Injection Molding Service Services

The first step in injection molding involves preparing the raw material:

• Plastic pellets (also called resin) are loaded into a hopper.
• These pellets can be made from various types of polymers, such as polypropylene, polyethylene, or polystyrene.
• Additives like colorants or reinforcing agents may be mixed with the pellets.

Once the material is loaded, it needs to be melted:

• The pellets are fed into a heated barrel.
• Inside the barrel is a large screw that rotates.
• As the screw rotates, it moves the pellets forward.
• The combination of heat from the barrel and friction from the screw melts the plastic.

After the plastic is fully melted, it’s ready for injection:

• The molten plastic is forced into a mold cavity under high pressure.
• This injection is typically done very quickly, often in less than a second.
• The pressure can range from 10,000 to 30,000 psi, depending on the part being made.

Once the mold is filled, there’s a brief pause called the dwelling phase:

• Additional pressure is maintained to ensure all mold cavities are filled.
• This helps compensate for material shrinkage as it begins to cool.

The cooling phase is crucial for part quality:

• The molten plastic begins to cool and solidify as soon as it touches the mold.
• Cooling channels in the mold circulate water or another coolant to speed up this process.
• The cooling time depends on factors like part thickness and material properties.

After the part has cooled sufficiently:

• The mold opens.
• Ejector pins push the finished part out of the mold.
• In some cases, robots or human operators remove the part.

The final step prepares the machine for the next cycle:

• The mold closes.
• The screw retracts, allowing more plastic pellets to fall in front of it.
• The process then repeats from step 2.