Lost Core Molding
My company is interested in investigating ‘lost core’ injection molding. It seems our competitors overseas are using this process and I wanted to know if anyone in the US has experience and can maybe provide some insight on the process and capital investment necessary.
I worked at a company that performed this in one of their European plants. There are two versions: one uses a low melting tin/bismuth core, the other typically uses a water soluable grade of acrylic. The metal core is removed via induction heating, the polymer version via submersion into a hot water bath. Both style of core materials can be reclaimed for use in more parts.
So you will need a core machine (PIM or injection molding press), robots to assemble (maybe) the cores and another to insert into mold, and the reclaim equipment. I'm sure since I haven't done this first hand, I'm missing some steps/equipment. I suppose that is why most intakes and manifolds are molded as two parts, then assembled with a seal material between the halves (welded).
Hope this helps,
Two main type of lost core used in automotive, high melt alloy (used with thermoset materials and low melt (138°c) which is used with Nylons, predominantley Pa66 35%GF although Pa6 has beenused succesfully.
Casting equipment supplied to us by Bachman, now no longer in existence but Ecklemann support programming (baswed in Germany)
Process for casting very similar to low pressure die casting so equipment suppliers for this process may help. Alloy return from melt out tanks will need balancing or flow issues will be experienced.
Melting out can be done using induction, this is susceptible to part size and also thermal using residence time in a bath of heated oil. LUTRON used mostly as can be washed off following melting out.
Tin Bismuith extremely expensive.. Only one global supplier that I am aware of.