Thermoplastic drive parts a disruptor for Industry 4.0

Engineering thermoplastic gear, guidance and conveyor component systems have become disruptor technologies in production engineering as Industry 4.0 produces smarter factories and processing plants that are more efficient, hygienic and productive as well as less wasteful.

Drive components made from materials such as nylon, acetal and UHMWPE — material types originally introduced to the market to fill niche applications — are more often becoming materials of first choice, according to Laurie Green, Managing Director of Cut To Size Plastics.

This is happening as machine builders and production engineers seek out materials that will enable their digitally communicating Industry 4.0 systems to function faster, with closer tolerances, less maintenance and downtime, easier washdown and less need for constant lubrication, attracting grit and wear.

“Thermoplastic technology is advancing quickly to fill many needs and these materials are extremely tough. Ultrahigh-molecular weight (UHMW) gear racks in use internationally, for example, have shown part lives multiple times longer — sometimes 10 or more times longer — than their metal predecessors,” said Green. “While most gears were traditionally made from various metals, plastic gear technology is pushing the previous limits of load bearing, torque handling and gear drive capabilities.

“As well as being highly suitable for new machinery, these plastic gears and gear racks can be identical in design to their existing metal predecessors, making them directly interchangeable with steel and other OEM and custom metal gears and racks.”

Self-lubrication is a key benefit of nylon gears because a constant issue with many metal drive gears is the need for external lubrication — a major problem when gears are hard to access or where lubricant will only exacerbate a problem (such as gears that operate in high-dust or gritty environments), says Green.

“Acetal is also great choice for plastic gears, for example, because the typical objective in such a device is to minimise the friction resulting from contact. Acetal is very slippery (with a very low coefficient of friction) and therefore minimal energy is lost in the internal contact interaction between gears,” he added. “UHMWPE and other high-performance plastic gears and gear racks also offer wear and noise reduction advantages over comparable metal products. UHMWPE is generally looked to when impact resistance is key.”

Green’s company, Cut To Size Plastics, has worked with industries extending from food and beverage to primary livestock and crop processing, machine building, resources, materials handling, construction and manufacturing to develop hard-wearing OEM and easily retrofitted gear components for multiple applications.

“Major advances in engineering thermoplastics formulation technologies — and a growing realisation of their unique benefits — mean industry no longer is as firmly rusted onto metals drives as it once was. Today, the options are far more plentiful and attractive,” he said. “While there is no one ideal answer to all applications — whether you are considering metals or thermoplastics — it is important to consider all the options and not automatically revert to old choices that may no longer be optimum for new needs.

“It could be that old choices are best, but it could be more likely that a cheaper, more durable and better-performing alternative has evolved in response to Industry 4.0.”

When selecting a plastic material for a specific application, Green says it is important to base the choice on critical properties associated with the task, such as thermal expansion or the plastic’s ability to change in shape, area and volume in response to temperature changes. The coefficient of thermal expansion is the degree of expansion divided by the change in temperature. The higher the coefficient number, the more change in size. Several major thermoplastic compounds exhibit acceptable thermal expansion performance, including nylon, acetal and UHMWPE.

Image credit: ©stock.adobe.com/au/FrankBoston