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Tonnage In Injection Molding

Save Money and Boost Accuracy When Calculating Tonnage in Injection Molding

  • Deluxe Plastics Staff
  • General

Tonnage in injection molding is a key component in ensuring the quality and accuracy of your molded product. Without the correct tonnage, you risk damaging your mold and producing a flawed product that requires another round of production to get it right. Miscalculating the tonnage for your project can cost you extensive time and money.

The injection molding experts at Deluxe Plastics have gathered everything you need to know about what injection molding is and why it matters for the quality of your project. Read on to learn the best way to save money and boost the accuracy of your product, and how trusting a high-quality molding partner with your tonnage calculation will ensure you achieve the right tonnage every time.

What is Tonnage in Injection Molding?

Tonnage is the measure of the force required to keep the injection molding machine closed during the injection process so your part forms free of avoidable defects. Also known as the clamping force, this calculation determines the size and strength of the injection molding machine needed to complete your project. 

Molding machines are classified in sizes based on their clamping force, from five tons to 5,000 tons of force. The larger your tonnage, the larger the machine is necessary. Calculating tonnage is a key step in every injection molding project because without the correct value, you may choose a machine too small or large for your mold, leading to costly damages to each. 

Why Does Tonnage in Injection Molding Matter?

Miscalculating the necessary tonnage for your product can result in damage to the molding machine and your part or prototype. Excess and insufficient tonnage can weaken the injection molding machine and damage certain parts within it, leaving it out of production and pricey to replace. Improperly calculated tonnage can also lead to a range of defects and errors in the creation of your machined part, including:

  • Burns – Air vents within the machine allow air from the cavity to be released. Too much tonnage can pinch these shut, resulting in air being trapped and growing hot enough to scorch your part.
  • Imperfections – When the tonnage amount isn’t appropriate for what your part requires, your part may have deformities, size inconsistencies, gloss level changes, and other imperfections. 
  • Inconsistencies – If you’re attempting to produce high volumes of the same part, they may differ from one another should your tonnage be miscalculated.

These flaws degrade the quality of your creations and often require another round of injection molding as you finetune the correct tonnage necessary. Save yourself time and money by ensuring your tonnage is calculated correctly from the start.

How to Save Money and Boost Accuracy When Calculating Tonnage in Injection Molding

In order to avoid costly mistakes and flawed batches of your products, achieving the correct tonnage is critical. Follow these three steps:

Calculate the Tonnage

Calculating the tonnage begins by multiplying the length of the cavity by the width in order to calculate the cavity’s area in square inches. Next, multiply the area by a tonnage factor, which is supplied by the material’s supplier. This value typically ranges from 2 to 8 and is measured in tons per square inch. 

To provide an additional layer of safety in your calculation, add a safety factor of 10-15 percent to your final number. This boost is small enough that it won’t add enough additional force to damage your creation with excess tonnage, but still large enough to allow for flexibility in your calculation in case more tonnage was needed than what you determined.

Dive Deeper: Learn more about how to calculate tonnage and clamping considerations.

Perform Mold-Flow Analysis

In order to ensure a more accurate tonnage calculation, we recommend utilizing mold-flow analysis tools. Mold-flow analysis is a computer simulation that examines how the resin should flow through the mold during production. This can provide more accurate measurements and help catch problems early in the design phase to avoid costly mistakes down the line.

Trust the Experts

The best way to ensure your products are of the highest quality and don’t include avoidable mistakes is to trust expert plastic injection molders to carry out production. As a high-quality injection molder with decades of experience bringing designs to life with the correct tonnage, we have all the tools and software necessary to ensure your projects have the proper tonnage every time. 

When you partner with professional plastic engineers like Deluxe, you can count on our skilled team to take away the stress of calculating tonnage in injection molding. We have the equipment and extensive experience to calculate the correct tonnage for your project the first time and avoid wasting your time and money with miscalculations. 

Contact Deluxe When Calculating Tonnage in Injection Molding

When you need to ensure you’re calculating tonnage in injection molding accurately before you risk needing to repeat production, we’re here to help.

Deluxe has nearly 100 years of experience serving customers like you with unparalleled service and top quality products made precisely to your requirements. From automotive to industrial to medical sectors and more, we serve a wide range of industries with superior molded products. Our robust quality management system and ISO 9001:2015 certification showcase our ability to create accurate, premium parts and prototypes every time. 

With 55 injection molding machines and a team of experts ready to determine the accurate tonnage for your project every time, we have the tools and techniques to empower your injection molding needs. Contact our team to help you save money and boost the accuracy of your injection-molded products today.

Deluxe Plastics Staff

Deluxe Plastics is a world-class injection molder that serves a variety of industries such as hygiene, appliance, industrial, and commercial. Since our inception back in 1928 we have been a family owned business that takes great pride in serving our customers. We continue to innovate and focus on quality and on-time delivery which allows us to provide superior products and services to all of our clients.

Full-Service Injection Molding & Engineering

Areas Served

Clintonville Location
220 Industrial Avenue
Clintonville, WI 54929
(715) 823-4200
(715) 997-7068

Medford Location
939 South Whelen Ave.
Medford, WI 54451
(715) 748-2227
(715) 748-1145




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