Shiny New Stuff
I’ve been wanting to get explore the world of CNC for a long time now and finally decided to jump in (head first) and see what all the fuss was about. CNC has been around longer than 3D Printing but it isn’t aimed at the consumer level i.e. the “one in every household” craze that swept us up in 3D printing all those years ago. Entry level is probably more at the “prosumer” or hobbyist woodworker who already has some knowledge of materials and workmanship to their name.
My experience so far has been full of little frustrations, a metric-tonne of “googling” and learning from some silly mistakes 🙄! Truthfully, I think I underestimated the learning curve on this particular fabrication method, especially when you look at how far laser cutters and 3D Printers have come; with full ecosystems of tools, templates and materials that are effectively pre-set and work Out of the Box.
‘So, what did we get’ you ask? After a lot of research we ended up purchasing a Shapeoko Pro XXL (note that this is not an affiliated link) which, in terms of quality of outputs, probably sits between prosumer and professional level machinery. This (exceedingly) heavy package was shipped from the USA to Australia and came without a scratch. The build experience in terms of the manual was pretty much flawless and the machine was intuitive / straightforward to assemble with seriously quality fittings and exacting measurements… things just fit together perfectly! Only complaint was the instruction manual which was one generation or so old and had me hung up on a couple of steps but there were plenty of YouTube videos to make up for this.
Through trial and error though I am finally seeing some nice results with a couple of prototype designs that have been banging around in my head for a while now as well as generally failing exploring what CNC’s can do. Check out the pictures below for a couple of products we are toying with making. I particularly love the custom Voronoi Tea Light Holder design which ended up being a perfect use case for all the scrap wood I’ve been collecting over the years - I knew I kept it for a reason 😁.
All pieces were designed using Fusion 360, carved on the Shapeoko Pro XXL, lightly sanded and finished with some penetrating oil:
Material: Voronoi Tea Light Holder - Pine | Bamboo Motif Serving Board - Okoume | Snowflake Motif Serving Board - Unknown (birthday present from my partner)
Post Processing: Finished with a light sand and a couple of coats of Feast Watson’s Kitchen TImber Oil
Also, read on below for my blow-by-blow summary of how “smoothly” the Voronoi Tea Light Holder went. It was my 2nd project on the CNC but perhaps a little too ambitious a design so early on… What doesn’t kill you makes you stronger right!
The Voronoi Tea Light Holder Saga:
A quick summary of how this “simple” idea of turning some scrap wood into a candle holder played out:
Attempt #1: forgot to zero the machine - sending it flying off to crash into the gantry while I fumbled about trying to hit the Stop Button
Attempt #2a: got my X’s & Y’s muddled up in orienting the part resulting in a heap of air cutting. My fault ultimately as I tried to visualise it in Fusion 360 (my design and now CAM software of choice) but the sample machines weren’t quite right for my needs and had effectively flipped the X & Y axis around. Furthermore, after some air cutting offstage the endmill made a direct beeline at my timber stock and that’s when I found out that I hadn’t secured it appropriately - workholding is a whole ‘nother thing with CNC! Anyway, this resulted in the timber stock lifting up off of the bed and the endmill just continued on its merry way gouging a nice big chunk out of it… so I hit the Stop Button again… At least I am getting quicker at finding that button!
Attempt #3: So, I went back to Fusion 360 and double checked my axis (L = left hand type stuff) and cut in some grooves on the side of the stock to give the clamps something to bite into. Hit the start button and everything was working perfectly… That is until I realised the program didn’t pause to let me change the endmills over from a “flat” endmill to a “ball nose” type - the Shapeoko series of CNC do not have automatic tool changes and it turns out if you don’t number your endmill’s suitably in Fusion 360 it thinks you are using the same endmill each time😱. By the time I noticed it was too far along and the damage was done so I let it run its course. The results weren’t terrible or maybe I was just expecting worse but you could clearly tell the quality wasn’t quite right and I was sure I could fix it in post???
Attempt #4: I thought I’d be clever here and effectively re-run the last couple of stages over the same area to take a nominal amount off to smooth it out. So back to Fusion I went, I split the program up into the components alI needed, set the height to be 0.2m lower and went back to the CNC. Well, the next few hours were spent going back and forth trying to work out why it was still air-cutting over the piece? Making tweaks here and there, muttering to myself, watching as it matched the contours perfectly yet did not make a single cut? Finally, it dawned on me and I realised that when the previous Attempt (#3) had missed the tool change this meant that the corner of the flat type endmill had contoured into my stock further than the radius of the ball nose would allow. I did some quick maths in my head and decided that if I could drop the “Z height” down by the radius of the Ball nose endmill then I might see some action finally… So, I messed around with the settings and then it happened… instead of adjusting the new Z Axis zero by taking the radius of the Ball nose off (~1.6mm) I wiped the work coordinates completely… Disaster! It was late, I was done and there was no way I could get the zero back to the same position as before so it wouldn’t have come out right.
Attempt #5: I spent a fair amount of time setting up my process in Fusion 360, fixing up the machine orientation (that wasn’t easy) and building in the capability for Fusion to recognise different endmill’s as also requiring a pause in the run so I could change them out (sometimes I wonder if I am asking too much! haha)…. I went and bought some already finished Pine from our local hardware store (Bunnings - plus grabbed a snag for good measure 😋), clamped it down tight; this one was not going to get away from me, said a little prayer to the carving gods and hit run! It was running beautifully, the birds were chirping and then OH MY GOD! The tool change pause that I thought I had fixed, was so not fixed! Hit the Stop Button again but I rescued it pretty quick this time so felt the blemish was relatively minor and could be “buffed out” in post!
Attempt #6: I left the stock in the machine and spent a lot more time fixing up my tool library, completely scrapped my Machine configuration and started again, then set about working out how to guarantee a tool change in Fusion 360 post process. This took me quite some time and then I stumbled on a video from no other than Winston Moy (super useful resource on all things CNC) and he stepped it through so clearly - turns out that the name of the endmill isn’t enough for Fusion to recognise that it is a different bit and that you effectively need a Part ID to differentiate them… this was not easy to find in Google but boy did it pay off! I loaded it up and this time, yes this time finally it worked like a charm!
The pictures you see above are the result of this particular run and sure, if you look close enough you might still see the blemish from the missed tool change but I finally got a working process downpat and an idea of what this product might look like if I ran it from go to whoa! To say I was happy (relieved) is an understatement! It looked exactly like what I had pictured in my head way back at the start and came out very close to the model in Fusion itself.
This is what I ultimately love about digital fabrication in that not only did I manage to create something that I probably couldn’t create by hand but the results are repeatable and able to be further polished or iterated on over time. At present, I have no intention of selling these Voronoi Tea Light Holders but stay tuned as this might change. If you are interested in something like this as a Commission or a customised version of any of the above feel free to reach out (using this link - click here) as, whilst this was frustrating, I learnt a huge amount and this experience was ultimately invaluable.