I can't recall if I ever cut through it. And even if I do, it is usually with a router or circular saw. So those blades don't usually clog up. But a small bur like your, I can tell.

The ideal for me would be find some way to secure the CF and sacrificial material to the acrylic tray using joint fasteners like one would do without the tray. But I can't find one yet that fits.

So for now I am using the carpet tape but only taping areas I know I will not cut - it's actually strong enough to hold everything in place even using smaller pieces. The problem is (and the water bath may be contributing to this), is that the untaped area that is being cut can tend to lift ... I think. Now that I think about it, it could also be the water logged MFD board warping ... bah so many factors lol. In any event, using this method sans joint fasteners requires me to cut much deeper than I would to cut all the way across the CF. In my last run, I cut 1.5mm to make sure I cut all the way across a 1mm plate of CF.

At some point, I really do need a better mounting solution.

Bit death count: 14

Before I set off on cutting the ... gasp ... BOTTOM PLATE lol, I thought I'd share some videos and pics of what this process is looking like for me so far.  Sorry for the bad lighting I still need to set up a proper video capturing mount for the GoPro lol.  But you can see how still the water is despite that bit cranking at 10K RPMs into carbon fiber.  I can actually tell if something is effed up when the water gets disturbed ...



The cool thing with the CNC controller (in this case, I'm using "Candle" grbl control program), you can see where the bit is and the Gcode being pushed through in real time.  You can pause and continue cuts too although I'd imagine you better have a very stable and bolted down setup for it not to effect cuts.  Admittedly, I've used this functionality multiple times already lol.



And here is the tray with all the carbon fiber dust floating around in there lol ...



And after many, many, many trials and errors and tribulations ...





... one set of cam plates YAYYYY!!!!!



LOLLL ... I know it's kinda sad.  But man I am really proud of these cam plates LOLLL.  And, actually, as I write, I have TWO sets!!  baha.  The white stuff is something Drone Mesh also called out in his videos and attributes it to cheap CF reaction to the water.  Frankly, at this point at least, I'm not losing sleep over it lol.

... and I got a legit pro tip.  After absolutely killing bit after bit after bit, I recalled pouring through CNC forum discussions earlier and buried in page after page of mini novels explaing how to avoid broken bits using feed and speed formulas, officially published chip loads for the specific bit, but oh wait consider the configuration of the flutes is it downard or upward cutting oh wait how about z axis calibration and the integrity of the z rod OI VEY!!! ... was buried a single one liner that proved more effective than anything for me ... and advised to add this to the water:





Bit death count: 14

Pro tip #2 ... don't design for a 1mm bit unless you happen to like giving yourself paper cuts and pouring lemon juice on it.

Bit death count: 15

Yea ... this is just getting way too ridiculous with a 1mm bit. I see why now frames are designed with just these huge rounded squares or circles. You can use a beefy 5mm bit for those lol. I am going to redesign everything for a 2mm bit as I'm down to my last 2 1mm bits and going through expensive carbon fiber like water. Kinda annoying. That means no more cutting until my 2mm bits arrive early next week. I really can't go beyond 2mm since I plan to make use of 2mm hardware, and I have yet to figure out how (and if my machine can even handle) to do multi-stage toolpathing where you change bits mid operation.

Bah. Super annoyed right now.

Bit death count: 16

Hello! I would like to offer my assistance if I may....
I have 18years of machining experience, 5 years of CNC programming experience. I have read through your adventures and think I might have some insight.

The name of the game in machining is rigidity. My trade school instructor said "remember the 3R rule!" Rigidity, rigidity, rigidity. Rigidity of your work setup. Rigidity of your cutter, rigidity of your machine.

If I were to approach this project using the equipment you have.... Here's what I would do.

Firstly, make sure your work is securely fastened. Tape, clamps, screws... Whatever you decide to do. Just make sure it's secure.

The biggest thing that will help you is buying a quality endmill and setting it up properly. I recommend going with something like this.... https://www.mscdirect.com/product/detail...drsrh=true
Chuck this up in your spindle as far as you can. Leave the bare minimum ,plus clearance , hanging out of the collet. You gain more accuracy and better cuts. I would recommend 10k rpm and at least .0015" chip load per tooth.... 30ipm. Step it down .01" per pass. Carbon fiber needs to be fed into with a purpose. Multiple fast passes with a 2 flute endmill will work the best. Try to divide it out so you just barely break through on your final pass....

Also, look into flushing the chips out of your cut. It doesn't need to be high pressure. A small pool pump, some hose and a bucket. As you cut, the gullets in the endmill fill up with chips. There is only limited space for chips before it clogs up and affects your cut.

Congrats on the new machine! CNC machining is a blast! You can literally make anything.... Let me know if you need anything! Or have any questions!

