Mold design

Tehmasimpex - mold design

A mould is one of the main production tools used in manufacture of plastic items by injection molding. This is quite complex device that determines the geometry of the manufactured products and is operated under the pressure of hundreds of tons in conditions of constantly changing temperatures. In many cases the shape elements must be accurate to second decimal places of a millimetre.

The engineers of TEHMASHIMPEX JSC have long-term experience in the mould design. We have developed moulds for a wide variety of products - home appliances, high-precision parts in electronics, household and domestic goods of various shapes, automobile interior and exterior elements.

Thanks to the qualifications of our employees we may design both the simplest and complex hot runner moulds of non-standard geometry.

Mold components

The mould components may be conditionally divided in two groups. The first includes process (operating) elements. They come in contact with the primary polymer and influence the final geometry of the product. This group includes plugs, blocks, inserts, rings.

The second group includes structural parts designed to ensure proper functioning of the process elements. They include clamps, shedders, guide posts, bushings, support bars, heating and cooling system, mould handles.

Gating system

Gating system is a mould element consisting of channels, through which the liquid polymer runs to the cavity for casting. There are two types of gating system - cold runner and hot runner.

In a cold runner system the gate is not heated. When the finished product cools down, the gate is cooled and extracted together with the product after the mould opening. The main advantage of such systems is reliability and low design and production costs. There is only one drawback - the presence on a product of unnecessary gate after the cycle completion, which impairs the product appearance and results in excessive consumption of raw materials.

In a hot runner system, the gate is in liquid or viscous state during the whole production cycle, which makes it possible to get rid of the solidified gate on the finished product. However, this is not cheap. The moulds with the hot runner gate system are much more complicated and expensive, require more electric power costs and enhanced cooling. They fail quite often, which may cause the whole production line stop.