Executives of Plasticraft Corp. and Dutchland Plastics Corp. had very different reasons for getting into industrial blow molding years ago, but they say adding the process recast both Wisconsin rotational molders as hollow-parts experts.
It's rare for rotomolders to diversify into blow molding. Peter Mooney of Plastics Custom Research Services in Advance, N.C., said only five North American rotomolders out of about 400 also offer blow molding.
Offering both processes means a company must invest in two sets of technology and skills. Rotomolders also face intense competition from existing industrial blow molders hungry to replace business lost in the depressed automotive sector, said Mooney, who has written reports on both processes.
Many rotomolders are small, so the investment can be daunting. But Gurnee, Ill.-based consultant Glenn Beall said more rotomolders should consider blow molding to retain higher-volume business that they end up losing to blow molding, which offers much higher outputs. He said a 55-gallon drum can be blow molded in 90 seconds to three minutes, while a rotomolded drum can take 15 minutes to an hour.
Plasticraft added blow molding in 1995, just five years after the company started in Darien. Plasticraft was rotomolding a monster product: hollow bases for driveway basketball setups that fill with water. The high-volume work maxed out Plasticraft's rotomolding machines.
``We certainly have redefined ourselves over the years,'' President Matthew Bushman said. After adding both processes around 2000, the company came to think of itself as a maker of hollow plastic parts. ``That's how we define ourselves, not as a rotational molder and blow molder. We don't care how it's made.''
Bushman, interviewed recently at Plasticraft's 200,000-square-foot factory, said the company can assist customers in designing products and in determining the more economic process that helps them compete.
Both Plasticraft and Dutchland started from scratch to add a new technology. Dutchland's employees adapted to blow molding. Bushman said Plasticraft tried to hire experienced people, but it didn't work out, so the firms' rotomolding employees tried and learned.
``It was so much fun,'' Bushman said with a sarcastic chuckle. Sometimes experts think their way is the only way, he said. ``We know what you can and can't do because we've tried most of the things and we've had a lot of failures and a lot of successes.''
Plasticraft runs seven extrusion blow molding machines, all Milacrons, with shot sizes of 5-35 pounds.
Consultant Beall noted that blow molders can run a broad range of resins, including engineering resins.
But rotomolding has advantages, too, including relatively inexpensive cast tooling.
``Once you get a down-and-dirty rotomold tool and throw it up on an arm, you can literally have a part in about an hour and a half,'' said Carl Claerbout, president of Oostburg, Wis.-based Dutchland.
Once production begins, the part can go straight into blow molding, if the plastics processor is involved in part design.
Blow molding is doing well for Plasticraft, even though the basketball base business ended up moving to China, Bushman said. A year and a half ago, the company added 40,000 square feet of space to make room for more blow molding.
The company runs 10 rotomolding machines, all independent-arm Ferrys. Earlier this year, Plasticraft added an Orenda pulverizer, so it can do in-house resin grinding.
Plasticraft employs 150 and generates sales of $15 million to $20 million a year. Its markets include toys, materials handling, displays, tanks, sporting goods, and lawn and garden.