Scepter cuts plastic, costs with customized automation
In order to blow mold a 22 gal. wheeled garbage can for a U.S.-based customer, Scepter Corp. first had to solve a nagging problem--how to cost-effectively trim a two and one-half in. section from the ...
In order to blow mold a 22 gal. wheeled garbage can for a U.S.-based customer, Scepter Corp. first had to solve a nagging problem–how to cost-effectively trim a two and one-half in. section from the top of the can to provide a clean, flush fit with the can’s lid.
The challenge proved not to be as simple as it may sound. It also had important implications.
“This can has a 0.055 to 0.060 in. wall thickness in sections and a 65 second cycle time,” notes plant manager Don Villers. “I don’t think we could have run the can economically if we didn’t find an automated way to trim it.”
Villers enlisted the support of Minatech, a Scarborough, Ont.-based manufacturer of customized automation equipment. Minatech president Michael Mrvayan began working up-front on designing and building a cutting tool, even as Scepter was building the mold for the can. The can’s soft, hollow shape, which made it difficult to hold in a secure position, and the material, tough-to-cut HDPE, presented the biggest challenges in the development of an automated method to trim the can. Villers credits Mrvayan’s persistence and ingenuity in overcoming these hurdles and getting a quick grasp of the physics of cutting plastics.
Villers describes the automated cutter as essentially a rotary table that grasps and turns the can as two rotary saws are indexed into it, providing a controlled, clean cut.
“It’s fully automatic. The operator pushes a button, walks away, and out pops a part.”
Minatech has also designed a similar cutting system to trim the lid for a blow molded box used to store spare marine motor parts; as well, is currently working on a machine to install wire on the hinges of an injection molded container made by Scepter.
“We anticipate using more of this technology,” says Villers. “We’re focusing on equipment and processes that will help us keep our labor costs down.”
In addition to cutting systems, Minatech also makes automation for leak testing, de-flashing, and flame testing of blow-molded bottles, as well as assembly systems.