About 400 people gathered Oct. 3-5 in Cleveland for the Association of Rotational Molders International's fall meeting. Plastics News senior reporter Bill Bregar filed these news items.
Pneumatic clamps made for rotomolding
Rotomolding machine operators typically use air-powered tools to remove bolts and open a mold, but industrial clamp maker De-Sta-Co Industries Inc. is pitching ``lean clamping'' using pneumatic clamps that open quickly.
The Madison Heights, Mich.-based firm has launched a line of clamps for rotomolding.
The company sold its general-purpose clamps to the rotomolding sector for years, but found that customers adapted the clamps to their manufacturing process, said Raymond Pachuta, a manufacturing applications engineer. ``So we've created a handful of products based on the modifications the mold builders and molders were making,'' he said.
Pneumatic clamps reduce repetitive-motion injuries and cycle times, and can cut labor costs, the company said.
In a case study, Pachuta said one molder was using two workers on a large-part job, one to unclamp the mold one bolt at a time and remove the part, and the other to load the mold with plastic. The pneumatic clamp takes just one or two seconds to open, cutting several minutes off the cycle time, Pachuta said, and the job now takes just one operator.
The system also provides more-consistent pressure all the way around the mold, reducing flash. ``It greatly reduced their trimming times and flash,'' he said, adding that the $4,000 investment paid for itself in four months.
Littleford Day offers primary equipment
Littleford Day Inc., which makes high-intensity mixers and upstream equipment for rotational molding and for vinyl pipe, profiles and windows, has entered the rotomolding primary machinery business.
The Florence, Ky.-based company started production three months ago and rolled out its rotomolding line at K 2004, said Charles Kroeger II, vice president of sales.
The machinery components are made in Brazil, then shipped for final assembly to the company's Italian unit, Littleford Plastic International srl in Milan, and to Florence. The Italian operation builds the machines for European customers.
The company is making two models, a single-arm machine and a carousel machine. The carousel comes in three sizes, with a swing of 8, 10 or 11½ feet.
Kroeger is director of the Italian operation. The general manager is Andrea Ferro, who formerly was with Italian rotomolding machinery supplier Caccia Engineering SpA.
Venting provides for safe pressure molding
Pumping air pressure into a mold can cut cycle times, but many molders are slow to change and worried about safety issues. Gareth McDowell has some answers from his company, called 493K Ltd., which works with Queen's University of Belfast in Northern Ireland.
493K's DynamiK venting, combined with pulsed pressure, pressures molds safely, McDowell said. In addition to cutting cycle times, internal mold pressure also reduces part warpage, he said.
The company is trying to standardize mold pressure for rotomolding. ``Safety is our prime objective,'' he said.
The system pulses pressure into the mold every 10 or 15 seconds. ``It's like pressurizing a mold, but doing it 20 times in one cycle,'' McDowell said.
DynamiK venting measures air pressure moving in and out of the mold, so users can tell if a pipe is blocked and the mold still is pressurized and presents a hazard.
McDowell said the pressure is pumped in at the back of the arm.
``The argument against pressurization is becoming weaker and weaker,'' he said.
