Generally plastic rollers are non-drive rollers, that is, idler rollers used to allow movement of equipment as part of a device, or to allow the smooth movement or transition of materials or products over the roller(s).
Noise Reduction – especially when operating on hard surfaces, plastic rollers will generate less noise.
Smooth Operation – due to plastics have lower stiffness the roller will operate in a smoother manner generating less vibration.
Light Weight – In addition to reducing the overall weight of a piece of equipment or system, light weight rollers, such as Sustamid (1/7 the weight of steel) have less inertia and therefore rolling resistance.
Reduced wear – plastic rollers generally will have better wear life, especially when operating on hard materials, such as metals or concrete.
Cost-Effective – plastics are normally cheaper, but also provide further cost-benefits.
Cost-Effective – plastic generally offers a commercial benefit over polyurethane.
Chemical resistance – plastics offer broader chemical and solvent resistance.
Eliminate Hub – often polyurethane rollers are cast onto steel hubs to be fitted to a shaft or have bearings inserted. These hubs can be eliminated with plastic rollers, i.e. they can be fitted directly to a shaft, or have bearings fitted directly, and retained by traditional techniques such as press-fits and/or cir-clips/retaining rings.
Dotmar has qualified engineers that can provide direct support with plastic rollers, by conducting load capacity calculations.
Material selection is a critical consideration when choosing a plastic for rollers, as it directly impacts the performance, durability, and maintenance requirements of these components. Here are some key material selection considerations for plastic rollers:
Load
The geometry and how it contacts the counter-face, together with the counter-face material stiffness all contribute to the contact area, and therefore the load carrying capacity of the a roller and material combination
Rolling Speed & Time
The rolling speed affects the load carrying capacity of plastic rollers; therefore, it is imperative to take this into consideration when doing calculations. Higher speeds cause heat generation, and stationary load can result in creep, therefore the duration of operation under must also be considered.
Temperature
The surrounding temperature for both short- and long-term exposure is important, as materials can withstand higher temperatures for short term periods compared to long term or constant exposure, which in turn affect their load carrying capacity. Heat aging is also a consideration. This is where specialised roller materials can make the difference.
Wear and Abrasion
Abrasive conditions provide different challenges to clean environments, and therefore the material selection. Materials such as Sustamid provide good all-round performance.
Friction
The co-efficient of friction affects the rolling action, therefore selecting materials with an appropriate level of friction to suit the application will result in improved performance.
Regulatory Requirements
Does the application have regulatory requirements such as food contact, drinking water, anti-static or flame retardant. The food industry may also require materials to be metal detectable, x-ray detectable and/or visually detectable by being coloured blue.
Other considerations
At times there may be other considerations such as chemical resistance, dimensional stability, machinability, insulation (thermal and electrical) and impact.
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