Basics of injection molding design
Injection Molding Machine
Injection molding machines, also known as presses, consist of a material hopper, an injection ram or screw-type plunger, and a heating unit. Molds are clamped to the platen of the molding machine, where plastic is injected into the mold through the sprue orifice.
Presses are rated by tonnage, which is the calculation of the amount of clamping force that the machine can exert. This force keeps the mold closed during the injection molding process. Tonnage can vary from less than 5 tons to 6,000 tons, although the higher tonnage presses are rarely used.
The total clamp force needed is determined by the projected area of the custom 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/in 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 is needed to hold the mold closed.
The required force can also be determined by the material used and the size of the part with larger plastic parts requiring higher clamping force.
Related Industry Knowledge
- Plastic Mould
- Introduction to Plastic Mould
- Main classification of plastic moulds
- Structural elements of plastic moulds
- Material requirements for plastic m...
- Material selection of plastic mould
- Technical application of plastic mould
- Mold Development
- Injection mould
- The composition of the mould
- What is mold?
- Different Types of Injection Moldin...
- The Gates In Mould
- The Gates In Mould- Gate Location
- The wall thickness in mould
- Mould Need To Do Texture
- Parting Lines
- Common Molding Defects
- ALUMINUM CASTING METALS
- Calculate Shot Size Vs. Barrel Capa...