Denim Maker Beat the Blues

A new control system enabled Denim North America to significantly reduce downtime, while boosting productivity by 21 percent.

Denim North America manufactures the denim used by high profile clothing manufacturers to make some of the most popular clothing in the world. Producing more than 75,000 yards of denim per day, Denim North America is one of the largest denim manufacturers in the United States. To help keep pace with a new global economy, Denim North America needs to maintain continuous production on its machines, while keeping costs down and retaining product quality.

The Columbus, Ga.-based company worked with Rockwell Automation Inc., Milwaukee, to design and implement an integrated control system across its process, material handling, packaging and other discrete applications. As a result, Denim North America reduced product variability, minimized downtime, eased maintenance and improved overall productivity across its entire facility.

Denim North America had a legacy distributed control system that managed the entire production line from the beginning of the process where the yarn enters the ballwarper, to the dye range where it gets its characteristic denim color, to the weave room where it’s woven into bolts of cloth, to the finishing range where specific customer finishes are applied.

Frequent failures

As the company’s distributed control system (DCS) aged, it began to fail more frequently, taking the production line down for three or more hours, multiple times each week. Technical support was essential, but unfortunately, the closest technicians were at least a two-hour flight away. With no local support, the failures contributed to lengthy downtimes and significant expenses.


In addition, the company’s operators found the DCS’s batch features complicated and difficult to work with, causing the company’s line workers problems getting recipes to function correctly. This meant that sometimes, the process had to be managed by hand. Due to this, changes in color, materials or other product modifications often required manual adjustments to fill the gaps.

Because of the level of manual control required, product consistency was not where Denim North America wanted it to be, and getting the correct color was a more difficult process than line workers and plant managers would have preferred. Quality levels and the amount of waste were not up to Denim North America’s world-class standards, leading the company to look for a partner that would help the plant rise to meet those standards.

“Things just weren’t working as well as they should have,” says Elmer Rumsey, technical support engineer, Denim North America. “To stay competitive, we needed to be the most modern and smoothly functioning denim manufacturing facility in the world and we weren’t yet there.”

Rumsey and the Denim North America management team decided to migrate to an automated system that would deliver the production uptime, efficiency and product consistency the company needed, while securing local support that would help it maintain a dominant market position.

Time for change

The team decided to get to the heart of the problem and replace the DCS system that was not living up to its promise. They conducted a comprehensive review and survey of its system, and catalogued its production needs. The team wanted an integrated system that would provide batching and recipe capabilities, solving the quality and consistency issues that had proven to be problematic on the last system. A key specification was that the new installation be user-friendly as well.

After evaluating several system design concepts, the team decided on a new automation system that came with a local support program. They went with a ControlLogix programmable automation controller (PAC) from Rockwell Automation. This platform leverages the same control engine, development tools, network and operator interface technologies and communications services across an entire line of controllers.

“Our engineers have been using controllers from Rockwell Automation on the discrete side of our operation for years,” says Rumsey. “By extending this platform to our motion, batch, process, safety and drive applications, we have a more connected enterprise that is much easier to operate and maintain.”

The ControlLogix PACs connect via ControlNet to Allen-Bradley Flex input/output modules, PowerFlex 700 drives and other field devices to coordinate the process applications, including the mixing, finishing and dying stages. They communicate with programmable controllers in Denim’s material handling and packaging applications for complete horizontal integration. The controllers also communicate via EtherNet/IP to business systems to provide detailed data on system status and reports on trend analysis for plant managers.

To eliminate manual adjustments and improve batch-to-batch consistency, Rockwell’s FactoryTalk batch software—with the ability to build signature templates and enforce command verification policies—improves productivity, and the company’s security and regulatory compliance efforts.

“What Rockwell Automation offered us was the chance to bring our plant up to, and even beyond, the state of the art at an attractive price,” says Rumsey. “The system addressed all of our concerns, and the Rockwell Automation post-installation service and support is head and shoulders above any other supplier.”
Minimal disruption

Rockwell Automation’s engineering team worked with Denim North America’s plant management and engineers to integrate and deliver the new line with the existing plant architecture. Rockwell Automation’s Delivered Solutions group evaluated the existing infrastructure to develop a plan to install and integrate the new components and software with minimal disruption to plant operations. As a result, the execution of the project was completed in a matter of a few weeks.

Implementing a single control platform across the plant floor has provided Denim with a number of advantages, including reduced spare parts, more synchronized processes, and lower maintenance and training costs. It has also improved plantwide integration by enabling the transfer of real-time data from the plant floor to the front office for better decision making and increased manufacturing flexibility.

Reports from the line are pulled every day for plant management to review and evaluate possible changes to increase efficiency, look for areas that may require troubleshooting, and help determine capacity for upcoming orders. Line efficiency is up dramatically, as engineers have taken advantage of the user-friendly batch and recipe capabilities to produce consistently high-quality denim with less waste.

Production is up by 21 percent, due in no small part to the significant reduction in line failures and the more readily available customer support. Previously, the line efficiency and downtime were not up to company standards. Now, the company experiences downtime only an hour once or twice a month for maintenance, and local Rockwell Automation service technicians are on site to get the system running on the rare occasion it needs immediate attention.

Rockwell Automation Inc.
www.rockwellautomation.com

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