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Ryan E. Day @ Quality Digest

Metrology

3D Laser Projection in Manufacturing to Reduce Rework and Increase Throughput

For Manitowoc Cranes, seeing ROI is believing

Published: Wednesday, January 11, 2017 - 12:00

Everything, it seems, has a vulnerability. For werewolves, it’s silver bullets. For Superman, it’s Kryptonite. For manufacturing—it’s rework. Rework means loss of throughput, which means loss of profit, which can mean death by a thousand rewelds. But, just as silver bullets can be dodged, and Kryptonite can be avoided, much rework can be prevented by adopting appropriate technology.

In 1902, Elias Gunnell, Charles West, and Lynford Geer launched the Manitowoc Dry Dock Co. to construct and repair wooden ships. Starting in 1925, West, then the company’s CEO, began building cranes on a subcontract basis for the Moore Speedcrane Co., a move that marked the beginning of a legacy of world-class crane manufacturing.

Today, Manitowoc Cranes, located in Shady Grove, Pennsylvania, manufactures lifting solutions including crawler, boom, telescoping, and tower cranes. A culture of ingenuity is important for Manitowoc to better compete in a global market and to “Build Something Real” for its customers, investors, employees, and partners. In this case, Manitowoc’s ingenuity takes the form of applying the proper technology to reduce manufacturing rework and increase throughput.

Tradition vs. technology

Manufacturing lifting solutions involves miles of welds; that’s a lot of opportunity for error and rework. When all aspects of rework, such as rework labor cost, lost production, and paperwork costs, are added up, it can easily take a 30-percent bite out of productivity. For Manitowoc, like all efficiency-conscious manufacturers, that’s an expense that’s unaffordable.

“The last frame we put together included about 8,000 inches of welding altogether,” says Samuel Dick, manufacturing engineer II at Manitowoc Cranes. “We previously used just blueprints, tape measures, chalk, and some physical templates to set all of the parts on each frame. All of that was done by hand and we would lay out each frame the same way.”

There were downsides to the traditional way of laying out each frame using manual measuring methods—for example, rework and all those associated costs. Parts located on the wrong side of a chalk line or parts welded on backwards because the holes were offset in the plate were typical errors requiring rework. Training new employees and cross-training veteran ones proved to be an ongoing challenge as well. There was also no effective way to catch if something was laid out or welded improperly without performing 100-percent inspection.

To deal with these challenges, Manitowoc chose the TracerM Laser Projector from FARO Technologies of Lake Mary, Florida.

“We wanted to speed up throughput and reduce rework on the assembly line for mis-located parts. We also wanted to be able to make engineering changes as needed in real time,” says Dick. “FARO’s TracerM laser projection system allows us to do just that.”

The TracerM accurately projects a laser image onto a surface or object, providing a virtual template that allows operators and assemblers to quickly and accurately position components. The laser template is created using a 3D CAD model that enables the system to visually project a laser outline of parts, artifacts, or areas of interest. The result is a virtual and collaborative 3D template to streamline a wide range of assembly and production applications.

Putting the brakes on rework

Manitowoc’s manufacturing engineers started the process of investigating rework solutions and then management made the decision to invest the capital necessary to upgrade to FARO’s TracerM solution.

“I’ve seen both sides of the reworking issue,” confides Dick. “I’ve supervised the area where we use the lasers and have also been involved in the rework process. When you have to send someone over to cut a part off because it was welded onto the wrong side of a [measurement] line, the team has to gather up their equipment, leave the building they’re currently working in, rework it, and then come back and get back to what they were doing. Rework just kills any forward momentum. The TracerM eliminates employees putting on incorrect or obsolete parts. Since we integrated the TracerM system, we have not had to rework any incorrect laser-set parts in more than 18 months.”

Naturally, the Manitowoc team had to overcome a certain amount of resistance to change within the ranks.

“People just don’t like change and so they make excuses why they can’t do something a new way. You just have to take away their excuses,” chuckles Dick. “I saw a few guys just shaking their heads while we explained how it works, but then we went down to the floor where some operators were setting parts on a frame. Once they see the projector in action, it’s really pretty simple to understand.”


Image 1: The TracerM projects alignment marks for a bracket onto a surface.


Image 2: The bracket is placed on the surface according to the projected marks and then welded in place.

Recent recession markets forced Manitowoc to lay off a number of people, which meant more seasoned employees had to take over in this area. They initially weren’t very happy about the new technology, but the TracerM‘s usability and usefulness eventually won the day.

