H.D.Plastics is an outstanding manufacturer of PVC Extrusion. With in-house extrusion die capabilities and custom engineering for your personalized PVC plastic profile extrusion needs, H.D.Plastics combines the industrial experience and expertise to satisfy the challenges of your custom extruded plastic profile.

For PVC Extrusions such as PVC doors and Frame, there is some situation for internal stress which is very common in plastic extrusion manufacturing.

There are three main types of internal stress in extruded plastic profiles.

1. Quench stress. This kind of stress sometimes disappears by itself when the product produces bubbles or dents and can be eliminated by annealing.

2. Construct volume strain. This is caused by the shrinkage in different directions formed by the geometrical dimensions of the part. The thickness of the part becomes more obvious, and it can only be eliminated by annealing.

3. The freezing of molecular orientation. This is the most important kind of residual stress. The residual stress remaining in the part due to molecular orientation and freezing is called frozen molecular orientation. This kind of force will cause the parts to crack, dimensional instability, and deformation when heated. In addition, the difference between the linear expansion coefficients of metal inserts and plastics is too large, and the chemical reaction fission caused by chemical solvents.

The appearance of residual stress is closely related to the injection conditions.

Mainly consider five aspects: mold temperature, the thickness of profiled parts, injection pressure, injection time, and material temperature.
We mainly slow down the cooling rate of the molten material during molding, so that the stress is fully relaxed, so as to minimize the orientation of frozen molecules, that is, to minimize the residual stress.

PVC Extrusion Profiles
Dongguan HD Plastic Products specializes in the production of extruded plastic profiles. The main products are PVC extrusion, various ABS, PP, PE, PC, PMMA plastic extrusion profiles, Pipes and bars, PC lampshades, PVC soft rubber strips, two-color co-extrusion, extrusion molds, etc.