Parts marking by manual stamping has been a tradition and virtual requirement in bridge fabrication, but a new marking technology is changing operations and improving the bottom line.
American Bridge Manufacturing (Pittsburgh, Pa.) specializes in the fabrication of new bridges and repair parts for the rehabilitation of existing bridges. The 100-year-old company seeks to optimize value by obtaining state-of-the-art equipment and production methods to reduce costs on its complex projects.
In the field of bridge fabrication, there is a mixture of both primary and secondary members. Although the primary members can be custom, one-of-a-kind pieces, the secondary members are often high-quantity duplicate pieces. As a means of coding and identifying these fabricated members, American Bridge used a traditional industry method of hand stenciling (stamping) to mark every primary and secondary member.
Although a slow, labor-intensive process, bridge fabricators commonly rely on hand stenciling to produce precise and readable markings. State regulations require the manufacturer to accurately mark all fabricated members, and these markings must be clearly readable after the member has undergone its final step in production, a three-coat paint process.
A manufacturer the size of American Bridge can become overwhelmed with the volume of hand stenciling required with its high-quantity fabricating output. Since no bridge project is the same, hand stenciling needs to be tailored to each fabricated piece. This takes hours of additional labor. Costly as hand stenciling is, an even greater issue is the potential hand stenciling holds for shop-related injuries. Because hand stenciling requires manual engraving skills, it is not uncommon for hands and fingers to become injured during the process.
Although hand stenciling is the most practical way to mark one-of-a-kind primary bridge members, the use of hand stenciling on high-quantity primary and non-stress secondary bridge members, including gusset plates, lacing bars and diaphragms, can be burdensome. Since ancillary production costs, such as hand stenciling, often increase a project’s bottom line, American Bridge was determined to find a more efficient process to replace this decades-old practice.
For American Bridge, the replacement process for hand stenciling needed to be safe and accomplish more work in less time. Just as important, the process needed to be accurate. The project management team at American Bridge was concerned that automated stenciling processes, although much faster than hand stenciling, would penetrate too deeply and cause stress risers in the fabricated steel members.
Because hand stenciling is a low-impact process, it is less likely to create stress risers. Sharp edges created by stress risers frequently become cracking points in the steel. If American Bridge were to switch operations to an automated marking process, the process would need to be one that was low-impact. At all costs, American Bridge wanted to avoid the chilling scenario of stress risers, and ensure that the markings on fabricated members were properly calibrated.
“We began searching for an automated process that could deliver on our list of requirements,” says Jon Young, plant manager at American Bridge. “After several months of considering various resources, our search was not looking very promising. In some cases, the marking process left too great an impact on the fabricated steel and challenged the highly critical fine line between an accurate impression and one that created a stress riser. Other processes we considered marked too lightly and failed to retain a clear and readable mark on the steel once the fabricated member was finished with the required three coats of paint.”
The search ended when American Bridge discovered MECCO’s SuperFast dot peen marking system with an H-Controller and portable N20 head. Although the system was clearly safer and faster than hand stenciling, American Bridge shop managers were determined to test the marking system to be certain it would meet the specifics of their marking needs.
“We had to be sure this system was going to leave a deep, clean, and legible impression and not create stress risers or cracking,” said Young.
“We set up the marking system in our fabricating plant and imprinted a range of primary and secondary members. The results were consistent, and the finished product, a fully-painted fabricated member, had a clearly legible impression. With the portable SuperFast marking head, we achieved the exact marking depth. Its work was as good as any I’ve seen with hand stenciling and with its speed, the hours of labor we saved were dramatic.”
Operating with a lightweight, 5-lb. frame, the SuperFast marking system with portable N20 marking head is mobile. One of the benefits of the SuperFast is its rugged, sophisticated computer system that easily adapts to a number of production scenarios at American Bridge. Because it is portable, it becomes extremely flexible and is compatible with all types of fabricating.
“We give our marking system a real workout by constantly using it on project fabrications of all shapes and sizes,” adds Young. “This marking system has been online for two years and continues to work as well today as it did the day we bought it.”
“Not only have we witnessed a decline in the number of hand-related injuries in our fabricating plant,” Young adds, “we are recognizing savings on our project costs. This system definitely gives us a competitive advantage.”
Prior to using the automated marking system, hand stenciling could take hours of additional labor, depending on the number of members to be used in a project. Using the portable SuperFast, the speed by which the identification mark is made and the depth of the mark meet the production standards set by American Bridge. The speed and precision of the portable marking system translates to substantially less time for hand stenciling, and its clients recognize the cost savings on their projects.
“Since our output of fabricated products is constantly changing, we really value the MECCO marking system,” notes Young, offering an example.
“You can see the difference in how we approach a bridge restoration project,” Young adds, “Typically this kind of project will require thousands of lacing bars. There was a time when the hand stenciling on this many members would take hours of extra labor. Now, we mark this high quantity order using MECCO’s H-Controller. The work is done quickly and accurately. Although it is still used for custom pieces, hand stenciling is no longer considered a primary operation on the fabricating floor.”
"There was a time when the hand stenciling on this many members would take hours of extra labor. Now, we mark this high quantity order using MECCO’s Controller. The work is done quickly and accurately." - Jon Young, plant manager