Injection molding machines consist of a material hopper, an injection ram or screw-type plunger, and a heating unit. They are also known as presses, they hold the molds in which the components are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can exert. This force keeps the mold closed during the injection process. Our injection machines vary from 77 tons to 2200 tons. The total clamp force needed is determined by the projected area of the part being molded. This projected area is multiplied by a clamp force of from 2 to 8 tons for each square inch of the projected areas. As a rule of thumb, 4 or 5 tons/in2 can be used for most products. If the plastic material is very stiff, it will require more injection pressure to fill the mold, thus more clamp tonnage to hold the mold closed. The required force can also be determined by the material used and the size of the part, larger parts require higher clamping force.
The Bottom Line:
Triad Fastener provides tight-tolerance large tonnage injection molding up to 2200 tons with shot sizes of 360 ounces. Typical large tonnage components include large fenders, hoods, and panels for the ATV, UTV, Lawn & Garden, Watercraft, Automotive, Appliance and Consumer Product Industries. Many of these components require Class A Finishes with engineering-grade thermoplastic resins. Triad Fastener has over 25 years experience in large tonnage molding. We will meet or exceed your requirements with on-time delivery of zero defect products. We’d be happy to visit with you regarding your product and it’s specific requirements.