There are a few undesirable results that are possible during the plastic injection molding process, and one simple example here is known as flash. What exactly is flash, and how can avoiding it help save time, money and hassle for any plastic injection molding part or process?
At EnviroTech Custom Injection Molders, we’re here to provide an unmatched range of plastic injection molding and related services, including bulk molding, over-molding, slab stock manufacturing and much more. We’re experienced in processes that avoid potential problems or issues, flash certainly among them. Here’s a primer on what flash refers to in the injection molding world, why it’s a problem, what causes it, and how we help you steer clear of it for any product you’re manufacturing with our assistance.
What is Flash in Plastic Injection Molding
For those unaware, the process of plastic injection molding involves injecting molten plastic at high pressure into a closed mold cavity. Once the plastic cools and hardens, it takes on the shape of the mold and is ejected as a finished product.
However, sometimes during this process, excess material can escape from the edges of the mold cavity, known as flash. This results in an unwanted thin layer of plastic extending beyond the desired part geometry.
Why is Flash a Problem
There are several reasons why flash is considered an issue in the injection molding process:
- It creates excess material that adds to production costs and wastes resources
- It requires additional time and labor to remove, increasing processing time and costs
- In extreme cases, it can cause part defects or prevent the parts from properly fitting together
Now, some parts can tolerate a minimal amount of flash – but in these cases, waste reduction is still a significant concern. In most cases, however, flash is considered unacceptable and must be removed before the product can move on to post-processing or assembly.
What Causes Flash
There are several factors that can contribute to the development of flash during injection molding:
- Improper mold venting: One of the most common causes of flash, inadequate mold venting can lead to trapped air and pressure build-up that forces material out of the mold cavity
- Too low a clamping force: A key factor in many injection molded products is proper clamping force. If it’s insufficient, the mold may not close properly and allow material to escape
- Mismatched part design: Design flaws such as excessive draft angles or improperly sized gates can increase the likelihood of flash during molding
- Excessive pressure: On the flip side of our clamping force bullet above, if injection pressure is too high, it can lead to material forcing its way out of the mold
- Worn-out molds: Finally, if a mold has been used too many times without proper maintenance, it may not close as tightly and allow for flash development
Steering Clear of Flash with EnviroTech
At EnviroTech, we’re well-versed in all these potential issues and how to avoid them during the plastic injection molding process. Here are some of the chief processes we use to ensure flash is never a concern:
- Monitoring and controlling clamping force: As we noted in our prior section, clamping force can be an issue on both ends of the spectrum when it comes to flash. We carefully monitor and adjust our clamping force to ensure it’s optimal for each part we produce
- Advanced venting techniques: Our team has experience in using advanced venting techniques that allow air to escape the mold cavity without also releasing molten plastic. This decreases the risk of flash developing
- Proper part design: We work closely with our clients during the design process to ensure their parts are properly designed for injection molding. Our experienced engineers can help identify potential issues and make necessary adjustments
- Regular mold maintenance: Molds themselves must be carefully maintained to ensure proper closure and prevent flash. At EnviroTech, we have a dedicated team of engineers who regularly inspect and maintain our molds to keep them in optimal condition
By taking these steps and more, we’re able to minimize the risk of flash during injection molding and provide our clients with high-quality, efficient production processes that save time, money and resources.
At EnviroTech Custom Injection Molders, we’re committed to producing top-quality plastic injection molded parts without the hassle of flash and other issues. Contact us today to learn more about our services or request a quote for your next project!
