Key Questions to Ask When Ordering Automotive injection molded parts

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Apr. 14, 2025

8 Questions To Ask Before Buying Injection Molds in the US

What questions should I ask before buying injection molds?

What is the molder’s expertise?
What standards do they follow?
How long will it take to build?
How much will the initial mold build cost?
Where am I in product development?
What is the part’s geometry, material, and size like?
How many plastic parts does it need to make?
Do they guarantee the molds for the life of the project?

You’re finally satisfied with your plastic part design, it’s now time to consider mold selection so you can start production. But, picking the right mold maker and designing the right mold is less straightforward than you expect — you might even find yourself presented with a laundry list of new decisions to make.

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Even more confusing, you might have molding project proposals from several injection molders, all with varying designs, costs, and more. So how do you make the right selection for your project?

To help you, here are the best questions to ask before buying molds in the US:

What is the molder’s expertise?

Most of the injection molders that you can find in the US will have their areas of expertise. It’s important to ask prospective parts what they are — their answer will help you determine whether they have the experience and know-how they need to make the best mold for your application.

You could also check their website or ask them directly for their portfolio, equipment list, and reputation. What you will see is a testimony of the quality and stability of their services and products. Try also asking for a few of their client references, specifically those who work in the same field as you do. Doing this will help you see if this injection molding partner can meet the specific requirements of your industry.

What standards do they follow?

Ideally, the injection molding partner you choose should follow industry standards.

The most important ones include ISO : for product quality and consistency and ISO : for environmental impact. Another industry standard to look out for is IATF, which shows that the injection molding company works on continual improvement, defect prevention, and reduction of errors in its services.

If your injection molder is adhering to all of the above standards — like Richfields does — then you can rest assured that the mold maker will go above and beyond the necessary quality requirements.

How long will it take to build?

Building a new mold is one of the longest tasks in any production project. While some molds can take just a couple of weeks to design and make, some may take several months. It’s important to present your part design and ask your potential partner what the lead time will be for your mold so you can adjust your production schedule accordingly.

If your part design still needs some tweaking, you can ask for a prototype mold to be made instead, which usually takes around 3 to 6 weeks to make. If you’re ready for full production, then your mold may take upwards of 12 weeks to make.

What’s important here is that your molding partner has a clear idea of what to make and how much time they need to make it. If they can offer intermediary solutions to help with long lead times, then this is a benefit to your production.

How much will the initial mold build cost?

With mold-making services in the US ranging in the thousands, you must get a quote early on to see if it aligns with your production budget. Several factors impact the cost of your mold, including mold classification, design complexity, mold cavitation, and specialty molding designs.

For example, prototype molds tend to be much cheaper than a final mold. And, having a specialized design, such as a multi-cavity mold, can also increase initial build costs.

Be upfront about what you want and need for your molds, so your potential partners will know what goes into your mold building price. And great mold maker, like Richfields, will help you find ways to make your design more cost-effective — getting you the most bang for your buck.

Where am I in product development?

Where you are in your product development process is a critical factor in how your mold is made. In the early stages of prototyping and pre-production, you can typically expect a lower construction quality mold — because they are made to make short runs of your prototype, and make it more cost-effective for several design iterations.

If you’re later in the development stages, then you can request a better-built, sturdier mold that is production-ready. Be careful about selecting your molds — make sure it’s suitable for where you are in your product development process to avoid spending more money on new molds and mold repairs over time.

What is the part’s geometry, material, and size like?

Depending on what geometries, features, and size you need for your plastic parts, your potential mold-making partners may need to use different mold-making approaches. Some designs will need molds made using hardened steel, or steel inserts, rather than softer metals like aluminum.

The material you’re planning to use for your plastic parts will also play a role in how the mold is designed and made. Some resins are incompatible with certain mold materials. For example, plastics like nylon will need a higher quality mold to fit part specifications.

Richfield’s molding engineers can help you examine all your part’s specifications to determine what kind of mold best suits your needs. Our team will also examine overall functionality to help in the mold design process — taking into consideration other features like snap fits, breakaways, and more to design the right mold.

How many plastic parts does it need to make?

You’ll also want to consider the minimum production requirements. How many parts does your mold need to make? Will you have a short production run of only a few hundred parts, or are you aiming for mass production that creates up to a million of them?

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If you only need a few parts, then you could probably go for a cheaper mold made from less sturdy materials, like aluminum. But, large volume runs will probably necessitate the use of things like hardened steel inserts, which cost more but helps in meeting your production needs.

Do they guarantee the molds for the life of the project?

Finally, ask if your mold-making partner guarantees the lifespan of their molds. If they do, then your molds should be able to meet your production requirements with minimal risk of error or breakage. If the molder seems confident that their molds can stand up to your strict requirements, it’s a good sign that they will be fit for your application — and less likely to need adjustments or repairs.

Key Takeaway

If you are considering which plastic mold maker to work with, then use these eight questions to ask before buying molds in the US to help guide you to the right partner.

