If you have never had a part injection molded before, there are a number of important factors you will need to know before you get too far into a project.
Assuming you have your part or parts designed and already have working prototypes, the next step is to get set up for production. You will have to visit some injection mold making shops and have them quote making a mold for your part or parts. You will need to supply at least 2-D prints and/or a 3-D solid model. You will also need to tell them what your production requirements will be per year for injection molding so they can determine how many cavities to make the mold. Some shops provide both injection mold building and also the injection molding. Toth Mold/Die Inc. located in Ohio, provides both of these services. The ability to have both services done at one shop is a big advantage as far as maintaining and repairing the injection mold. Specifically, there would be no need to ship the mold to an injection mold making shop in the event the injection mold needs to have work done to it. The quote you obtain should have a list of items that will be included in the injection mold price. I have listed below some of the most important ones that should definitely be included:
- Mold design
- Mold base
- Steel type
- Gate type
- Ejection type
- Cooling lines
- Samples
- Mold life
- Payment terms
- Delivery date
It is always a good idea to look at some of the molds built by the shop you are considering and also to get some references. This is a big investment for you and everything must be covered. You should only give a down payment and never pay for the mold in full until the part or parts are approved. Usually engineering changes that need to be made are the responsibility of the customer and not the injection mold making shop. Some things such as fits and hole diameters can be adjusted easily if steel needs to be removed. It should also be stated on the quote who has ownership of the mold.
As a customer, you should also be entitled to have updates on the mold build and even be able to visit and look at the status of the mold. You must also tell the injection mold building shop the plastic material you want to use for injection molding your part or parts. All materials vary in shrink rates and the shrink must be taken into account when building the injection mold. There are a lot of variables that affect the shrink of a part. The responsibility of what shrink rate should be used must be agreed upon. Most shops want the customer to supply the shrink rate and do not want the responsibility. Toth Mold/Die Inc. takes full responsibility of choosing the shrink rate. We have no problem doing this because of the years of experience we have in the injection molding industry. The specifics you need to know about having your part or parts injection molded will be discussed in a future blog.