Plastics

Plastic injection molding offers high speed production capability. Plastic injection molding has its own unique challenges as thermoplastic material properties have wide tolerances. Also some thermoplastic material properties are dependent on process settings. Product/part development for injection molded plastics has become an international collaboration. During the process of product development and in production for injection molded plastic product/part multiple entities are involved. For most of the projects; design engineers, mold makers and production molders are not under the same roof, mostly not in the same country.

Plastic parts development can be categorized in 3 major stages

1. Part design
2. Tool/mold design
3. Process design

Part design guides tool/mold design and tool/mold design limits processing window and process window can limit part quality/performance. Each stage is usually team effort with suggestion/recommendations from other stage experts. Each stage has its own challenges and guidelines from other 2 stages. Thermoplastic injection molding is sometimes treated as black box, as there are only guidelines no rules. With help of experts some guidelines can be pushed and some can be ignored. Most of the projects experience delays or defects in the parts due to lack of co-ordination between the 3 stages of development. Plastic material properties have wide tolerances than metals. Tooling and processing can influence thermoplastic material properties, i.e. crystalline materials which are mostly translucent can be processed to look clear by rapid cooling.

Injection molded plastic parts have following properties

  • Light weight - low density,
  • Low conductivity of heat and electricity - insulating properties,
  • Low hardness,
  • Lower strength than metals,
  • Ductile,
  • Dimensional stability- not as good as metal

But plastic injection molding also comes with following defects

  • Flow lines
  • Vacuum voids
  • Short shots
  • Burn marks
  • Sink marks
  • Weld lines
  • Warping
  • Jetting
  • flash

How we can help you

  1. We offer a complete product development services from part design, tool/mold design and process optimization.
  2. We have experts in all 3 stages of plastic parts development and can help consult on one or any combination of stages during product/part development.
  3. We can help with the smooth transition from design engineer to mold maker to production molder.
  4. We have deep experience in managing part design, mold development, mold validation and set up for production molding and secondary processes.