Peter Poodiack, vice-president of sales and marketing at Seaway Plastics Engineering, sits down with John Maher to talk about low-volume injection molding. He defines low-volume injection molding, talks about the industries that use it, and explains the prototyping and production process.



John Maher: Hi, I’m John Maher. I’m here today with Peter Poodiack, vice-president of sales and marketing at Seaway Plastics Engineering. Today, our topic is low-volume injection molding. Welcome Pete.

Peter Poodiack: Thank you, John. Good morning, good to be here.

What Is Injection Molding?
John: So Pete, tell me first, what is injection molding?

Peter: John, injection molding is a general term used to describe a process where a multi-material in our case that would be a thermal plastic is injected under high pressure into a mold, held there for a period of time while it cools, solidifies, then released from the mold having formed the desired shape or plastic part that a customer requires.


Types of Plastic Used in Injection Molding

John: Okay. Are there different types of plastic that can be used for injection molding?

Peter: There’s a very broad range of plastic materials, and typically a plastic engineer will work with a customer to specify the best plastic for their application. That can be based on temperature, it can be based on environmental conditions, it can be based on, fairly, a broad range of factors that determine the material that’s selected for the application.

Factors That Determine the Type of Plastic Used in Injection Molding
John: Right. So depending on what they want and the end product, if they need it to be flexible or they need to be very rigid, that would sort of make the decision as to what type of plastic they’re going to use, that type of thing?

Peter: Correct. Mechanical properties, chemical resistance, all factors that contribute as well as the configuration of the part itself. Some plastics lend themselves better to different configurations than others. So we all have to take that into account when we’re designing the part and specifying the plastic for the application.


What Is Low-Volume Injection Molding?

John: Okay. So today we’re talking about low-volume injection molding. So what is that specifically as a part of injection molding?

Peter: So the injection molding processes can be a very efficient way to produce a high number of plastic parts quickly and efficiently. The majority of injection molders produce plastic parts, often in the millions of pieces and many times, running injection molding machines 24 hours a day, seven days a week. Low-volume injection molding refers, as it sounds, to the quantity of molded parts being required. And here at Seaway, we cater to this market.

We define low-volume as the quantity of parts typically being in the hundreds of thousands. We service this market well, and we have for many years, we do also carry into mid and higher volume applications. But historically, the niche that Seaway has filled has been in this low-volume market. Most molders are not interested in this market.

It requires their operations teams to be very efficient, not only with the injection molding but also with the setup and removal of the mold themselves. The presses, injection molding machines, as we refer to them in the industry, need to be producing parts for the business to be profitable, efficiency with the setup and removal is critical to maximize press runtime in low-volume operations like ours here.


Differences Between Low- and High-Volume Injection Molding

John: Right. So most companies that do injection molding would rather just keep a mold on the machine, be able to just run it constantly day after day and not really have to swap those out all the time, because that might take time or they have to have certain efficiencies in order to be able to do that. Whereas you have that capability to be doing, like you said, 100s or 1000s of a product and then swapping out that mold for somebody else’s mold and running that, and that creates a different business and the way that things run.

Peter: Correct, John, and here at our Port Richey facility, we have 21 injection molding presses. And on an average week, we will have 65 to 75 mold change outs.

John: Wow.

Peter: So that would be many multiples of what most injection molders would see in a facility a similar size.

What Industries Use Low-Volume Injection Molding?
John: Okay. So what, what types of markets or projects are looking for that type of low-volume injection molding in general?

Peter: Here at Seaway, our quality systems and procedures have been developed with attention to the needs of specific markets. For us, these would be the medical, aerospace, defense markets, as well as precision industrial applications. Within these markets, the applications we’ve tended to focus on are typically highly engineered. These can include high-temperature plastic resins, clean room environment molding, and assembly, post molding, machining items such as inserts, artwork such as pad printing and painting, sprayed-on shielding, and also complex assemblies and packaging such as surgical kits.


Low-Volume Injection Molding for Medical, Aerospace, and Defense

John: What is it about medical and aerospace and defence that makes them require low-volume injection molding, is it just that they just don’t have a need for hundreds of thousands or tens of thousands of parts, or what is it?

