Dissertations and Theses @ UNI
Machining process changes as a function of surface roughness, specific to machining cylindrical bores
Open Access Thesis
Reaming -- Quality control; Metal-cutting tools -- Design and construction;
Manufacturing professionals are challenged everyday to produce products to higher quality standards in a way that is economical and efficient. Manufacturing needs to minimize non value added costs such as reducing inventory, (non machined and finished goods), reduce work in process, and most of all eliminate waste. To exist, customers must be satisfied at the time of purchase and throughout the products lifecycle. To be competitive and remain a world class manufacture, companies must be flexible and be willing to change. Single point flexible manufacturing versus fixed spindle rigid machining greatly improves the ability to make changes. If a process demands tighter tolerances special equipment may still be required. Unfortunately, this may drive a company to purchase a dedicated machine, thus going away from flexible machining, which will result in higher capital and expense investment costs.
This research focused on the process of finishing roller follower bores in a cast iron six cylinder diesel engine, specifically improving the surface roughness of follower bores. The machining process studied was a non flexible dedicated station, which was part of a transfer line. Station studied had one head that contained twelve fixed spindles. Each spindle was tooled with a finished reamer dedicated to producing a hole that satisfied size, roundness, taper, and surface roughness specifications. The ultimate goal with this research was to improve part quality while maintaining current production costs and supportive resources as apposed to changing process adding costs associated with capital, expense, supporting resources, and process complexity.
The heart of this research concentrated on performing a tool performance comparison between two types of finish reamers, controlled and experimental. The controlled reamer was the existing reamer currently used in production while the experimental reamer was a new design made from solid carbide, consisting of combination left hand spiral and straight cutting edges. The dependent variable was the resultant surface roughness of finished reamed follower bores. Applying standard F and T tests to resultant data, the research proved there was a significant difference in variance and means between controlled and experimental tools. A process capability analysis was applied to both controlled and experimental tools and proved that the experimental tool performed superior over the controlled reamer.
The process that analysis was based involved finish reaming twelve roller follower bores utilizing six controlled and six experimental finish reamers. Forty one parts were randomly selected during a three thousand piece production run. Parts were cleaned and moved to a special investigative lab. A surface roughness gauge was used to measure each of the twelve bores and resulting surface roughness were recorded in tabular form.
Along with the analysis of tools the research examined a superior finishing process called, super abrasive reaming. This would be the alternative reaming process if experimental reamers did not perform well enough to meet customer specifications.
In summary, by performing F, T, and process capability analysis, this research did prove there was a significant difference in variances and means between the controlled and experimental reaming tools. The process capability of the experimental reamer was superior over the controlled reamer.
Year of Submission
Master of Arts
Department of Industrial Technology
1 PDF file (65 pages)
©2007 Thomas Patrick Olsen
Olsen, Thomas Patrick, "Machining process changes as a function of surface roughness, specific to machining cylindrical bores" (2007). Dissertations and Theses @ UNI. 1311.
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