Polyshot Corp. has introduced its vacuum brazing technology to moldmakers for fusing of multi-component mold cores and cavity assemblies for cost-reducing conformal cooling systems.
For hot runners, Polyshot’s fusion technology fuses together two or more steel plates to create internal flow paths. Polyshot’s technology allows the creation of internal full round flow paths that allow generous sweeping curves and no hold-up areas, the company reports. These internal flow paths withstand very high injection pressures and external forces while still maintaining the integrity of the brazed joint.
For conformal cooling systems, Polyshot’s vacuum brazing technology is a proprietary process which makes use of a high-temperature vacuum furnace. Rough cores and cavities with machined conformal cooling paths are fused together by Polyshot in a stack which is typically one to six layers. Typical materials that are fused include H-13, 420 stainless steel, and S-7. Cores are shipped back to the customer in a soft state, approximately 30 RC, and require additional post brazing hardening at a local heat treat facility. The typical turnaround time for the process is one to two weeks.
The use of conformal cooling in mold cavities can have a substantial impact on mold cycle time, part quality, and part repeatability. Conformal cooling channels follow the shape of the cavity and core and are able to reach hot spots and promote temperature uniformity of the molded plastic materials. They reduce cooling time and achieve overall cycle time reductions of up to 60 percent, resulting in substantial cost savings, the company notes.
The vacuum brazing process is targeted for high-cavitation molds (32-128 cavities) for high-volume packaging applications such as caps and closures.