Fit/Dimensional Stability Committee
Hosiery Technology Center, Hickory, NC
August 15, 2000
Regina Speed opened the committee meeting and went over the Mission Statement and objectives of the committee.
Dan St. Louis then reviewed the latest findings of the Fit Subcommittee. Verification trials were performed last week on the various machines, which led to several conclusions. These are:
- There is X% variation in our controlled knitted fabric. Even under controlled conditions there is some variation due to yarn, stitch formation, etc.
- A spring is the best way to measure machine-to-machine variation. The spring does not have nearly the variation as a controlled knit fabric.
- When using a spring, it must be without drag, twist or operator induced error, as inaccurate readings will occur. The spring must operate freely and in a straight line.
- Calibration requires multiple pulls. If you rely on one check of the calibration spring, you will get into trouble eventually.
- Any changes to the machine will require a recheck of the machine.
- Believe the data, there is a reason for the numbers. In all cases, there was a reason when the data showed significant variation.
Other items of note were that the Hifomaco machine passed all tests now and will be included in the procedure write-ups. A new machine from Cimation was introduced since the June meeting and it also met the requirements for testing. This device is called the Cimation 4800.
A discussion of the calibration springs then followed. The group decided we need a standard method to make sure the calibration springs have not changed. Gregg Ellis, Brent Jones and Chris Burns volunteered to work on this and report back to the group.
Tony Whitener and Regina then discussed the procedure write-ups that have been done on all machines. It is currently on the web at http://www.legsource.com in the Sock Testing Consortium section. The group is to review these procedures by August 22, 2000 and reply back with any changes needed to Tony or Dan using the response form on the web site. These procedures will be published in booklet form for the meeting on September 19th.
The Cetme Machine test results were discussed next. Although it was statistically ok for cross stretch, it failed in length stretch. This was probably due to having variation caused by the operator having to put the load on the sock verses having some type of machine controls to put the load on. Doug Farmer said that they had one at DuPont and saw the same thing, but that they had modified the machine to take care of this problem. The machine now works for them and he offered help to anyone in the group if they had a Cetme in their mill that needed modifying.
The upcoming Standard Methods Rollout Meeting to retailers was then discussed. There will be a dinner reception at the Gateway Center Hotel in Hickory on the 18th with the actual standards rollout meetings the next day at the HTC. Speakers planned at the reception include Jim Black, who is the NC Speaker of the House and Dr Blanton Godfrey, who is the new Dean at the NCSU College of Textiles if his schedule allows. The committee then worked on the actual meeting that will be held at the HTC on September 19th. We brainstormed different topics to be sure we covered.
These included:
- A general overview of the committee
- The timeline of committee work since the beginning
- The various machines that were evaluated and the criteria used in evaluation.
- Improvements made as a % reduction in variation.
- Sources of variation within the process, between machine variation and operator variation.
- Calibration
- How it affected results
- Standardization of calibration methods.
- Illustrate the reasons why the shift from socks to tubes to springs as our material used to test the machines.
- Statistical tools used.
- How the data was used to identify special causes.
- Tools available
- Information available on the web atwww.legsource.com
- Upcoming Hosiery Testing Classes available
- Conclusions and Question and Answer period.
- Next Steps –
- Taking to ASTM or AATCC
- More research on springs, machine correlations, settings for different fabrics, dimensional stability, etc.
- Vendor demonstrations.
Presenters at the September 19th meeting will be Regina Speed, Dan St. Louis, Tony Whitener and Roy Johnson. They are to get together before the meeting to work out the details on the presentation.
We tentatively set the date for the next meeting on October 3, 2000 to review the September 18 meeting and plan for the next steps. It will begin at 10:30 am at the HTC in Hickory.