Concept for collision avoidance in machine tools based on geometric simulation and sensor data

Collisions are a major cause of unplanned downtime in small series manufacturing with machine tools. Existing solutions based on geometric simulation do not cover collisions due to setup errors. Therefore a concept is developed to enable a sensor-based matching of the setup with the simulation, thus detecting discrepancies. Image processing in the spatial and frequency domain is used to compensate for harsh conditions in the machine, including swarf, fluids and suboptimal illumination

Collision avoidance and adaptive path planning in machine tools by matching live image data with a geometric simulation

A major cause for unplanned downtime in small-series machining are collisions. While there are solutions to avoid collisions using geometric simulations, these do not cover collisions caused by setup errors. To address this problem from batch size one, a system has been developed which matches a geometric simulation with image data to detect deviations, modify the simulation and recalculate NC-Code to fit reality. Building on previous work regarding image-preprocessing, an iterative matching algorithm is developed, as well as a microservice based system-architecture which allows the integration of matching, adaptive path planning and collision avoidance simulation. The system is validated on a machining center

Steps towards a protection system for machine tool main spindles against crash-caused damages

High productivity and availability of machining centers can only be achieved by avoiding unplanned machine downtimes. Machine failures induced by wear can be coped with by implementing preventive and conditionbased maintenance strategies so that downtimes are as short as possible. In contrast, machine damages caused by collisions cannot be avoided by these strategies, but only fixed afterwards by reactive maintenance, leading to high repair costs and long machine downtimes. This article presents a new approach for the avoidance of damages to the main spindle unit caused by collisions in machining centers. The mechanical components of this protection system enable the controlled reversible decoupling of the main spindle from the machine structure in case of exceedance of an adjustable force limit. Decoupling leads to a reduction of the whole machine stiffness, resulting in the decrease of the acting collision force. Consequently, all machine components in the collision’s force flux are protected against overload and damage. Once a collision occurred, a general method is shown, where the spindle and its collision objects are separated automatically by the machine’s numerical control. Due to the reversible decoupling mechanism of the protection system, the described retreat strategy eases the handling after a collision for the machine operator