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Mold Opening Stroke Calculator

Calculate the required opening stroke from part depth and runner length; machines with a suitable opening stroke and tie bar spacing are listed automatically. Free and no sign-up required; you can switch to the other 14 tools from the tabs above.

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Required opening stroke420 mm

Formula: 2 x part depth + runner + removal clearance. The depth counts twice because the part has to come off both the fixed and the moving half. On deep parts (buckets, crates) the opening stroke usually decides the machine before the tonnage does — assess it together with the result on the Clamping Force tab.

These calculations produce guide values; the final selection has to be based on the part geometry, the mold design and the data from the material manufacturer. For an assessment specific to your application, contact our technical support team.

How is this calculated?

When the mold opens, the part is first pulled off one half and then pushed off the other half by the ejector — which is why the depth counts twice. With a cold runner, the runner needs its own length as extra travel in order to drop clear, and clearance is left for robot or manual removal.

Required opening stroke = 2 x Part depth + Runner length + Removal clearance

On deep parts (buckets, crates, containers) the machine is usually determined not by clamping force but by the opening stroke: a machine with enough tonnage may not have enough travel. The tool therefore compares the result against the catalog opening strokes of the DKM models; if you enter the mold width, the tie bar spacing is checked as well.

The method, the formula and the limits of each tool are explained directly underneath it, and the explanation changes with the tab you select. The results are engineering guide values; for an assessment specific to your application when choosing the final machine and equipment, contact our technical team.

Prepared by:Uğur Çamlıca· Teknik Part · Sources: manufacturer documentation and field practice