Is anyone having problems with their X axis? Specifically is it missing steps? For the 2nd time in as many days, my parts are being miscut on the x-axis. I am running a 2 flute up cut 1/4" carbide bit at 18000 rpm and 1/4 bit radius (.0625) depth of cut and 35 inches per minute with 8 inches per minute plunge and 3 inches distance, cutting 3/4 inch pine ply. That is pretty much the maximum I can cut with this machine.
I welcome your comments and suggestions.
I don’t use 1/4" bits, I use 1/8" ones. But your numbers seem very small.
Converting to metric, you’re using 1.5mm doc and 3.3mm/s. Assuming you could double that for a 1/8", that’s still at least half of what you should be able to do. Are your bits good cnc bits?
What controller are you using? What motor drivers? If they are drv8825s, what voltage setting? How are they wired (series or parallel).
Are you sure the gantry is tracking straight? Can you look at the Z pipes in a cut like that and see if the gap on either side is changing? I added tracks inside the wheels because mine wouldn’t drive straight for some reason.
Do things move smoothly? Is everything square? Nothing’s binding?
Diablo 1/4 carbide windmill
My setup is exactly what Ryan sent. Plugged in just like he suggests
Gantry tracks fine.
Maybe I will try cutting with 1/8 bits. What speed and depth are you running on 1/8 bits?
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Those numbers are low even for a 1/4" Can you send a picture of what you are using. Most router bits just don’t work like a proper endmill. Plunge and chip evacuation angles must be different or something.
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What I am seeing from the video looks like the cnc might not be square or you got a snag. I have no idea how to articulate this. Your machine started off fine, got down the cut and something interfered with the gantry and it came back to a different position. It is off in the X direction because the Y got hung up. If the X missed a step the entire thing would have shifted, instead you have a triangle cut, I think. Hard to see from that video.
You should lift your router above your work piece and drive it manually past your cut, like a dry run. For a while after you know what you are doing that isn’t usually necessary. When you bring it back you can make sure it is still square. It can hit the side, it can snag the cord, or more commonly the hose. If your build is not square it can even snag on the table. Speaking of that sand the sides a bit so they are smooth and the Z rails can slide of them nicely if they need to.
One more tip, hang the bit out less. Push it in the collet as far as you can, and pull the router up if you need to. The lower the machine is the faster you can cut.
I have never had a problem with the y axis I start from a zeroed position where both sides are square to the work, within 1mm
I must be missing something If the x axis misses a step the next cut along the y axis will be off set by the am out of the error which is exactly what I am trying to show in the video
The bit I am using is a Diablo 2 flute spiral from Home Depot. While I understand some bit geometry cuts differently than others, if it was the bit I would be having the same issues when cutting x and y.
I have not had any issues with the machine not returning to home for bit changes. This tells me that it is holding square. Just with this piece I have had 2 instances of the c axis missing steps. The first time it happened I thought it was because I was trying to run too fast (50 ipm) so I slowed back to 35 imp.
Table? The work moves as it gets mounted, it should be square to the table.
Not always, the Y has two steppers, the X has one. I can’t see what the issue was though. Do you have like an overhead shot of what happened. A skipped step will have a stair step effect, and a very clear ground zero if you will.
35in/m is 15mm/s with a 1/4" bit. I run 9mm/s with a 1/8" single flute bit 6mm DOC and that is pretty rough as chip removal is my issue at that point. The smaller bit has 4X less loading while plunging and during slotting that can get much larger, and on top of that I am using one flute which is basically half the loading of a single flute. This is why we both first assumed the bit you are pushing it hard. You are removing a ton of material. I am not saying it can’t do it but I would start a little less drastic.
So I am just running too fast. That is good to know I will slow the next cut down and see what happens.
I am not sure. An overhead picture would really help. A skipped step rarely only happens once in a job if you let it keep going it tends to get worse.
I agree that it should happen more than once, but the miss was so early into the cut that the increased load on the stepper was not so overwhelming that it caused a cascading effect of more misses.
This is my opinion and it is just based on my limited experience. The X axis has a lower threshold for overload because it has only one stepper. That’s why 35 ipm might be totally fine for the Y axis but too much for the X. Now, I don’t think the speed needs to be dramatically lower to reach a speed that works. I am going to dial down to 30 ipm and see what that does. I will report back.
