Quality in Raw Material Purchasing - A New Approach

Purchasing by specification
Many companies were not using specifications and did not communicate well with their suppliers. Numerous problems were noted of handling unworkable materials and of producing unserviceable garments. The properties of raw material affect not only its handling characteristics during production, but also the quality of final product as well.

Thus if there is to be any continuity in production and product quality from lot to lot, and style to style, there must be some assurance that little or no change takes place in raw material properties. This can be guaranteed only by establishing a rigid set of practical specification.

Once specification has been established, there is no reason to restrict their use to vendor and purchaser. They can also enhance the communications between the designer and the selector, between local management and quality inspectors, and between fabric producer and fabric finisher, trims suppliers.

The four ingredients of a fabric specification:
1. Physical characteristics: Details should be stated about fibres, yarns, material construction, finishing treatment, finished width and acceptable tolerances.

2. Performance characteristics: All important characteristics need to be specified, together with tolerances. Typical areas are shrinkage, colourfastness to light, washing, laundering, rubbing etc, strength, care characteristics, flame retardants features.

3. Visual defects: The grading system to be used should be specified, together with the level of acceptance.
Ex: 4-Point system, 10-Point system.

4. Shade specification: The colors of the purchased materials should be specified, together with tolerances between batches and pieces and within pieces.

The raw material specification sheet provides an effective means of communication; it should never be made the exclusive channel of information flow. Companies who are implementing a policy of continual improvement are seeking to promote long term relationships with reliable suppliers, and are recognizing the need for direct communication at managerial level. This suggests the need for vendor rating and for clear policies on communication in the context of quality assurance. However, the fashion business is dynamic and every season sees new combination of cloth and trims. The selection, inspection and testing of materials has to be done very carefully.


Common Fabric Defect and Testing


Automated Fabric Inspection

Fabric inspection has proven to be one of the most difficult of all textile processes to automate. It has taken decades for computer and scanning technology to develop to the extent that practical, consistent and reasonably user-friendly systems could be produced.

Today's automated fabric inspection systems are based on adaptive, neural networks. They can learn. So instead of going through complex programming routines, the users are able to simply scan a short length of good quality fabric to show the inspection system what to expect. This coupled with specialized computer processors that have the computing power of several hundred Pentium chips makes these systems viable.

They are designed to find and catalog defects in a wide variety of fabrics including greige fabrics, sheeting, apparel fabrics, upholstery fabrics, industrial fabrics, tire cord, finished fabrics, piece-dyed fabrics and denim.

The Human Factor

Typical fabric inspection speeds and fatigue limit most human inspectors to detecting from 40 to 60 percent of defects. Automated fabric inspection systems' capability to find fabric defects at 80 to 95 percent. Finally it takes years to train a good human inspector, and these automated systems can be installed and "trained" in a matter of weeks.

Fabric Scan

Fabriscan, can inspect fabric at speeds up to 120 meters per minute and can detect defects down to a resolution of 0.3 millimeters. It can handle fabric widths from 110 to 440 centimeters. Zellweger Uster has several installations in Europe covering range greige fabrics including apparel, denim and industrial fabrics. The cost for Fabriscan starts at $200,000. Zellweger Uster estimates that the system has a payback of about 12 to 24 months, based on labor savings, cut optimization, and improved flagging accuracy to customers.

The Future: Expect Automated Inspection to Grow

As the MFA Quotas came down in 2005, it will be possible to source fabric worldwide. Garment manufacturers as well as industrial fabrics users will increasingly need a comprehensive, consistent way to establish the quality of goods. In addition, the digital maps that automated inspection systems provide, which reliably pinpoint defects, may well be required by the cutter. EVS has been working for years to brand fabrics inspected with its system using "I-Tex Inspected" stickers. The ability of a mill to certify that its fabrics have undergone automated fabric inspection could very well become a requirement for certain applications or markets.

New Developments in testing fabrics

Objective Measurement
The above table shows that manufacturers have been primarily concerned with visible defects.

There is a growing awareness that there are numerous fabric properties which are invisible, but nevertheless have important consequences for manufacturing and customer satisfaction.

The challenge of the future is the efficient large scale production of high quality textile materials and garments using fully automated machinery. These products will be demanded by consumer requiring good product appearance plus reasonable durability and performance. In order to achieve these, The Kawabatata Evaluation System is developed which is the scientific system of objective evaluation for the quality, appearance and practical characteristics of textile materials and garments. This equipment designed to find out the handle property of the fabric by objective measurement of stresses in tension, shearing forces, bending forces, and to sense surface friction and surface smoothness, weight of the fabric.


Conclusion

As the Fabric constitutes 90-95% of the garment it is very important to assure the quality of the fabric by the new approach as discussed above such as Purchasing by specification., Automated Fabric inspection System, New Testing methods of Fabric. The New quality control approach gives the following benefits such as: