Tests & Tools
My very first tests!
Nothing to brag about, but I'm so proud! :-D. I created a 2D square, sort of, using ArtCam, created and saved the corresponding toolpath, setting a cutting bit, and ran my CNC for the first time!
Almost everything went fine... The square is not so square at 3 of the corners...
Something I needed to understand. Probably another miss-hap in the setup. Talking with BlueElephant support again tells me I probably need to adjust the belt tension on the step motors that drive the X and Y ball screws. It's true the machine goes fast, very fast even, and when it comes time to slow down for those corners, I may have a few steps skipped because of the strong deceleration.
Making great progress!
I read a few articles on the net , from experienced users and it turns out my issue with corners is a classic problem people encounter when using CV milling (CV for constant velocity which is a way to optimize CNC bit cutting, trying to keep a constant speed all over the job). I went on and adjust a few parameters to tell the CNC to wait as long as possible before applying the turning vectors on sharp angles. The result is obvious from the picture on the left. All 4 corners are clean and sharp!
I also used this test to validate measurements/accuracy of the X&Y dimensions - all good.
Talking with BlueElephant support team, they also proposed to use Step mode vs. CV, and lower the acceleration of the spindle moves in X and Y. I tested this too, and it also gives very good results. I nevertheless found it to be quite slow when engraving text for example and the machine seems to decelerate/accelerate at each small segment it is asked to travel.
I probably will play with both modes, depending on the geometry of what I am carving. Big curvy shapes such as a guitar body will be fine with CV mode while tiny inlay work may be better using Step mode.
More advanced testing using Aspire...
One of the nice things with a CNC is you can envision to engrave, texture and shape surfaces. I found a crocodile skin bitmap sample from the net, scaled it down and applied it as a gradient for carving (the darker the deeper), to see how it would carve out. Still using a small 50x50mm area, I made a quick test, using one of the carving bits that were sent with the CNC.
The area highlighted in yellow is the approximate position and coverage of my 50x50 area.
I was very careful with the CNC settings, probably too conservative on speed and so on... it took 45mns to carve, but I like the result, despite this is on scrap wood (MDF)!
Many tests will be necessary before using this kind of work on a real (i.e. guitar) body, but it is very encouraging, and not that difficult to prepare.
This was carved using a 30°, 0.5mm tip carving bit that came with the CNC.
Wait... I can make my own tools too!
As I was waiting for a few bits to arrive, I designed a sanding block I plan to use when making fretboards and having to level frets. I thought that rather than buying a block from one of the online merchants, I would use some oak I had around to make my own sanding block. Belo a few pictures of the result, starting with a 290x70x40mm wood blank.
Small diversions...
Carving BoxWood for the grandkids :)
I need(ed) to practice my letter carvings, especially in hardwood. As one can see, the neck head logo is not very nice looking. Not sharp and the finer letters jamming together, killing the actual lettering.
So I created small projects with lettering for my Grandkids :-) and tested lettering carving with tiny carving bits (3.15mm shaft, 10°, 0.2mm tip. The result is much better :-) This is with a 0.7mm depth. Carving has been filled with graphite (from a 0.5mm pencil) and graphite secures with cyanoacrylate glue, before a quick sanding to 220. The result is quite nice, validating lettering for neck head, and I can probably use the same technique for neck fretboard inlays.
A quick project for my neighbors
I also worked on a larger (in size) project, 1.5m x 0.45m board, with carved lettering on it for my neighbors and friends who have been so kind in helping bringing in the CNC and run a small shop at their farm, where they sell organic vegetables.
This is now proudly hanging at their shop, painting/colors will come later, when there's less work at the farm.
Signs....How small can they be?
I played with cutting text shapes... Not as easy as it looks.. The result can be quite fragile, especially when trying to 'peel off' the result from the CNC bed. Anyways, here's a small sign (2cm height), so it can be done! Bigger signs are easier to manage.
New Fretboard (16" radius) plane block, and fret sorter Jig
Having done a neck for my first guitar with a 16" radius, I had to carve a new sanding block. I used a combination of pine wood (top) and Cumaru (an exotic hardwood) for the bottom part that receives the sandpaper.
Fretting Jig
I created a fret slotting jig out of a Cumaru (hard exotic wood) board and scraps of medium. Will be useful for fret slots (current and future), I belive it's much faster than using the CNC and keeping breaking ø0.6mm bits!
The jig and the saw in use, worked great!
New Fretting Jig .... a Project for 2024
I saw (watching a Youtube video) a nice fret slotting jig, capable of handling several scales with one jig. Found that quite clever and it would make a great little project for my next builds, as I'll have to create a fret slotting jig for a 34" scale bass guitar anyways...
I'll carve the plate into Cumaru, very hard wood.
Left a simulation of what this could look like
Simulation
Update February 2024
The multiscale jig is done!
I used blueish epoxy to fill in the text and lines
And verified its accuracy... All OK!