Identify every movement

In addition to the platens, ejectors, slides, clamping mechanisms and part-removal robots may move. A stop must produce the necessary response across the installation, not only in the component visible from the control panel.

Assessment distinguishes production, normal part removal, setting, purging and mould changes. Each involves different access and energy conditions. A stuck component must not be retrieved by reaching over, under or around a guard.

Gates, access routes and remaining inside

Interlocking devices and guards must prevent exposure to dangerous movement during the cycle. Sensors must not be bypassed to work with a gate open. Checks should also cover rear and overhead access and product discharge openings.

Where whole-body entry is possible, consider someone remaining inside after a gate closes. Visibility from the reset position and measures preventing hazardous startup must form part of the design and its validation. Closing the gate alone does not establish that the area is clear.

Nozzle and hot plastic

Protection around the injection unit must address contact with hot surfaces, splashes and unit movement. Purging requires the manufacturer’s procedure and trained personnel; it must not be improvised by removing a shield.

The processed material and its temperature conditions may also generate emissions. The need for Ventilation and local exhaust ventilation and other controls should be assessed for the polymer and process. A raw-material change requires review of these conditions and compatibility with the machine.

Mould changes and maintenance

Tool changes involve heavy loads, possible elevated access and stored energy. Plan lifting arrangements and a Lockout/Tagout (LOTO) procedure appropriate to the intervention. The normal production gate is not automatically a substitute for these precautions.

After changes to moulds, attachments or auxiliary equipment, review interference and protection across the installation. Checks should retain evidence of defects and their resolution. If safeguarding fails or unexpected movement occurs, stop using the machine and arrange competent examination before production resumes. Training should clarify who may carry out each task and who authorises the return to service.