Bore Gage Becomes Key In Quality Control Program

A state of the art bore gage, intensified training programs and extensive machine tool maintenance regimes are making it possible for Eskridge, Inc.--a machine shop specializing in rotation drives, planetary gear boxes and fail-safe brakes--to shorten delivery times, boost part accuracy, improve overall product quality and increase employee efficiency.

The company, which employs 56 and whose business is growing rapidly, most recently began using Fowler/Bowers (Fred V. Fowler Co., Inc., Newton, Massachusetts) pistol grip bore gages which have shortened gage set-up time by a factor of five, advanced accuracies to a reliable 0.00015 inch and significantly reduced work while expanding useable machine time.

This Bowers Holematic pistol grip bore gage is used directly on the production line and has a 0.00005"/0.001 mm resolution. It has been particularly attractive to Eskridge, according to Tim Brown, Quality Assurance Supervisor, because its digital features tie into the new comprehensive data acquisition system the company is installing to increase overall quality of its output. It replaces dial bore gages, which were said to be less accurate and slower to provide needed checks.

Other gages would need battery replacements every day or so under continuous use, but with Fowler gages, they were getting three to six months (battery life is actually 3,000 hours) continuous use under the same conditions in comparison to the older dial gages used.

Now gathering data manually, Eskridge is in the process of establishing a new data collection system which will be able to transfer digital data from the Bowers gage via Opto/RS-232 cable to small station computers and then to a central computer. "This will permit us to take real-time dimensional checks and gather a great deal of other production information. " says Mr. Brown.

The system will permit Eskridge to make a higher class of gears requiring stricter quality standards than it currently produces. Over 90 percent of the component parts used to produce the company's product line are manufactured in-house.

Another aspect of Eskridge's attempt to expand into a higher gear class involves automatic gear checks. Recently, the company added a new coordinate measuring machine (CMM) which can check up to 200 points on a selected tooth, giving a very accurate topographic profile. "We are now able to accurately check index, pitch and lead variation as well as profile and topography. We also can check runout and eccentricity more accurately than before since we are able to check this at the pitch diameter instead of at the root diameter. Overall, we know more than we ever did before, says shop supervisor Steve French.

"Our machine tool equipment and the special program we have for its maintenance are extremely important in our overall quality. The Okuma lathes and LeBlond horizontal machining center are frequently checked to be sure there is no gap in maintenance. In addition, three years ago, we moved into manufacturing cells... As a result of this and the speed and accuracy of our on-line dimensional checking--just the other day we set up the same job four times and each time only took from ten to 15 minutes--with no loss of parts. That's a rarity."