When designing mold cores for undercuts and side-action molding, the designer has several lifter system options.

The first is using sliding cores and angle pins. This option requires considerable mold space and may result in selecting a lifting core with a smaller platen size at the expense of a larger die height.

Conventional lifter cores also have limits on the angles allowed. If the molded undercut is large, the mold footprint may need to be increased to accommodate the required side travel of the lifter core, increasing the required die height even further.

The single-rod lifter system is designed with the core, sliding plate and gib plates within the ejector plate assembly. Close alignment of the core is accomplished through tight tolerance entrance and exit holes in the core plate. This results in additional cost and added processing problems. An overriding problem of the conventional configuration: bending moment acting on the lifter rod, which leads to increased friction, abrasion and side loads

If the lifter rod is not sized properly, premature wear or even breakage can result. Therefore, designers often over-design the lifter rod to account for additional loading. This increases component costs and limits the number of applications for the lifter mechanism.