PLASTICS SIZE REDUCTION

Size Reduction Service Tips

• Ensure all users and maintenance personnel are adequately trained on how to safely use and service each piece of equipment.
• Dull knives in your granulator cause excessive wear and tear on critical components leading to very costly downtime. Sharp knives set to the proper gap always work to your advantage.
• Dull knives, worn screens or non-optimal knife gaps can lead to excessive vibration and amp draw. This can also reduce the amount of reusable regrind back into the process, ultimately costing the plant money.
• Amp draw can be monitored as an indicator of dulling knives for more predictable maintenance.
• Vibration can be monitored as an indicator of dulling knives or imbalance.
• Do not resharpen knives beyond their minimum height. Always replace knives when they reach the minimum height.
• Periodically check the setting of your bed knife shields. Approximately 1/32” of the bed knives should be uncovered by the knife shield for film, and 1/16” for other materials.
• Shredders can be periodically checked for dulling cutters. Most cutters can be rotated for a sharper cutting surface before having to be replaced.
• Periodically inspect all safety devices for functionality.
• With any rotating machinery, it is always a good idea to periodically check for loosened bolts before startup.
• If a jam is encountered, be sure the jam is cleared and the machine is cleaned out before attempting to restart.
• Proper air flow is required to evacuate the regrind. If material is building up under the screen(s) check the setting of the damper, it may not be sufficiently open.
• Proper drive belt tension is important for many reasons. Check the drive belt tension monthly and adjust according to the instructions in your operator’s manual.
• Follow local lock-out/tag-out procedures as required.
• When in doubt, call the professionals for help!

Granulator and Shredder Safety

The size reduction of plastics is probably the most hazardous operation in the plastics industry. Unfortunately, it is the lack of knowledge of the machinery that can make working with the machinery a dangerous occupation. Rotary shears, densifiers, shredders and granulators are designed with two main thoughts in mind: the first and utmost is safety, the second is to design a machine that will do a job efficiently.

Granulators come complete with a safety switch that is connected to the cutting chamber to terminate its operation if it is opened while the motor is running to prevent a person from getting injured. At no time should anyone have to open a machine while it is running.

Any adjustment to the knife or drive system should be made with the machine off and power disconnected. When a serviceman or a machine operator has to perform any kind of work on the machine, that person should shut the machine off and disconnect the power at the main power source for that machine. In most cases this would be the lockout box or disconnect. A padlock should be put on the box to be sure that the machine does not get energized accidentally.

At no time should it be necessary for a person to put any part of their body into a granulator, rotary shear, densifier or any piece of machinery. That includes climbing into a large granulator to free a jam-up or for cleaning purposes.

The instructions for the machinery should be read very carefully. The warning label should be followed in its entirety.