Calculating Substrate Compression Ratios in Embossing Operations
Substrate compression ratio measures z-axis compaction, balancing tool impression depth against fiber strain limits to maximize embossing height without shearing.
Bevel Draft Angle
Cutting Geometry
Angled surfaces on the cutting edge of a steel rule die determine the force required to penetrate paperboard and the ease with which the material release occurs during converting. This inclination, known as the bevel draft angle, typically ranges from one to several degrees off the vertical axis to minimise friction during the downward stroke. It establishes the wedge profile that divides the paper fibres during die cutting.
Controlling this parameter helps prevent the board from binding against the tool.
Release Behaviour
Reducing the contact area between the metal tool and the freshly cut edge of the substrate accelerates the ejection phase of the platen press. When a bevel draft angle is correctly ground, the ejector rubber pushes the board away with minimal resistance, preventing surface scuffing. High ejection forces can bend the flaps of a carton.
Correct geometry ensures that the board pops free without damage to its coated surface. In high-speed packaging lines, even minor delays during the release phase can accumulate, lowering the overall output. Substrates with thick starch coatings are especially sensitive to binding, making the draft angle essential for preventing board damage.
Die Wear
Wedge thickness at the shoulder of the rule alters how the compression is distributed within the tool. A steep bevel draft angle places higher lateral stress on the tool holder, which accelerates wear on both the cutting rule and the counter-die matrix. This structural stress shortens the production lifespan of the tooling.