Pressure Forming process:
The pressure Forming is the process used to produce injection mold quality, high definition plastic component parts, housings and containers without the huge expense of tooling. It involves positive pressure to force the heated plastic into the mold cavity. This is called pressure thermoforming or blow forming.
Pressure Forming Working Operation:
The highly versatile pressure forming process utilizes air pressure, from 20 to 150 psi, to force the heated sheet into a temperature controlled mold cavity. Vent holes are provided in the mold to exhaust the trapped air. The final part features sharp definition of intricate contours and tight radii. Textures and accurate details are built right into the tooling. Low-cost, highly aesthetic plastic parts of varying sizes are possible due to the application of air pressure, as well as more sophisticated process controls that better monitor tool and sheet temperatures while controlling material shrinkage during forming.
Types Of Molding operation:
- Positive Mold
- Negative Mold
Negative molds have concave cavities. A positive mold has a convex shape.
Pressure Forming over Thermoforming:
The basic advantage of Pressure Forming over Thermoforming is the cost advantage for small production items. The mould cost for thermo forming is considerably higher in comparison to pressure forming thus for a lower quantity, precision job the best suitable method used is pressure forming.
Pressure forming is used to create in a wide array of plastic products used for packaging of food trays, blisters, covers, internal parts, housing equipment, bezels, bases, and spare parts for use in business machines, electronics, computers and peripherals, bio-medical applications, and instruments.
Pressure forming achieves features beyond the capabilities of vacuum forming including louvers, ribs, recessed areas, crisp details and logos.
Pressure forming is ideal for small to medium sized production runs that do not justify the high cost of injection molding dies. Additionally, because the aluminum tooling used in pressure forming has an unlimited life cycle, due to the non-abrasive process versus injection, it saves a great deal of money over many years of continued use. Pressure form tooling usually costs less than 10% the cost of an injection tool. There are also a significant time savings (sometimes 25%) in tooling lead time. Sheet gauges 0.020″ – 0.500″ are capable of being pressure formed.