Our Sites

The impact of lean manufacturing on structural steel fabricating

New technology helps to make fab shops smaller and more productive

Figure 1 All-in-one structural steel processing systems have been designed to handle 95 percent of the material typically sent through a shop. This involves all coping, beveling, notching, holemaking, and cutting to length.

Although the basic requirements of structural steel fabrication may not have changed much over the last 20 to 30 years, many of today’s structural fabrication shops look quite different than they did back then. They generally are smaller in both footprint and staff size, yet still remain highly capable and competitive.

Market pressures and technological advances have spurred this big change. Traditionally steel fabricating companies primarily were large operations with hundreds of workers. Although most moved toward faster production rates by installing automated, special-purpose equipment, such as saws or a beam line, they were best equipped to handle large jobs. So when the next big project didn’t come through—maybe the new skyscraper project went to a competitor—things could get rough.

Today, the vast majority of structural steel fabricators operate out of smaller facilities and employ just 20 to 50 people. This model allows these companies to pick up smaller jobs and change direction quickly, both of which make it easier to deal with economic slowdowns. The increase in the number of small and medium-size fab shops also has given the industry as a whole more flexibility. Smaller projects have local suppliers readily available. And when a large project comes along, it’s not uncommon for several smaller fabricators to form a team to take on the job.

How Do These Shops Compete?

The fabricator’s end product—structural steel that has been welded and prepared to go into a building or a structure—is very long, heavy, and takes up a lot of space. As a result, transportation is a big issue in many of these projects.

For that reason, structural steel projects often are sourced locally. This means customers are shopping for someone to fabricate their steel in a market that has a lot of similar-looking competitors. Most structural steel fab shops are pulling labor from the same area with similar demographics, education, and wages. The facility costs, operational costs, and taxes also are relatively the same. In many instances, the fabricators in these local markets even are using similar software in their businesses.

If everything is the same in these kinds of shops, how does one fabricator win the next job?

It turns out the shops focusing on the amount of time they spend on a piece of steel—trying to lower their labor-hours per ton—are the ones that generally do well. In this type of competitive environment, the labor-hours per ton may be the only cost they really can control.

Following Automotive’s Lean Lead

Adoption of lean manufacturing techniques has prompted much of the recent turnaround in the North American automotive manufacturing industry. These now widely known and accepted principles also can apply directly to structural steel fabrication; in particular, eliminating waste, eliminating waiting, and eliminating unnecessary material handling.

Nesting software and programs that automatically prepare cut lists have been a huge help in reducing waste. They have come into use as powerful parts of the migration to 3-D structural design. Coupled with other software tools that track steel inventory, these program components already have succeeded in helping many fabricators optimize material use.

Large doses of both waiting and material handling were long accepted as necessary evils in traditional fabrication shops. However, when shop owners and operators begin to think in lean manufacturing terms, they realized working to reduce both has major benefits to the bottom line.

Figure 2 Marking instructions on a beam eliminates the guesswork for those that have to erect the structural steel pieces.

A batch-processing approach in the fab shop, for example, often creates significant waiting. If company management automates one part of the shop, that area then overproduces in comparison to the other areas. If a beam needs to go through five processes and only one of those processes is fast—processing 100 pieces per day when other processes can handle only 10 pieces per day—that creates major bottlenecks on the shop floor. The fab shop is not getting any advantage from that automation. Either the fast process runs out of parts and sits idle, or it oversupplies the next workstation.

The emergence of automated, special-purpose machines—ones that were really fast at one process—over the last decade created these bottlenecks in many structural steel fab shops. Because the shops failed to upgrade other processes, they failed to capture the efficiencies that modern technology can deliver.

This has motivated shop owners and machinery operators to change the way they are thinking. They realize they need to move away from a job shop mentality to that of a factory, choosing machinery that will facilitate a smooth, consistent process flow through the shop rather than one that is stop-and-start, depending on the automation level or lack thereof.

Even when all of the single-purpose specialty machinery in a fab shop is operating at a balanced pace, it still requires coordination and efficient material handling to keep the steel moving from one process line to another. The problem is that customers to whom the shop is selling the steel don’t care if the steel is lifted and moved three times, five times, or 500 times. They aren’t interested in the labor-hours needed to process a ton of steel, but shop management should be. The shop has to realize that it isn’t adding value to that piece of steel while it is moving it. These shops should be seeking to eliminate as much material handling as possible.

