3 Pass Boring Method – Kalkylator

Static bending on tooling structures is common in any machines. When there is a pay load on the cutting tool structure, the tool will bend with deflection which affects the final dimension of the machined work piece.

It is possible to compensate the static bending, and unlikely in conventional method, the internal turning tools requires that we compensate the “0 – zero” reference 2 times, and therefore, we have the the 3 passing method which is commonly known among experienced machinist.

When vibration is removed, the static bending can be affected by a number of factors, such as tool wear development, work piece material impurity, and alignment of moving axis. Such variation gets magnified when it comes to internal turning or machining with long overhang, which naturally lower static stiffness comparing to short and sturdy setup.

Luckily, it is possible to reach H7 tolerance with long overhang, and the 3 passing method is developed for that.