When does a punch/laser make sense?

Shops that process enough of the right parts can increase uptime and reduce secondary operations with a combination punch/laser machine. Photo courtesy of TRUMPF Inc.

Business growth led Hawkeye Industries President and CEO Bryan Hawkins to seek a machine that could punch and laser-cut material. The Tupelo, Miss., job shop—which fabricates parts for more than 100 customers in specialty lighting, defense, HVAC, and several other markets—was getting more and more orders for parts that required both operations. Using stand-alone punch presses and laser cutting machines, workers had to prepunch sheets of metal. After that they moved the sheets to a laser to make cuts that couldn't be done on the punch. To meet the growing demand, the company purchased a combination punch/laser machine.

A combination machine made sense for Hawkeye Industries. Such a machine can increase profits for some shops, but add cost for others. Before taking the plunge, shop owners need to look closely at whether they need the equipment and how they will use it. Here are three questions they need to ask.

1. Is this my company's first capital equipment purchase in the area of punching or laser cutting?

Hawkins said a job shop shouldn't make a combination machine its first purchase or its only purchase unless it has a product mix that can justify it. Doing so can hinder a shop's competitiveness.

"A combination punch/laser machine is not as competitive as a pure punch for punching parts, and it's not as competitive as a flatbed laser on parts that need just laser cutting," he said. "It's slower, and the fixed costs are higher because you're taking the cost of a stand-alone punching machine and the cost of a stand-alone laser machine, and you add those two costs together and subtract maybe $200,000, and you've got the basic cost of a combination machine."

2. Does my company have enough work for the combination machine?

Mike Morissette, product manager for punching and combination machines, TRUMPF, Farmington, Conn., said understanding the most efficient way to process a part is important because each technology has specific advantages. Holes in some parts can be either punched or laser-cut. Depending on the application, one technology might be more cost-effective than the other. Morissette said a combination machine allows a shop to choose the process that will produce the most satisfactory results and minimize the cost of the part.

"If I have a part that gets welded underneath a table, and nobody's going to see that part, I can completely punch it out on the punch side of the machine and not have to worry about overlap marks or anything like that, therefore providing a less expensive part than if I were to laser only that part," Morissette said.

Understanding which parts are suited to a combination machine will help shops determine what kind of return on investment they can expect from it and whether or not they process enough of those types of parts. The return on investment relates directly to how quickly a shop can start loading up the machine with work, Hawkins explained.

"In general, you need to have that machine loaded by at least 50 percent within the first year," he said. "If you can't load it up in terms of 50 percent of its capacity within the first year, I wouldn't recommend [buying one]."

3. Does my company have the right work for the combination machine?

Stand-alone laser cutting systems and punch presses offer different advantages, said Mike Palmer, laser product manager for Finn-Power, Arlington Heights, Ill. Laser machines can accommodate various material types, thicknesses, and geometries. Punching machines can do forms, countersinks, perforations, tapping, and extrusions.

A laser provides a smooth edge without burrs on most cuts, Hawkins said. And it does sweeping contours, curves, and irregular cutouts. A punching machine punches round holes very accurately and can do formations like lance forms, extruded holes, and tapping.

Parts that require many different types and sizes of holes are a good fit for a combination machine. Photo courtesy of Finn-Power Intl.

"You take the strength of what a punch does, in terms of forming of material, and the speed of a punch, in terms of punching holes, and you take a part that has wide, sweeping contours and irregular shapes, and you put those two types of geometries into a part [and it] has a lot of holes and formations in it—that's the perfect combination machine part," Hawkins said.

Jason Hillenbrand, laser product manager for Amada America Inc., Buena Park, Calif., said combination machines are best-suited for parts that contain forms, extrusions, or embosses, as well as hole-intensive parts with complicated external geometry. They also are good for flowing radiuses, tangential radiuses, and parts that require good edge quality, according to Morissette. Punching machines punch holes faster than lasers cut them. However, punches also require tooling changeovers—excessive changeovers reduce productivity. Combination machines address this problem with standardized tooling. When a part requires a shape that the tooling can't provide, the shape can be cut with the laser.

Fabricators also can choose the appropriate operation based on the different types, sizes, or numbers of holes, Hawkins said. If a large square part requires many different-sized holes, for example, the operator would have to change the punch tooling often, so laser cutting might be the better choice. On the other hand, if a large part has just one hole diameter, then it would make more sense to laser-cut the holes. But certain features, such as a lot of formations, make a part less suitable for stand-alone models and more suitable for a combination machine.

"You only pick the holes that there's a lot of, not any individual hole, to absorb a tool-change time but in the beginning, if it's got formations and a lot of holes and a lot of contours, that's your first inclination that it needs to be a combination machine," Hawkins said. "After that you decide which parts of it you want to laser-cut and which parts you want to punch."

Don't Forget the Part Designer

Transitioning a part designer from designing for stand-alone punches or lasers to combination machines should require minimal adjustment and few, if any, changes to the way they do their jobs, according to Morissette and Hillenbrand.

"A typical part is designed and saved into a company's server as a DXF or some type of functional part format regardless of the machine it is intended to go on," Hillenbrand said. "The software, which programs the equipment, can take most part file extensions and import that file into the machine programming software. The part is typically programmed automatically for the desired machine it is to be processed on, whether it is a straight laser, straight punch, or combination machine."

With a combination machine, a designer has more flexibility to add contours and extrusions to parts they could not have added for stand-alone models. If, for example, the designer prepared a part program for a 2-D laser cutting system and included only the attributes that the laser could produce, other attributes, such as forms and extrusions, would have to be added later in secondary operations. With a combination machine, the designer can include the attributes both machines can handle, reducing the processing time for that part. In addition, the software can help users learn to design parts for a combination machine.

"Software features like Teach Mode that create graphical icons in the CAD cycle can initiate laser and punch processes automatically and are hugely helpful with design incorporation of the laser punch system," Finn-Power's Palmer said.

A Lean Look at Combination Machines

For those companies that have embarked on a lean manufacturing journey, they will find that a combination machine works well in a lean environment. If you look at a part's overall processing time, you see that a combination machine almost always processes the part faster than stand-alone machines because of the reduced handling time, Morissette said.

"It supports a lean environment very well by [completely processing] a part," he said. "By that I mean being able to tap, extrude, form, bend—pretty much anything you need to do to a part while it's in that machine."

Combination machines are designed to process a part completely with a low overall processing time. Photo courtesy of Amada America Inc.

Some companies mistakenly compare the time it takes to manufacture the part strictly on the basis of cycle time, Hillenbrand said. If they punch a sheet first and then move it to a stand-alone laser, they record the combined time for the punch and laser as the total processing time for that sheet. However, this calculation does not account for the non-value-added time and labor costs a shop assumes when it transfers material from one machine to the next.

Combination machines also benefit lean manufacturing programs because they reduce labor requirements and are designed to accommodate automated material handling systems, as well as run unattended, according to Morissette.

"It goes back to Manufacturing 101, in which the goal in any manufacturing operation is to handle a part as little as possible and to do as much to it while you're handling it," he said. "That's what a combination machine allows you to do."

Combining the Results

Hawkeye Industries has benefited from purchasing a combination punch/laser machine, and if the business lands a large contract that overloads the machine, it will consider adding automated loading and unloading systems, Hawkins said.

"It helped me be more competitive when I quoted new parts that would lend themselves to that type of technology," Hawkins said. "It's increased my sales, and it's also increased my competitiveness in those types of parts."