Laser system with automatic shuttle tables improves uptime, cuts heavier materials and opens new doors for precision fabricator
For some sheet metal fabricators, the risk of capital expenditure in the face of challenging business conditions far outweighs the benefit. Others, like Nitram Fabricators Inc. (Elk Grove Village, IL; www.nitrammetal.com), believe investing in advanced technology is the only way to remain viable.
When Nitram was established in 1974 the precision sheet metal shop focused its business on high-volume runs for the telecommunications and medical industries. Today, the company handles smaller lot sizes, more complex part profiles and a range of thin and thick materials, producing component parts and complete assemblies for diverse industries and doing a growing amount of design and prototype work.
The company credits its flexibility to the addition, last year, of a high-speed flying optics machine equipped with a 4kW CO2 laser and shuttle tables, an Axel 3015S system manufactured by Strippit/LVD (Akron, NY). For Nitram, the investment in this system made good economic sense, because investing in advanced technology has kept the shop flexible, growing and open to new business opportunities.
Over the years, Nitram has seen its production runs shrink as its customers' product life cycles have shortened and as more products are manufactured outside of North America. In the midst of a down economy and with stiff competition from overseas markets, Nitram management realized that using advanced equipment was one way to remain competitive in its design, prototyping, pre-production and medium volume work. The company viewed its purchase of the new laser system, which replaced an older standalone laser machine, as a means of keeping its business viable. Nitram employs 31, occupies 30,000 square feet of space, and typically generates up to $11 million in annual sales.
"The laser is an investment that gives us greater capability and widens our horizon," says Pat Ferrara, an officer for Nitram. "We realize that we need to change to create new avenues for growth." In purchasing the laser, Nitram had three key objectives: increase uptime, cut heavier materials and improve accuracy.
Maximizing uptime with automation
Improving uptime required outfitting its new laser with automatic shuttle tables. These enable the company to remove finished parts from one table or load a new sheet while the machine is cutting on the other table. The shuttle tables are especially effective for one of the shop's repeat jobs—an intricately designed part up to 96 in. in length produced in a 45-minute cycle time. Prior to the new laser, it took a maximum of 20 minutes of downtime to carefully remove the delicate finished parts from the skeleton. Now, finished parts are removed from the skeleton while the machine is cutting the next workpiece. Though the amount of time required to unload the parts has not changed, machine productivity has significantly improved, as production is uninterrupted and there is no loss of cutting time.
Processing heavier materials
To process heavier materials as well as a broader range of thicknesses at higher feed rates, Nitram's General Manager, Peter Lengsfeld, turned to a higher laser power. Nitram's 4kW laser is able to cut mild steel up to 3/4 in., stainless steel up to 1/2 in. and aluminum to 3/8 in. The GE Fanuc 4kW CO2 industrial laser gives Nitram increased processing power for high-speed cutting of thin plate and improved cut quality in thicker materials. Its previous 2.5kW laser was limited to 090 stainless and, while it was able to process 190 aluminum, it did so at much slower feed rates.
The laser provides a broad range of processing capability to address a wide variety of application requirements. An edge function feature enables sharp corners to be cut in a range of materials, including thick plate. A total power control feature automatically adjusts the laser power in relation to the cutting speed.
The ability to cut heavier materials is key to Nitram as the company pursues new business. Its primary industries—telecom and medical—generally specify lighter gauge materials. The 4kW laser gives the shop the ability to be competitive outside of its principal markets. "The higher wattage opens up a whole new market for us in processing heavier materials," says Lengsfeld. "Heavier parts are historically handled by machine shops that machine or plasma cut the workpieces. We are pursuing this business by setting ourselves up as a service shop to these machine shops."
Nitram is leveraging its relationship with machine shops to get a share of work in heavier materials. Recently, it began supplying Chicago-area machine shops with laser-cut blanks, which are then finished machined by the shop. Providing a laser-cut blank dramatically reduces the machining time required per part, thus reducing costs. In one case, the laser cut four different jobs in a single day. Machining these parts would have taken at least one week. "The customer was pleased with both the quality and the turnaround," says Lengsfeld. "We were able to get a job we previously would not have been able to consider."
The increased cycle times of the new laser have also enabled the shop to drastically reduce prices on some of its products/jobs. At the end of the day, there's a greater amount of finished parts, which translates to greater profitability.
Improving accuracy consistently
Nitram can process existing parts with greater accuracy. The machine has positioning accuracy of ± 0.002 in./40 in. with repeatability of ± 0.0004 in., which ensures consistently accurate processing.
Nitram's laser features a constant beam length system that keeps the diameter of the laser beam constant and consequently always maintains a fixed focal point position. This not only results in higher cutting speeds, but also maintains a good cut quality over the entire working area.
A part used in medical diagnostics, as large as a bed frame, is now produced with higher accuracy. The 4-ft × 8-ft frame is constructed out of tubes, which were previously individually machined, and then welded together. The heat of the welding process would often distort the frames, making the precisely machined holes out of tolerance. Now the frame is first welded and then the entire frame is placed on the laser's 5-ft × 10-ft table where the frame is completely processed on one side, and then turned over and processed on the other side, in a matter of minutes. Tolerance from hole to hole is extremely accurate and consistent from part to part. The part is processed burr-free and can now be produced in from one to two minutes per side.
Having better control
The transition to the new laser was simple, in part because of the system's GE-Fanuc control with which the shop's operators were already familiar. Says Lengsfeld, "The control on our previous system seemed to be a hindrance. Plus, the Fanuc control combined with the Fanuc laser and servo drives definitely contribute to the quality of the finished product."
The CNC control integrated with the GE-Fanuc RF CO2 laser provides high reliability and low maintenance. The system integration ensures reliability and fast response time, due to the absence of interfaces.
In recent years Nitram has streamlined the flow of production through its shop as another way of improving its competitiveness. The process, which it continues to fine tune, is credited with reducing lead times from 12 to 16 weeks down to 2 weeks. By combining an orderly process flow with advanced production machinery, the shop is able to reach an annual target of $11 million in sales without adding to its staff. "As our margins have shrunk in terms of hourly rates, our increase in throughput enables us to make up our sales volume," explains Lengsfeld.
Nitram's shop management and operators view the addition of the new laser as an important step in keeping the job shop thriving.
Steve Crane is an engineer with Strippit/LVD, Akron, NY. For laser system information e-mail: email@example.com or www.lvdgroup.com.