Automated Subtractive Timber Manufacturing—Joinery Machines Versus Industrial Robots

A high degree of automation, especially through the use of robots, is state of the art in the automotive and electronics industries. Even though the construction sector is currently lagging behind, an increase in automation and the use of robots can be observed. To assess the potential in industrial timber construction with a focus set on subtractive machining, this paper presents the state of the art in terms of the use of industrial robots and joinery machines, compact joinery machines, and gantry-type joinery machines in regard to milling processes. The capabilities of different types of joinery machines are evaluated and compared with vertical articulated industrial robots equipped with machining spindles. An overview of the history and an assessment of various parameters in the categories: Quality, System, Machining and Economy, is given. Publications, manufacturer information, and industry findings are reviewed to answer pressing questions on automation in timber construction. Limitations such as robotic stability or the limited working space of joinery machines and the affordability of robotic systems are elaborated and CAD/CAM (computer-aided design/computer-aided manufacturing) processes are scrutinized. After the evaluation and comparison of four different systems, an approach for future research is proposed. The main findings are a very low degree of robotization and data availability within the timber industry, lower acquisition costs for industrial robots while increasing the flexibility of the workspace, and task-specific advantages of the respective systems, including machining power, potential for improvement in automation (especially CAD/CAM), and machining quality.