Our customer injection molds plastic rings that are about 12” in diameter. The rings are a food grade plastic used as edging on round food containers. If they just pile the rings in a box, they get deformed, so they needed a machine that could stack them in a neat column and then secure them with a sleeve of heat shrink plastic.

Packaged this way, the rings arrive undamaged and their customer can load the rings into their machine easily. We designed and built a machine that automatically stacks the rings on mandrels.

There are four pairs of mandrels, mounted on an indexing table, so when two stacks are completed, the machine indexes to start the next two columns of rings. An operator slips a tube of heat shrink material over the two finished columns of rings and when the machine indexes again, the mandrels are spun in front of heater elements that shrink the sleeve tight against the column of plastic rings. Finally, in the fourth station, the operator removes the sealed stack of plastic rings. Contact us today to learn more.


Product Description

This system is used to automatically stack and seal 12″ plastic rings.

Capabilities Applied/Processes

We designed the new machine in 3D Cad and then produced our own set of prints for our internal manufacturing needs, some of which were then processed with CAM software to develop CNC programs used to run the parts.

We also designed, wired and programmed the controls in house.

Equipment Used to Manufacture Part

We used manual and CNC mills, lathes, and Wire EDMs to make all the parts. We also had weldments that were welded in house.


Stacked the parts automatically, which saved labor time and cost and reduced human contact for better sterility of the product.
Secured the rings for damage free shipping.


The included in feed conveyor stages the rings and pushes the rings out onto a trap door style dispenser. When rings are in position in both trap door stations, they are dropped onto the mandrels below. Four pairs of mandrels are mounted to an indexing table and the mandrels all spin.

When the stacks are complete, the indexing table spins a quarter turn to start the next stacks. The operator then slips a tube of heat shrink material over the two completed stacks of rings. When the machine indexes again, the spinning mandrels spin the stacks and the heat shrink sleeve in front of heater elements that seal the stacks.

Overall Part Dimensions

10’L x 45″W x 72″T

Tightest Tolerances


Material Used

Mild and Stainless Steels, Aluminum, Delrin, UHMW, Conveyors, Ceramic Heater Elements.

Material Finish

Anodize Plating, Powder Coating

Industry for Use

Injection Molding, Food Packaging, Dairy Industries


Eight Parts Every Ten Seconds

Delivery/Turnaround Time

Four Months from Receipt of Order to Delivery

Delivery Location

Lee’s Summit, MO

Standards Met


Product Name

Ring Stacking Machine