Thanks Orange.  All really great advice.  I can only secure my machine so much so I know I have to pay that price in my feeds and speeds.  I am happy to report that using the larger 2mm bit has resulted in zero breakage so far!!

However, I had a VERY concerning thing happen.  Just when I was getting comfortable enough to not stare at the machine waiting for the bit to break, the grblcontrol software I'm suing, Candle, somehow lost the toolpath entirely and the spindle went off on its own drilling through the CF, through the sacrificial material, through the acrylic tray, through the friggin aluminum bed!!!  WTF????  How does that even happen??  I would presume all controller are made equal since it's just software and some instructions.  I caught an "error:16" in the console which is pretty broad in definition.  Also, these cuts were just 2 small cam plates which I cut well within the boundaries of the cutting bed.  Or is this Candle software crap?

Good news is the bit did not break LOL.

Defeat. 

I gotta call a tactical retreat on this one guys.  Try as I might, I just can't get the setup I am currently constrained to to reliably cut carbon fiber.  As Orange pointed out above and as I and anyone else that goes down this rabbit hole very quickly realizes, the efficacy of your machine is a direct function of how well bolted down the thing is.  Put another way, even this super entry level CNC I am confident can make good cuts ... if bolted down properly.  Note that the use of a water bath makes this concept doubly, triply, maybe quadruply complicated.  Because rather than just being concerned about bolting down working and sacrificial material, you now need to factor in securing the bath tray as well as the materials ... all while fully submerged in water.  

I as doing good with 1mm cuts.  1.5mm cuts required lower feeds and speeds but I was getting confident in that too.  It's when I went to 3mm that the problem really started to show.  Even at a snails pace plunge rate, the cuts were poor at first catching onto the carbon fiber sheet and literally pulling the entire bath tray up off the table from its side clamps!  So I introduced a C clamp holding the tray up front.  While that served to secure everything down, the spindle would shut off I'm guessing as a safety precaution from getting locked up.

And to give you a sense, my speeds and feeds are ridiculously tame.  For 1.5mm I honed in on 55mm/min feed, 10mm/min plunge and 0.4mm depths at 10K RPM which is my spindle max.  For 3mm, I think I halved the plunge rate and it still locked up drilling holes.

I am fairly confident that this poor performance is due to the lack of rigidity in my setup.  I am sure that with a higher end machine (like Drone Mesh's), you have a lot more slack.  But despite making sure every bolt was tightened, every axis was calibrated, I just cannot get this machine to make the cuts I want it to make.

And if this were 3D printing, it wouldn't be so bad since PLA comes cheap.  But at the price of carbon fiber, every mistake is a VERY costly one.  And I have so far made TONS of mistakes.

Kinda pissed.  (read:  FCKING FURIOUS lol) ... But hey live and learn.  I may revisit this later but for now, this thing has really sucked the energy out of me. 

I did sell most of my drones for this but I'm not pissed about that.  I had already resolved to refresh my fleet with drones I actually I'm not scared to fly in public lol.  But I was dreaming / hoping I would be flying my own designs and frames. 

Ah well.

That's disappointing to hear. Maybe it would be good to just take a break and revisit it again in a few months with a fresh view. I went through some similar frustrations when I first started in 3D printing and ended up taking a 2-3 month break where I didn't even switch the printer on at all during that time. When i came back to it with a fresh head things then started to click into place. Maybe it would be better to start using your CNC machine with materials that are a bit less adventurous than CF, and once you've built up some experience and knowledge, have a go at cutting CF again.

Agreed, Snow. I was super upset earlier. Although that doesn't really change my assessment, I will give it a fresh set of eyes after a bit of a breather.

And I did decide to keep the machine for exactly what you suggested - other materials such as wood.

Bummer ronin, but I would suggest the same thing to just take a step back and come at it again in a few weeks.

I think some practice machining prototype parts from a different material like delrin may be a good way to learn without breaking the bank, its 1/10th the cost of carbon fiber and unlikely to break a bit. It would allow you to experiment a bit with setup.

Hi Ronin,

I just found this thread...WOW...THANK YOU.

I have been tinkering with the idea of getting a CNC Milling (router) machine, but haven't quite convinced myself that I should.

This is the most informative and comprehensive information that I have found...and from someone that I trust. WOW.

GOOD JOB  

... and with that said, ask me if I've ever even touched the thing since my last post on this thread?     LOL no.  

In fairness, I have been neck deep with roninUAV trying to get everything ready to go.  I could have returned it since I used Amazon strictly for that purpose.  But after a lot of deliberation decided to keep it since I can imagine it to be even far more useful than my 3d printer - if I think beyond just carbon fiber.  It's just got a much steeper learning curve that I suspect does not plateau as quickly as with 3d printing.  I am looking forward to making ronin nameplates out of super thin 0.5mm carbon fiber that I'll put on my radio, goggles, etc.