How Plastics are Machined and Assembled

December 08, 2016

Plastic machining and assembly in Toronto consists of different processes during manufacturing. Different methods utilized for different plastic parts in order to meet client requirements, such as injection molding, thermoforming and blow molding. Once the manufacturing is finished, it undergoes fine tuning.

The process of machining is considered only a secondary method in cases where the plastic materials have already been molded or formed. Machining is performed on plastic materials that are in solid forms such as bar, rod, or flat sheet. There are differences between how machining is performed in both plastics and metals because of these reasons:

  • Thermal expansion. Plastics can expand up to 10 times more compared with metals.
  • Plastics are known to be more elastic than metals.
  • Metals have faster heat dissipation rate than that of plastics.
  • It is easier to melt plastics while metals require very high temperature.

There are three classifications of plastics which determine the resulting effect of machining:

  • Soft plastics. With this type of plastic, machining will produce curly and long chips.
  • Hard plastics. When hard plastics undergo machining, the resulting materials will form into short shards with resemblance to crystal.
  • Reinforced plastics. Reinforced plastics contains abrasive fibers thus the need for very sharp tools during machining.

For machining and assembly to be completed, the parts must be assembled after it has been machined. There are different methods used in joining plastic components with another plastic or metal.

  • Mechanical fasteners. Installation of the fasteners can be either manual or automated. Some examples of fasteners used are eyelets, rivets and screws. In order to make sure the mating screw is in place, a threaded metal may be used as reinforcement.
  • Snap-fits. These are also fasteners but installation must be done by molding it along with the plastic parts to be joined. Once assembly is done, it locks in place very easily. It’s the best option for quick and easy joining of different parts.

If the above options are not feasible, welding techniques may also be employed to assemble plastic materials such as:

  • Ultrasonic welding. This type of welding employs longitudinal vibrations with high frequency range.
  • Spin welding. This welding is done by creating frictional heat through the rotating component that rubs continuously on a stationary component.
  • Hot Gas welding. With this technique, a welding gun releases inert air or gas.
  • Vibration welding. A component vibrates through this welding method which then produces frictional heat.

Many factors are involved in machining and assembly, therefore it is important to choose the type that is compatible with the materials. For any questions about machining and assembly in Toronto, contact our helpful staff at RWD Tool & Machine LTD.