Some owners of industrial plants that fabricate different components from engineering plastics, such as ABS plastic, may be concerned about the number of products that they discard due to the detection of defects that can occur during the injection moulding process. This article discusses the causes of some of those defects and presents solutions that can be used to prevent a recurrence of those defects.

Surface Delamination

Components may have layers of plastic that can be peeled from their surface. These layers usually form due to the presence of impurities that prevent the engineering plastic material from bonding uniformly within the injection mould.

You can combat this problem by increasing the mould temperature so that all impurities can be destroyed during the injection moulding process. You may also need to reconsider your choice of mould release agents. This is because those agents may be forming layers within the plastic that has been poured into the mould.

Burn Marks

Another common defect during injection moulding of engineering plastics is the appearance of discolourations on the surface of the part after it has cooled. Excessive heating of the engineering plastic usually causes those burn marks during the moulding process. Overheating of trapped air can also cause burn marks.

You can fix this problem by ensuring that the moulds are properly vented so that any trapped gas within the mould can escape as the molten plastic is poured into the mould. You should also adjust the process temperatures so that the plastic on the edges of the product does not degrade after it has been subjected to excessive heat.

Warping

Warping refers to the deformation due to the uneven shrinkage of the different parts of your moulded components. This may be due to the uneven thickness of the various sections of the component. Warping may also result when the cooling time is so short that some parts of the component cool much faster than other parts.

Several remedies can be considered for this problem. For instance, you can change to another form of engineering plastic that is less prone to warping, such as plastics that are not in crystalline form. You can also increase the cooling time so that the finished parts can cool uniformly. Ensure that the moulds have even wall thicknesses so that all parts of the finished product can cool at the same rate.

Many more remedies exist for the defects that may be present in your moulded products. Consult an engineering plastics expert for help in case the remedies above are unable to fix the problems that you are experiencing.