Why Knowing Melt Temp Is Critical!

Measuring melt temperature in plastic injection molding is critical because it directly affects the quality, strength, and consistency of the final product. Here’s why it’s essential:

1. Material Properties Control

• Different plastics (like ABS, polypropylene, or polycarbonate) have unique melt temperature ranges where they achieve optimal flow properties. Keeping the melt temperature within the required specifications helps maintain the plastic’s intended properties, such as flexibility, strength, and durability.

2. Avoiding Material Degradation

• If the melt temperature is too high, the plastic can start to degrade, leading to issues like discoloration, loss of strength, or release of gases. Degradation also results in poor surface finish, increased brittleness, and, in severe cases, contamination of the final product.

3. Consistent Mold Filling

• Accurate melt temperature is crucial for ensuring the plastic fills the mold uniformly, preventing defects like warping, incomplete filling, or sink marks. Proper temperature control also allows for better control over flow rate and viscosity, which affects part dimensions and surface finish.

4. Reducing Waste and Defects

• By consistently controlling the melt temperature, manufacturers can reduce the number of defective parts, resulting in less wasted material and lower production costs. It helps maintain consistent cycle times and minimizes the chances of rejected parts, saving time and resources.

5. Optimizing Cycle Times

• Maintaining the correct melt temperature helps reduce cycle times by balancing cooling and solidification without compromising quality. Overly high or low temperatures can lead to extended cooling times or require rework, affecting overall production efficiency.

6. Enhancing Mechanical Properties

• Incorrect melt temperatures can weaken the final part’s mechanical properties, leading to failures in applications where strength and durability are critical. Proper melt temperature ensures that the plastic has the correct molecular orientation and crystalline structure for improved performance.

Monitoring and controlling melt temperature in plastic injection molding ensures that parts meet the required specifications and that the process runs efficiently and cost-effectively.

Success Story from Tim Roe, Process Engineer, Nolato Contour

Our corporation currently has 22 MTMS kits. The system is being used at sampling to document melt temperatures. Then the MTMS Kit is used to trouble shoot issues when they arise during production. The repeatability is very good as the system eliminates the human error when measuring the melt temperature.We were validating a new tool for a medical application which required more volume than we could produce with a single tool. When validating the second tool, the cavity pressure decay curve was off by 3500 psi while the input setting where the same as the previous press setup. The MTMS system was utilized and found that the melt temperature was off by 30 degrees F. The temperature difference was due to a different screw design. The melt temperature was adjusted to match the first press output, and the cavity pressure curve came back to within 150 psi of the original cavity pressure curve. All this was done in less than 2 hours. This issue was solved with the aid of the MTMS.