Time to don those 3D glasses

We are moving into a new dimension.

CNC machines are not restricted to 2D patterns and simply cutting in to produce a raised (or recessed) pattern.  Nor are they restricted to 2.5D, which is how patterns that are cut in 2D then built up to produce a 3D image are classified.

eds_plane insignia-screen

True 3D means the cutter is moving through all 3 dimensions as it is cutting.  This can still produce something like a bas relief image, but irrespective of how complicated, or simple the result, the motion of the cutter throughout the cut is the defining parameter.

Finding 3D patterns to send to the CNC machine are not as easy to find as I expected.  The 3D printing community openly creates and exchanges their creations, including the required files, and open source development programs, whereas the 3D CNC community charges significant fees for each and every pattern, and the software to develop your own costs $thousands.

I did download a sample file from VectorArt3D.com who also provide the code generator program (for free, but it only works with their files) called Vector Art 3D Machinist.  Bit of an experiment-was not sure if it would work on the CNC Shark, but it was fine.

va3dm-1-largeThe program produces the required G-Code for the CNC machine control program, but has an interesting additional output, that of a roughing out pass.

Given how much material the can be removed to create a 3D object, it is good being able to first run a heavier cutter to take a few quick passes to remove the bulk of material before the fine, final cutter moves in to refine the design.

Rather than just use any router bit to attempt to machine a design, I turned to the precision Amana Tool bits that are specifically developed for 3D CNC routing.  These come from Toolstoday.com, and are Zirconium Nitride (ZrN) coated router bits.  I know it says coated, (which to the layman suggests painted or dipped) but I suspect they may be produced using one of the physical vapour deposition techniques.  This is an important distinction.  A coating can rub off over time.  A vapour deposition has characteristics somewhat akin to welding, where the coated layer fully penetrates into the surface of the base material, effectively creating an alloy at the surface.  Localised, controllable, surface alloying is a particularly effective modern technique for producing exceptional products.

6225_7_The bits are all up-spiral, pulling material up and out of the cut, while the cut itself is not a chipping action, but a slicing one.  They are particularly sharp, and smooth.

Photo 8-02-2014 16 41 17

The first pass was a roughing pass, using the largest bit seen to the left here.  It quickly scallops away the bulk of material, leaving the finer router bits to produce the detail, without having to push through tonnes of material.

Photo 8-02-2014 16 45 58Once that pass was done (4 minutes), the bit was swapped over for the one making the final passes for detail.

Photo 8-02-2014 17 00 10The final result looks a bit rough – more refinement by me I think.  It is definitely not the router bit – the ZrN bits performed superbly.

Photo 8-02-2014 17 24 24Final pass, which was about 16 minutes for this size pattern.

The additional benefit of these router bits, is their ability to handle other materials, such as aluminum, brass, copper, graphite, phenolic composites, plastic, sign board, & wood.  The ZrN surface is particularly useful in preventing buildup of the material being cut, such as plastic and other gummy materials.

The benefit of having a set of bits is having the right ones available when you need them (and less costly than purchasing individually).

The set of 4 covers a good range.  If you are heavily into 3D CNC woodworking (and as a business), consider the 8 piece set.

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