Correction factors for standardised approach speeds on metalworking machine tools

• Applicant: Professor Dr.-Ing. Martin Schmauder
• Subject Area: Human Factors, Ergonomics, Human-Machine Systems
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545611846

A machine is considered safe if there is no danger to users when used as intended, including reasonably foreseeable misuse. According to the legal requirements, machine operators must be protected against the separation, shearing and crushing of body parts, in particular limbs, caused by dangerous closing movements. DIN EN ISO 12100 prescribes the development of an inherently safe design as the first and most important step in minimising risk (DIN ISO 12100: 2011). If not all hazards can be eliminated by design measures or if the remaining risk cannot be tolerated, suitable protective devices must be selected in accordance with the Machinery Directive 2006/42/EC. One option for non-separating protective devices is the increasing use of electro-sensitive protective equipment, such as light curtains. Depending on their granularity, these detect fingers or hands. Sufficient safety distances must be maintained in accordance with DIN EN ISO 13855 (DIN ISO 13855: 2010) so that the machine can switch off in good time if the light beam is interrupted. An essential part of the calculation is the approach speed of the body, which is specified with a fixed value. The specified value of 1.6 m/s is not questioned and is demonstrably suitable for an average situation in which a person moves towards a danger zone without obstacles. In practice, environmental conditions often deviate from this ideal situation. Due to structural conditions, larger machines often have to be placed on existing foundations. The approach speed of the machine operators is reduced by stairs, steps and floor gratings, among other things. The change in speed caused by these measures is not taken into account in the current safety distance calculations. For conditions that deviate from the ideal normative situation, the safety distances are generally set too large without increasing the safety of the machine operators. For this reason, the project will use laboratory tests to determine the change in approach speeds for typical access conditions at hazardous points on machines compared to the approach speed without access restrictions. With regard to the limited resources and the growing importance of optimally utilised hall areas and the lowest possible machine space requirements as well as optimal distances in the work process, the correction factors determined for standardised approach speeds are intended to contribute to greater flexibility in machine layout design. The extended use of DIN EN ISO 13855 is intended to provide companies with greater flexibility in the design process.

• DFG Programme: Research Grants