November 2007 Edition

automotive manufacturing

Lasers and material handling streamline chassis production

The plant's maintenance manager, Emilio Lozano, calculates that the plant's six Bystar laser cutting systems boast an average uptime of 97 to 98 percent, with beam-on-time reaching as high as 85 to 86 percent.

NACCO Materials Handling Group Inc. (NMHG), a subsidiary of NACCO Industries, designs and builds internal combustion and electrically powered lift trucks sold globally under the brands Yale and Hyster. In the U.S. market alone, there are more than 130 varieties of lift trucks that lighten the load for those working in manufacturing, warehousing, retail, container handling, or heavy manufacturing.

At NMHG's manufacturing facility in Ramos Arizpe, Mexico, 190 miles south of the U.S. border at Laredo, TX, innumerable chassis await export to the United States. The steel infrastructure of every model sold in the United States is prototyped, tested, and put into full production at this facility. Final fabrication occurs at NMHG's manufacturing facilities in Kentucky and North Carolina.

Motorized hand trucks and lift trucks are designed with a range of capacities. Some models can handle loads in excess of 15,000lb.

Alejandro Oliva, general manager of the NMHG Mexico S.A. DE C.V. operation, has managed the facility for six years. During this time, the company has realized a 300 percent increase in growth. The plant now has six laser-cutting systems, 360 employees, and a production area greater than 170,000 sq ft. The first two lasers, a Bystar 3015 and a Bystar 4020, were installed when the facility opened in 1998. Production began in 1999, and additional lasers were installed as product lines evolved and expanded. NMHG now has five Bystar 4020's — four with 3.0kW and one with 4.0kW — and one Bystar 3015, 4.0kW laser. Each Bystar has a Byloader 4020 material-handling system and a shuttle table. They also have two automated material storage systems, one with four shelves and the other with five.

High-speed laser cutting equipment, automation, and kanban are only three parts of the company's overall production configuration. To ensure that its daily goals are met, NMHG follows a set schedule of routine maintenance that is performed by its employees.

NMHG already had Bystronic laser-cutting systems in its European manufacturing plants, and results were positive. The philosophy in 1998 was to bring this same level of reliability and productivity into the Ramos Arizpe facility.

Oliva says the laser-cutting systems have also helped the facility achieve better quality. "We have noticed an improvement not only in our finished edges, but in our ability to maintain exceptionally tight tolerances," he says. "The quality of our overall product has certainly increased because of these systems."

Adding kanban

Designed to lend a helpful hand in the moving of materials, motorized hand trucks and lift trucks are designed with a range of capacities. Some models, designed for tough applications such as steel and logging yards, can handle loads in excess of 15,000lb.

Oliva explains that the operation runs three shifts per day, six days per week. The six lasers process 2,500 tons of metal each month — which equates to 115 sheets of steel cut every day. On this schedule, seven tractor-trailer trucks — each hauling 40,000lb of product — leave the facility at the end of every day. "For us," explains Oliva, "our high productivity comes from the cutting speed of the lasers. They are very fast. The only downtime we experience is when the shuttle tables switch positions or we perform routine maintenance." In adhering to the lean-pull system, it is important that every machine on his floor is up and running.

While most material that enters the NMHG facility is in the form of plate steel or flat bar in a range of thicknesses, the lasers regularly process steel 1.5mm to 12mm thick. Occasionally, material up to 16mm will be processed on the Bystars when accuracy and high tolerances are specified.

Maintenance manager Emilio Lozano says the lasers run at roughly 85 percent beam-on-time, an average that includes material-loading and unloading time as well as minor adjustments. In being asked about the differing levels of automation on the various lasers in relation to productivity, he explains that the kanban card system is very helpful in maintaining consistently high productivity on every machine. Lozano explains:

"As part of our lean system, operators know 24 hours in advance what they are going to cut, so they ask for the materials they need in whatever thickness required for the next day's processing. The material is then loaded into the automation's storage towers or placed next to the Byloader tables in the sequence in which it will be cut. Our automation works very well within this system."

High-speed laser-cutting equipment, automation, and kanban are only three parts of the company's overall production configuration. To ensure that its daily goals are met, NMHG follows a set schedule of routine maintenance that is performed by its employees. Oliva explains that this initiative is possible because Bystronic machines are easy to maintain. "After attending Bystronic's maintenance training programs," he says, "my employees had the knowledge and confidence needed to do their job.

Easy maintenance

While most material that enters the NMHG facility is in the form of plate steel or flat bar in a range of thicknesses, the lasers regularly process steel 1.5mm to 12mm thick. Occasionally, material up to 16mm will be processed on the Bystars when accuracy and high tolerances are specified.

"Every part on the laser systems is replaceable — so I am able to simply take it out and fix it." Lozano explains. "Although the technology is sophisticated, it is very easy to understand." He estimates that scheduled maintenance for each machine runs 10hr every month. Every six months, Lozano performs more detailed preventative maintenance and a thorough cleaning.

Lozano calculates that the plant's six Bystar laser-cutting systems boast an average uptime of 97 to 98 percent with beam-on-time reaching as high as 85 to 86 percent.

"Our first Bystar laser-cutting machine was installed in 1998 and has an estimated 45,000 or 50,000 hours on it," says Oscar Llamas, the plant's engineering manager. He estimates that the uptime on this system is only 1 percent less than that of the newer laser-cutting machines. "While we choose not to cut thicker materials on this system, our oldest machine is just as productive as our newest in cutting thin materials." He says that each of the six lasers had worked flawlessly 24/7 for over two years. In 2005, they changed to three shifts, six days per week.

"My operators and maintenance personnel like to work with the lasers because they are sophisticated pieces of equipment." Llamas continues. "There is quite an element of pride in going through the Bystronic training courses and in being certified to repair and operate these machines. We have found the training very helpful."

Quick programming

At the heart of the machine's user-friendliness is the Bysoft programming software. The team likes the software, believing that its capabilities have enabled it to implement Kanban more effectively. In keeping with lean, it cut only what is going to be consumed in the line that same day. The team has established a card system in which every part that is to be manufactured is represented. On average, the programmer has 150 parts (or cards) that need be entered into the Bysoft program and nested before the day's production can begin.

Pablo Trujillo, manufacturing engineer in charge of programming, finds the software convenient. "I have never had a problem with Bysoft. The nesting, the part parameters, everything, it's all very fast and very easy." He programs the six lasers to process over 2,000 different parts every week from his desk. "This task takes me four to six hours each day," Trujillo says. A time investment that he believes would increase more than 50 percent were it not for Bysoft.

When Trujillo nests different parts from various product lines on the same sheet of metal, Bysoft helps track the diverse part inventory. Llamas explains that Bysoft enables the team to print out a complete part catalog with specifications as to each part's thickness, geometry, and weight. With this feature, anyone on the floor can quickly identify a part without part etching. "When you have a multitude of parts running through your machine every hour, it helps to be able to identify them. Without our Bysoft software, it would be almost impossible to do what we do here. You would need an army of people just to do the nesting," Llamas concludes. Bystronic Inc., www.rsleads.com/711tp-150