Peter: When we look at the volume required, most markets do have both high and low-volume applications. Let’s take the medical market, for example, we could be looking at a diagnostics application as part of a test kit. These would typically be consumable. They would be a single-use application. It could be a plastic vial with a cap that you might put a sample in. It’s typically only used once and then the product is discarded.

The applications we tend to focus on, and we’ll stay with the diagnostics market might be the enclosures. So the diagnostic instrument itself, you’ve seen these in the laboratory, we know they have covers around them. These covers are typically plastic. It might have the artwork for the company, the manufacturer’s logo. They could have steel or brass inserts in them, which allow them to improve the assembly process as well as things like sprayed-on shielding. As I mentioned, one of these services that we offer. So there’s applications within each of these markets that would be catered to low-volume as well as high-volume.


Rapid Tooling and Prototyping

John: Okay. And are rapid tooling and prototyping part of your injection molding process, and what are those?

Peter: Seaway produces about 80% of our annual new mold builds in-house. We do produce both steel and aluminum, sometimes referred to as soft-tooling mold. Most of us have heard of 3D printing technology. This technology has improved greatly over the past 10 years, and it supports much of the early prototyping and development phase nowadays, but there are limitations with the 3D printing process regarding materials and design.

And while much of the development phase does now utilize this technology. There are many applications Seaway continues to support within this phase. Our in-house mold production aluminum tooling options, they can offer a lower initial cost versus steel tools, as well as speed to market for applications that are typically not well-suited to other technologies currently available, such as the 3D printing.


3D Printing and the Prototyping Process

John: Right. So you’re able to help a company to prototype something, whether it’s out of steel, like you said, or if it’s 3D printing or something like that, so that they can test a part initially, make sure that it works before they go into a full production with it. Is that the idea?

Peter: So now, Seaway has really stayed focused on molding technology. We do have some 3D printing capability in-house, but we primarily no longer offer that to customers and what we can offer them if 3D printing is not well-suited to their prototyping needs, we can deliver tooling and plastic parts in as little as three weeks. Typically, we see five to seven weeks as an average, but we do have, relative to other options, we can produce plastic, custom parts in a relatively short lead time.


Materials for Low-Volume Injection Molding

John: And in terms of creating products in low-volumes, are there only certain processes or materials that are available, or can you do low-volume injection molding with any type of process or material?

Peter: Yeah, so that’s a good question, actually comes up a lot. So last year, Seaway produced plastic components in over 700 different materials. So the general answer is no. However, there can be limitations with resin manufacturers as far as the minimum purchase requirements.

So this could mean there’s an application requiring only, let’s say, 100 pounds of plastic resin to produce the quantity required, but a customer may be required to purchase a minimum of 200 pounds. In general, most resins, we can purchase them in an amount to support the volume required for the customer.

John: Okay. So it really depends on what you are able to purchase and what the minimum amount of the plastic material is that you can purchase that dictates it.

Peter: Correct. Yes. And we have multiple sources that we use for plastic resins, and generally most of them know Seaway very well, and they usually accommodate our requests.


Turnaround Time for Low-Volume Injection Molding

John: And then what kind of turnaround time can customers expect on low-volume injection molding projects? Are they able to get something into production right away?

Peter: So there’s a lot of contributing factors to turn around time. It can include the complexity of the part availability of the resin, which we’ve seen some challenges with over the past year, production scheduling, and, really, a quality validation requirements. So these can all impact the general turnaround time for the customer when they have a plastic part.

Typically, we can produce a plastic part from a mold in-house, as I mentioned earlier, in as little as three weeks and, on average, five to seven weeks. So this would be what we would call a T1 sample phase. This is basically your first plastic part to print off the tool, any of the other requirements for customers application, which could include quality validation requirements, extensive peak app, or first article inspection requirements, would of course add to this timeframe. And many times those requirements, a customer will have very specific needs. So it’s difficult to generalize how long that might take.

John: All right. Well, that’s really great information, Pete. Thanks again for speaking with me today.

Peter: All right, John, it’s been a pleasure and I look forward to speaking with you again.


Contact Seaway Plastics Today for Low-Volume Injection Molding

John: And for more information, you can contact Seaway Plastics Engineering at or call 727-8453-235.

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