Mold should fit "right" against order quantity that is two meanings.

* Quantity to be produced with regular quantity

1.) Cycle Time: (shots/min)

  • Cooling structure & cooling metal type
  • Part remove method: Free fall / robot arm / manual
  • Hot runner: maybe it is a valuable investment considering labor cost and non-recyclable resin like PC or GPPS, if parts is transparent.

2.) Cavity Number

Cycle time x Cavity number = Quantity/Min. These two are interrelated. The better cooling effect, the fewer cavity number you need. It is hard to tell which is more cost-effective, since it depends on parts case by case. Leave it with us. We can make some reference after study drawings.

* How many years will this product be ordered?

3.) Mold Lifetime

We have three classes of mold lifetime guarantee as 300,000 shots, 500,000 shots and 1million shots with different steel hardness and components standard.

Four levels tolerance can be assigned as Normal, Accurate, Precision and Precision Special. It is expensive to pursue high tolerance group in injection molded parts, since many factors have an effect on the dimensioning besides mold tolerance.

  • Material: type, shrinkage rate, stiffness
  • Process condition: injection molding machine, environment, personnel
  • Design: uneven wall thickness

Molded parts where tolerances are not complied with do not have to be rejected if the function is "right".

Based on properties of the plastics, the functional accuracy may not be as high as you expected. Provide fitment parts and we will choose suitable tolerance group with effective mold cost.

pdf logo DIN16742 Plastics Moulded Parts Tolerances

injection molded parts tolerance

"Right" mold must fit plastic material applied. Four factors of material are taken into accounts in mold building.

1.) Difficult molded material: The surface defects occur often.

  • Polycarbonate: any chance to be replaced with PC+ABS?
  • GPPS with thin wall: any chance to add some HIPS?

2.) Transparent parts with PC or GPPS. Need special steel with high polish capability.

3.) Corrosive material: PVC. Need stainless steel.

4.) Abrasive material: PA or PP or PC with glass fiber filled. Need high hardness steel.

plastic material