With over 30 years of experience in the industry, one question that we see come up quite often is our clients asking what the difference is between thermoforming and injection molding. As such, we thought we’d take this opportunity to give a quick overview of the two major processes in plastic packaging.
Thermoforming and Injection Molding 101
Before we begin the in-depth portion of this post, we’d like to talk about the processes themselves. Thermoforming is a process that heats a sheet of plastic to the point where you can form it into the piece you want. Another term for this is vacuum forming. That’s because you use vacuum holes to suck the plastic and fit it into place.
Injection molding on the other hand, literally injects plastic into the mold. Basically, you take plastic pellets, heat them, and mold them into the final product.
As we mentioned earlier, the process of thermoforming is centred around heating and molding plastic. As you can see in this image found on Euro Extrusions, it’s pretty straightforward. Since the process is easier, it allows for a lot more projects to be developed. Check out some of the clients that we’ve worked with and to get a better sense. For example, we work with retailers and food packagers for our clamshells. We work with chocolate and multi-national companies for our trays. Lastly, we work with pharma and retail companies for our custom blister packs.
Injection Molding Applications
To recap, injection molding works by feeding plastic pellets into the hopper of the molding machine. There is a hollow barrel inside the machine with a rotating screw that pushes the plastic into the mold. During this process, the barrel is heated to melt the plastic as it makes its way down. Once in the mold, the plastic hardens to take the shape of the final product.
Injection molding has a wide array of capabilities. You should know that injection molding makes the most sense when you want to run larger volumes. Also, it’s a great option when you want variable thickness in your parts.
Key Differences Between Thermoforming and Injection Molding
Put simply, here’s a breakdown of thermoforming and injection molding. Thermoforming is a better option for lower volume sizes. That’s because tooling is generally cheaper in thermoforming vs. injection molding. Generally, a thermoformed tool may cost you $6,000 – $10,000 on average compared to $80,000 – $100,000 + for injection molding.
On the other hand, injection molding usually has a cheaper part price. For example, we were bidding against an injection molder for laundry detergent scoops. Our competitor had a higher tool cost, but came in at $.03 per part whereas we came in at $.05. The numbers may not seem like a big difference at first, but when you’re talking orders of 5 million units, it all adds up.
Another thing to note is lead times. With thermoforming, you can expect somewhere between 11 – 13 weeks for a new project start to finish. With injection molding, you’ll see somewhere between 22 – 24 weeks.
In summary, thermoforming and injection molding both get the job done. However, they both have applications which make more sense for each. Just remember, thermoforming can have cheaper tooling and a higher part price and injection molding can have a cheaper part price and more expensive tooling.
If you still have any questions, please feel free to contact us or give us a call at 905 459-4545 and we’ll guide you through your packaging journey.