Resources » Blog » Custom Fixture for Plastic Drinkware

Custom Fixture for Plastic Drinkware

The red plastic cup. Something often found at family parties or American backyard events, the iconic red plastic cup has even been featured as the subject of a well-known country song. But, what happens when the product starts to become commoditized and brand-name manufacturers are forced to compete with generic or store-brand counterparts? Leading brands need to continue making their required margins no matter what happens in the marketplace. One of the best ways to do this is by reducing costs.

Reducing the cost of these plastic cups comes down to using less material or different formulations, risking production of an inferior quality product whether perceived or actual. Creating a durable product with the lowest material costs allows a company to be competitive on price and also maintain margins. This is where materials testing becomes a critical phase in product design. Being able to accurately test existing products to create a baseline and compare those results to new product revisions is the best way to qualify new designs.

By being able to test the durability of the cup in a true-to-use fashion, quality can be gauged to ensure that a change in design or material to save costs does not affect the customers’ perceived value or actual quality of the product. This allows a brand-name manufacturers to continue to compete and make their required margins in an increasingly commoditized market.

Typically, a simple top to bottom compression test is how these cups are tested, however this does not accurately reflect how drinkware is used. This is where our custom solutions group came in. Recently we completed a project for a leading plastics manufacturer that wanted to test cups the way they are used in the world, that being sidewall compression or how a hand typically grasps a cup. The difficulty of this application stems from the conical frustum shape of the cups. If the cup was tested by laying it on its side on the lower compression platen, the upper platen would first come into contact with the rim of the cup, not the sidewall. This would not mimic actual use (see image to the right).

The solution is a custom fixture where the bottom of the cup is attached to a mount which slides vertically and is counterweighted to not affect the test results. A set of compression anvils sit to the left of the mount; one fixed to the base of the machine and other attached to the moving crosshead. The mount can be adjusted horizontally for varying cup heights or to test different cross-sections as necessary. After the cup is attached, the sidewall rests on the lower anvil. The upper anvil is then lowered to contact the cup sidewall and begin the compression test.