What is it?
Hand load mold inserts are mold components that are installed manually by an operator and then ejected with the molded part in order to create undercuts or threaded features.
Typical Method to Product Undercuts
Typically undercuts are created by side actions or core pulls that automatically retract at some point during the molding cycle. These features can be quite expensive to build and take time.
Pro's and Con's
| Hand Load | Core Pull | |
| Tooling Cost | Cheaper | More Expensive. Can be very expensive |
| Time to Build | Faster | Slower |
| Part Quality | Lower: Seam lines are more pronounced and prone to more flash | Higher: Seam lines are cleaner and less likely to flash |
| Durability | Lower: Hand loads, especially larger ones, are prone to damage from inserting into the mold or just being dropped. | High: Actions are never removed from the mold. They are more damage prone than fixed components |
| Part Cost | Higher: An operator is required by definition and parts run much slower. If an operator is required for other reasons then this is not an issue. | Lower: Typically runs automatically and quite fast. |
When to use Hand Loads:
Use hand loads when tool cost or time to market is important or when part features cannot be produced any other way.
Use core pulls and side actions when part cost and quality are primary concern.
Example
In this example the green hand load insert (green) produces the threaded feature of the part ( purple). The insert is unscrewed manually by an operator after ejection. Multiple inserts are used so that a new part can be molded while the other is unscrewed. In a traditional mold and expensive unscrewing mechanism would be employed.
