A Case skid steer.
Powerful yet quick, multi-attachment tractor skid steers can spin on a dime and move heavy loads of material quickly. The multi-attachment tractors are sold to a variety of industries and many municipalities for use in construction, road and bridge building, landscaping, and agriculture applications.
Many of these skid steers are designed and built by 700 employees in CNH Global NV’s 360,000-ft2manufacturing facility in Wichita, KS. The CNH Wichita plant is a dual-branded manufacturing center that produces both the Case and New Holland brand skid steer loaders. Wichita is also home to the Skid Steer Loader Product Development Team, which partners with the manufacturing operation on the next generation of Skid Steer Loaders. Multiple brands are produced on the same production line.
Constantly searching for improvement opportunities, CNH Wichita recently embarked on a project to improve the operational efficiency of its paint system.
Audit and Analysis
CNH consulted with A.B. Myr Industries (ABMyr), an industrial engineering firm based in Belleville, MI, that specializes in finishing operations. According to a plant spokesman, CNH selected ABMyr because of its engineering knowledge of finishing system air control and the level of detail that the company uses to analyze and understand three dimensional airflow characteristics.ABMyr performed a detailed analysis using a formal inspection process and a comprehensive air audit of the cure ovens, flash tunnel and spray booths. The inspection team also used anemometers to measure air velocities in the exhaust ducts and in the openings of the booths.
Solutions
In a quick shutdown period over the 2006 winter holiday break, ABMyr implemented the following airflow changes:- Replaced the tube axial fans with vane axial fans. Vane axial fans are equipped with vanes that trail behind the propeller in the airflow to straighten the swirling flow.
- Installed variable speed fans to provide additional air control. Fans deliver air in an overall direction that is parallel to the fan blade axis and can be configured to deliver a high flow rate when working against low pressure. Conversely, the fan slows down against high pressure when the filters fill.
- Adjusted fan speeds and positioning
- Installed an automated airflow monitoring and control system (ABMyr Industries’ AirOPS)
- Installed a filter maintenance system
The spray booth airflow control and filter management system automatically adjusts airflow to maintain spray booth balance.
Air Monitoring and Control
One of the most significant changes was the installation of the spray booth airflow control and filter management system, which maintains spray booth balance. The system automatically adjusts the fans and dampers to keep airflow in the spray booth consistent at all times. Airflow and pressure sensors measure and monitor in real time how much air is moving through the spray booth, while a filter management system simultaneously measures and monitors differential pressure at filters to detect blockage.The system uses real-time data from numerous sensors positioned throughout the spray booth and ventilation ducts. It compares the air speed, pressure, temperature and other environmental data with a computer model for the ideal process using baseline data.
The automated spray booth balancing system provides CNH with:
- Real-time operational monitoring
- Automated air flow control
- Filter management
- Statistical process control (SPC) reports
- Built-in tuning tools to further boost product quality and production productivity while cutting operational costs
The Results
The modifications greatly improved the efficiency of the plant’s finishing line.“The results have been incredible,” said Peter Maitwe, CNH Paint Manufacturing Engineer. “The ABMyr airflow improvements have significantly increased our line productivity and extended the life of our filters.”
The airflow changes have provided CNH with increased productivity and reduced operating costs to better serve the needs of its customers.
“The AB Myr engineers have tremendous design skills and ingenuity. They were able to do so much in a short timeframe. And it all worked right the first time with no issues,” Maitwe said.
For more information about ABMyr, visit www.abmyr.com. More information about CNH can be found at www.cnh.com.
