Hydraulic cylinders are commonly used on injection molds to actuate movable core. When considering “How to Size” a hydraulic cylinder for moving the core or preloading the core, PFA recommends to review three positions – initial breakaway, movement during stroke, and end position. After determining the limiting condition, a proper size may be determined. PFA’s KOR-LOK® Side Action Systems, which function as high force preloading Hydraulic Locking Cylinders with stroke sensor positioning and verification, are most often the perfect choice to cover the three positions with optimal results. Typically the core set position requires a very high preload force to maintain position, moderate to low breakaway forces and almost no load during stroke. KOR-LOK systems are optimized for this profile, resulting in much smaller cylinders, lower hydraulic needs, and faster movement.
For more information visit the article “Forces and Calculations are Key to Sizing Core Pull Hydraulic Cylinders” in the recent issue of Moldmaking Technology Magazine on the MMT website.
For sizing assistance, see the PFA core force calculator that provides forces and KOR-LOK sizing recommendations and the Hydraulic Cylinder Sizing sizing page for formulas and charts.