How much a plastic mold tool will cost is dependent on several different factors, including the size and complexity of its parts, how many cavities it contains, its tolerances, the tools and steel used, the earning actions of the tool, its anticipated lifespan, the particular resin used for the part, and the part’s aesthetics. While all of these costs will eventually be recouped once a certain number of parts have been produced, it’s important to note that the real cost will also have to take into account the manufacturing process and the molding cycle as well.
For instance, a three plate or hotrunner may be more expensive at first, but unlike two plate tools, they don’t need anyone to operate them or separate the runner. This will mean that you save money on the piece part price, even though the tool cost is higher.
Don’t put the full responsibility for tool buying on your purchasing department, though. That’s because there will likely be factors that they don’t fully understand. Make sure that you determine and specify your tool requirements in full before you start the buying process.
Ideally, you’ll want to choose the right tool for the lowest cost, produced by an experienced and knowledgeable molder. The checklist below details the various areas of interest that you need to consider when purchasing a mold.
- How many dimensions are required on the print- this will determine the cavity complexity, as well as the part tolerances.
- The number of different surface finishes which will be necessary.
- The number of necessary tight tolerances and their requirements.
- Part surface area in square inches.
- Any required functions in mold operating, such as earning or unscrewing.
- Balanced tool requirements- these can be determined by tolerances.
- Part resin.
- Number of cavities in the part, determined by tolerances and part volume required.
- Tool type, e.g. hotrunner, two plate, or three plate.
When you have answered all of those questions, you’ll want to figure out the amount and type of materials and components that you’re going to need, and use supplier catalogs to come up with a total cost.
With that done, you’ll then need to put together a list of manufacturing and assembly procedures. Make sure you include the total number of cavities, and whether or not CAD/CAM information is available to use to cut those cavities. After that, the cooling requirements are considered, and the cooling line placements around the cavity for temperature control are determined accordingly.
With all this information at your fingertips, you will be able to calculate the estimated time required for each procedure, and how much it will cost you per hour. You’ll then have to add extra costs such as the heat treatment, polishing, finishing, surface texturing, and so on, to take into account every aspect of the project.
If you have all this information when buying the first few molds, then your buying department will be better equipped to fully analyze the factors in a specific job, and then create a realistic price range for your budgeting and tool selection decisions.