Shrinkage is a common problem in all Pet Preform Mould injection molding processes, including plastics. As long as you work with a skilled manufacturer with extensive material science knowledge, they should know how to explain the shrinkage in your design. Some plastics have different shrinkage rates, and plastic shrinkage can also cause sinking, which is a big problem for atheists.
Shrinkage is always considered in mold design. Based on the material data sheet and shrinkage, the manufacturer increased the cavity to 1 - 4% larger than the required part. As the product cools or solidifies in the mold, it begins to shrink. This section will continue to shrink in the next 24 hours. If you have ever measured the critical dimensions of a part, it should wait until 24 hours after molding.
Plastic shrinking sink
After molding, the plastic can shrink its size by 1-4% anywhere. Therefore, it is important to add shrinkage in the mold design. Different wall thicknesses will shrink at different rates, which is why sinking. When the area of ​​the plastic part is too thick, sinking occurs. It is important to thin these areas and create equal wall thickness throughout the part. The pool looks like a piece of turf in a thick area.
Submerged silica gel injection molding
Parts shrink when cooled, and when the area is very thick, cooling takes longer, causing the area to shrink excessively. Using experienced molds, they will be able to mark this situation and help you design manufacturability.
shrink
The speed of contraction is about the same; therefore, it can be more predictable. Shrinkage is simply embedded into the mold design. Although the sink is not a big problem, we must still be careful about plastic thick-walled parts. Thick-walled parts can result in insufficient cure, deformation, or back skin.
Undercut: Thick plastic parts take a long time to cure, so when it is removed from the mold, the interior may still be soft and uncured. This will result in late baking.
Deformation: When the inside of a thick part is still uncured, it may deform when removed from the tool or when the part solidifies outside the mold.
Back: If we try to increase the curing time inside the tool to complete the curing, instead of baking, the plastic part will start to expand at high temperatures. This causes the material to press against the side of the tool and tear at the parting line. This is called the background. This may be a difficult idea to understand, but any plastic molding machine is proficient.
These common shrinkage problems can be avoided, as long as they work with a skilled China Pet Bottle manufacturer who is proficient in materials science. Working with the right manufacturer will help your component produce for the first time, reducing production time and costs. If you would like to find a manufacturer for your injection molded components, please contact us today.