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Denim Mill Modernization Continues

By Brandy Reed

Responding to dramatic changes and new demands of the textile industry remains top priority as Plains Cotton Cooperative Association’s ACG Denim Mill continues its latest modernization project.

PCCA’s Board of Directors approved a $7 million modernization project in November, 1997, to improve weaving efficiency, quality and diversification at the mill. The project is the continuation of modernization and expansion efforts that began in 1993.

To meet the needs and requests of mill customer Levi Strauss & Co. (LS&CO.), PCCA’s board approved the purchase and installation of an I-Tex 200 model Elbit Vision System (EVS) for fabric inspection, two Amsler Slubbing Devices for specialty yarn manufacturing and 81 Picanol Omni Airjet Looms to replace 247 Picanol PGW looms that were installed in 1981. The EVS and slubbing devices already have been installed.

EVS, originally developed by the Israeli Defense Ministry, has been installed in finishing on both of the mill’s sanforizers, which are the machines that shrink the fabric before it is put up and shipped, according to Plant Manager Danny Davis. EVS determines denim quality by evaluating visible defects. Cameras continuously photograph both the face and back sides of each yard of fabric as the denim passes through the system. Information from the photographs is sent to computers which save only the frames containing identified defects.

The cameras also photograph and log all of the relevant cloth data such as lot numbers and exact locations of defects. Ultraviolet sensitive spray is directed onto the fabric to mark and synchronize the yards of cloth going through EVS. Yardage and defect location information then is sent to the cutting tables where computers automatically label defects as cloth is fed through the system.

The cutting tables can run 150 yards of cloth per minute through the system. The computer uses the ultraviolet markings to identify the region of the defect so once the system is within 20 to 30 yards of the blemish, it can slow down and stop on the defect. Prior to installing EVS, finishing department employees visually inspected each yard of fabric individually and tagged each defect by hand.

“It cuts down on the inspection time needed,” Finishing Superintendent Rocky Bowman says. “What takes an hour and a half now will only take 15 minutes once the system is fully operational.” In addition to increasing fabric inspection efficiency, EVS also will reduce Levi’s fabric seconds.

Two Amsler Slubbing Devices were installed by late January in yarn manufacturing. Slubbing devices cause intentional slubs in the yarn by controlling the speed of the sliver as it enters the spinning unit, giving the fabric a striated or streaked appearance. “Slubbing changes the character of the yarn and makes the denim look more like it did 20 years ago,” Davis says.

LS&CO. has asked the mill to develop slubbed fabric because the “retro” style is desirable for modern fashion. The slubbing devices currently are running through evaluation trials. A representative from LS&CO. has visited the mill twice and met in El Paso with mill officials to monitor the progress of the modernization projects.

Weaving department looms will drop in number from 363 to 197 with the installation of the 81 Picanol Omni Airjet Looms. One airjet loom was installed in the mill during April for weaving department employee training. Davis says installation of the remaining new looms will begin in June and should be completed by September.

The new looms will be much more productive by more than tripling the filling insertion speed of the old looms. Filling insertion is the rate at which the white yarn is inserted into the dyed yarn. Old looms use the rapier weaving method in which the white yarn is carried across the loom mechanically at a rate of 230 filling insertions per minute. The new airjet looms use tiny jets that “blow” the yarn across the loom at a rate of 760 filling insertions per minute.

Davis says the modernization project is going well so far and will result in considerable labor savings. The new machines are running at full speed but not full efficiency since they have not been completely integrated into the entire system.

“The inspection portion of EVS is working really well,” according to Davis. However, he says the greatest hurdle for the modernization project is the tie-in between the video inspection system and the cut optimization software that will be used on the cutting tables because the systems were developed by two different companies.

Payback for the modernization project is expected to be seen within three years. Overall efficiency at the denim mill will be improved, and the diverse needs of LS&CO. will be better served as well. Both factors will result in increased earnings for the mill and its customer.