Computer aided design and simulation of an injection mold process for plastic gears

Gears are critical machine elements used in power transmission. Gears are utilized with other elements such as shafts, bearings, etc. to transmit torque and rotary motion from one shaft to another. Gears can be found in many applications from simple mechanisms like a tin can opener to rather complex helicopter transmissions. Therefore, gear design or selection is essential for the required duty (job) to be performed satisfactorily without any failure. Plastic gears (with relatively moderate loading capacity) are replacing metallic gears in many applications since the plastic gears are lighter, less noisy, and cheaper compared to metallic gears. Besides, plastic gears represent self-lubrication, corrosion resistance, and more forgiving tolerances than with metal gears. These plastic gears can be produced by hobbing, stamping, or by injection molding, and injection molding is one of the essential processes in the plastic manufacturing industry. Injection molding is used for mass production operations where it saves time and cost of manufacturing. In this project, the plastic spur gears are designed and manufactured by the injection molding technique. The Solidworks software is used to design the CAD model of the spur gear (molded part) and the mold components. The plastic tool of the Solidworks, also, is used for plastic filling simulation of the injection process. Then, the mold components are manufactured by traditional CNC machining and wire EDM cutting. Later, the mold is operated to produce plastic gear products with the use of (PA6 GF30) plastic pellets. Finally, the molded gears are inspected according to AGMA and ISO standards.