is there any cons besides the longer worktime on getting dust by advancing very slowly?
Some materials are dusty by nature and will not produce nice sliced shavings. The real point is the material removed is what is transferring heat away from the cutting tool, so the more substantial the piece of material leaving the cutting tool the more heat is being removed from the tool. This increases tool life and cut quality.
To answer your specific question, yes there is two cons other than longer run times. Number one you will overheat and dull your cutting tool which directly goes to con number two - the overheated tool will melt/burn the material you are cutting. If you can smell the material burning you are getting your tool too hot.
Now the big issue with the X carve is that it isnāt rigid enough to cut at the feedrates that are standard in the industrial world. For example acrylic cuts like butter around 300ipm @ 18k rpm on an industrial sized machine, but the x carve flexes and causes the tool to chatter long before hit those speeds so we are left cutting very shallow cuts at a fraction of the feed and thus much slower RPMs.
Hello.
I have my X-Carve for 6 month now and did not know what a CNC was before that, so the following is nothing more that a newbeās though.
I found a way to go at ot near recommended speeds by using very small depth of cut (DOC). For example, using manufaturerās chipload I cut aluminum at FR=1500mm/min, RPM = 10300 (max on my 100VDC spindel) and DOC = 0.075mm.
I tried tou double DOC at 0.15mm but it chatters.
If anyone else have succeded at deeper DOC, please let me know.
The DOC (depth of cut) in our X-Carve universe is a battle between machine rigidity and the hardness of the substrate we are cutting. The write-up I did is generalised for the principles of machinging but everything has its limits and in the case of the x-carve it is the machine flexing under tool load. More often than not the flexing (which results in chattering and horrible sounds) happens before an optimal feed and speed is reached at the desired DOC. This means we need to take shallower DOCs to still hit the optimal feed and speed as chip load is far more important than a deep cut. The goal is to always keep the tool cool by removing a nice slice of material with every rotation of the cutting tool. The heat from friction is proportional to DOC and the amount of material removed. This means that if you are getting the proper thicknesses of chip (chip load) then the hight of the chip (dictated by your DOC) dosnt matter to cut quality up until there is too much load on the tool resulting in something flexing (tool or machine) and chattering the cut.
The down side is tool life. If you are cutting a .5" thick part and cutting at .05" then the .05" tip of the tool has cut ten passes. If you cut the same .5" part at .25" the the toolās tip has only cut the part twice. This means the .05" cut is dulling the used edge of the tool five times faster than the deeper .25" cut.
Now to your specific application. I dont know the exact cutter you are using or how many cutting edges it has but 1500mm/min sounds very fast to me at 10k rpm. 20-25" (500mm) per min sounds like a more realistic feed but I dont know what tool you are using so only a guess. Aluminum is also tricky because it will melt as it is cut if it is poor quality aluminum and if the feed and speed is incorrect. This is evident with the chips rewelding to the material behind the cutter and/or the flute of the cutter looks like it has a layer of aluminum paint in it. Using a lubricant can prevent reweld and material build up on the tool.
A trick I havent tried yet is using clay or plumbers putty to make a shallow wall around your cut and flooding it with cutting fluid so the cutter tip is submerged may be a good low cost solution to a spraying system.
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Crossing streamsā¦
Hi Richard and thanks for the great info.
Iām using an IMCO 32646 1/8 2 flutes. I Also used Onsrud 1 flute (63-606) with same results, except that I had to run at lower feedrate (half), because it has half flute.
I followed your advice and measured the thickness of the chips and I measured 0.09mm (=0.0035 in) wich is right on the target (0.002 to 0.004 in specs). I donāt see any melting sign as far as I can see. So far so good.
Iām building electronic audio stuff, and I use my CNC for panel cutting and decoration. The aluminum I cut is only 2mm thick. That is possibly helps for the melting issue.
you can see the result here to understand the context:
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really nice work
Richard, very nice tutorial. I bought my X-Carve to work with aluminum to show my students that we can go from drawing to part. I have a superPID controller, the X-Controller, NEMA 23s, and Dewalt 611. I can go down to 500rpm. I am getting different results than others and am not sure of the problem. I can break an 1/8" bit with little effort.
Easelās default settings for Aluminum are: 5 in/min and 0.001 in DOC. I set up a vacuum for the chips and the stock metal does not change temperature. (when cutting 1/4" aluminum) When I use these settings in MeshCAM; I actually get a pretty good chip load. However it takes days to make a part. When I go for something more aggressive, no joy.
Thanks Malcom.
It was a steep learning curve to get there. I was making audio devices before, but now they look great. They even sound better, thanks to the x-carve that allows me do multiple test PCBs until I get to the right recipe.
I love my x-carve, despite itās limitations that comes with itās low price, wich allowed me to step in.
A bit designed for aluminum (like Destiny Viper) with no more than two flutes, move 50 inches per minute at .002" DOC, spindle at 15,000 rpms. This works flawlessly me for me (was recommended to me by others on forum doing production level milling with the x-carve). If your bit still break bits - your machine needs work. Seems like there are a lot of forumlas floating around and different ways to skin a cat - but this works great for me milling 1/2" aluminum plate.
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Lots of good tips.
I am not CNC knowledgeable and learned a great deal while waiting for the X-carve to arrive.
I found one video tutorial that covers similar here.
My first run the results were perfect. I used balsa wood as a bit dragging through it would be less forgiving.
To my surprise it came out near perfect. I then decided to work on my other project. I created a knob for the one missing on my chop saw (Miter saw). It came out way better than I expected. According to the 2 fluke bit and a calculation I had the router running at its max speed with 300mm per min and I had no heat and the part was sharp like a laser cut. The chips were dust rather than large chips. My next goal is to construct a shell around it and keep that dust/chips where they belong. I am also 3d printing out a dust catcher. 
.002" DOC, really? That seems like a very light cut, only .051mm. I was expecting something more like .5mm, or even greater.
Learn by doing. If I could grab a hold of your machine Iād bet there is a fair amount of flex. Start there and get more aggressive. Iāve seen enough crazy recos on this forumā¦ so I am sure you can find the DOC you desire in someoneās thread.
oh man i wish id seen this days agoā¦just got mine up and running. Threw in a 1/4" bit and went to testingā¦an hour later the bit was burnt upā¦i had it set on 5 1/2. lol Well now i know. Thx, much needed chart.
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I still donāt understand how to calculate my DOC. I have a 1/4" 2 flute up spiral bit and a DeWalt 611. Using that spreadsheet above: when cutting MDF I need a chipload a little below .002. If I set my Dewalt on 1 and set my IPM at 60, I get that chipload. But I still donāt understand how to determine my DOC. Help?
Generally the Depth of Cut needs to be no more then 1/2 the diameter of the bit. If your machine is nice and tight with no flex try 1/8" with a 1/4" bit. I usually use a 0.08 depth of cut in MDF as it tends to give me a cleaner cut.
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thanks, good insight!!
Thanks for this incredibly useful information! It is exactly what I needed. Does anyone know if Inventables has the recommended chip load for the bits they sell posted anywhere?
Hi all
I have only two days with the machine ready to rock and roll. I am new with CNC. Question for the expert.? To stsrt with a CNC whatās the āMost Have itā bits set to work with wood, plastic and aluminium. For cut and Engraving.
I recommend this chart for formulas and convertion for Milling Formulas.
Inventables does sell an engraving bit set, which, presumably, includes a good set of engraving bits. Bit Set for Fine Detail Engraving ā Inventables, Inc.