“It didn’t even take a week to sell them on it,” says Dick. “We have the computer screens set up right there at the welding stalls and when you walk by and all the screens are lit up green you know they’re using the lasers.

“Some of the guys didn’t trust it at first. They would look at the line it was projecting and measure to the line just to verify it,” Dick continues. “That has changed, though. Now, if the TracerM doesn’t come online for any reason—which doesn’t happen very often—I get a phone call from the floor. In fact, on the rare occasion when, say, the network goes down, the guys will go work on something else that’s manual until the laser is back on line. Plus, when they’re not going back to cut parts off—and they know why—they’re sold.”

Kicking throughput into high gear

The same attributes of the projection system that reduce rework have the additional benefit of increasing throughput. Although Manitowoc employs robotic welders for long runs, there are still many pieces that must be manually attached to each frame.

“Rather than chalking off every single part that has to be welded onto a frame, we use the TracerM projector to set 70 percent of the parts,” explains Dick. “A frame can have up to seventy or more ‘trinket’ pieces to weld on, so each individual measurement adds up to a lot of time. It takes less than 10 minutes to set the projection system up and find the targets. If we are building multiple frames we can use the auto align option, which cuts set up time in half. We cut four hours off production time on the last big frame we built—that’s half a shift."

The TracerM system includes the RayTracer software suite to guide the assembly process, which enables the Manitowoc production team to customize the build program. Using CAD files to provide a virtual templating solution eliminates the need for physical templates and hard tooling, and the risk of human error and costly scrap during assembly is significantly reduced. Manufacturers can avoid the time and expense associated with using large, heavy templates while significantly improving quality control processes. An easy-to-use operator interface minimizes both the time and the skill required for operation.

“The program is built in layers, so after the operator verifies the first measurement of a run, he or she then just sets the parts designated in the first program layer, toggles to the next layer, sets the parts for that layer, and so on,” says Dick. “The software allows us to set up those layers with groupings of parts so the operator doesn’t have to keep walking around frame. The process is now the same for all rough terrain (RT) frames, so cross-training employees across the product line is much easier and faster.”

Enhanced engineering

“In a world of ‘planned obsolescence,’ Manitowoc cranes are engineered to be a profitable part of our customer’s business for years to come. In fact, our products last so long, we often find ourselves working with customers still using the same equipment they bought from us 20, 30, even 40 years ago. We wouldn’t have it any other way.”
—Manitowoc Cranes

Samuel Dick began his tenure with Manitowoc as a welder, worked his way up through supervision, and then into manufacturing engineering. At that time, engineering new equipment was synonymous with engineering new templates and jigs.

“I used to be a template guy myself,” confesses Dick. “But when I got into engineering, I saw how much template work—and cost—was involved when you go to make an engineering change. Sometimes you’re not able to rework the original jig, and you might see a $4,000 template turn into junk. Now, with the TracerM, if there’s an engineering change, I just load the new data into the program. Days of template rework is replaced by less than an hour of time loading the new model into the program.”

The TracerM has greatly reduced Manitowoc’s use of physical templates and is revolutionizing its engineering efforts.

“It is possible to develop an entire build program in one day,” says Dick. “Once the basic program is built, changes can be made in minutes and we don’t lose time or have the cost of making so many new templates or obsoleting the old templates.”

Revision changes can be done and programmed before the frame ever makes it into the weld stall.

One can only imagine the revision headaches avoided with all changes made in the program itself—no more multiple blueprint revisions floating around the shop floor or squirreled away in an engineer’s desk.

Return on investment

“I did some time studies last spring and saw one operator set 27 parts in about 22 minutes,” boasts Dick. “Those time studies showed ROI for three projectors in less than a year. Another investment in FARO laser technology paid for itself in ninety days.”

The cost savings of less time to build the product and not having to perform rework on the assembly line is obvious. The subtle takeaway is that during lean market times, the technology cuts down on production time, thus increasing net profit. In boom times, the time to ROI decreases dramatically.

From frame build to engineering to subassembly on fixturing tables, Manitowoc’s team continues to find new ways for the FARO TracerM to increase throughput, reduce rework, and lean out its processes—which, of course, improves its bottom line.

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About The Author

Ryan E. Day @ Quality Digest’s picture

Ryan E. Day @ Quality Digest

Ryan E. Day is a contributing editor and the content-marketing coordinator at Quality Digest. With a varied career from mechanic to artist to inventor holding a U.S. patent, but a journalist at heart, he’s produced freelance feature articles, op-ed pieces, ad copy, and display communications.