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According to Murphys Law, whatever cargo wrong, will. This probably sums up the way many plastics processors feel about their raw materials handling systems. There are, after all, so many different raw materials handling components to go wrong. Adding to the difficulty, processors, under mounting pressure to manufacture more parts more quickly, may not always give their systems enough close attention...until a problem arises.
Here are solutions to some of the most common problems, provided by several leading raw materials handling equipment suppliers.
[ballot X] PROBLEM: MATERIAL IS NOT DRYING
CAUSE:
Tom Martin, head service technician for Motan Inc., highlighted several leading sources of this problem. "First, the customer might not be allowing the material to be in the drying bin for the recommended residence time," he said. "In addition, filters and breather screens on the dryer may not be maintained at the proper intervals; and processors may also be neglecting to change the desiccant material in their dryers at the proper intervals."
[checkmark] SOLUTION:
The solution is very simple, suppliers say: follow the directions and maintenance as dictated by operating manuals, particularly as regards regular changing of desiccant.
Also, if the material being dried is very hygroscopic, processors need to use a closed-loop conveying system that doesn't introduce ambient air. "Typically, if a processor is running a closed-loop conveying system properly, they shouldn't encounter any problems in drying material," said Joe Corturillo, engineering manager at Wittmann Canada Inc. "And as long as the dryer is sized properly for throughputs, there shouldn't be any issues in conveying the dried resins, either."
[ballot X] PROBLEM: DROP IN THROUGHPUT
1ST CAUSE:
Pelletized materials require sufficient air to be transported, and there are several common reasons for airflow to weaken, resulting in a drop in throughput. "Clogged filters in vacuum receivers, vacuum takeoff boxes, and vacuum pumps are the most frequent causes of this," said Novatec Inc.'s Les Mischaud, installation manager, and John Kraft, marketing specialist.
[checkmark] SOLUTION:
Mischaud and Kraft recommend inspecting and cleaning filters on a regular basis. "Also, don't forget to empty the catch pans under cyclone filters if you have them," they said. "If the pans fill up, dust can be pulled back through the system to clog the filters again."
2ND CAUSE:
Another...