Pellet shape matters for your plastic products, here’s why

Posted by ACS Valves on October 04, 2016
Pellet shape matters for your plastic products, here’s why

Plastic products with un-melted pellets fused into them? Or how about an extra leg on that doll you’ve designed?

Unique plastic products can set you apart from your competitors. But individuality in each separate end-product can sometimes come as a surprise, and your equipment might be to blame.

Getting the same, high-quality product that you meticulously planned for depends on pellet shape, and getting the right features in your equipment that won’t degrade your feedstock.

Here are some steps to get your proverbial rubber ducks in a row and ensure your products are looking great:

The importance of pellet shape

It’s important that your input doesn’t negatively impact your output when it comes to plastics manufacturing. This means maintaining uniform size and shape in your pellets and resins throughout the conveying process.

If there is any pinching or size variation, your plastics will melt at different rates during the molding process. If resins aren’t uniform, they won’t create identical parts during the molding process.

You or your buyers will also have partially melted polymers and pellets stuck in equipment—meaning much more maintenance and shorter equipment lifecycles. 

Maintain precise tolerances in your rotary valves

Make sure that your rotor to housing clearances stay at the NFPA compliant 0.004 inches to prevent friction and material drag. The clearances are there to prevent creating an ignition source in your rotary valves, but over time they will increase due to material wear. Your pellets will have the potential to get jammed or dragged inside the housing.

Eventually your rotor will need to be replaced. Keeping a proper maintenance log will give you a good idea of how often you need to replace it. 

No cracks or crevices mean longer equipment life

By avoiding material drag, you will also avoid creating cracks and crevices in your equipment where pellets can get jammed or pinched, shortening the overall lifecycle of your machinery. Applying the proper coatings to your machinery can also help with this.

At ACS, our valves are CNC-machined and have U-shaped rotor pockets, meaning fewer crevices from the get-go. These will also prevent material build up and keep your plastics flowing through your machinery.

Follow these tips to avoid any ugly ducklings in your end-product, and check out our rotary valves for plastics manufacturing here.