Updated: Dec 26, 2020
We've had a few Uber-creative brochure projects where we've been exploring wooden front covers. Yes - you heard us right!
So it was a good time to invest in a CNC machine. We went for a pretty basic option but wanted to commit what we learned into words, hopefully for others to learn from.
It's a pretty daunting process for newbies. We began even before the machine arrived by watching a lot of YouTube videos! Our favourites were by James Dean Designs and covered building the machine, designing for it and cutting. Although, we're pretty used to svg files given that we do graphic design!
We're designing files by doing the following: designing our own in illustrator or affinity design, deigning in Canva Pro and exporting as svg (a new feature), designing in easel (some good clipart and text).
We're setting up and grabbing our g-code: By importing our designs into Easel or creating straight in easel. Once we've set the bits, speeds, feeds etc we can then pull the g-code from the Machine tab.
We've controlling the machine using: GRBL Candle - this was preloaded on the USB we received with the machine or can be downloaded on Github. We've dabbled with UGS too (also Github) but the visualiser has been a little temperamental.
Moving on to actually use the machine, we've learned a few lessons.
Firstly, we thought we'd run into big errors when the drill bit kept wanting to run beyond the machines axis. We soon found that the machine starts on it's bottom left (when looking at it with the rails and control board at the back. For some reason we assumed that it started at the corner where the control board attaches. Once we'd got the right start point we were away.
Secondly, we couldn't figure why the spindle with the drill bit wasn't turning when we set it to carve our designs. We're generating our G-code (the language the machine speaks) through a free CAD programme called Easel by Inventables. It turned out that the machine settings in Easel were not set to program the spindle to spin automatically. We moved from manual to automatic and problem solved!
After doing a few chunky cuts we wanted to get a bit more intricate. Here we were met with another issue. The drill bits for a v-carve (the 20degree blue bits that came with our machine), are shorter. We'd already lowered our spindle in its mount to accommodate this. However, we didn't factor in that our spindle would lower further to actually do the cutting depth we'd set. Next time we'll make sure our bit can not only reach the wood but also plunge the depth it needed. This time, it resulted in a nasty grinding sound (surely not good for the mount), and a less than smooth finish in the depth of the cut (it was ok as we were epoxy filling the carved bit anyway - see picture below).
Edit: Another lesson: We’d seen recommendations to use locktite or nail varnish to stop the grub screws attaching the axis rods to stepper motors coming loose. ‘We’ll be fine we thought’ - we diligently checked them before each use but then we noticed the x axis blue rod holder moving a little during a cut. The grub screws we couldn’t get to had come loose. We removed the stepper motor, accessed the screws, gave them a dab of nail varnish and have reassembled- let’s see how they do.
That's the lessons we've learned so far but look out for more!