Success through accessories
Nicholson also purchased and added on a variety of accessories, including a micro-drop head that sprays fine droplets of coolant onto his work. This is needed when cutting non-ferrous materials, such as aluminum and brass.
Particularly key to his success has been a vacuum table, which saves time by avoiding the need to clamp down every piece he cuts with the router.
“I might cut out 200 letters in one setup of the machine,” he explains. “It would be a nightmare to clamp down each of them in place. With the vacuum table, I simply place a full sheet of plastic on the surface and ‘nest’ the lettering in the software to get the best material yield. The vacuum holds everything in place as the sheet is routed.”
In addition, a vision recognition system accurately orients the cutter with respect to printed image to be routed. It accomplishes this by viewing printed dots on the sheet and correcting automatically for any linear or rotational errors in either the image or the placement of the material on the machine, thus ensuring the contours of the shape are routed perfectly.
In a ‘reverse engineering’ practice, meanwhile, a touch probe inserted into the machines’ collet can be used to copy a 3-D surface. When a client brought in a handmade wooden carving to Nicholson Design that he wanted reproduced and engraved, for example, he used the router to collect a 3-D ‘point cloud’ representing the object, which he then imported into his computer-aided design (CAD) software. Using a variety of other design software programs, he was able to manipulate the CAD data accordingly and cut the new part. Without his router, this job would have been impossible.
Dimensional images
Indeed, the majority of Nicholson’s business comprises 3-D engraved signs. The process begins as he paints or applies vinyl to the background material for the sign. Next, he applies a masking material to the surface.
Using pointed V-carving bits, Nicholson machines the text and/or images into the sign’s surface. Then he paints along this machining.
Once the mask is removed, then, the painted artwork shows clean edges against the colour of the sign’s background. Achieving this level of crisp detail would be very difficult and time-consuming by hand.
When he produced a sign with a 762-mm (30-in.) wide face of Medusa, the monster in Greek mythology with snakes instead of hair, Nicholson machined Medusa’s head in 51-mm (2-in.) thick slices of high-density urethane (HDU) foamboard, to accommodate the cutting path of the machine, and glued them together to complete the sign.
Many router software suites today offer ‘tone extrusion,’ whereby the tone of a digital image is corresponded to a physical depth. The darker the tone, the deeper the resulting relief. Adjusting tones in an image-editing program means a complicated photograph can be replicated in three dimensions, using the router software to extrude the tone before the imagery is machined into the sign using the router.
