Laser cutting update: Tube and pipe

Metal cutting lasers are nothing new. Introduced to the metal fabrication industry decades ago, their use is so widespread that seeing a concentrated and focused light beam slicing through metal with ease—a phenomenal feat of physics—is essentially commonplace. However, this doesn’t mean that the innovations have stopped. Indeed, laser technology continues to advance, as do the machine options and software that contribute to laser cutting capability and versatility.

Two longtime tube laser machine manufacturers, TRUMPF and BLM Group USA, introduced new equipment at Tube^®, the biennial tube and pipe expo in Düsseldorf, Germany, and others have made inroads into the tube laser market. LVD, a manufacturer of sheet metal fabrication equipment, produces tube laser machines these days, and Bystronic recently purchased tube laser manufacturer TTM Laser S.p.A.

The innovations aren’t limited to machines and the software that runs them. The Internet introduced the concept of an information network to computer users throughout the world in the 1990s, but this wasn’t the first network. In this regard, Mazak Optonics Corp. might have the most experience, having established a networked factory in 1981, but that said, the others have joined the trend and have made progress in the digital revolution, embracing Industry 4.0.

Progress in Hardware

While every model is unique, laser machines designed to cut hollows generally have a few things in common these days, regardless of manufacturer. Many have two loaders, one on each side of the machine (see Figure 1). The main loader is used for large bundles of tubes for long production runs; the other loader is for hot jobs, allowing the operator to interrupt the big job, make a few parts, and then resume the original job.

Another feature that is gaining ground is an onboard measuring system. By measuring the workpiece and comparing its dimensions to the cutting program, the software determines whether the two match. If they don’t match—that is, if the operator loaded the wrong material—the machine doesn’t attempt to start cutting. This prevents wasting material, wasting time, and possibly damaging the machine.

An onboard measuring system also helps the machines to deal with dimensional variations inherent in tube and pipe. A little camber is not uncommon, nor is twist, which often is noticeable on long lengths of squares, rectangulars, and other shapes. To prevent the laser head from crashing into the workpiece’s surface, the measurement system determines the amount of bow or twist and adjusts the cutting parameters so the laser head follows the contours of the actual tube, not the programmed tube. Many machines use additional supports along the tube bed’s length to support the tube to compensate for another dimensional issue: sag.

The resonator choices, CO₂ and fiber, likewise follow common trends. While CO₂ technology ruled the metal fabrication market for decades, the newcomer has nearly displaced the original in applications for medium- to thin-wall material. Fiber lasers are favored for their efficiency, maintenance requirements, versatility, and cutting speed, but they are limited in the material thickness they can cut efficiently.

“We sell mainly fiber machines,” said Andrew Dodd, North American sales director for BLM Group USA. “We still sell a few CO₂ machines, especially to fabricators that handle a lot of material thicker than 0.250 inch, but that’s it.

If the material is thinner than this, there’s no good reason to buy a CO₂ machine.”

Finally, while “bigger” often equates to “better” or “faster,” the tube and pipe laser market doesn’t always adhere to this guideline, especially in power. When cutting tube or pipe, the resonator wattage has a practical limit, and it’s somewhere around 4 kilowatts (kW). Beyond this much power, the user risks damaging the far wall after cutting through the near wall.

Makes, Models, and More

TRUMPF’s latest offering, TruLaser Tube 7000, cuts tube and profile up to 10 in. outside diameter (OD) and up to 0.4 in. thick, and it can make bevels up to 45 degrees (see Lead Image). At the heart of the system is the manufacturer’s 4-kW TruDisk 4001 disk laser. Compared to a conventional CO₂ laser, the company estimates that this solid-state source provides a 15 percent increase in cutting speed.

The system’s software has a PierceLine function that accelerates the piercing process so cutting can get started sooner, and its RapidCut capability associates laser head motions with tube axis motions, which the company says provides a fourfold improvement in machine dynamics.

The loading system can accept up to 6 tons of raw material. As the tube is loaded, a sensor system monitors the clamps to verify that it has adjusted to the workpiece geometry, and sensors also monitor the unloading process, ensuring that parts are sorted correctly.

