Plastic Injection Molds: 8 Tips For When Requesting Quotes

Some companies get to the point where they need plastic injection molds for their innovative product, typically for the enclosure and maybe a few plastic internal parts.

Here are 8 tips for actions you should take before you confirm a quote for your injection mold tooling.

First, on the supply chain side.

1) Look at the website of the companies that give you a quote. Do they clearly focus on plastic part manufacturing?
In many cases, a prototyping supplier offers to fabricate tooling and a quick look at their website shows work mostly on metal parts that go through CNC machining, for instance.
if they don’t do either mold fabrication or plastic injection molding in house, it’s very probably all subcontracted. Are they transparent about that?

2) You need to have a clear idea of (a) who will fabricate the tooling and (b) who will do mass production (injection molding) of the plastic parts.
If you engage one company for the molds and then another company for mass production, the first company won’t suffer bad consequences if the mold leads to extra costs in production (for example the need to trim the parts manually one by one).
In the worst-case scenario, good plastic injection molding shops will refuse to work with bad molds… So, in most cases, it makes sense to keep accountability for both mold fabrication and mass production on the same company’s shoulders.

3) If the same supplier is going to make both the molds and the plastic parts in production, you’ve got to ask for quotations for the mold and for the plastic parts at the same time.
Asking for both at the same time is quite typical and normal. It will allow you to compare several suppliers’ offers. Here is a theoretical example, just to make the point:

• Supplier 1: Mold is 7,000 USD and the plastic part unit cost is 0.4 USD
•  Supplier 2: Mold is 4,000 USD, plastic part unit cost is 0.65 USD (it seems this one is going to amortize a part of the tooling cost on the unit price, and in the long run it may be much more expensive)
•  Supplier 3: Mold is 10,000 USD, plastic part unit cost is 0.3 USD (maybe this is a better-optimized mold, maybe it has several cavities, etc…)

(Yes, it is typical to get such wide-ranging quotations in China.)

Second, a few tips on the technical side.

4) Make sure the supplier specifies certain important attributes of the mold in their quote.
At the very least, you need to know the materials of the core and of other elements, the number of cavities, how many shots it’s able to handle in its lifetime, and if the 2D/3D drawings of the mold will be provided to you.

5) You also need some information that will be important during mass production to be written down.
This will include: the type of injection press needed, size & weight and plastic type of the parts to be made, expected shrinkage, etc. You may have to specify the maximum percentage of regrind material (if any). And, if you are looking for very specific performance, it’s often a good idea to specify what exact polymer is to be purchased, from what brand (e.g. Dupont, Chimei…).

6) For custom-designed parts which are a bit complex you may need the supplier to do a DFM review.
Custom-designed parts, especially those that are complex, are at risk of suffering from more issues than standard off-the-shelf parts, therefore a DFM review should be done in this case (typically with a presentation that shows potential issues) as well as subsequent adjustments made based on its findings. If the supplier makes the adjustments, make sure you get your hands on the final 3D drawings!

And finally, don’t forget the legal side.

7) Get the supplier to sign a manufacturing contract that’s legally enforceable in their country.
If you send the supplier money and you don’t have a legally enforceable contract that spells out that (1) all related IP rights belong to you and (2) you can pull out the tooling at any time for no reason, then you have no leverage over them as they hold your tooling and they might try and take advantage of you.

8) Be prepared to pull your tooling out on your own terms with a minimum of drama.
Countless importers have come to us for help because they have no straightforward way of pulling their tooling out of their supplier’s factory. And in some cases, the situation is beyond repair… Remember, when you announce “We need to get our molds back”, it sounds to the supplier like “we never want to hear from you again, you’ll never get any more business from us in the future”…

The most important is to prepare well in advance so this final step is less likely to occur and so there is way less drama. We wrote about it in our e-book about transferring production to another factory.

Your key takeaways

Our general advice is to work in a simple way which can be summarized as follows:

• Specify what you want, and get quotes that specify what you will get in a very clear way.
• Make sure you own all IP rights and you can pull the molds out from a supplier at any time.
• Pay for the tooling entirely, so there is no difficulty in transferring it to another factory if needed.
• Avoid the temptation of “amortizing” the cost of mold, as it usually does not end up in your favor.

Get help with your molds from Sofeast

• Tooling Management for Plastic Injection Molds in China – In this post, we’ll outline some of the key risks you face when manufacturing and managing your tooling for plastic injection molds and some of the solutions that Sofeast offers to give you peace of mind throughout the tooling fabrication process and beyond.
• Plastic injection mold tooling management program – If you have tooling made in China it is a large investment you want to secure. Risks are especially high when molds are transferred to another company. Sofeast helps you validate those molds while they are still in the fabrication shop, where adjustments can still be made relatively quickly and inexpensively.
• Mold capability validation supervision (in China) – Fabricating your tooling in China? Our engineer goes on-site to oversee the fabricator’s testing so you have peace of mind that the molds reach your standards and can be shipped out safely.
  Typically used for plastic injection molds.
• Tooling custody management (in China) – If you don’t want your supplier to have excessive freedom and leverage, Sofeast can help you by being the trusted custodian of your tooling between productions and by performing inspections at key milestones.
• Plastic injection molding for your parts – This is from our subsidiary, Agilian Plastic and Molds, where we can manufacture your plastic parts in-house as well as the tooling.