Graduate Research Papers


Open Access Graduate Research Paper


The following paper is an investigative project on the subjectivity of visual inspection by finished goods inspectors at a custom cabinet manufacturer located in northeast Iowa. The company manufactures custom and semi-custom kitchen and bath cabinets; with very few of the ~ 1.6 million pieces shipped each year being exactly alike in design, wood species, or color. The company employs over 1200 associates that support a three shift manufacturing operation.

The focus of the study involved the subjectivity of visually inspecting the company's finished product, while exploring elements in the manufacturing arena which affect inspector decisions. Some variables explored include knowledge, skill, and attitude of the inspector, as well as the process flow and physical elements of the factory (such as lighting).

The company's products are primarily made of wood and wood product composites, and from a visual standpoint, wood is unlike most other engineering materials. Produced by nature, no two pieces of wood are exactly alike. If one considers wood species, graining, growth patterns, and machining and finishing operations during manufacturing, it begins to become clear, the individuality of the wood itself is as unique as a snowflake. Furthermore, consider the choices made by craftspersons as they choose raw wood components to build a particular cabinet or access6ry - the graining and natural flaws, such as: pitch pockets, mineral streaks, and knots - all elements which affect the visual beauty of the finished goods. And finally, once the wood component or assembly receives a colored stain, paint, and/or protective topcoat, the individuality of the wood component or assembled cabinet becomes even more unique.

The author found that developing visual standards for cabinets and accessories is time consuming and expensive. Standards that identify each and every variation and deviation to a particular piece are impractical to implement in regards to finished product inspection procedures because, from a visual inspection standpoint, no two pieces of product are exactly alike.

The results of this study show that lighting intensity, as measured in lumens, appear to affect perceived quality as viewed by inspectors. Additionally, possibilities exist for improvements in product quality by developing and implementing a formal training program for inspectors.

Year of Submission



Department of Industrial Technology

First Advisor

Shahram Varzavand


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Date Original

Summer 2005

Object Description

1 PDF file (vii, 44 pages)