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Injection Molding Lock-out/Tag-out Policy

For starters, my belief is that it's always best to be cautious and practice lock-out/tag-out in the situations, especially if there is any doubt about risk to an employee. Remember that any injection molding machine can easily crush body parts if safeties fail. Certainly, if the part removal or maintenance activity requires climbing on to or in to the injection molding machine, it must be locked out. However, there are instances where I do think that shutting an injection molding machine down to perform some routine maintenance is too extreme. Below are three scenarios, and my opinion based on 25 years running machines sized from 25 to 1500 tons, and molds weighing from 50 pounds to 11 tons.

1. Do you allow to remove a molded part stuck on the core pin?
If a part can be easily removed from a core pin without climbing on to or in to the machine, then lock-out is not required. However, if the part must be cut off the pin, for example, or the removal requires both hands and arms to be placed into the molding window, then the injection molding machine should be locked out. Basically, the mold tech should have one hand free to hit the "E-Stop", or the injection molding machine gets locked out.

2. Do you allow to cleanup a vent between plates?
Any mold dis-assembly in the press requires the injection molding machine to be locked-out. Though repairs or cleaning between plates may be done in press, there is the remote chance that somebody may accidentally active ejection, etc. causing the other individual to lose fingers, hands, etc.

3. Do you allow to disassemble a slide for cleanup and greasing?
Daily mold P.M. follows the same rule I have for item 1. However, removal of slides etc. requires a lock-out of the equipment. Though repairs, changes, or maintenance on the component may be done externally from the injection molding machine, damage to the mold could result if the mold is accidentally closed, core pulls or ejection activated.

Also, never allow an untrained person to perform these operations. An operator at the press should not have the authority to stop an injection molding machine to extract crushed parts or wipe down a mold for routine maintenance. They do not have the required skills to identify potential hazards or damaged tooling. This practice greatly increases risks to both personnel and equipment.

When you do determine exactly what your lock-out/tag-out policy is make sure you formalize it in a written procedure, or update your current procedure. Then train all personnel who perform these activities to the new practices. Be specific to equipment types, also, as different types of equipment will require different methods. Don't write something so generic that it is of no practical value.

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