Reduction and stablising of the rejections in plastic injection

All the versions of this article: [English] [français]

Gains achieved:

- Identification of the influencing factors and the adjustments to be made to minimise the rejection rate
- The rejection rate is levelled off and reduced from 7% to 5% over the whole of the factory in 2 months.

Company description:

Injection, treatment, cutting and assembly of polycarbon glass, about 100 employees.

Distinct peculiarity:

The presses were producing rejects inexplicably, despite mechanical devices and other controls.

Methods used:

- experimental plans (Taguchi method), trials
- visual management
- Parameters identified: type of machine, times and maintenance pressures 1 and 2, rotation speed of the worm screw, pipe diametre, rate of humidity of the material (granules), type of plastic material (Gilamide) colourings.
- Put in place follow up and work place training schemes.

Other benefits: Réduction rebuts injection plastique Rejection Rate indicator:

- reduction in the time cycles: increase in rhythm,
- homogenisation of the temperature,
- precision of the measurements,
- mastering expansion,
- applicable to silicon injections and thermoplastic elastomers.