Lower Punch Tip Bending / Buckling

In mini-tablet manufacturing, slender punch tips are prone to bending or buckling under excessive force. Traditional TSM force ratings can overestimate safe limits because they don’t account for these failure modes, often leading to inaccurate safety margins. The Rankine-Gordon formula provides a quick adjustment to reduce TSM ratings, offering a better prediction of punch tip limits. Using Euler-Bernoulli beam theory, engineers calculate the theoretical load, factoring in tool steel elasticity, moment of inertia, and punch length. While helpful, this theoretical load is typically too high for microtip tooling since it assumes a longer column and lacks considerations for side loading or crushing strength.

The Rankine-Gordon formula refines this by reducing the allowable load, ensuring the punch tip remains stable. Additionally, tool strength can be increased by shortening punch tips, often with a support shoulder to reduce length. Using this method helps protect microtip tooling against costly errors by achieving a more accurate force rating.