When designing plastic parts, you are involved in a complex task that involves many different factors.  You must constantly be thinking about how the part will be used, how it will fit into other parts, and what kind of loads it will experience when it is being used.  Also, a complicated subject is a process of creating the part using plastic molds and injection molding equipment.  Molten plastic enters fills, and cools within the mold to form the part, and it needs to be done right the first time.

What injection molding equipment do you need to properly begin injection molding?

Injection Molding Machine

This machine, also known as a press, consists of a material hopper, a heating unit, and an injection ram or screw-type plunger.

Machines are rated by tonnage, calculating how much force the clamp can exert.  The range of tonnage on injection molding machines can range from less than 5 tons to 6,000 tons.  Since each part is custom, the tonnage that is needed to secure the clamp with the right amount of force depends on the projected area of the part being molded, the material used, or the size of the part.

Buying used injection molding machine is an economical option that will give you the freedom to create the custom parts you need instead of buying them on the market.  If you are going to buy a used injection molding machine, make sure it has been fully inspected and tested before delivery so you don’t suffer the loss of production due to breakdowns.

Mold

This refers to the tooling used to produce the plastic parts in molding.  The material used to make these molds is usually steel, aluminum, or beryllium-copper alloy. What are the advantages and disadvantages of these materials?

• Steel

Will generally cost more to make, however, this cost can be offset by the fact that it will last longer, thus offering a higher number of parts made per lifespan.

• Aluminum

At a price that is far less than steel molds, this can be an economical option for molding hundreds or thousands of parts.  There is also the added benefit of a quick turnaround and faster cycles because of better heat dissipation.

• Beryllium copper

Normally used in areas of the mold which make fast heat removal necessary, or areas that see the sheerest heat generated.

Buying used plastic molds is a good and economical option. These molds are tried and tested to produce every time and are less expensive than buying new.  Used European molds are a far better option than used molds from China, and the slightly higher price is worth the quality.  Also, buying a used mold gives you faster availability than ordering a mold to be made.

Choosing the right parts is a must when beginning your own injection molding process.  Whether you buy used injection molding machines or used molds, or whether you decide to buy these parts new, always look into the specs to make sure this is exactly what you need to make your custom plastic part.