Except for off-the-shelf gears, plastic gears are never designed alone but in mating sets with specific functions. Plastic transmission design and development must therefore take into account the broader relationship of materials, drive layout, shafting, bearings, and housings.
While plastic gears give the engineer enormous flexibility, they are much more complicated to design and develop than those in metal. Injection-molded gears can achieve high quality standards. However, plastic properties and dimensions will change over the range of operating and environmental conditions. This means the engineering effort to accommodate such changes is accordingly greater.
The first step for the project engineer responsible for building a plastic transmission is assembling the expertise required. For most successful plastic transmission designs, the project engineer requires the cooperative effort of a gear engineer, plastics engineer, manufacturing engineer, quality-control engineer, molder, tool builder, and resin supplier. The team needs application information, first to choose a drive concept, then to select the appropriate materials.
Each gear set is sized first for nominal operating conditions, then modified by optimizing for worst-case operation. Computer programs enable drive designers to model gear sets in worst-case scenarios and make the required engineering decisions to optimize the gear set.
To speak with a Ticona representative, call the Ticona technical hot line at (800) 833-4882.
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