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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)

Date HIFO DSC Scissors Cimation NAHM Durometer Hatra
1st Runs (98 & 99) 1.01% 1.41% 1.33%   2.87% 21.76%
9/21/99 1.87% 2.71% 2.33%      
1/05/00 2.29%          
2/14/00 1.67% Note: Low bottom weight used on HIFO
2/14/00 1.30% Note: High bottom weight used on HIFO
3/23/00       1.67%    
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
9/21/99 6.94 4.10 SD  
2/14/00 3.71 4.41 NSD  
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
9/21/99 11.24 2.73 HSD
3/30/00 0.05 4.10 NSD

 

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
3/23/00 (Cimation) 1.28 4.04 NSD

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.

New Business

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.

Agenda Items:

Standards & Testing Committee Meeting Attendees 6/21/00

Jerry G. Tew

AATCC

Dean Allred

Hosiery Technology Ctr. – Asheboro

Tania Gomez

ETI

Tina Coltrane

ETI

Mike McClung

Chipman-Union

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

John Loveless

Jobst

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

Roy Johnson

NCSU

Jan Pegram

NCSU

John F. Simon

Neuville Industries

Ann McColl

Sara Lee Sock Company

Regina Speed

Great American Knitting