An assessment of manufacturing quality variation and an SPC handbook for the pallet and container industries
Today, American industries are in a highly competitive international market. To achieve the competitive edge, manufacturers are demanding excellence from their vendor/suppliers. The pallet and container industries are the suppliers to the other companies. Statistical Process Control (SPC) is one-way to prove to the buyer the quality level of their products. One part of the this thesis is a handbook, which explains a step by step process of implementing an SPC program for the pallet and container industry. In addition, the thesis examines the quality levels of materials that goes into the pallet including the finished product such as raw material, cut-stock, fasteners, and workmanship.
The raw material proved quite variable from the different sawmills. The between board variation was greater than the within for both the thickness and width. The cut-stock had less size variation in thickness than width. The workmanship of the finished pallets showed that the number of nail splits and uniformity of deckboard spacing to be a problem. While the number of missing nails, protruding nail points and heads, and the "out of squareness." It was not a problem. The physical characteristics of the fasteners proved extremely variable from one characteristic to another. There are a number of fasteners being produced outside of the NWPCA criteria for wire diameters. The most popular fastener gauges are the 11 and 11.5. In addition, the most popular fastener length is 2.25 and fastener flute number is 4. The MIBANT angle variation is higher for the stiffstock fasteners then the hardened fasteners.