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Chemical copacker cuts out inkjet maintenance, supervision

For certain SKUs at Mill-Chem, the switch from continuous to thermal inkjet meant simplicity alongside reduced babysitting and cleanup.

Redimark T12 thermal inkjet system
Redimark T12 thermal inkjet system

For more than 30 years, Mill-Chem Manufacturing, Inc., Thomasville, NC, has served as contract manufacturer and contract packager for private label household chemical products. As a SIOP (Sales Inventory & Operations Planning) business, the company’s portfolio is varied, producing cleaning supplies for janitorial/industrial markets, branded personal care and home use cleaners for the consumer side, and even some nutraceuticals or specialty enzymes destined for food producers.

But even with such wide a variety of products, there exists a common thread. As the company grew, it began to differentiate itself by gravitating to “green” cleaning formulas, with “green” meaning organic in this case.

“We were one of the first companies in our segment to try to go green,” says Elliott Miller, Asst. Production Manager, Mill-Chem. “We had our struggles at first, but now, of our 350 different products, roughly 30 percent of them are organic.”

Floor care products, household cleaners, and laundry detergent are among Mill-Chem’s largest volume categories, as are fully organic cleaning products that are shipped to retail destinations like Walmart, Whole Foods, Lowe’s, Kroger, Meijer, and Ace Hardware. Increasingly, Grainger and Amazon fulfillment centers are the products’ destination.

Coding and marking a priority
Given the plurality of SKUs moving through Mill-Chem at any given time, the complex chemical nature of the products, and as a requirement to maintain its organic and GMP certifications, traceability to batch and lot is important to the company. It's also important to its customers, and to the retailers that sell the cleaners and detergents. This puts a lot of pressure on the coding and marking systems—not only to accurately mark product, but to handle a variety of geometries and sizes and keep the line up and running without smearing or clogging that would create downtime.

“I'm always trying to find a way to be more efficient because the less money it takes me to put a bottle together and to package that bottle, the more money I make on the backend,” Miller says. “Coding and marking is an important variable in that equation.”

He says has used well over a dozen different types of coding and marking systems in his more than 27 years with Mill-Chem, with continuous inkjet being the most recent standard. But Miller perceived problems with some continuous machines in that each print head required maintenance and constant observation to be sure it was working. It became labor intensive to be constantly cleaning the heads to keep them functioning as they were supposed to. And if the heads aren’t constantly maintained, that can lead to line stoppage, he says.

“A line that’s down in my production facility comes out to roughly $725 per hour that I lose in labor, overhead and lost earnings,” Miller says. “That's not including product loss for errant marks, smudges, and things that require rework. And we tend to run at about 1,600 to 1,700 bottles per hour, so that’s the amount of product we aren’t moving through for every hour we’re down. That’s a lot of opportunity cost.”

He also noticed that continuous inkjet coders require two inputs—ink and attendant solvent—so there’s more to order and more to inventory than the alternative, cartridge-style coders that require a single input. He began experimenting with cartridge-based thermal inkjet, an impulse capillary vaporization technology that essentially superheats liquid ink to a vapor in the form of a bubble, then without the need for any pressure, applies superfine ink particles in such a way that allows for extremely high resolution and small character size.

Now, a tradeoff with this technology is the throw distance. Thermal inkjet requires close proximity to the substrate, less than 4 mm compared to continuous inkjet’s 10 mm or more. But for the right set of applications, Miller saw promise in cartridge-based thermal inkjet. Even so, his first foray into this tech unfortunately left a lot to be desired.

“My first cartridge coder wasn't a touchscreen; it used a dial that wasn’t very intuitive for operators to use. But more importantly, the cartridge leaked profusely, and that caused a lot of problems because leaking ink got inside the coder and caused shorts. I probably had to scrap 1,000 or so filled bottles in the six months I was using that system because of those cartridges. Every bottle was money, so you can do the math on what I lost there.”