This employer specializes in the manufacturing of PVC irrigation pipe and tubing for spas and pools. They also do custom extrusion products in any size and color for various other applications.
The company buys raw materials of prime or virgin “beads” and post-consumer scrap. Raw materials, internal production scrap, and color pellets are mixed together in one of several formulas. The dry mixture is then dumped into hoppers, automatically fed into heating units, and extruded into pipes and tubes of various diameters and lengths.
Mixing is a very labor-intensive job
Mixing requires repetitive lifting of 5-gallon and 10-gallon buckets of dry mix weighing 22 pounds and 35 pounds respectively. After mixing, the employee (called a mixer) will carry, lift, and hoist full buckets of mix from floor level to an overhead hopper. Total weight manually handled can be anywhere from 4,000 to 5,000 pounds, or 2 to 2-½ tons per day per mixer.
Mixing raw materials is done in a large plastic bin measuring 26″x38″x27″. A bin contains various components (flake, scrap, color pellets, and virgin resin), individually stored in barrels, boxes, and large cardboard bulk bins in the mixing area. A batch is made of the various components and hand mixed with a trenching shovel. A trenching shovel is preferred because the blade is thin, producing less drag in the materials.
Improvement options
For the mixing of the raw materials, an electric or gas-powered concrete and mortar mixer could be used. The three pictured below are electric. If a gas-powered mixer is used, ensure that the area is well ventilated. Although smaller batches may have to be made, this would eliminate having to mix by hand with the trenching shovel. To control for using a shovel to transfer mix from the mixer into buckets, a pouring spout or funnel could be fabricated to channel the mix into buckets.