Influence of machining parameters on subtractive manufacturing of elementary geometries in glued-laminated timber using an industrial robot

Abstract

With the growing demand for timber construction, more advanced production methods need to be developed and applied. Multi-axis industrial robots (IR) show a high potential for increasing the efficiency and extending the workspace within subtractive manufacturing. To apply IRs, it is necessary to understand the interaction between the robot and the mechanics of machining and reveal optimal settings. This study investigates the effects of machining parameters (axial and radial depth of cut) and robot kinematic settings (acceleration, jerk) using typical milling tools for the machining of elementary geometries (lines, rings, pockets). The results are evaluated based on the surface finish (tactile measurements and optical/haptic assessment) and nominal/actual comparison of the geometry. Axial and radial depth of cut is high relevance: higher values lead to lower quality while mid-range settings frequently lead to the highest quality. The robot's kinematic settings have higher effects when using relatively small diameter tools. The tool manufacturers feed recommendations for CNC-machines are also applicable to robot machining and all examined parameters are relevant factors influencing the quality. The results achieved with the IR can compete with conventional joinery machines and are able to meet the currently required industry standards with further potential for improvement.