Unlike the auto industry, in which 500 tasks performed on a car are broken down into one-minute operations, structural fabrication shops don’t get to make the same thing over and over. That makes it more difficult to streamline the process, but it’s not impossible.

One of the things that increases the possibility of streamlining structural fabrication and eliminating waste related to excessive material handling and waiting has been the introduction of all-in-one systems that take full advantage of 3-D structural design capabilities (see Figure 1). These machines can eliminate several pieces of machinery and expedite throughput.

The process is relatively simple. After a building or structure is designed in 3-D software, a click of a button generates one file for each steel member in that structure. If such a structure has 500 pieces, the software produces 500 files, which then can be shared with the fabricator. The fab shop then uses it to create manufacturing instructions for its all-in-one structural steel processing equipment.

The operator doesn’t have to guide the machine by providing specific instructions, such as a hole should be 2 inches from the end and 3 in. down. The machine’s software takes its guidance from the part file and automatically programs the machine to make all the cuts and features needed. With the press of the start button, a structural steel beam is cut to length and bolt holes and slots are added, as well as copes, bevels, notches, and cutouts.

A part number can even be placed on the beam.

A skilled worker would need a long time to duplicate the same job. The worker would need to read the drawings and figure out the location for all the holes and cuts. Then the worker would have to use measuring and marking tools to lay out the cuts and use various equipment such as drills, punches, hand torches, grinders, and hand stamps to cut the material. Steel fabrication machinery speeds up this process.

This structural steel processing technology can even lay out and mark the position of other items that need to be welded to the main beam (see Figure 2). The data comes from a 3-D model, and that 3-D model knows how all the pieces intersect. Much of the effort previously required to prepare the piece no longer is necessary. The layout marks for other connection plates and stiffeners that need to be welded to that main piece are made by the machine, saving even more time.

Remember the lean manufacturing principle of eliminating waste? Using this automated approach goes a long way toward eliminating the waste of defective parts because all the design information covering multiple fabrication processes is transferred directly to the equipment. This approach of transferring 3-D model information directly to the machine reduces the possibility of errors in the field and makes life a lot easier for erectors.

How This Changes the Shop Floor

Fabrication shops of all types have incorporated all-in-one structural steel fabrication machines into their operations in a variety of ways. Some small and medium-size shops that focused on manual operations never thought of process flow on their shop floors. However, when they installed this type of automated technology, it solved some obvious production problems and quickened the pace of fabrication. These structural steel fabricators were forced to upgrade operations in the rest of their shop to keep up with the automated equipment.

On the other hand, a lot of fab shops already have some modern fabricating technology in place, such as a drill line and a saw. These larger shops also may have special-purpose machines for coping and punching—all connected by conveyors and cranes. This traditional approach to fab shop organization is quite different from the concept of an all-in-one fabrication system.

Rather than replacing equipment that is still functional, and perhaps handling a healthy percentage of its work, these shops might add an all-in-one automated processing system and operate it in parallel with its existing drill line. Production that requires only bolt holes and cut-to-length could then be sent straight to the drilling machine while other, more complex parts that also include copes, bevels, and notches go to the new equipment.

Applying Lean Principles in the Structural Steel Shop

Fabricators of all sizes can benefit from the application of lean manufacturing principles. They apply to operations with several machines dedicated to one fabricating process or to shops with a single machine capable of several tasks. However, lean principles are more difficult to apply in multiple-machine setups because it is difficult to balance processing times for different machines and to move structural steel pieces from one machine to another.

With an all-in-one machine, the shop can find efficiencies much more easily. For example, the operator can be doing different things while the machine is processing the part, such as offloading the piece that just came off or preparing the next piece to move on. Basically, the operator can be involved in any activity that contributes to getting from one piece to the next as quickly as possible, which reduces a key metric: labor-hours per ton.

In the end, these shops can rely on automated structural steel processing systems to eliminate waste. This approach lets them do less material handling, get materials out faster, and have better quality control. Fabricators also begin to see where additional improvements can be made in their shop.

About the Author

Paul Kwiatkowski

Sales Manager

63 Innovation Drive

Hamilton, ON L9H 7L8 Canada

905-689-7771