Presentation of a novel cutting technology for precision machining of hardened, rotationally symmetric parts

Abstract

In this paper a new cutting technology similar to hard turning is presented to cut rotationally symmetric parts made of hardened materials. This novel technology, which is named rotational turning, is based on a combination of hard turning and circular milling. An analytical model is developed to describe the engagement parameters between tool and workpiece. It is shown by the model, that the virtual tool corner radius in rotational turning, which takes effect during the cutting process, is more than 50 times larger than in state of the art hard turning. Due to this, feed marks, which are common in turning, can be reduced to a level, where they are not measurable anymore. It can be shown in experiments, that the minimum achievable surface roughness is therefore not limited by the feed rate anymore, like in turning processes usual, but by other effects like the waviness of the cutting edge

A forgácsleválasztás sajátosságai rotációs esztergálás esetén

“…Az egyik fejlesztési irány, a forgácsleválasztást más kinematikai viszonyokkal és szükségszerűen más szerszám-élgeometriával megvalósító eljárások kifejlesztése és vizsgálata. Ilyen eljárás a rotációs előtolású esztergálás [3,4]. Ezzel az eljárással a precíziós megmunkálásoknak megfelelő forgácsleválasztási feltételek, valamint a köszörült felülettel megegyező pontossági és érdességi értékek előállítása a cél, a forgácsleválasztás hatékonyságának megtartása mellett.…”

Verification of New Computing Method for Determining of the Roughness Parameters for Rotational Turning with Non-Linear Cutting Edge

“…For machining, the tool rotates from position A to position B thereby the contact point between edge and rotating work piece where material is cut is moved axially along the workpiece rotating axis. The rotation of the tool can be achieved by NC-tool turrets with torque drive, which is state of the art in many turning machines [1,2]. Turning with rotational feed (rotational turning) of outer cylindrical surfaces can be characterized by a tool which works with a slow, rotational movement -in contrary to the axial feed in traditional longitudinal turning -thus generating the machined surface by the non-linear contact of the cutting edge and the workpiece instead of point contact.…”

“…1. [1,6,7] 2 THEORETICAL CALCULATION OF RT Rt (total height of profile) can be used to foresaw the quality of machined surface, as its theoretical value can be simply calculated from machining parameters and tool geometry in conventional turning. To achieve theoretical value of Rt in turning with helical cutting edge, it is necessary to define it graphically and then defining its equation using parameters which defines the technology of turning with helical cutting edge as the revolution of tool, that is the main difference in comparison to conventional turning.…”

Computing of the Theoretical Value of Roughness Parameter Rz when Turning with Helical Cutting Edge

“…However, a major disadvantage of hard turning is the correlation between achievable surface quality and the feed rate/the machining time [6]. [10] When high surface qualities are to be generated, low feed rates are required due to the specific process kinematics of turning. This makes hard turning not suitable for large scale production where small cycle times are usually desired.…”