Molding & Tooling
Below are the different types of molding and tooling QC Plastics has the capabilities to do. Click on the titles below to learn a bit more about each type of molding.
- Pros: It cools much faster, may speed up cycle times and will last much longer that composite tooling. Used best for thinner gauge plastics.
- Cons: More expensive than composite tooling.
Water Cooled Molding
Generally the preferred cooling method because water does a better job at cooling parts at a consistent temperature. This is critical with high shrinkage plastics like polyethelynes.
- Pros: Reduces cycle times, parts are more consistent , tooling lasts much longer.
- Cons: More expensive
There are several different types of composite tooling, most commonly used are Ceramic, fiberglass, wood,foam, felt covered or epoxys.
- Pros: They are easy to handle, design,shape and repair. They are usually lighter weight and often a cheaper options.
- Cons: No way to control warping with certain plastics. They have a shorter life expectancy.
Single Cavity vs. Multi-Cavity Molding
Helps with cost reduction but has a higher up-front cost. Works best for shallow draw parts. Shorter lead times per batch.
Single Cavity produces one part per cycle where multi-cavity can produce multiple parts per cycle which in turn will speed up production time and minimize your cost per part.
Used to per-stretch the sheet prior to turning on the vacuum pump so the material doesn’t thin out. This type of mold gives a more uniform thickness throughout the part and is best used with deep draw parts.
Pre-Stretch Boxes (Snap Back Box)
This is the least expensive option vs a plug assist. The pre-stretch box is pushed into the heated sheet of plastic creating a seal to form around the edges. The vacuum sucks the hot plastic up into the box and stretches it to a desired depth, usually 2/3 of the depth of the part. When the plastic hits the desired height the vacuum is shut off the plastic is quickly “snapped” to the mold surface using the vacuum. This option can be applied in both make and female molds.
Male vs Female tooling (positive/negative)
- Male: Male molds(positive) are usually less expensive. Generally, male molded parts will retain color and texture better because the plastic sheet shrinks as it cools during the molding process and adheres to the mold surfaces.
- Female: Female molds (negative) are more expensive of the two but a better surface finish depending on the part design. Plastic will shrink as it pulls away from the tooling.
Often used with composite tooling, drape forming uses a single mold on which a sheet of heated plastic sags and conforms to the shape of the mold under it’s own weight or with slight pressure applied by the operator.