Finding Z0 bit broke

[japanwood]

Axiom Basic 4

Yesterday I placed the puck on the wood and press the ON/OFF and MENU buttons to lower the bit to find the Z0 point. Normally it will lower slowly, touch the puck and then raise back up. Yesterday it pressed down extremely hard into the puck and broke the bit. I have done this hundreds of times before and never had an issue. Any ideas what may have caused this?

[gerry]

The puck forms a single line of continuity from the puck, puck cable, electronics, to the spindle, finally to the bit. You should be able to put a clip on the bit, then on the puck, and get a complete electrical connection. If you don't, then you can use a continuity tester on sections of the path. Test a section at a time.

The most likely cause is a broken wire from the puck through the lead wire on the puck. If the pluck plugs into the gantry, unplug and test from the puck to the tip of the lead wire. Clip them on, because you want to be able to wiggle the puck and the wire. You're looking for a break in the wire, or a loose wire.

[japanwood]

I had no idea thats how that system worked. Thanks. I'll look into this.

[aluomala]

Check the connection in the gantry for the pucks wiring: I had a very poor connection (and ruined 3 bits in one day....) because the nut securing the wiring was loose, and the connection was intermittent. I have stopped using the puck because it is so dodgy (the wiring into the puck itself can also be sketchy (I have 2 Axiom machines (AR4 and AR8), as I had that issue as well). After ruining a number of bits (30 degree scoring bits in particular) and use the paper method all the time now. If you only use large bits, it's not such an issue, but I use tapered ball nose (down to 1/64" radius) and scoring bits (30 degree mostly, but 18 degree on occasion) so much that I can't trust the puck at all anymore.

Allan

[gerry]

Nov 21, 2020 15:44:35 GMT -5 aluomala said:

Check the connection in the gantry for the pucks wiring: I had a very poor connection (and ruined 3 bits in one day....) because the nut securing the wiring was loose, and the connection was intermittent. I have stopped using the puck because it is so dodgy (the wiring into the puck itself can also be sketchy (I have 2 Axiom machines (AR4 and AR8), as I had that issue as well). After ruining a number of bits (30 degree scoring bits in particular) and use the paper method all the time now. If you only use large bits, it's not such an issue, but I use tapered ball nose (down to 1/64" radius) and scoring bits (30 degree mostly, but 18 degree on occasion) so much that I can't trust the puck at all anymore.

Allan

The puck on the AR8 Pro+ works perfectly fine. If you break bits, it's one of two problems: poor continuity or incorrect lowering speed. Intermittent errors are most likely a poor connection or a broken wire. You can easily trace and fix either problem. It's a very simple single wire system. It's widely used and not prone to errors. I've replaced my lead wire a couple of times. I replaced it with quality silicone stranded wire. I use 1/32" (0.03125 or smaller) bits quite often. It's been a looonnng since I've broken any bit on the puck.

I've also dropped the speed for lowering the bit considerably (my Toolset Speed 150.000). I place the puck NEXT to where the spindle will descend, manually lower the bit to within 1" of the top of the puck WILL BE. It's easy to judge the bit distance. I then slide the puck UNDER the bit and hit TOOL SET. At this point the bit descends slowly, but it's only lowering an inch. This entire toolset procedure takes less than 30 seconds. 

If you don't think the zero distance is accurate, calibrate CAD THICKNESS. It only takes a couple of minutes and a thickness gauge or paper to calibrate.

[johnb]

Perhaps not relevant to this situation, but...
Be advised that the puck should NOT be used when setting Z for a diamond drag bit.

There is no electrical conductivity through the diamond. If you were to use it, it would likely bury the diamond tip into the puck and continue downward until the spring completey compressed and the metal portion of the bit contacts the puck (completing the circuit). By that point, you would either have a destroyed bit, a broken diamond tip, or a destroyed puck...or all three.

[johnb]

Considering that puck wire failure seems to be pretty common, and your "first notice" that it has occurred is likely to result in a broken bit, it might be a good idea (when using the puck) to add the following step to your routine:

When you start the Z-0 process, elevate the bit a good ways off the workpiece, hold the puck between thumb and forefinger. As soon as the bit starts to descend, raise it up to contact the bit. If the puck is working, the machine will "think" it's completed Z-0 and retract. You then place the puck on the workpiece and re-run Z-0

If the puck isn't working, it will keep moving, so you then slap the e-stop before it hits something. If you've lowered your toolset speed (as Gerry describes above), you'll have plenty of time to do all this.

[Mezalick]

I have found that dust from my cuttings, either wood or HDU, on the puck or lodged into the bit, might restrict the electrical connection between the bit and the puck.
I make sure to clean the bit and puck every time.

Michael

[aluomala]

Nov 22, 2020 12:42:49 GMT -5 johnb said:

Considering that puck wire failure seems to be pretty common, and your "first notice" that it has occurred is likely to result in a broken bit, it might be a good idea (when using the puck) to add the following step to your routine:

When you start the Z-0 process, elevate the bit a good ways off the workpiece, hold the puck between thumb and forefinger. As soon as the bit starts to descend, raise it up to contact the bit. If the puck is working, the machine will "think" it's completed Z-0 and retract. You then place the puck on the workpiece and re-run Z-0

If the puck isn't working, it will keep moving, so you then slap the e-stop before it hits something. If you've lowered your toolset speed (as Gerry describes above), you'll have plenty of time to do all this.

I used to do this (check the continuity BEFORE I commit to using it), but I still had issues (due to the bad connections) so I abandoned it. All of that "pre-puck" testing ends up taking longer than just using a piece of paper, and the only time I damaged a bit using that method was my own fault (I moved in the y-axis by accident (instead of raising the Z-axis first) and it snapped off the tip of a 30 degree bit.

The quality control/build quality on this particular item is pretty poor (you'll notice that when it's brought up in the forums, people will say "You're too rough with it! You broke it!" even if you baby the thing) and I wouldn't recommend it being used, unless you are using larger bits (1/4" endmills and larger) and aren't particularly concerned with accuracy: I do primarily 3D carvings, and I will use 2 different tapered ball nose bits, usually a 1/16" for flat(tish) areas ands 1/32" for more detailed areas, and if I'm not exactly on the money, you end up with a "halo" effect around the model, where the 2 different bits meet up/overlap), so I use the piece of paper method (using the same spot on the scrap portion of the wood), and drop the bit down in Fast mode (.5mm increments) until it's just above the paper, and then switch to Low mode (.1mm increments) and lower it until the paper is trapped under the bit, and then drop it one further "click" (.1mm) for good measure. If I repeat this for the next bit change, the results are usually seamless (unless there is movement in the wood, from tension release (so much material being removed) or if the clamps loosen up (don't ask how I know this....)).

My experience is probably outside the norm (people using larger bits don't need to be so anal), but after ruining 3 bits in one day (that was an expensive day....) I decided to retire Senor Puck and go low tech. I would like to use it (since I paid for it...) but I don't like that sick feeling in the pit of my stomach, wondering if it will pick that exact moment to ruin a $50+ bit (and probably the only one I have of that particular bit on hand). But, yeah, if you want to tweak it (replace wiring because it's shite) and make it Senor Puck 2.0, go ahead....

Allan

[redwood]

I've also used the paper method for quite awhile now. I have not broken a bit since switching to this strategy and it really takes very minimal time. However, yesterday, in a senior moment, I forgot to switch the Z movement to step and plunged my 1/4" endmill into my almost finished piece of work. Cost me a day, while I repaired the damage to the piece.