To avoid Iron filings remain in the threads of powder metallurgy parts

The problem happens in the Post processing after sintering. In order to get better strength, Heat treatment is an essential process for powder metallurgy products. If the parts also need drilling threads, we face two choices when comes to arrange which process first: drilling or heat treating?

If heat treatment is done first, the PM parts will become very hard to be machined. The increased tool wear and machining time means huge cost. However, if drill the thread first, Iron fillings remain in the threads of powder metallurgy parts occasionally. According to one of our clients NOK reports, there were about 50% NOK parts found.

If heat treatment is done first, the PM parts will become very hard to be machined. The increased tool wear and machining time means huge cost. However, if drill the thread first, Iron fillings remain in the threads of powder metallurgy parts occasionally. According to one of our clients NOK reports, there were about 50% NOK parts found.

So here comes the question: How to avoid the Iron fillings remain in the threads when drilling threads first? We have analysis two reasons can cause this problem.

• Not clean-up after drilling the threads. If the iron fillings are not totally cleaned up right after drilling threads, the iron filings will stick to the inside of the threads during the following heat treatment process.
• Iron fillings in the threads come from the blastering process when doing deburring. Small iron fillings from the flash or burr will stick to the threads during blastering.

Two steps better to be taken to completely solve the problem:

First, strengthen employee training, ensure to clean up the threads after drilling by visual checking.

Secondly, update production process, inspect the the threads with tooling right before final QC and packing.

If you have any other ideas on how to avoid the particles in the threads during sintering parts production, welcome comment and contact us.