Building Better Inserts with Metal Additive Manufacturing

PTI Engineered Plastics is among one of the first plastic injection molding companies in North America to add metal additive manufacturing to boost productivity and quality. Research and testing have led PTI to utilize this technology for sinks, over-long cycles and "impossible" cooling challenges.

Powder Bed Fusion

Aided with 3D data, the powder bed fusion process (DMLS or SLM) supplies a thin layer of metal powder to the machine base plate. A laser beam sinters the metal powder to form shapes and grows the insert on the plate. This allows for the creation of varied designs not possible before with the subtractive manufacturing process.

Advantages:

Molds with complex geometries can now have contoured cooling channels integrated into it to match part surfaces. This will increase cooling efficiency and shorten the cooling cycle time. By keeping a more consistent, even temperature, there is better control over part variation from shot to shot. Cycle time reduction is achieved by having the ability to place water into areas previously unobtainable with conventional drilling methods. A reduced cycle time means less time required for the mold to be in the press, resulting in a more competitive piece price.
Currently, PTI is breaking ground using metal additive manufacturing to make hollow inserts. Inserts have only a 4-7mm thick wall supporting plastic pressure and liquid carbon dioxide on the inside to help spot cool the insert. This blend of new technologies allows for cooling of the entire part surface rather than in local spots like conformal cooling or drilled water lines.
Density can be varied by precise control of the sintering. Placement of porous structures within critical areas of the mold are nearly unlimited. This will reduce gas traps and improve part quality. Vents can now be placed in any location without diminishing surface finish.
By growing the molds, insert or parts from nothing, the need for extra material is eliminated. No wasted graphite for EDM. No metal chips that require recycling as with the subtractive (conventional) manufacturing process. Think of only paying for the metal you actually need.