What are the Advantages and Disadvantages of Plastic Injection Molding?

Plastic Injection Molding

You may already have a bit of knowledge about plastic injection molding if you have landed on our blog today. Plastic injection molding is among the most commonly used processes for manufacturing, creating a huge number and a massive variety of pieces and parts.

Overview of Plastic Injection Molding

Injection molding is commonly known as injection molding, a manufacturing process utilized in plastic parts mass fabrication. It consists of injection of the molten plastic material into the mold, where it will solidify and cool to its final form. It is the best mechanical assembly for the higher volumes of plastic products serving various individuals and industries.

The mold is customized during the design & development stage giving the proper shape to the part. It can also create several parts that are dimensionally consistent and identical, even on parts having complex designs allowing lower tolerance on dimensions.

Advantages of Plastic Injection Molding


#1. Precision

In terms of manufacturing intricate parts, plastic injection molding is perfect. Molding allows you to incorporate several features at smaller tolerances than other techniques. The mechanical assembly of this machine has several smaller parts.

#2. High Repeatability

The identical products are made repeatedly once the molding tool is created. The mold tool has longer life as it is made decently as long as it is treated appropriately through molding the machine setters.

#3. Low Cost Per Part

The cost per part is quite low, while there is an initial high investment for the tool for plastic injection molding. The other processing techniques would involve several operations like polishing; injection molding can be done all together at once. The CNC machine will cost hundreds of pounds for each part. Injection molding is the best way to go if you are searching for complete production.

#4. Fast

The cycle time is as low as 10 seconds. Combining this with a multi-impression injection molding tool can allow you loads of products quickly. Some parts take a bit longer since it is a specialist material with several features that need molding in a precise way. 

#5. Material Choice

There are a massive amount of materials that are available for plastic injection molding. There is a range of more common materials with things like antistatic plastic, chemical-resistant plastics, thermoplastic rubber, and more. You even have endless color choices, too, with masterbatch coloring or color compounding.

#6. Special Surface Finishes, Engraving, and Printing

The injection molding tool is made out of special finishes that show on the molding along with the range of colors. You can get all types of finishes like the leather look, sparked, higher shine, l and more. You can even have logos along with other texts engraved into the mold. Lastly, you can have your moldings printed as a range of inks are made available and printed well onto the plastic.

Also Read- Importance of Good Plastic Molding Dies

#7. Little Plastic Waste

The part repeatability is quite high for injection molding even the runners and sprues are there, with the leftover bits of plastics being created out of tunnels through which the plastic material reaches the actual mold. And the reground and material is reused.

Disadvantages of Plastic Injection Molding


#1. High Initial Cost

Several rounds of molding and designing are required before the production, or the go-ahead is given. After which injection molding tool is required for making the moldings, including designing and manufacturing.

The mold tool is the essential piece of work, cutting down on the manpower and material cost, along with several machining hours for making and representing the largest cost one gets in injection molding. Surely, once everything is done, the part cost is quite low, and repeatability is very high.

#2. Initial Lead Time

The final part can take months of design, testing, and manufacturing of tools from the production concept. If you know what you wish, you can have the finished moldings within 6 weeks. Once the tool exists, it takes quite less time to operate the moldings, especially while you have a multi-impression mold tool, as you have already noted under the benefits.

#3. Large Part Size Limitations

There are massive machines that are required for making plastic injection moldings. The larger parts require a massive mold tool that becomes quite expensive in manufacturing. The process involving plastic fabrication is the best choice as it depends on the type of product that you needs.

#4. Careful Design Needed

The plastic moldings require careful designing under mechanical assembly to avoid the tooling issues involving the undercuts, locked-in features, and not sufficient draft. The temperature and material will be taken into account in the wall design. Else, the mold will not be filled fully. The placement of cooling lines and ejectors needs consideration to ensure that the product appears good.

So, these are a few aspects you must know about plastic injection molding.


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