Source: RJG, Inc.
The concept of DECOUPLED MOLDING(SM) is simply separating the molding process to specific fill, pack and hold portions of the process. Then, utilizing this separated approach, we teach the process o
The concept of DECOUPLED MOLDING(SM) is simply separating the molding process to specific fill, pack and hold portions of the process. Then, utilizing this separated approach, we teach the process of molding from the plastics point of view. A Decoupled II process suggests filling to position, then joins the packing and holding phases together, utilizing second stage pressure to pack out the mold and hold until gate seal. Decoupled III is a process of filling to a position, utilizing a second stage of fill or machine packing to pack the mold to a set cavity pressure, and then holding over time until gate seal is achieved. Decoupled III is most commonly applied using cavity pressure set-points to control packing, but a machine Decoupled III is also taught. The basic premise of the Decoupled II and Decoupled III process' are as follows.
DECOUPLED #2 Benefits:
- Repeatable injection speed control compensates for effective viscosity variations while filling the mold - reducing variations in the cavity(ies) during this phase.
- Filling speed is independent from how the mold is packed.
- Cavity to cavity imbalance has less effect on how much plastic is packed into each cavity.
Additional machine requirements: DECOUPLED #3 Benefits:
- Packing and holding are coupled from the "plastics point of view."
- Packing is viscosity sensitive and will vary.
- Same as all benefits of Decoupled #2!
- Independent control of packing rate and how much plastic is "held" in the mold.
- Packing the mold is not viscosity sensitive when using cavity pressure transfer.
- Allows precise control of the amount of plastic packed into the cavity(ies) due to low inertia effects.
- Most repeatable method of molding.
Additional machine requirements:
- Packing the mold to a position transfer, in lieu of cavity pressure transfer, will allow more variation due to changes in viscosity and non-return valve performance.
- Cavity pressure control - preferred.
- Injection velocity profiling capability with very repeatable low velocity performance.
RJG, Inc., 3111 Park Drive. Tel: 231-947-3111; Fax: 231-947-6403.