Drying Parameter for Electroless Nickel-Plated Aluminium Diecast Parts

The die cast surface is porous, so the cleaning process needs to aggressively remove all contaminants (discuss with die caster) and thoroughly rinse off all cleaning solvents. This is more important than the drying. If you limit the drying temperature, you will need to extend the time to at least an hour or more depending on the mass of the parts and the accessibility of the circulating air to all part surfaces.

5-8 microns thickness is not sufficient to prevent external contaminants from corroding the aluminum base metal or from any base metal contaminants from bleeding through to the finished nickel surface. You will need at least 100 microns (.0001") and up to 2-3 times that for harsh environments.

To obtain the rated hardness, and both wear and corrosion resistance you are supposed to post-plating bake the parts at 275 deg. C for 3 hours and preferably 375 deg. C for 4 hours if it does not damage the parts. This does not sound possible for you unless you replace your racks and maybe the oven is not capable of those temperatures.

Not knowing what the parts your plating and what they are used for, I can not recommend more than this. You need to get together with the die caster and your customer to work these issues out. Good luck!

65-70° C is normally more than sufficient to dry the pores. You probably have micro cracks (more than pores) due to a defect in die casting. This will make washing difficult. You will need to wash the pieces better and keep them immersed in water for a longer time to dilute the chemical in the cracks. If you have a high pressure jet it will do the job well. You do not need to raise the temperature to dry better , just increase the time. Once the piece reaches 70°C it will dry very quickly..