A method for the reduction of machining time by the simulation of NC-programs in virtual reality

摘要

There is an interesting technique, popular among the manufacturers of dies and moulds: instead of replacing a worn out mould by a new one each time the tolerances are lost, the geometry of the old one is refreshed by a shift along one of the axis (typically "Y") and machining it with the original NC-program once again. This leads to savings of material (due to the reuse), to reduced volume of chip - and, consequently, savings of energy and tools - and to time savings (due to skipping of the roughing). The main problem of this method is the fact, that if the same NC-program is used both for the first and for the following machining, the mill spends most of its time (up to 90%) in "cutting air". This useless work cannot be avoided, but it is possible to reduce dramatically the time necessary for performing it. This article presents intermediate results of an in-progress research, which attempts to minimise the "air-cutting" time based on the NC-programs alone (i.e. without the help of any additional CAD, CAM or similar systems, and without having access to the rated or required geometry). Since the implementation of the proposed solution is based on HTML, VRML and Java, it is by design network-ready and portable without additional efforts. The safety of the method is guaranteed by 4D machining simulation with process and result visualisation.