CNC Standards for Machine Guarding

CNC machines are high-speed cutting tools for metal and plastic.

Machine guards protect users from being hurt while a machine is running. From debris sent flying by high-speed cutting processes to the blades themselves, computer numerical controlled (CNC) tool safety standards require machine guarding to protect operators and bystanders.

Electrical Interlocks

Electrical control interlocks turn off a CNC machine when the machine guard is not in place. According to "Practical Machinery Safety" by Dave MacDonald, interlocks prevent movement of hazardous parts by blocking the control circuits; guard positions are detected by safety rated limit switches.

Perimeter Guards

Perimeter guards are machine guards that enclose the tool. Perimeter guards can use light sensors or pressure sensors. Pressure mats can be used as machine guards by shutting down the equipment if a person steps onto the pressure mat in front of the tool. Perimeter guards can also be a locked enclosure that requires opening a door.

Tool Programming

CNC machines can be programmed to ensure operator safety. The CNC machine can be programmed not to run if the machine guard is not in place. CNC tools can be programmed to lock the machine guard in place while the cutting tool is running. The machine guard then cannot be opened unless the cutter has stopped.

References

• "Computer Aided Manufacturing"; Shanmuga Sundar, Sunder Selwyn, C. Elanchezhian; 2005
• "CNC Machines"; B. S. Pabla, M. Adithan; 1994
• "Product Design"; Lesley Cresswell, Lambert; 2004
• "Practical Machinery Safety"; Dave Macdonald; 2004
• "CNC Programming: Principles and Applications"; Mike Mattson; 2009

Resources

• "Understanding Industrial Practices in Resistant Materials Technology"; Jet Mayor; 2004
• "Tube Forming Processes"; Gregory Miller; 2002