BLM’s latest, the LT7, has a 3-kW fiber laser and handles round tube in sizes up to 6 in. OD and comparable sizes in square, rectangular, and profile. Two automatic functions, Active Piercing and Active Speed, optimize the cutting process, while Active Focus maintains the optimal focal length in thick materials. These functions work together to determine the optimal cutting speeds and other parameters, shortening the cycle time to make the machine more productive, according to BLM. It also has Active Tilt, a combination of software and hardware that optimizes the cutting process for small features (see Figure 2).

Mazak’s tubular laser machines include the Space Gear 510 Mk II, a combination machine that cuts sheet up to 5 by 10 feet); round, rectangular, and triangular tubes; and C, H, I, and L-beams up to 6.0 in. diameter. It uses a 5-axis torch that has ±360 degrees of rotation in the A-axis and ±135 degrees of tilt in the B-axis. It’s powered by a 2.5- or 4-kW laser source. Also available with 2.5- or 4-kW resonators, the company’s 3D Fabri Gear 400 III likewise handles a variety of shapes, using four chucks to accommodate workpieces up to 26.25 ft. long and up to 16 in. OD.

Its Versatile Compact Laser-Tube 100 (VCL-T100), intended for low-volume production, handles tube and bar from 1 to 4 in. round (1 to 3 in. square) in lengths up to 12 ft. (24 ft. optional). Equipped with a 2-kW laser, it cuts mild steel up to 0.250 in. thick.

LVD’s tube laser models—TL 2450-FL and TL 2665-FL—cut ODs from 0.375 to 5 in. and 0.75 to 6.5 in. respectively. The first handles infeed lengths up to 24 ft.; the second accepts lengths up to 26 ft. They are equipped with versatile chucks and software that allow the machines to handle essentially any cross section, and all use fiber laser technology. Its software, CADMAN-T, imports 2-D and 3-D drawings and allows the programmer to design various features, specify end cuts, and copy repeated features when necessary.

Founded in 2000, long after many other industrial laser manufacturers had established a foothold in the metal fabrication market, TTM Laser S.p.A. is the relative newcomer on the scene. The company has found a market in providing a combination of capabilities intended to appeal to service centers and job shops.

All of its tube cutting lasers provide 3-D cutting capability. Its smallest-diameter machine, the FL-170, handles diameters from 0.5 to 6.6 in.; at the other end of the spectrum, its FL-800 covers diameters from 5.9 to 32 in., which is the largest range available from any manufacturer, said Davide Rebessi, North American sales manager for TTM. It covers this diameter range with five machines.

The infeed and outfeed units handle lengths that are unusual. Model FL-300’s infeed system can accept lengths up to 41 ft.; the outfeed handles lengths to 40 ft. Its higher-capacity machines, the FL-400, -600, and -800, have infeeds and outfeeds that accommodate lengths up to 59 ft.

The company also pays close attention to optimizing the logistics involved in the beam-off time. For example, one custom machine it developed uses two sets of chucks to compress the time needed for loading the incoming workpiece, measuring it, and unloading it. The first chuck pair is used for loading, measuring, and about half of the cutting. The machine then transfers the tube to the other chuck pair for the rest of the cutting while the first chuck pair gets to work on the next piece of incoming material.

“The cycle time improved by 35 to 40 percent,” Rebessi said.

TTM isn’t the only laser manufacturer to look for a unique market segment. Niche manufacturer 3D Fab Light found some space in the low-volume and prototyping sector. Its machines are so small that they don’t need a special foundation or a rigging crew to install them. The company’s tube machine handles rounds and squares from 0.5 to 2 in. dia. in lengths up to 50 in. (an extension to handle parts up to 120 in. long is optional). The company doesn’t offer loaders, unloaders, or much in the way of bells and whistles, but the big advantage is that its machines cost less than some high-end luxury automobiles.

Lasers 4.0

It might be a bit bold to say that cutting is the heart of fabricating, but indeed it’s not far off; for the most part, cutting is the first step in the sequence of processes that get orders to the shipping dock. Optimizing the cutting process and, more importantly, synchronizing the other activities, maximizes throughput.

