Statistical Process Control

Although Statistical Process Control (SPC) has recently received much attention in the technical community, ALMA Member Companies have been implementing SPC practices for the last several years as a manufacturing tool to reduce or eliminate scrap, rework, and customer returns.

The fact that SPC is a must for any manufacturer in today's environment is a given. When the process is controlled, the product will meet the features necessary for the form, fit, and function of the final product.

ALMA has now completed a project to define those product characteristics which have the greatest effect on form, fit, and function of self-locking nuts. Attached is a listing of those characteristics, with illustrations, of a variety of styles of self-locking nuts.

This project was undertaken by ALMA in order to help those less familiar with self-locking nuts to recognize the characteristics that should be considered for inspection and/or design to assure proper or required product performance. We hope that this document will be used as an educational tool and guide for other interested parties by those already familiar with the products.

Manufacturers know at which point in their processes SPC has to be exercised, and what needs to be controlled for continuous improvement based on product knowledge, method of manufacture, process capabilities, and other factors. The concerns of both the manufacturer and the customer must be considered to ensure that meaningful data are generated, and that the parts will function as intended. The goal of the ALMA Member Companies is to control their processes to ensure the manufacture and timely delivery of quality products.