The Pro’s and Con’s of Mold Insulation

I just received this question regarding adding insulation between the mold and the platens…

I want ask you if it is a good to put plate between mold and machine platen? Some technician told me yes, cause you need isolate warm mold from cold platen.

My Response
Just to clarify for our readers… many injection molders will position insulation plates between the A and B clamping plates and the stationary and movable machine platens. The purpose of these plates are two fold… (1) to prevent the machine platen from influencing the heating and cooling of the two mold halves in an attempt to stabilize mold tempertaure. (2) to reduce the heating and expansion of the platens… which may affect mold safety on larger machines and clamp tonnage on toggle machines. Over time, this can also affect the squareness of the molding machine.
Most processes can benefit from these plates as they tend to eliminate variables in the process and reduce machine maintenance. There are two ways to go about adding insulation plates to the molds.
Wrong Way – Many injection molders solve these problems with generic plates they just wedge between the mold and the platen during setup. I am not in favor of these plates as they get damaged easily and can shift during production. If they get damaged, they can apply uneven clamp tonnage which will affect part quality and platen alignment. If the plate shifts, you can create a serious risk to both your employees and your equipment.
Right Way – Such plates should be individually fitted and bolted to both the A and B half of each mold. This approach will help prevent damage to the insulation, and ensure consistent performance in the application. This may seem like an expensive option initially, but the reduction in die setting time and uniformity of clamp tonnage should outweigh the initial expense.
Additional Thoughts
These systems most benefit anyone operating a hot runner system, hot sprue, or high-temperature molding application with oil-coolant will benefit from an insulation plate between the clmap plates and the platens.

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