The added cost of gear pumps can be justified by savings of material because aim thickness can be lower. Another benefit is reducing the load on the extruder, which may include pushing the melt through a static mixer to improve appearance, properties and maybe production rate.
Allan Griff started attending NPE back when it was held in the Chicago Stockyards exhibition area. A lot has changed since then, but the essentials remain the same.
Screw design is important but it’s not the only factor, as mixing can also be promoted by static mixers, water-cooled screws and wise selection of ingredients.
From PVC film and filaments for flame-retardant Christmas trees to the shrink wrap on turkeys, Allan Griff counts the ways that extrusion applications make the season merry and bright.
Distinguish between preventive and responsive maintenance. Preventive maintenance includes calibrating instruments and testing incoming raw materials. Responsive maintenance fixes what’s broken, of course, but should also include written records of such actions.
When troubleshooting extrusion issues, many people look to the equipment. Allan Griff explains why you should also look at materials for solutions, especially because that’s where most of the money goes.
I’ve talked in past columns about the four evils of overheating: Polymer degradation, cooling problems, sizing problems and the effect on additives. Summertime seems like a good time to revisit and expand on this theme.
To estimate the value of a used extrusion line, invoke the rule of thirds: Offer the seller one-third of the cost of a new line similar to the used one and set aside another third to fix what’s broken and for shipment expenses. The final third is your reward for buying used.