Gathering and analyzing shop data, and lots of it, can help fabricators identify and remove bottlenecks, increasing the shop’s pace.

This concept goes by many names—digitization, Big Data, the Internet of Things, and Industry 4.0.

“LVD had already implemented the principles of Industry 4.0 before Industry 4.0 had a name,” said Matt Fowles, the company’s group marketing manager. Founded in 1952, LVD has developed extensive expertise in building machines for fabricating sheet metal, such as lasers, punching machines, and press brakes. While fabricating tube has little in common with fabricating sheet metal, the principles and applications of Industry 4.0 are as relevant to tube and pipe as they are to flat products. The basis of it is straightforward.

“The big picture is the flow of data, which leads to the flow of parts,” Fowles said. An order starts the flow of data, which is augmented by data generated by the machines on the shop floor; capturing and using this data is the essence of Industry 4.0.

While doing research on fabricators that use a traditional order-entry system and a conventional manufacturing process, LVD benchmarked an order that took 34 days to process. From the time the customer placed the order until it was entered took about five days. Fabricating the order required two days; assembly took nine days; a quality control inspection, packing, and shipping required eight days. In measuring the specific steps for order entry and the actual machine time, LVD determined that a mere 2.4 percent of that time was productive time and the rest was idle. The actual time spent on order entry was just three hours, fabricating the order took 12 hours, assembly took 2.5 hours, and carrying out the last three steps took two hours. It might be impossible to wring out every spare minute, but this example illustrates the possibilities. The path to completing this order in 19.5 hours is a route named Industry 4.0. It works by generating continuous streams of data, compiling that information, analyzing it, and using it to take steps that improve part flow. A side benefit is that it also can cut scrap.

Although LVD’s focus is on efficiency in sheet metal—nesting as many parts as possible on each sheet, then optimizing the flow through the shop—it demonstrates possibilities for tube and pipe fabrication.

“The first challenge concerns handling several orders at once,” said Kurt Debbaut, product manager of LVD’s CADMAN software suite. “The system has to nest the parts, filling the sheet or partial sheet as efficiently as possible. It can be a benefit to wait for additional orders so the software has a bigger variety of parts to work with, resulting in a tighter nest and less waste.” The downside is the second challenge: sacrificing time to save some material. Mixing parts from several orders on one sheet of material means that accurate part sorting is necessary, which is the third challenge.

Many equipment manufacturers provide software that addresses these issues and others, feeding data to the company’s enterprise resource planning (ERP)system so the information can be used effectively. In LVD’s case, the company’s CADMAN-SDI uses a handful of part parameters to figure the job’s cost. Another program, CADMAN-JOB, figures process times, determines the optimal part flow, and creates schedules. It also verifies that the necessary tooling is in the tooling library. Another offering, Touch i4, sorts parts coming off the machine and goes one better by using a vision system that can identify defects. It segregates any defective parts and issues replacement orders on the next sheet that comes through the system.

It gets interesting when these sorts of programs have enough information to start making more complex decisions. For example, to make an assembly, LVD’s software schedules the parts appropriately so that parts that are needed first are made first. Internal components are manufactured before external components, so assemblers get them in the right order. Also, to prevent wasting material, the nesting software uses every bit of every sheet that it can. If it finds some leftover space on a sheet, it adds commonly ordered parts to the nest and allocates those extra parts to future orders.

BLM’s perspective is that the machine operator does much more than recall programs and load raw material.

“The operator is a material manager,” said BLM’s Dodd. The company’s ProTube software is a monitoring system that, in part, helps the material manager understand just how well he manages that material. It helps users to make accurate time and cost estimates based on processing time for an entire production run. It also prepares work orders and sends them to the machine, while a remote management feature provides real-time production progress monitoring, system operating statistics, and estimates for the next batch change. It can be integrated into an ERP system to distribute work orders automatically to all connected BLM machines.

