A CNC router is one of the workhorses of the signage industry, and manufacturers are constantly looking for new ways to help their clients get more out of their machines. Lately, that means adding accessories that open up new markets by allowing sign makers to venture into new markets. But it also means speeding up current processes to get jobs done faster.
Buddy Warner at ShopBot Tools doesn’t have a “favorite” accessory for his computer numerical control router, but he knows the accessories speed up the process in his side job as a sign maker.
“The primary advantage of CNC and related accessories is time savings, and time is money. If you had to do certain things manually, it would take much longer. You might have to turn jobs away if you don’t have the right accessories and tools,” says Warner, who uses a 4′ x 8′ Alpha ShopBot router to make everything from small plaques to subdivision and municipality signs. “Not having the right tool for the job will, in the long run, cost more than the initial investment.”
Accessories such as a vacuum table, an automatic tool changer, a misting system and a “cold air gun” open up new application possibilities and can help increase profitability for sign shops that rely on a CNC router to cut and carve the two-dimensional and three-dimensional parts for the signs they sell.
A CNC router is an automated, computer-controlled piece of equipment that cuts through or carves wood, composites, plastic, foams, and urethane and harder, denser materials such as aluminum and other non-ferrous metals. The tool paths used for cutting are saved as a computer-aided machine, or CAM, file that moves the CNC tool to cut parts, bypassing needing to manually cut by hand. This provides more consistent and precise work that can be repeated over and over once the file is created.
“Every shop will buy at least one of the accessories, or two to three of them, depending on the size of the shop,” says Steve Alvarez, national sales director of Laguna Tools.
The most common accessories
One such accessory is the vacuum table, a perforated tabletop containing a vacuum chamber and vacuum pump that creates pressure to keep the workpieces in place, Alvarez says. The pieces are held down by the pressure differential between the chamber and the outside air that results in a suctioning motion while allowing complete access to the pieces.
The vacuum table saves time, allowing the sign maker to immediately start cutting, Alvarez says.
“If you have this router cutting out a part on a sheet, your part is probably going to shift,” Alvarez says. “In the past, people had to drill (or clamp) the sheets down to a machine or use double-sided tape … or leave thin tabs to keep control of the parts and then do a final cut with a utility knife to clean up the parts.”
Another accessory sign shops use is the automatic tool changer, a timesaver for sign work that requires several router bits, Alvarez says.
The sign maker does not have to manually change the bits, which are spun at high RPMs by a spindle, the main motor of the router, to cut through the material-the bits vary depending on the material’s diameter and density and the work to be done.
The tool changer, which can be expensive, consists of a rack with tool clips that hold several bits the machine can pick up and drop in place for each routing task, Alvarez says.
“The machine picks up the tool, routes what needs to be routed and picks up the next tool,” he says.
Another accessory for the bits is the misting system, a fairly inexpensive add-on used for metals like aluminum and plastic.
The misting system applies a fine mist of coolant to keep the bits cool and to preserve a good cut line, Alvarez says. Without it, the bit or the material being cut can get too hot and possibly melt, leading to poor cutting quality, he says.
“The main goal is to maintain the temperature on the tool as well as the metal sheet that you’re cutting,” Alvarez says.
Carl Ondracek, president of Computerized Cutters, finds that the misting system is one of the most important accessories for a router when cutting metals.
“It keeps the router bit cooled and lubricated, so it doesn’t get heated up and break,” he says.
A cold air gun, which mounts to the spindle and is similar to a misting system, blasts a stream of cold air to the cut line with the actual tool doing the cutting. It is used for cutting things like plastics.
“It maintains a certain temperature and keeps the material from possibly melting,” Alvarez says.
Other options to consider
An accessory sign shops might forget, especially those buying a router for the first time, is a dust collector, which collects dust and debris and prevents it from contaminating nearby equipment like a printer. The dust collector is connected with a flexible hose to a shroud that surrounds the spindle, and the shroud places the dust and chips into a bin collector. The collection is done through a sucking motion.
“It can be like a shop vac to suck dirt and dust away,” Ondracek says.
Another accessory sign shops might use is an automatic Braille ball inserter for ADA signs. The inserter replaces manually inserting Braille dots by drilling holes using a bit, removing beads from a hopper and pressing the beads into the holes.
“Doing that by hand is very tedious. It’s a very laborious job,” Alvarez says.
The final and most important accessory for a router is the design software, which drives the drawings the machine needs in order to cut the parts for a sign or the shape of the entire sign, Alvarez says. The designs are generated in computer-aided design, or CAD, software but the machine needs CAM software to translate or convert the drawings into machine language for the actual cutting work, he says.
Smaller add-ons & less common acccessories
A few accessories that are smaller add-ons include a plotter pen to draw directly on the material without making cuts and various drag knives used in place of the spindle and cutter bits, when the desire is to not have a spinning motion for cutting, such as for thinner materials.
Sign shops working with a paper-laminated foam core may want to use an oscillating tangential knife, which employs a motorized knife blade instead of a spindle to cut through materials. Or they might use a drag knife to cut octagonal boxes or odd shapes. The knives pull across the surface similar to scoring with a utility knife, quickly moving up and down to smoothly cut more difficult materials.
An accessory that is less common is a diamond engraving bit that does scratch engraving or etching and is used for materials such as mirrors, glass, marble, granite and acrylic products. It produces a fine line on hard surfaces with a look similar to laser etching.
Another less common accessory is the digitizing probe, which is used to take a design and reproduce it. The probe is mounted in the collet, a steel sleeve that holds the bit, and moves in small increments over the item to be copied, memorizing it with every touch until the whole image is recreated for a file format. The result is a copy or scan of the image.
“If you have an item that is hand-carved or something you found that you want to re-machine or incorporate into the sign, probing the item to a file can allow you to do that,” Warner says.
If sign makers are printing an image on a flatbed printer to cut it into a material, they can use a Vision Registration System. The system, geared for odd-shaped items, consists of a computer program and a registration camera that finds the registration materials on the printer sheet, so the router knows where to make the cuts. The program will command the router to find three dots to be able to locate and then position the object, ignoring the other parts of the design.
Without it, sign makers have to orient and scale a photograph or a traced drawing of the image to do the cutting, Warner says.
“Accessories take advantage of the useful available functions that are often overlooked by CNC owners,” Warner says. “Having the right bits or accessories available often make the difference in profitable production.”