Equipment Specifications for Flipping Molds and Dies
CRANE 1 receives many inquiries for mold and die handling cranes.
In the die maintenance area, the requirement to flip the dies is usually specified. This can be done with two hoists operating in tandem on a single or multiple crane or with die turning devices such as upenders or specialized lifting beams with a rotating device incorporating slings which roll the load within the slings grip. Die handling is rough on overhead cranes; causing shock loading, side loading, and swaying or drifting loads which all contribute to damaging wear and tear to the cranes system’s wire rope, motor, gear box, couplings, and brake components.
Beyond the expense of requiring two hoists for the flipping operation, the hoisting equipment features required to ensure a proper system also add to the overall systems cost.
- Hoists perpendicularly oriented to the crane’s bridge beam are essential when using two hoists on a single crane in order to turn a mold. This ensures that the wire ropes maintain seated into the rope grooves and are not pulled across the drum ridges potentially damaging the wire rope.
- Hoists using rope guides are also not recommended as the guides are very susceptible to damage from the slightest side pull. The rope guides commonly found on European style hoists are expensive to replace as well.
- Double reeved (“True Vertical Lift”) hoists are also preferred as the hook always remains stationary in the same position relative to the hoist body ensuring equally distributed loads.
- Although many flipping operations specify the use of two different capacities of hoist, a far safer and conservative approach is for both hoists to be of sufficient capacity to hold the load. This reduces the chance of a damaging overload and anticipates the likely shock loading that the units regularly see in a flipping operation. A secondary mechanical load brake is a feature that provides some measure or additional safety in the case of a motor brake failure.
- A robust design will extend the life of the often abused hoists and help extend the life of the hoist while enduring shock loads.
- Load limiting devices are an essential feature to ensure that the hoists do not lift damaging loads.
- Control stations allowing the selection of a single hoist and trolley or both. This allows the hoists to travel and hoist in tandem or individually. We recommend the use of remote radio controls to enable the operator to maintain a safe distance from any traveling load.
- The travel speed of the crane and hoist need so have the ability for slow speeds for precise placement. We recommend the use of variable frequency drives on the hoist trolley and bridge to allow the programing of slower speeds.