British Sculptor Alastair Mackie used the 3D laser cutting capability of Lairdside Laser Engineering Centre‚s Prima Laserdyne machine and Camtek's PEPS SolidCut 5-axis CADCAM software to produce his latest work entitled "Bipolar". The work comprises of a genuine US Marine's helmet into which has been cut an Islamic style fretwork pattern. The piece was exhibited at the Mark Moore Gallery in Los Angeles during October and November. Six more pieces will be cut as a limited edition.
Not surprisingly the laser cutting of the item was not a simple engineering project. Martin Sharp, Lairdside Laser Engineering Centre (LLEC) manager explains "The whole project required considerable effort from Alastair, a leading CADCAM software company and ourselves. It‚s often the case that when an artist attempts to introduce a hi-tech engineering process into his work, what often appears as a relatively simple process becomes problematic as the bounds of the technology are pushed."
The concept was straightforward: take a 3D scan of the helmet, superimpose the fretwork pattern and then cut it! A scan of the helmet was simple to procure, but the overlay of the pattern was by no means simple. Then, when LLEC received the imaging file they were able to look at its image but were unable to generate the necessary CNC programming code to control the laser cutting. At this point Camtek, suppliers of the PEPS CADCAM software worked on the computer model of the sculpture to ensure that the data was able to be processed by PEPS. Terry Antrobus, Director of sales at Camtek UK comments "The designer used 3D Studio Max to generate the initial images of the piece. DXF was the CAD format that could be provided from it. The DXF data, however, yielded in excess of 20,000 3D lines, which did not have a sense of 3D orientation and were of little use for generating a 5-axis laser tool path. What we were really after was a surface model of the component, but were told that this could not be provided from the imaging package. Working with Lairdside, an IGES file was provided which generated nearly 7,000 Wire Bodies‚ forming a 3D facetted mesh representation of the helmet
"Being presented with this kind of data - thousands of unrelated 3D facets, with no sense of connectivity - can be a nightmare for a part-programmer needing to get a job out the door, or for any CADCAM salesman trying to sell his wares for that matter. But generating usable data proved to be very easy with SolidCut Laser - we were able to create usable data very quickly and automatically by generating 3D solid entities from the triangulated facets and to join them together to create a single contiguous solid model suitable for machining. Applying the tool path was equally easy. Our Autocut function generated a complex 5-axis laser path including lead-in and lead-outs for all of the trims ˆ nearly 750 individual cuts - within seconds.
Once this was done, the PEPS SolidCut system supplied by Camtek to the LLEC readily produced the optimised NC code required to drive the machine. "The cutting of the helmet was then relatively straightforward", said Martin Sharp. "We used the automatic 3D fixture design function integrated within PEPS SolidCut Laser to generate a nest of interlocking plates to support the helmet during cutting. SolidCut Laser even nested and profiled these 2D plates for us."
The piece was completed with only hours to spare before Alastair flew to Los Angeles for the exhibition. "I was overjoyed when the helmet arrived by Courier, the afternoon before my flight. To hold in my hands what I'd only seen on a computer screen was thrilling."
Further examples of London-based Alastair Mackie‚s work can be seen at http://www.alastairmackie.com/
The Lairdside Laser Engineering Centre is a knowledge transfer centre set up by the Laser group at the University of Liverpool. Its brief is to help companies take up or improve laser processes in manufacturing, and is the only open access centre of its type in the UK. More information can be found at http://www.lasers.org.uk/llec/index.htm.
Contact: Terry Antrobus