Twin sheet forming keeps slushie maker cool and collected

Twin-sheet formed lid insulates commercial juice and frozen drinks

A food service equipment manufacturer had to overcome a problem with their existing drink mixer. They turned to Profile Plastics to create a clear insulated lid that outperformed the original design. 

Drink mixer lid project background

The OEM’s original point-of-sale drink dispenser was a common sight for decades at frozen custard stands and burger joints across America. Two clear tanks with spiral mixing paddles were mounted above the cooling unit and dispensers. The contents were often brightly colored juice-flavored drinks or frozen slushies. 

Even though the product line was approaching end of life, reports of problems with the insulated tank lids were coming in from the field. The product team needed to solve a quality issue that stemmed from the design and manufacturing method. 

Challenge: Surface cracks came from the design

The lid was designed to promote the mixing function of the drink dispenser as well as keep the liquid cold. Originally, the lid used two injection molded polycarbonate parts ultrasonically welded together. 

Unfortunately, the welding weakened the plastic and caused stress on the two parts. Surface defects called crazing, a network of fine cracks, showed up especially around the corners. 

The design was also insufficient for normal use in the field. It was easily damaged when food service employees removed the lids to refill the tanks. Even the temperature difference between the inside and the outside layers of the lid contributed to crazing.

Solution: Twin sheet forming the lid as a single part

insulated clear twin sheet thermoformed lid

Profile’s experience with twin sheet forming was key to solving the customer’s lid problems. 

In the twin sheet process, two plastic sheets are formed at the same time then fused together into a single structural piece. That eliminated sonic welds.

Engineers also recommended switching to PETG plastic, which provides nearly the same clarity with higher performance for the insulated application. PETG also costs less. 

Considering the late phase of the product life cycle, the customer decided to go directly to production tooling. That reduced development time and cost. 

Superior results

Drink mixer lid detail

The new part performed well in the field and Profile twin-sheet formed several thousand lids over a multi-year window. The lid won an award in a thermoformed part competition. Most importantly, success in the market provided the OEM time to develop their replacement product line.