Impernation process for Aluminum Castings

[Tammy C]

I have been looking for information on impregnation processes. Does the process add material to machined areas if the process is done after machining? If it does how much allowance should I include for the process?

Thanks for your help

[Kelly_Bramble]

I suspect you are referring to impregnation to control porosity issues in castings... I do not believe the impregnation processes used on castings is additive.

Would you please clarify what process and materials you are referring to?

[Tammy C]

The print calls for Impregnation with an anaerobic thermoset polyster resin with a vacuum method to be used. I am having problems with threads. After the process the thread gauges are binding. With black light inspection there does not appear to be any build up. I cannot find anything for thread allowance to cut the threads before the process. I am not familiar with the process and the print specifies inpreg to be done after machining. I was told there is not any build up because of the rinse process. The threads were fine before the process. I need to know how much to compensate to cut the thread

[Kelly_Bramble]

Well, my best suggestion is to measure and document the threads pre and post impregnation process on a test coupon. With this data you should be able to modify the threads as required to accommodate the apparent impregnation buildup.

I do think that you should task the folks that are processing the “anaerobic thermoset polyster resin with a vacuum method” with what could be the root cause of the thread gauge binding.