11 Questions To Ask Before Picking A Plastic Mold Manufacturing ...

When you’re getting ready to begin the injection molding process, the first choice you make—and one of the most crucial decisions—is which plastic mold manufacturing partner you’ll select. The partner you choose should, of course, deliver on all your mold requirements—but they should also prototype your part, help you with part design adjustments, warranty their work, and much more. And most importantly, the right partner will ensure you don’t end up with a useless mold that doesn’t produce quality parts—or, as we like to call a faulty mold—a boat anchor.

By asking potential plastic mold manufacturing partners these 11 questions, you’ll all but eliminate any doubt that they will be a great partner for you.

11 Questions To Ask Your Plastic Mold Manufacturing Partner

1. Can you build a tool that will match my annual volume requirement?

Molds are most often constructed in one of three classes: Class 101, 102, or 103. Each class varies in the material it uses, how (or whether) it’s hardened, the maintenance it requires, and the cycles it can tolerate before it requires adjustments. A class 101 mold, for example, is most often built from hardened stainless steel—but if you’re only going to run 50,000 parts a year, a class 102 tool built from a different, less expensive material may be more appropriate for your part. A good plastic mold manufacturing partner will walk you through the benefits and considerations of each class of mold, and guide you to the class that is ideal for your situation.

2. Can we get a warranty on the tool?

Be advised: Many plastic mold manufacturing companies do not offer warranties unless you specifically request one. Even if they do, study the ins and outs of the warranty and precisely what it covers before signing on the dotted line.

At Micron, we typically warranty a class 101 tool, for example, for up to one million cycles without any cost to the customer. This means we’d cover any and all maintenance and/or expense on the mold up to that point. So if you have a 64-cavity tool from Micron, this warranty would last you through 64 million parts.

3. Do you do mold-making in house or are they made overseas?

Some plastic mold manufacturers simply broker a mold deal between your company and an overseas mold maker. There can be major differences between a tool created in China vs.the U.S.—check out this article for a full rundown.

4. Do you have the ability to rapid prototype or 3D print parts to reveal potential flaws in the design?

The creation of your tool is one of the most expensive parts of the injection molding process, so doing it wrong is not an option. You can make adjustments in the prototyping stage until the mold is correct—but otherwise, changes are expensive.

Here at Micron, once we have a tool order, we print a prototype of the part for free. Giving customers a chance to see alternate ideas, or flaws in the design, helps us both in making a better part.

5. Can you build a mold for the size part I need?

Not every molding manufacturer is equipped to mold extremely large or extremely small plastic parts. If you’re building an injection molded car bumper, for example, some plastic mold manufacturers won’t have the capability to mold something of that magnitude. If the company asserts that they can build an unusual-size injection mold, ask for examples of similar parts they’ve previously created .

6. What materials will the finished mold be able to handle?

If your plastic part will be molded using highly abrasive plastic material—or a type of plastic material that is injected at very high temperatures—you’ll want to be certain the company you’re considering can build a mold that will handle these requirements.

7. How do you achieve the right mold tolerances?

Specific mold tolerances may be critical for your plastic part, and understanding how the molder achieves and validates those tolerances is useful information to have. Additionally, if any part of your mold needs specialized measurements—say, an one-dimensional automotive part that needs to be extremely precise so there’s no variation part-to-part—be sure to let them know ahead of time.

8. What is your process for high-cavitation molding?

If you need a high-cavity mold, find out how your potential mold manufacturing partner manages the mold building process. For example, to ensure that plastic evenly distributes in your high-cavitation mold, your partner should include a high-quality hot manifold (used to inject plastic into the mold) to assist with this distribution process.

9. Can you validate that the mold will work?

To validate what they build, your mold manufacturing partner will need to sample the tool to ensure it produces quality parts. If you’re getting your mold separate from your injection molding manufacturer, be sure that the tool is sampled at the same cycle and cooling time you’ll need when you move to production. For example, if your part requires a 30-second cycle time and the part needs to cool for 15 seconds, but the sample only includes a 2 second cooling stage, the sample parts won’t be an accurate reproduction of what you’ll get during production.

10. What specific molding capabilities can you accommodate?

If you need to fit a small metal bearing inside your plastic part, you likely need a vertical injection mold. If you’re molding a computer mouse or a toothbrush with a hard plastic material and soft plastic grip, you’ll need either two-shot or overmolding. Be certain your mold manufacturer can create a mold for the characteristics you require.

11. How quickly can you turn out a mold?

Everyone wants something fast, cheap, and high quality—but we typically tell our customers they can can have two out of three. For example, if you want a high-quality mold created fast, it’ll cost you. And some mold manufacturers specialize in rapid tooling, but these molds are typically fast and cheap, not high quality. At any rate, be sure the mold manufacturing company you select can turn out a mold in the timeline you require. Here at Micron, if you need a tool built more quickly than usual, we can often partner with outside resources to save time. Or, if you need a mold built for less than our mold shop can create it for, we can partner with outside tool builders that will work under our quality and engineering guidelines.

You know what to ask a potential mold manufacturer—but what about your injection molding manufacturer?

In this ebook, you’ll learn about 13 questions to ask an injection molding company before selecting them. Download it for free today!

For more information, please visit Automotive injection molded parts.

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