of measured result between our client and us. The reason is we measured the dimension by our own instrument, but our client use the go and no go gauges, dial gauges and inside micrometer from the end user. If we want to control the tolerance within +-0.022mm strictly, we must use the same tools with our client. So we purchased the same gauges from the appointed Japan company. 2. The surface of samples appeared bubbles after electrophoresis. Our engineers analyzed the situations, and also consulted the mature experience from our client. Because the sintered process is porous structure, if we infiltrate less copper than the needed quantity, the air in the holes will cause the bubbles, conversely, the total cost will increase, we need to figure a quantity out to get the balance between the effect and cost by many times test. Another is the temperature of baking after electrophoresis. We finally solve this problem with our electrophoresis partner. 3. It requires no EDC paint at the spline area, but if we just use the rubber plug to seal the spline, there still will be leakage in the electrophosesis process, so our engineer developed a new fixture tool with bolt for the seal and finally got the good effect. After 3 different types, 5 version of revisement of drawings, 6 times of samples, we developed this product out in the end. The final success depends on the efficient exchange of information and feedback, good communication and technical support from both of our two sides.


  • Title:Sintered Spline Hub
  • Start Date:2014.07.25
  • Confirmed:2015.06.10
  • Services:CSD
  • Principal:Alan
powder metallurgy work flow


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