All the components of a utility and control-cabinet key are manufactured using one of the following processes. If the key is made from more than one piece, the pieces are manufactured separately and then fitted together as the final step.
Литье под давлением
Non-ferrous metal (metals that don’t contain iron) products can be made using the die-casting process but ferrous (iron-containing) metal products cannot.
Molten metal, in this case zinc alloy (see {{widget type=”cms/widget_page_link” anchor_text=”What are utility and control-cabinet keys made of?” title=”See What are utility and control-cabinet keys made of?” template=”cms/widget/link/link_block.phtml” page_id=”3368″}}), is pushed under high pressure into an iron mould, or die, in the shape of the component.
The metal solidifies within minutes and the die is opened to release the solid part.
Often the part will be attached to other parts by strips of metal that form during the casting process in the channels, or runners, that connect the cavities of the mould together.
A trimming press cuts off the excess material and the finished part is produced.
Литье под давлением
The injection moulding process is used to make plastic and steel parts for utility and control-cabinet keys.
Литье металла под давлением
The metal injection moulding process is used to form ferrous metals in a mould because they cannot be die-cast.
Very fine metal powder is mixed with thermoplastic powder and heated. The plastic melts but the metal does not. The plastic binds the metal powder together. It is shaped into pellets to make it ready to be used in the injection mould.
The pellets are melted in the injection moulding machine and the mixture of molten plastic and fine metal powder is injected into a mould the shape of the component to be cast.
When the plastic in the mixture has cooled and solidified, it is removed from the mould and placed in a chemical bath which dissolves most of the plastic.
Heating removes more of the plastic polymer through evaporation. The component is now made up of 40% air.
It is heated again, this time in a furnace at a much higher temperature, to increase the density of the metal by removing the air. The optimum temperature is 85% of the metal’s melting point. For instance, if the metal’s melting point is 1000 degrees Celsius, then the ideal temperature to heat it to is 850 degrees Celsius.
Removing the air spaces causes the component to decrease in size by between 15% and 25%. This means that the mould at the beginning must be larger than the part you wish to produce. Manufacturers can calculate this to a high level of accuracy and so the finished products are exactly the right size.
Литье пластмасс под давлением
The plastic injection moulding process is simpler than metal injection moulding.
Plastic beads are melted and injected into a mould. Once the plastic is cooled the mould is opened to release the solid plastic part.
The parts are removed, using a trimming press machine, from the solidified channels, or runners, that feed the mould.
Sometimes the plastic used to make parts for utility and control-cabinet keys are reinforced with glass fibres to make them stronger and more durable.
