When you need to manufacture a rubber part with a distinctive shape, platen-based molding processes provide high-quality results at an attractive cost per part. By pressing steel platens onto heated rubber stock, the material distributes evenly to achieve the intended shape. While this process offers many advantages, rubber may stick to the steel platens and slow production. Here’s how a Magnaplate surface treatment helped one rubber part manufacturing customer keep its presses in motion.

The company required an anti-stick coating for steel press platens used to press two sheets of uncured rubber stock to a set of steel cables that form the core of a conveyor belt. The press runs at room temperature under 560 psi, and the platens each measure 84 by 39 inches. The rubber is similar to tire compounds as well as one type with a lot of natural rubber mixed in.

Whenever the press was opened, it was as if an “explosion” occurred, according to our customer. The rubber would stick to the platens, and separating them each time was a struggle. Our customer had to buff the platen as often as every two workpieces in order to remove the rubber buildup.

To address the sticking issues, we applied one of our Plasmadize® surface treatments. Plasmadize thermal spray composites are custom-blended with metals, ceramics, polymers and dry lubricants to suit application needs such as non-stick and release properties, wear or friction prevention and chemical resistance. In fact, Plasmadize surface treatments can resist acids, alkalis, chlorides, most organic solvents, sulfites, thiosulfates and pulp bleaching chemicals. These coatings are especially desirable and cost-effective for use with large surfaces or parts like steel press platens. Additional features and specifications include:

• A wide operating temperature range of -200 to +1,300 F (-129 to +704 C).
• Thicknesses from 0.002 to 0.010 inch.
• Hardnesses beyond the Rc scale.

After the steel platens were coated with Plasmadize, the customer no longer experiences explosions or has to play tug-of-war with the press. In fact, the staff was thrilled to watch the first “shot” release all by itself — without any noise!

Magnaplate surface treatments have proven effective when addressing sticking problems in many industries. When sticking threatens your equipment uptime and reliability, our engineers can help you select an appropriate coating — like Plasmadize — to improve the non-stick properties of critical surfaces so even the stickiest substances will release easily.

For more information about Plasmadize, please visit our product page.