 Ask Jim
Dr. Jim Watson, Associate Director of TexED and TexLabs, joined TexED in 1993. He has worked in the textiles industry for over 40 years. He uses his vast experience to develop textiles-based professional development courses and to develop tailored training programs to meet each client's unique needs. In addition to his education and training work, Jim oversees TexLabs, the applied research arm of the College of Textiles. Jim received his Bachelor of Science degree in Textiles from the Georgia Institute of Technology in 1963 and his Doctor of Business Administration from California Coast University in 2006.
Q: What is meant by ripstop fabric?
A: Some fabrics need to have extra protection against tearing to allow them to serve a definite need. Performance products such as parachutes, luggage, backpacks, etc. are designed so that they have high tensile strength because they are subjected to heavy loads or forces during their use. While these fabrics have high tensile strength, they may not have good resistance to tearing, which can be promoted by these same forces.
A regular plain weave is usually used to achieve properties such as low permeability and to promote tensile strength in these performance fabrics; however, the plain weave has the lowest tear strength of any weave having the same construction and yarn geometry. This is because the yarns in the weft and warp interlace oppositely on adjacent yarns creating a fabric which has each individual yarn held tightly in the fabric. Once a tearing force is applied, only one individual tightly held yarn is present to resist the tearing force.
This can be seen by taking a plain woven fabric and cutting a small snip into the fabric then tearing it by pulling on both ends of the cut. It will tear (or rip) very easily. To stop the tear, reinforcement must be placed in the path of the tear to stop it from going further.
Ripstop fabrics are woven using a special reinforcing technique that makes them very resistant to tearing and ripping. During weaving, extra or thicker yarns are used every so often as reinforcement threads. These extra or thicker yarns are woven in at regular intervals in a crosshatch pattern in the fabric. The intervals at which reinforcement threads are woven in are typically 5 to 8 millimeters (0.2 to 0.3 in) apart. To form the weave, a base weave is selected and at places in the pattern, in both weft and warp directions, either 2 or more threads are woven as though they were one or a thicker yarn is used in place of a thinner yarn. This design forms small blocks in the fabric where the warp and weft directions cross each other. When a small tear develops the extra yarns or the thicker yarn stops the tear when it contacts the reinforced area.
To picture this structure, imagine a checkerboard. The squares on the board (fabric) are formed by the crossing of the reinforcing yarns. Thin or lightweight rip stop fabrics have a 3 dimensional structure due to the thicker threads being woven in thinner cloth.
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Ask Lori
Dr. Lori Rothenberg, Associate Director, Extension Education and Quality Programs, has worked for 20 years in the areas of applied statistics and program evaluation. She coaches and trains Lean Six Sigma Yellow Belts, Green Belts, Black Belts and Master Black Belts. In addition to her Lean Six Sigma teaching, Lori is a faculty member in the College of Textiles, collaborating on grant proposals and serving as program evaluator on the projects. Lori received her Ph.D. from the University of North Carolina at Chapel Hill in 1991.
Q: What are some examples of the use of DOE in the service industry?
A: Design of Experiements (DOE) has long been used in manufacturing settings; however, the use of DOE in a service or transactional setting is not used as often. Part of the reason for the lack of use may be the difficulty in envisioning when they could be used. So, what are some examples of the use of DOE in the service industry? DOE can be done in several places. Here are a few examples:
- A store wants to make sure that sales associates adhere to a policy for the use of coupons by customers. They looked at the used of written instructions (yes, no) and oral directions from the manager (yes, no).
- A credit card company is interested in whether the Rewards Offer, the Intro APR, and the Creative Designer of the mailer have an effect on whether a person accepts or rejects the credit card offer. They design a full factorial experiment with Rewards (Yes, No), Intro APR (0%, 2.99%) and Creative Designer (Firm A, Firm B).
- A retailer is interested in whether they can make the screens on the registers easier to read. They design a full factorial experiment with Font Size (14, 16), Font Type (arial, times new roman), and Background (white, black). Readability is assessed by asking associates for their preference.
- A large company wanted to reduce their receivables from 200 to only 44 days. They designed a full factorial using Bill Delivery (With Shipment, Separate Invoice), Followup (Letter, Telephone), and Billing Service (Contract, In-house).
- A sales team wanted to improve the percent of successful closures. They designed a full factorial experiment using Attire (suit, casual), number of sales people (one, two), and presentation (high pressure, low pressure).
- A physician’s office wanted to reduce the wait time to see the doctor after arriving at the doctor’s office. The office manipulated two variables: type of sign in (electronic kiosk, sign in with receptionist) and where vitals were taken (in a common area, in the examining room).
If you have done an experiment in a service or transactional setting, please share it with us on our Facebook page.
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February Events
Design and Innovation with Computer Simulation
February 1-4, 2011
College of Textiles
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Register for Master Black Belt Credit
Nonwoven Micro and Nanofiber Production
February 7-10, 2011
College of Textiles
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Lean Six Sigma Green Belt with Minitab
February 7-11, 2011
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Lean Six Sigma Black Belt with Minitab
February 7-11, 2011
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Textile Fundamentals
February 14-18, 2011
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March Events
Forensic Photography Workshop
March 8-10, 2011
College of Textiles
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Design for Six Sigma
March 8-11, 2011
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Register for Master Black Belt Credit
Fundamentals of Technical Fabrics
March 22-25, 2011
College of Textiles
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April Events
Master Black Belt Core Training
April 5-8, May 3-6, 2011
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+2 Upgrade to a Black Belt with Minitab
April 11-15, May 16-20, 2011
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Nonwoven Meltblowing and Spunbonding Fundamentals
April 11-15, 2011
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Dyeing and Finishing Fundamentals
April 19-22, 2011
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Karl Mayer Opens US Training Academy
-Brian Davis, knitting lab manager, attends inaugural course
The Karl Mayer Academy held its first training course in the United States this summer. Brian Davis, Knitting Lab Manager for TexLabs at NC State University College of Textiles, attended the inaugural course in Analysis and Design of Warp-Knit Textiles.
The course, the first Karl Mayer has held in the United States, was held at the KARL MAYER Academy. Topics such as innovative machine components, layout of pattern chains, design and analysis of tricot fabrics, and
use of analytical equipment were taught by training instructor Robert Kuna.
The overwhelming response to the course showcased the increased
need for technical training for American textile companies due to many manufacturers focusing on technical textiles. The Karl Mayer Academy will help meet client training needs in the US and joins partner training academies in China and Germany.
Source: Kettenwirk Praxis, Karl Mayer, 3rd Quarter, 2010 p. 40.
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Six Sigma Benefits Industries for the Blind
When Barry Self of Forsyth Community College had to select a project for his Lean Six Sigma Black Belt certification, he chose to work with Winston-Salem Industries for the Blind (IFB). During his work with this organization, Barry not only assisted IFB in recognizing significant savings, he helped save the jobs of over 250 people.
Barry’s project revolved around improving materials management, including increasing throughput capabilities and improving visibility of all materials. His main focus was on the elimination of errors that were resulting in large variations in inventory value. Through the use of an integrated bar coding system, reorganization of the warehouse storage locations, and implementation of warehouse management software, IFB is expecting to see savings of more than $500,000 over the next year. These improvements in materials management and the added capability for voice directed picking have also expanded employment opportunites for the blind and visually impaired workers at IFB, allowing them to work in inventory management in the pick/pack finished goods area for the first time.
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