Custom plastic injection molded parts

Custom plastic injection molded parts and components are made by HYX in their millions each year. We offer small batch through to medium and large volume production runs, as required.

So how are custom injection molded parts made?

After the mould design stage (all performed on the computer in our state-of-the-art dedicated design suite) the designs are “virtually” modelled so as to be tested on the computer prior to proper production. This includes Moldflow analysis, after which designs are fine tuned if necessary. The same data used in the design stage is then used in our dedicated mold tool production department where the metal molds are produced which will be used in the final production process. This is a high precision job using advanced equipment, processes and machinery.

During the actual production process, molten plastic is injected into the molds under high pressure. Molds will have been carefully designed so that on completion the components will not be locked inside. In order to do this, sides of components will typically not be 100% parallel with the draw direction, which is the direction in which the various parts of the molds are separated (molds are normally made in at least 2 halves, called the “core” and the “cavity”). So, sides of components (and molds therefore) are angled very slightly and this will be evident if one looks closely at many household objects and electromechanical components made using this process. This angling is known as the “draft”.

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Other, more complex, types of molds include sections known as “slides”, which are moveable and are inserted into the plastic molds so as to form particular required features which cannot be formed using only a core and a cavity approach. On completion, they are released to allow for the component to be removed.

The raw material which is going to make the components and parts is usually in pellet form. It is made into the molten form using heat and shearing forces and is then forced into the mold through channels which allow access to the main chamber. On completion the material will cool and solidify not only in the mold itself but also in the channels, so forming a frame attached to the finished component. The frame consists of “sprues” and “runners” (the former being parallel to the direction of the draw, the latter being perpendicular to it and being used to take the molten material to the “gate(s)”, which are the point(s) of introduction of molten material into the mold itself. Sprues and runners are normally detached from the finished component but can be easily recycled. In some designs, it is possible for the sprue and runner framework to be automatically stripped due to the clever design of the mold itself.

HYX Engineering Solutions can work in a large variety of materials including many different types of thermoset and thermoplastics, which are selected for their properties, intended use, target environment and material cost. A fine balance needs to be met which addresses each of those issues and, with a 40 year lifetime of experience behind it, HYX are at the top of their field and can advise where required or suggest alternatives where worthwhile. A list of materials can be found at this location.

Quality is at the heart of HYX’s workflow. A steady stream of quality components can only be realised through high quality in the design of the mold and part, through the quality and care taken in producing the mold and also during the molding process itself. For instance, the molten resin needs to be at just the right pressure and temperature so that it can flow to all parts of the mold (this is where the earlier Moldflow analysis at design stage pays dividends too) so as to avoid all imperfections in finished components. HYX has an enviable record in this respect with the percentage of components which are below absolute top quality being staggeringly low at only 0.01% of the overall total produced.

If you are interested in plastic injection molding services, would like to chat over a potential project, would like to see our company profile, need a fast quotation or if you would like to check some technical issue with our engineer, your are very welcome to contact us without obligation. Please send us an email