Fit/Dimensional Stability Committee
Hosiery Technology Center, Hickory, NC June 21, 2000
Regina Speed opened the committee meeting and went over the Mission Statement and objectives of the Committee.
Dan St. Louis gave a brief summary and timeline on the history of the committee since its inception in March of 1998. Committee membership is made up of people from 42 hosiery manufacturers, 22 from schools and industry associations, 13 from hosiery suppliers, 7 retailers and 2 testing labs. Trials have been run at DuPont, NCSU and the Hosiery Technology Center. To date there has been over 2685 different trials run on various testing devices on various sock types. This has been an industry venture with many contributors and has made significant progress.
Tony Whitener and Regina Speed then demonstrated the devices that have proven to be the most statistically repeatable both within machine and between machines. These were the Dinema Size Control, Hifomaco and Cimation Stretch Device. The positive and negative aspects of each machine were discussed along with the changes made to the devices that have been made as a result of the studies.
Calibration was a critical issue with all the machines. It was felt that documentation of the calibration method was a critical part of the committee’s final report. This has been a crucial factor in the improvement shown on all three devices. Another important item was that placement of the socks on the device had to be the same or error was introduced. Tony and Regina are working on a draft document for using these devices to include calibration and sock placement. This will be done before the next meeting so the full committee can review the drafts.
Roy Johnson then discussed the statistical data generated from the project. He stated that the statistical tools used to analyze the data were: 1) Standard Deviation to compare results within one tester, 2) Coefficient of Variation (CV) to compare results from different testers, 3) The F-test and Anova test to compare variation within 2 or more testers of the same type.
Roy then reviewed results of the CV, F-test and Anova tests for all testing machines since the beginning of the project. The summary is as follows:
Variation Summary by Tester for Cross Foot Stretch (% CV)
|1st Runs (98 & 99)||1.01%||1.41%||1.33%||2.87%||21.76%|
|2/14/00||1.67%||Note: Low bottom weight used on HIFO|
|2/14/00||1.30%||Note: High bottom weight used on HIFO|
|3/30/00||1.60%||DSC much better after proper calibration|
Note that the NAHM Durometer, Hatra and MST testers were dropped after the first round of tests because of much higher CV% than the other three. The committee agreed that the NAHM forms are still the best way to measure the volumetric size of the sock.
Tester-to-Tester Differences Anova Results (HIFO)
|Date||F Calculated||F Table||Conclusion||Notes|
|2/23/00||26.00||4.10||HSD||Low Bottom Weight|
|2/23/00||5.25||4.10||SD||High Bottom Weight|
Tester-to-Tester Differences Anova Results (Dinema DSC)
|Date||F Calculated||F Table||Conclusion|
Tester-to-Tester Differences Anova Results (Scissors and Cimation)
|Date||F Calculated||F Table||Conclusion||Notes|
|9/21/99 (Scissors)||0.28||3.16||NSD||There was significant variation within each tester|
Legend – NSD = No significant difference SD = Significant Difference HSD = Highly Significant Difference
The summary of machine capabilities is as follows:
DSC – Good within machine and between machine variation in both cross stretch and length stretch.
Cimation– Good within machine and between machine variation in cross stretch only as it presently does not measure length stretch. A better calibration method is needed.
Hifomaco – Good within machine variation and between machine variation in length stretch. Cross stretch is ok within one machine but has significant variation between machines in cross stretch measurement.
In all cases the statistics showed a significant improvement in both within machine variation and between machine variations over the last 2 years. Roy congratulated the group on its efforts.
Manufacturers representatives then discussed how each machine was calibrated. All agreed with these methods and said that these procedures must be followed industry wide in order to get consistent results from various locations. Gregg Ellis of Cimation said that he is working on a new method to calibrate his machine that will be much more accurate than presently available for his machine. He said it would be ready by the next meeting.
The approximate costs of the devices are as follow:
|Scissors X Stretch||~ $100 Does not do length stretch|
|Cimation||~ $300 Does not do length stretch|
|Dinema DSC||~$7500 Does both Cross Stretch and Length Stretch|
|Hifomaco||~$6000 Does both Cross Stretch and Length Stretch|
Note that these are approximate costs.
A request was made to test another device used particularly in sheers was made to Dan at the IHE show in Charlotte. It is an Italian machine called Cetme. Dan said that this device will be tested in July and the results discussed by the group at the next meeting. Dan briefly discussed the plans for the rollout of the standard test methods to retailers that will be held at The Hosiery Technology Center on September 19th, 2000. It will consist of three concurrent sessions lasting approximately 45 minutes each. Each session will be repeated to cover the Fit, Abrasion and Colorfastness work done by the committees. There will be a dinner the night before. More details will be discussed at the next meeting. The next meeting will be held at The Hosiery Technology Center in Hickory on Tuesday August 15, 2000 beginning at 10:30 am.
- Review calibration and procedure documents for each machine
- Discuss Cetme results
- Review the new Cimation calibration method.
- Discuss September rollout to retailers.
Standards & Testing Committee Meeting Attendees 6/21/00
|Jerry G. Tew||AATCC|
|Dean Allred||Hosiery Technology Ctr. – Asheboro|
|Rachel Willis||UNC – Chapel Hill|
|Cortney Griffiths||UNC – Chapel Hill|
|Daphne Harvey||UNC – Chapel Hill|
|Paul Fogleman||Carolina Hosiery Association|
|Ed Moser||Great American Knitting|
|Jennifer Moreland||Great American Knitting|
|Chris Burns||Hickory Foundry & Machine Co.|
|Jane Terrell||J. C. Penney|
|Earl Russell||Henderson Machinery|
|David Culp||SDL America|
|Wrennie S. Edwards||NCSU – College of Textiles|
|Art Caldwell||Hosiery Technology Center|
|Tony Whitener||Footprints International|
|Regina Dula||Hosiery Technology Ctr. – Hickory|
|Doug Bradley||Industrial Lab Equipment|
|John F. Simon||Neuville Industries|
|Regina Speed||Great American Knitting|
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