In almost any application where there’s a drive, driven or idler lever, engineers and designers have to think about the qualities from the materials utilized in timing lever construction before investing in your final design. Nylon and aluminum are two of the most common construction materials for timing pulleys. Both materials get their pros and cons with respect to the application.
Nylon timing pulleys are lightweight, offering excellent inertia control which enhances energy savings. They have good put on characteristics, natural chemical resistance, material financial savings and also have no oxidation issues.
Aluminum timing pulleys will also be considered lightweight, although heavier than nylon. They’ve moderate inertia control, and display excellent put on characteristics. They’re robotically durable, but possess some oxidation issues if untreated (obvious coat or anodizing).
Additives towards the nylon can provide the finish user important, and often necessary, qualities including material that’s UL94-V0 flame retardant, Food and drug administration and RoHS compliant or non-conductive for static sensitive processes. Nylon pulleys, timing or else, don’t have any magnetic signature. With respect to the application, the tensile strength of nylon, although under those of aluminum or steel, is frequently greater than sufficient for low or fractional horsepower drive systems.
For designs where timing pulleys might have to endure temperatures exceeding 120 levels Celsius (250 levels F), nylon pulleys are robotically seem, but they are approaching a temperature where material deflection is really a possibility. Most synchronous timing belts possess a maximum suggested operating temperature close to 82 levels Celsius (180 levels F). Although financial savings will make a nylon lever attractive, in hot temperature applications aluminum could be the smarter choice. Either in situation, the restricting factor would be the temperature where the selected belt will fail.
Nylon is a touch less then 2.5 occasions lighter (g/cc) than aluminum when evaluating solid shapes. But, with regards to correctly designed timing pulleys, nylon is often as almost as much ast five occasions lighter than aluminum, yet able to experienceing this same torque and speed needs.
How’s that possible? Just since most of aluminum automobile wheels have 4 to 6 spokes in order to save cost and weight without compromising strength, balance or performance, exactly the same concepts apply with regards to designing and molding nylon pulleys.
The net from the lever and also the hub are equipped for strength, material savings, and price savings. For many nylon lever profiles, an aluminum web can be used to get rid of deflection, increase strength and reduce the opportunity of deformation throughout the cooling cycle after molding. Nylon timing pulleys could be provided as all plastic or plastic by having an over molded metal insert. These metal inserts could be provided using aluminum, steel and stainless and could be keyed, broached, splined and have set screws as being a solid aluminum or steel lever.
Both nylon and aluminum pulleys can discover double or single row radial bearings pressed in to the hubs. Both may also be provided with double or single flanges and provide a multitude of the most typical tooth profiles. Nylon pulleys could be provided as walked pulleys when several different pitch diameters are pressed onto a typical bushing and staked into position.