By Randy Hough
Mold components play a very important role in plastic injection mold making. There are numerous basic components that are common to almost every injection mold, and often some components that are specifically engineered for special applications. Both of these make up the reason you should use off the shelf mold components, whenever possible.
The common components would include items such as:
- Mold bases
- Ejector pins
- Core pins
- Hot runner systems
- Angle pins
- Water cooling components
You might think that nobody would bother making any of these things anymore, but they do. It might make sense for a highly specialized purpose, but generally it is highly unprofitable to make your own standardized components. I know mold makers from the not-so-distant past who made their own ejector pins! Talk about inefficient use of skill and time!
Mold bases seem to be the most likely item to be a possible candidate for in-house manufacture, but increasingly it is possible to have almost anything custom made better and cheaper by companies that specialize in mold bases. You don’t need massive milling machines, large grinders, radial drills, gun drills, Blanchard grinders, boring mills or a lot of space to accommodate such an undertaking. “Do what you do best and leave the rest.”
Very large mold making companies might be able to justify making components because they have the machinery and capacity to turn a profit, but very few small to medium shops can succeed at this.
The engineered components would include such items as:
- Plated wear plates
- Gate inserts
- Date wheels
- Side locks for three plate molds
- Sprue bushings
- Hot runner systems
One of the main benefits of using purchased mold components is innovation. New ideas pop up all the time to solve old problems and if you are stuck doing things the same way year after year, you miss out on more efficient and practical ways of doing things.
Take slides, for example. You can buy standardized slide units in many sizes that make the mold designers job simpler as well as the mold maker. You can use them in a modular sense to simplify everything.
Lifters are another great example. Why have to invent a clever lifter with every new application? There are numerous ingenious lifters on the market that are highly adaptable to your needs. This also makes it easier and faster for the designer, and especially the mold maker! Lifters are always difficult to work with, for everyone.
Another reason is your customer
Some customers require the use of specific brand names and specific types of components. This assures them of a consistent result and performance. Some mold makers try to substitute off-brands as a way to save money, but this is a slippery slope, for sure.
Make it predictable for your mold makers
It is more efficient to use your mold makers for core and cavity work than doing machinist work. Not only that, but they will become familiar with the features of the standard components over time and become much more efficient in using them
It saves time and money and makes your operation more efficient and productive. Overall it makes sense to use off-the-shelf purchased injection mold components whenever possible.
About the Author
|Randy Hough||Randy Hough lived, traveled, and studied in Europe for 3 years after college at Colorado State University, where he was an art major. After marrying in Denmark, he and his wife settled in Wisconsin, and he graduated from the Winona Technical Institute in Minnesota in 1978. Randy then became a mold making apprentice with the state of Wisconsin. After the 4 year apprenticeship, he worked at several shops to broaden his experience and finally settled in the beautiful Upper Valley of Vermont, where he lives and works. His main emphasis has been CNC EDM and the hand work side of mold making. At present Randy is involved in web site work regarding plastic injection molding/mold making as a means to make use of some of his accumulated knowledge.|
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