Safety is often overlooked, but it is one of, if not the most important, responsibilities of the workplace. Large machinery is very heavy and consists of moving parts that can lead to serious injuries, if safety is not taken seriously.
Before working on an extruder, always lock out or tag out the panel to cut off all power to the machine and other auxiliary equipment. This is done to avoid the extruder from unexpectedly turning on. Also, be careful when handling parts because they can be very heavy. Depending on what style of extruder you have, chambers can weigh up to 85LBS a piece.
Even after the power is cut off from the extruder, you must remain cautious because pressure and high temperatures are still present. To minimize the pressure and temperature of the extruder, clear out all of the product that is still in the chambers, when possible. This can be done by shutting off the feeder and letting the extruder run for about a half minute with no feed going in.
By running the extruder without feed, it will help clear out most of the product that is still inside and some of the pressure. This doesn’t necessarily release all of the pressure, so, it helps to also open up the nose cone about two turns while the extruder is still running, to help clear out as much pressure as possible. Once that is complete, turn the extruder completely off, and put some high temperature gloves on (leather and/or welding gloves work great) and wait for the extruder to come to a complete stop.
To continue, remember to never stand in front of the nose cap when you perform a shut-down. Taking the nose cap off is a vital concern as there still may be pressure behind it. Instead, remove the clamp bolts about halfway, and while grabbing both sides of the clamps, try to move them back and forth. If they move easily, that’s usually a good indicator that there is not much pressure left in the machine, but not a guarantee. To finish off, still standing off to the side, remove the clamp bolts completely and take the bottom clamp off.
These are just some of the most important aspects of safety when servicing or shutting down an extruder, but every situation and person is different.