A definitive guide to custom injection molding

What is Custom injection molding?

The first question that comes to mind on hearing the term Custom injection molding is what is Custom injection molding? Custom injection molding refers to the making of plastic parts for specific applications i.e. customizing the components as per the customer’s requirements.

Injection molding of Custom Plastic Parts

Injection molding is a process in which plastic pellets are melted and injected under high pressure into a mold cavity. The molded parts are then ejected, and the process repeated. The finished products can then be used as is, or as a component of other products. To do so requires an injection molding machine and tooling (often called a mold or die). The molding machine consists of a clamping unit to open and close the mold automatically, and an injection unit to heat and inject the material into the closed mold. Injection molding utilizes very high pressures and typically the machine is hydraulic or, increasingly, electric. Tooling for production injection molding applications must be able to survive under high pressure and is made from steel or aluminium. The potential high cost of tooling often drives the economics of a plastic molding application. Injection molding is an effective way to make custom parts.

The process broken down

There are three main components in the injection molding process. The injection apparatus itself which melts and then transmits the plastic, the mold, which is custom designed, and clamping to provide controlled pressure. The mold is a specially designed tool with a base and one or more cavities that will eventually be filled with resin. The injection unit melts the plastic granules and then injects them into the mold by either a reciprocating screw or a ram injector. The reciprocating screw offers the ability to inject smaller amounts of resin in the total shots, which is better for producing smaller parts. After injection, the mold is cooled constantly until the resin reaches a temperature that allows it to solidify.

Complications with Injection Molding

Injection molding complications are few and can be easily avoided by paying close attention to the design of the mold, the process itself and caring for your equipment. Parts can be burned or scorched when the temperature is too high, which is sometimes caused by the length of the cycle time which may be too long. This causes the resin to overheat. Warping of parts happens when there is an uneven surface temperature for the molds. Surface imperfections (commonly known as bubbles) happen when the melt temperature is too high, which causes the resin to break down and produce gas. This can also be caused by moisture in the resin. Another complication is incomplete cavity filling, which occurs when there isn’t enough resin released into the mold or if the injection speed is too slow, which results in the resin freezing.

As stated throughout this guide that, if you or your company needs plastic products with specific types and dimensions, then you should turn to custom injection molding companies. These manufacturers have the ability to make plastic parts for specific applications – they can customize virtually all plastic components per your requirements. They can stamp your logo or messages, produce unique colours and designs and package them specifically based on what you want and need.

Choosing a custom injection molding company

Most of the custom injection molding companies can produce any plastic product you specify, but not all of them go the extra mile to take care of ‘finishing services’ such as decorating, assembly, labelling and packaging. Some even have a design group that can assist clients with plastic part and mold design. From rapid prototyping and tooling to injection molding, ultrasonic and plastic welding and stamping, these companies can assist you every step of the way. Go for manufacturers that offer these added perks – you will end up saving time, money and effort.

Note that some custom injection molding companies do not do these extras in-house – they hire sub-assemblers and finishers but are still able to produce products at par with your standards.

Also examine the manufacturing company’s logistics and scheduling system. They should be able to handle your delivery needs no matter how demanding they may be. You should also go for companies that implement strict controls to monitor the whole custom injection molding process. They should have the latest inspection equipment at hand to allow them to match the closest tolerance and thus provide quality consistently.

The custom injection molding company’s plant climate is also very important. They should have facilities that ensure mold cooling system control. You may contact any companies in the internet directory for your custom injection molding needs.

So to make sure you get the best services, be sure to check this out!