Rapid Custom Manufacturing

For the low and middle volume plastic parts production such as 500-5000 pieces, some customers want to injection molding their products by aluminum tooling instead of the conventional costly steel mold to reduce the production cost. Does aluminum tooling effectively reduce the low or middle volume injection molding production cost? Here we can briefly analysis the possibility from the following factors:

Mold Material Cost. No matter the aluminum tooling or steel mold, the mold base must be the rigid ferrous steel to make sure the mold clamping force and packing pressure during the injection molding, so the mold material cost difference comes from the mold core. For the steel mold core, its material cost normally takes around 10%-20% of the total mold material cost though it is much higher than the aluminum mold core cost, so the final mold material cost difference between them is not big.

Mold Fabrication Cost. Either the mold material is aluminum or the rigid mold steel (normally NAK80, S316, 718H), the mold fabrication process and steps are the same with nearly the same fabrication time. So the mold fabrication costs are nearly the same.

The Injection Molded Part’s Quality. Compared to the rigid steel mold cavity, the strength and toughness of aluminum mold cavity can not weather the abrasion and deformation caused by the injection molding material under high temperature and high pressure, especially for injection molding the material with strong corrosion to mold cavity and needs more molding temperature and pressure. So the aluminum tooling can not deliver the consistent size stability and accuracy to its injection molded parts.

The Effective Injection Molding Time. Since the relatively much lower material strength and toughness, the aluminum mold core has to be replaced and remade after one batch or several batches of low volume injection molding production, while the rigid steel mold cavity has much stronger injection molding capability than the aluminum one. So steel mold better suits for the projects with low volume production each time but many times’ production at different times.

All in all, aluminum tooling couldn’t effectively reduce the low volume injection molding production cost, what’s more, it couldn’t deliver the consistent and continuous injection molding quality. As a matter of fact, we usually use aluminum tooling for our RIM (Reaction Injection Molding) process to rapid low volume (normally under 100 units) manufacturing or prototyping the big plastic covering parts with common accuracy requirement and simple geometry.