Planning a Machine Enclosure for Noise and Chip Containment

What is a machine enclosure for?

A machine enclosure is a guard that physically closes off the hazard zone of a machine. It retains chips, cutting fluid and flying sparks, lowers the noise level at the workstation and prevents access to moving parts such as spindles, tools or robot arms.

The governing standard is DIN EN ISO 14120 (formerly EN 953), which sets general requirements for fixed and movable guards. The legal basis is the Machinery Directive 2006/42/EC, which calls for safe design and a risk assessment to DIN EN ISO 12100.

How do you plan walls, doors and windows?

The build-up follows the protection goal. For pure chip containment, sheet-metal or polycarbonate panels in an aluminium profile frame are often enough. For noise control, insulated sandwich panels with an absorption layer are used, achieving roughly 15 to 20 dB of reduction depending on wall thickness.

Polycarbonate viewing windows are impact resistant but lose strength over time due to cutting fluid and UV. DIN EN ISO 14120 refers to ISO 14119 and the test standard for workpiece retention; replace windows after the service life stated by the manufacturer.

• Fasten fixed guards so they can only be removed with a tool.
• Fit movable doors with an interlock, adding guard locking per ISO 14119 where run-down occurs.
• Keep safety distances per DIN EN ISO 13857 to prevent reaching in.
• Size viewing windows for process observation and document material and service life.
• Make cable and media pass-throughs emission-tight and sound-tight.

Which safety requirements are mandatory?

Every access door that can be opened during operation needs an interlocking device per DIN EN ISO 14119. If the machine keeps running dangerously after opening, guard locking is also required to keep the door closed until standstill.

Safety distances follow DIN EN ISO 13857: fixed guard fences are usually at least 1400 mm high, more where the risk is higher. Openings in the panel must be small enough that the hazard point cannot be reached with fingers or arms.

• Interlock without locking only where the machine stops immediately.
• Guard locking mandatory with run-down or stored energy.
• Provide emergency stop and safe isolation of the energy supply.
• Document residual risks in the operating instructions.

How do you approach the planning?

Start with the risk assessment to DIN EN ISO 12100 and derive protection goals, materials and the interlock concept from it. Only then define geometry, access points and viewing windows.

Frequently asked questions