Injection molding offers numerous advantages. It minimizes molding costs and is a highly repeatable method for producing high-precision plastic or elastomer parts. Once set up, it can manufacture a large number of parts per hour, including various types of plastics and other materials such as liquid silicone rubber.

However, like any manufacturing process, it does have some drawbacks. If these drawbacks prove to be significant to the success of your project, you may be better off exploring alternative manufacturing technologies such as 3D printing or CNC machining.

In this blog, we will take you through the main advantages of injection molding and discuss when it might be better to consider alternative production methods.

What are the Advantages of Injection Molding?

1. High Efficiency and High Output
   After developing the mold, the process is very fast, with cycle times as short as 10 seconds. It is ideal for medium to large batch production, ranging from 10,000 parts to more than 100,000 parts, depending on the mold used.
   Sometimes, you can increase output by using multi-cavity or family molds, where one press produces multiple parts to further improve manufacturing rates.
   If you are outsourcing molding, it is also important to consider efficient front-end design and order processes – check out our on-demand manufacturing.
2. Low Unit Cost
   For high-volume production runs, the cost per part is very low. Even for medium volumes (10,000 to 25,000 parts), you can use aluminum molds instead of steel molds to reduce costs.
3. Repeatability
   You can manufacture the same product over and over again. This is ideal when you need parts with high tolerances and reliability in mass production.
4. Wide Material Selection
   You can choose from a variety of plastic materials based on the required properties of the final part. And you are not limited to plastics; Protolabs also offers liquid silicone rubber molding.
   You can even use fillers in the molding material, which add greater strength to the finished part, and you have a variety of colors to choose from. Discuss with us what you need your part to achieve – there are usually many different options.
5. Low Waste
   Compared with many other manufacturing processes, the injection molding process generates very little waste. Even if there is any unused or waste plastic, it can be recycled for future use.
6. High Detail
   The process involves injecting molten plastic into the mold under very high pressure. This forces the plastic firmly against the mold, enabling complex shapes and many details.
7. Little or No Post-Processing
   Generally, you need very little post-production work because the parts usually have good post-molding aesthetics. We can produce tools with special surface finishes that will be immediately visible on the injection-molded parts. You can even have your logo or text engraved on them.

What are the Disadvantages of Injection Molding?

When should you consider alternative manufacturing methods to injection molding?

1. Initial Cost
   If you commit to steel mold tooling for high volumes (100,000+), production can require significant time and machining, which can be a huge capital cost. If you need a smaller number of parts, this will affect your cost per part, and it may be worth exploring other options, such as using aluminum molds.
2. Initial Lead Time
   Producing steel tooling can take up to 12 weeks. If you need to start production before that, check out our on-demand production; by using aluminum molds and digitizing our front-end processes, we can ship 25 to 10,000+ parts within 15 working days or less of your first CAD upload. Sometimes parts can be shipped in as little as one day.
   For very low-volume runs, there are other technologies, such as 3D printing or CNC machining, that can provide more cost-effective solutions faster.
3. Design Limitations
   You need to consider certain design elements, such as:
   • Using draft angles and radii to help eject parts
   • Avoiding undercuts and sharp edges
   • Controlling wall thickness
     If aesthetics are important, you also need to consider where to place gates, ejectors, and cooling lines. Remember that changing the design of the mold is also difficult – you can remove a part of the mold or add plastic to the final part, but not the other way around.
     For smaller production runs, 3D printing allows you to design almost any shape or geometry you need. As a rapidly developing technology, we can produce more and more plastics and other materials, even metals.
4. Small Part Runs Are Not Always Cost-Effective
   Most people think they should only turn to injection molding when ordering 100,000+ parts; however, there are other options when you can use this process for smaller production runs.
   With more affordable aluminum molds and fast turnaround times (as fast as one day), our on-demand service helps reduce your cost per part. It is ideal for 10,000 to 25,000 parts but can help control costs for even smaller production runs.
   For low-volume runs of a few hundred or fewer, it is also worth exploring other manufacturing technologies such as 3D printing and CNC machining. With these technologies, the cost per part will be lower, and you won’t face the initial setup costs or lead times involved in producing molds.

Injection molding is an excellent manufacturing technology for producing medium to large batches of plastic and liquid silicone rubber parts. It has evolved over time, so it is worth exploring new ideas that can help you reduce the cost of parts in small-batch production.

It is also worth investigating whether other technologies, such as CNC or 3D printing, can provide better options for small-batch production or even custom parts.

For more information, please contact us at Debaolong Seiko. You are also welcome to upload your designs to Debaolong Seiko for a quote.