Laser cutting technology has significantly moved the needle for fast processing of flat sheet metal. But what about cutting tube and pipe? Today’s laser tube cutting machines are specifically designed to cut a large range of mill-length tube and pipe, whether round, square, rectangular, or triangular. Some of the more advanced options can process I- and H-beams, C-channel, angle iron, and other user-defined shapes.
Tube Cutting Basics
There are some significant differences between laser cutting tube versus flat sheets. Operators need to be aware that cutting tube requires an ideal finished cut so the machine can move on to the next part. With laser cutting sheet metal, the machine is not affected by the previous part and can simply move on to the next sheet regardless of the quality of cut. It is important that the last cut of the part be of a quality to allow the finished part to be separated from the unprocessed material stick. If the finished part does not separate it can present a challenge for the unloading process and can also present a challenge for the start of the next part if the previous part does not separate properly from the raw material.
Laser cutting can lend itself to completely new product designs. Innovative and complicated designs are easy to process with the laser and can make a product stronger and more aesthetically pleasing, often reducing weight without sacrificing strength. Tube lasers excel at supporting the tube assembly process. Special laser-cut features that allow tube profiles to be bent or joined easily can simplify welding and assembly greatly and help reduce the product’s cost.
A laser allows the operator to cut holes and contours precisely in one working step, eliminating repeated part handlings for downstream processes (see Figure 3). In one specific example, making a tube connection with a laser instead of sawing, milling, drilling, deburring, and the associated material handling reduced the manufacturing cost by 30 percent.
Easy programming from a computer-aided design drawing makes it possible to program a part quickly for laser cutting, even if it is for small-batch production or prototyping. Not only can the tube laser process parts quickly, but setup time is minimal, so you can make parts just-in-time to reduce inventory costs.
After taking inventory of your typical manufacturing steps, your next step is to review the available features and decide which are essential.
Keep in mind that most tube lasers are equipped with resonators that deliver 2 to 4 kW of cutting power. This is sufficient to cut the typical maximum thickness of mild steel tubing (5⁄16 inch) and the typical maximum thickness of aluminum and steel tubing (¼ in.) efficiently. Fabricators that process substantial amounts of aluminum and stainless steel will need a machine at the high end of the power range, whereas companies that work with light-gauge mild steel can likely get by with one at the low end.
The machine’s capacity, usually rated in maximum weight per foot, is another critical consideration. Tubes come in a variety of standard sizes, typically from 20 to 40 feet and sometimes longer. The capacity of a tube laser cutting machine will be measured by the maximum weight per foot.
Some manufacturers will order custom tubes to ensure there is the least amount of excess during production. Avoid scrap by having tubes designed specifically for the materials you are using.
3. Load and Unload
Another factor in machine selection is its ability to feed in raw material. A typical laser machine, cutting typical parts, runs so quickly that manual loading processes cannot keep up, so tube laser cutting machines typically come with a bundle loader, which loads bundles of up to 8,000 lbs. of material into a magazine. The loader separates the tubes and loads them one by one into the machine. The bundle loader also can deliver a number of raw tubes into a buffer magazine to reduce the loading times between tubes to as little as 12 seconds. Switching from one tube size to another is made simple by an automatic mechanism within the loader. All adjustments needed for a new tube size are handled by the controller.