What about doing a second pass in each slot, exactly the same as the first pass? Just to pull the chips out, not to actually cut anything. Could even do it at a higher speed to save time?
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Any amateur builders using their own CNC?
- Thread starter Jeff Siddall
- Start date
That might work, but really the right way is to use a ramp. It is never recommended to plunge an end mill, I was just hoping to get away with being lazy!
When my buddy Rob Allen cuts his fret slots with his big CNC, he does them in three passes to reach the full depth. He's been doing it that way for years, and says it's the optimal sequence. Slow feed, upcut bits, vacuum dust collection. It's a slow process, and he still breaks bits occasionally. It's actually comical watching his 12,000 lb Fadal with its 20 hp spindle, spinning a 0.023" cutter, delicately cutting fret slots in a fingerboard.
Another update: it was hard to capture well, given how tiny everything is, but there is a steady stream of chips being ejected from the slot and flying off to the left (as well as many piling up around the slot) in the video below:
Fret Slot Video
The chips are heading to the left because of air currents caused by the spindle cooling fan.
I cut several short slots at 40 mm/min and nothing is broken yet. So far so good!
Fret Slot Video
The chips are heading to the left because of air currents caused by the spindle cooling fan.
I cut several short slots at 40 mm/min and nothing is broken yet. So far so good!
I stumbled on a cooling mist setup which included some [presumably knock-off] loc-line, plus a metal manifold with adjustments for air and oil, fittings, a pickup hose etc. More than I needed for my simple LASER air assist/CNC chip clearing requirement, but then I saw the price: $9.19 CAD (about $7.25 USD) including free shipping:
Ummm... yes please!
Ummm... yes please!
A few more updates: I installed some EC3 connectors (60 A) on the battery/power supply leads to make for easy quick-disconnects. However, after unplugging and re-plugging the connectors in rapid succession to test their holding force there was a bang and some smoke as the boost converter powering the CNC motors and laptop fried. Guessing some back-EMF from the larger spindle boost converter exceeded the limits of the smaller converter switching transistor. Anyway, I had a larger 400 W converter on hand so just swapped that in.
Then the old laptop that was running the G-code streamer stopped booting. Oh well, had a spare one of those around too so not much lost other than a bit of wasted time setting it up again.
Unfortunately the latest version of bCNC also seems to be having problems with the user programmable buttons so I need to figure that out. Those are handy but don't stop the CNC from working.
Since things were back up and running again I did a test fretboard (technically half a fretboard since the test blank was only about 1.5" wide), this time with a hard maple board and with two toolchanges: one from the ball nose bit used for surfacing, to the tiny end mill used for the fret slots, and another to an engraving bit used to mark the perimeter, which is useful when aligning the board on the neck and cutting it down to size. All worked great! Here is a close-up view with 0.5 mm pass spacing and the first two fret slots:
The surface is so smooth it is hard to see the tool marks from the surfacing passes but if you look closely in the middle of the picture where it is in focus you can see them. Nothing like this would have been possible with the original 3018 CNC.
The air assist, and some hose to hook it up, have now arrived and I will install those once I have a chance. Other than that this thing is finished! It has exceeded my expectations for how well it cuts and I am really looking forward to seeing what all I can make with it... starting with two fretboards for some in-progress builds.
Then the old laptop that was running the G-code streamer stopped booting. Oh well, had a spare one of those around too so not much lost other than a bit of wasted time setting it up again.
Unfortunately the latest version of bCNC also seems to be having problems with the user programmable buttons so I need to figure that out. Those are handy but don't stop the CNC from working.
Since things were back up and running again I did a test fretboard (technically half a fretboard since the test blank was only about 1.5" wide), this time with a hard maple board and with two toolchanges: one from the ball nose bit used for surfacing, to the tiny end mill used for the fret slots, and another to an engraving bit used to mark the perimeter, which is useful when aligning the board on the neck and cutting it down to size. All worked great! Here is a close-up view with 0.5 mm pass spacing and the first two fret slots:
The surface is so smooth it is hard to see the tool marks from the surfacing passes but if you look closely in the middle of the picture where it is in focus you can see them. Nothing like this would have been possible with the original 3018 CNC.
The air assist, and some hose to hook it up, have now arrived and I will install those once I have a chance. Other than that this thing is finished! It has exceeded my expectations for how well it cuts and I am really looking forward to seeing what all I can make with it... starting with two fretboards for some in-progress builds.