Although TTM is a relative newcomer with a small staff, it has developed machine software that interfaces with MRP systems and assists in Industry 4.0 efforts.

“We sold two machines, one for tube and one for flat products, to Liebherr,” Rebessi said. This manufacturer of material handling, mining, and construction machines needed a cutting system that would feed parts down the line for sandblasting followed by robotic welding. TTM didn’t have extensive experience in Industry 4.0, but the company rolled up its figurative sleeves and got to work to develop a system that integrated all the hardware on the production line.

“The cutting machine is the heart of this sort of system,” Rebessi said. “You need to cut parts to produce parts.”

Going Digital

Digitizing every bit of information available and sending it over a network looks good on paper, but does it work? In short, yes. On Sept. 12, 2017, TRUMPF opened a facility in the Chicago area to demonstrate just how digital technology can provide an interconnection for every machine, and therefore every process, on a shop floor.

The first few steps involve preparation, of course, but even these illustrate the comprehensive capabilities of digital technology: import a part file, feed that information into the ERP program, and finalize the part modeling. The next few steps get a little deeper—creating a work order, developing process instructions, nesting the parts, requesting material, and scheduling the order. So far, no physical activity has taken place, but the system has already accomplished a lot, compressing hours of traditional work into a few minutes.

When the work order pops up in the processing queue, you won’t see a worker retrieving material from inventory. A self-guided cart comes to life, makes its way across the shop floor, and parks itself where it can be unloaded—automatically—to get the fabrication process started.

From there, it’s a matter of cutting, punching, and bending. Parts move from place to place and get processed with little worker intervention. Unstackers and robots do quite a bit of the lifting and placing.

A marking strategy—labeling every part with a QR code—eliminates paper. In TRUMPF’s factory, an order’s status can be called up at any of the various monitoring spots throughout the building. And anyone who has access to a Wi-Fi signal anywhere in the world can log into the system to check on an order’s status. If you can imagine letting your customers check on the status of their orders in your shop, you can imagine how much digitization can do for customer relations.

Mazak’s modern version of connectivity is the iSMART Factory™, which debuted in its factory in Oguchi, Japan, and is used at its factory in Florence, Ky. The communications protocol it uses, MTConnect®, allows the company to monitor every activity on the factory floor—machines, cells, and devices—and gather data from them as well to enhance decision-making.

Mazak also offers SmartBox, which provides a secure data pathway from machines to management systems via MTConnect. It’s designed to prevent unauthorized access to the network, and it’s not limited to interfacing with any particular company’s machines or any particular software. An open standard, SmartBox can monitor data from any machine regardless of make, model, or age, according to Mazak, and it supports third-party analytical software platforms to gather the data.

Of course, automated initiatives are a little easier when processing sheet metal rather than tubular workpieces. The raw material stacks nicely—a luxury tube and pipe fabricators don’t have—and often the finished parts are easier to handle, too. As it is processed, a tubular workpiece often needs a specific orientation so that every feature ends up in the right location relative to the other features for bending and end forming. They also might need a lubricant applied before bending and removed before welding.

Automating such tasks can be difficult, but difficult is a long way from impossible. Various technologies are available that solve most of the common difficulties, helping to implement the automation that accompanies Industry 4.0.

A proper orientation often requires weld seam detection, and sensor technologies keep getting better. After the seam is detected, making a small mark or piercing an inconspicuous hole might be enough to provide an orientation reference for subsequent machines. For tube handling, modern robots are dexterous and vision systems keep improving, helping them to pick and place workpieces quickly. As far as lubrication, a metered amount from a misting system or microapplicator might be sufficient, and some chemistries these days don’t interfere with subsequent welding.

Tying up all the loose ends to make Industry 4.0 successful for tube and pipe won’t happen immediately, but it will happen. It’s just a matter of time.

BLM Group USA, www.blmgroup.com

Bystronic, www.bystronicusa.com

LVD, www.lvdgroup.com

Mazak Optonics Corp., www.mazakoptonics.com

3D Fab Light, https://3dfablight.com

TTM Laser S.p.a., www.ttmlaser.com

TRUMPF, www.trumpf.com