Watson-Marlow adds polish to Arista's printing process

Arista Tubes Ltd, a packaging manufacturer for the pharmaceutical, cosmetic and food industries, used the Six Sigma programme to focus on its lacquer-printing area, which formerly relied on a manual-thinning process to control the media’s viscosity, or stickiness.

Initially, Arista used diaphragm pumps to deliver lacquer from the newly installed controller to the roller applicators and then back again. However, because the lacquer flowed through the body of the pumps, cross-contamination quickly became a problem.

“When you change from one lacquer to another, you have to clean everything,” says Dean Onno, Arista’s Six Sigma implementation manager. “Unfortunately, there was no easy way of cleaning the diaphragm pump and it became coated with lacquer, which had the potential of affecting the overall look of the customer’s tube. For instance, the lacquer might not cure properly, or it might not be as shiny as we expected.”

Dean describes the diaphragm pumps as the weakest link in the new system, a position that became untenable when he discovered Arista spent up to £200 a month maintaining the pumps which often failed.

“We had to come up with a solution,” Dean says. “It made sense to move to peristaltic technology, so we looked at three manufacturers and Watson-Marlow came up with the best pump in terms of guaranteeing the integrity of the tube, which was crucial because we wanted to run it continuously.”

With no valves, seals or glands, and the lacquer only making contact with the inside of the pump’s tube, cross contamination was quickly eradicated following the introduction of Watson-Marlow’s high-performance 521 pump. The close-coupled industrial circulator also provided a double-headed solution that was able to send lacquer from the viscosity controller tank to the printing rollers and back again.

Incorporating low-friction rollers; a fixed track gap and spring-loaded roller arms to minimise roller impact, the 521 was able to deliver versatile and reliable pumping in Arista’s challenging operating environment. It also featured an easy-grip hub and clutched rotor, which Dean says helped Arista cut contamination and slash changeover times.

More information on 500 series pumps