The Nitrofreeze Deflashing process provides molders and OEM manufacturers with a reliable, efficient method to deflash their molded silicone parts. Cryogenic deflashing utilizes polycarbonate blast media and part tumbling in a cryogenic atmosphere to remove residual flash material. Below is a study of a serviced part:

Material : Silicone   Description : Orange Housing    Area for Concern : Thick ID Flash

The Challenge
Nitrofreeze was contacted to reduce or eliminate the parting line flash on 60 Shore A liquid silicone rubber aerospace and defense housings. Current customer method entailed hand trimming the parts with knives and tweezers in order to remove enough flash to meet the 0.005” flash tolerance. After several weeks in production it was determined that deflashing by hand was inefficient. Mold machine operators spent two minutes to deflash each gasket and yielded inconsistent results. Production lot sizes averaged 2,000 pieces per week.

The Solution
Drawings and samples were evaluated at the Nitrofreeze facility. The part (1 cubic inch) had parting line flash measuring 0.005” thick and extending 0.200”. These parts were deemed suitable candidates for cryogenic deflashing due to the material composition and the orientation and thickness of the flash. The cryogenic deflashing process employs part-on-part tumbling with polycarbonate bead blasting within a cryogenic atmosphere. Initial sampling was successful and production parameters were developed for batch processing.

The Result
Nitrofreeze was able to cryogenically deflash batches of several hundred parts at a time. The first production order of 2,000 pieces was received on a Tuesday. Thursday the parts had been processed and were shipped backed to the customer. Samples were inspected per customer specified AQL measuring consistently under 0.005” tall flash. This two business-day turnaround was maintained for future orders. Based on the customer’s reported tweezer deflashing time of two minutes per piece, the service removed from the molder sixty-six (66) labor hours per week. Cost for deflashing a 2,000 piece order was reduced an estimated 68% versus previous manual trimming.

Learn More

Nitrofreeze’s Cryogenic Deflashing service works for silicone parts molded out of Wacker, Momentive, Bluestar, Shin-Etsu and Dow Corning liquid silicone rubber materials. The deflashing process works best on parts molded out of 10 to 80 Shore A liquid silicone rubbers. Liquid silicone rubber materials are viscous by nature and tend to flow beyond the limits of their respective mold tooling’s cavities, especially as the tooling wears.