Extra Large Economies of Scale

Each XL table can accommodate as many as four 5 ft by 10 ft work pieces and, with the addition of a pallet changer, that total can be doubled to eight 5 ft by 10 ft pieces. Mitsubishi is not an integrator. They manufacture the entire system in-house, from resonator to bed, from head to controls, meaning they can easily blend technologies over any footprint, big or small.

In the XL configuration, they took all of the good qualities of the eX machine and stretched them out over a much larger table, gaining scale advantages along the way.

CASE STUDY: THE OBELISK
The extra large gantry construction of the XL Laser, combined with a 10 ft by 20 ft table, can process 4 sheets of 5 ft by 10 ft material, or a single 20 ft long piece. Hank White, a laser application engineer with MC Machinery, devised a project to demonstrate this massive table capacity and specific capabilities at the recent FABTECH show in Las Vegas.

“Most standard machines can cut only 10 ft to 12 ft in length, so we decided to design a structure that would push the XL to its limit,” explained White. “We decided on a 20 ft part pulled from a single piece of material. Ordinarily for something of this length, a manufacturer would need to cut something in multiple pieces and weld them together.”

But floor space at a packed show limited their options, so the company decided to go vertical and settled on the tallest structure they could come up with that still had a small footprint: an obelisk. The obelisk is not only an art form, it’s also a free standing structure which the wrappers are processed from a single sheet of 20 ft long material.

Before fabricating the show piece, though, the structural underpinnings needed to be built – and there are a lot of them. The first thing that needed to be designed was a light internal structure, starting with a round, 3/8 in mild steel base. White welded four internal support stanchions to that base, each being about 3 ft tall. He bolted a piece of 6 in by 6 in square stock to the stanchions.

“In that square stock, we were actually able to cut reliefs with the XL machine because of the Z clearance on the machine. We have 6 in of Z capable of producing a slot to place the square stock in,” White says. “These reliefs gave us the ability in the square stock to reduce weight. The next step was to add a 2 in by 2 in upper stanchion out of a piece of square stock. This enabled us to add supports to which the outside skin would be bolted.”

The obelisk is composed of 55 parts and weighs in at a total of about 600 lb. Every part on the display was cut on the XL, which provided the advantage of sheer size. With 20 ft to work with, White did not have to reposition different sheets for different weldments. Instead, he was able to order one solid piece of material to accomplish the entire outside wrapper.

Again, with the internal structure and the square stock, most machines don’t have enough Z clearance or a table length long enough to cut square stock without removing the pallet. White was actually able to set the square stock into the machine only by removing several slats. This gave him plenty of room and flexibility to cut every component on one machine with very minimal set up and very short process time. In fact, the outside wrapper was only 15 minutes of process time.

“Now in the industry, we find that a lot of manufacturers are going larger,” added White. “They want to produce parts out of one sheet of material with no weldments, forming components out one piece instead of forming several together. This reduces set up time and cost. You see this a lot in the crane-building industry, the mining industry, even with sub-frames in the trucking industry. This has really increased our ability to produce larger parts on a larger scale with reduced setup, reduced cost.

There were four total setups for the obelisk. The primary setup was the outside wrapper, complete with a Mitsubishi logo, that was made from 304 stainless steel in approximately 15 minutes, or five minutes per side. The internal structure with the 3/8 in mild steel base and weldments took about a half an hour for the full process. The square stock, two pieces with all of the manual flip-overs, took about a half hour as well.

All of these cycles combined for about an hour and a half of total process time for the entire part. Without the XL, a comparable machine tool would have required much more set up time and used three extra sheets to cut the full length. The welding time and prep time needed to assemble those parts would be substantially higher.

Material cost can be a factor when using a larger machine like this, but coils can be ordered at any length. By purchasing an entire coil and using the whole thing for that length, money can be saved – as well as time.