The Y carries more weight. I shoot for balance but I honestly could not tell you if I achieved it.
Instead why not start much lower. As I said you are already using two flutes, a larger diameter, and faster. On top of that a router bit that is unproven. I understand wanting to go fast but you can do that with an 1/8". With all your more aggressive settings I really think a much slower jump is better.
30 only brings it done to 12.7mm/s from 15. 30-35 sounds like a lot but it is sort of the wrong scale to use for these speeds.
This is the bit I am using. I am not sure how it would differ from any 1/4 2-flute spiral up cut bit.
On the topic of speeds. This is exactly why we need some sort of chart or table to use with this build configuration. If I just used the feeds and speeds that come from commercial apps and formulas I would never get a single successful cut. If you go by ANY of these charts and formulas disasters are imminent.
Let’s take Freud as an example. They say the chip load for a 1/4, 2-flute, upcut endmill is .006".009" in plywood. The formula is as follows:
Speed (16000) x flutes (2) x chip load (~.0075) = 240 inches per minute
Freud says these chip loads are based on full bit width cut depth. So, I am assuming that if I am cutting at 1/4 bit width for depth of cut my numbers would actually be:
16000 x 2 x .03 = 960 ipm
I am trying to run at 1/28th of that speed and I am still having problems.
I realize that the formulas are for rigid commercial machines, and I understand that we are compromising speed for size and cost. I get that and I am totally willing to accept those limits. But what am I missing? There have to be some common parameters here that we can expect to start within and then dial up or down to match the “personalities” of our machines.
Here are the examples I am using to try and find the right speed/feeds. I am quickly learning these are not applicable to our situation.
http://www.freudtools.com/admin/manuals/SolidCarbideSpeedsinParticleBoard.pdf
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I understand, but the nature of this design and everyone varying builds make this impossible. on top of all of that, you have zero knowledge of exactly how fast your spindle is turning, how does it effect the numbers if you are 1000rpm off, at 10k to 30k rpm it is huge. I have narrowed it down as far as I can on the Milling basics page.
This works for most all my machines in wood, those are real numbers, no guessing or formulas are involved. From there we all have videos and post what we use with our dimensions, materials and bits. Other machine come in one size from one manufacturer, so they could possibly make a decent chart. Even for something like a Giant mill it is still a range, they do not tell you an exact number. If you use my given range above it will work. From there you can push it when you understand a variable well enough change it. Then you have to start taking in account as the bit dulls it will be able to handle less of a load.
- Single flute upcut bit.
- 8mm/s Feed Rate (The speed at which you move through the material).
- 3mm/s Plunge Rate (The speed at which you move vertically into the material).
- 1mm Depth of Cut (The thickness of material your bit will be removing per pass).
- 45% Step Over (The percentage of bit diameter that should be in contact with the material)
- Use the Peel pocketing strategy.
As for the formula you are using, or want to use, you just need to find the right chip load. You give the range of 0.006-0.009 (there site even says each machine varies and the true range for that bit is shown as .005-0.12). You say that does not work, for your machine. You just need to find the correct number (chip load) for your build (material and bit). From there you can use it every time…but it does not have to be that hard. Use my specs above then the next paragraph says,
If that works at this point the only variable you should be changing is the depth of cut. You can vary this and it will increase the load on your machine in trade for more material removed per pass or decrease the load by taking shallower bites.I think the big issue here is just some test cuts. Did you try the same cut in foam first? That will tell you if it is a machine or chip load issue fro your current cut. You seem very frustrated by this but I promise with just a few good cuts under your belt it is really easy. You just need to hear a a few good cuts and you will instantly recognize a bad one. I have given you numbers and advice to go slower and use different bits but you want to do it your way. Try mine first, then change variable as you understand them. By going out on your own you will have to be the guy that tells us what a Home Depot router bit should run at. I can only tell you how to run the bits I use. Is that bit different, I am not sure, it does not say it it is plunge cut capable that is important info if you are trying to use an unknown.
This comes up a lot, and after 3 and a half years no one has made a chart because of this. Heck we just found out this same design we had for two years is capable of cutting steel…we baby it, but with the proper load, feed, and speed it can do more than you think.
He sells more than one controller, but I’ll assume it mini rambo and the firmware was flashed by him. I’ll assume it’s series. If that’s all right, then that’s not your problem.
W.r.t. bits. I’m not an expert, buy I’ve used some unproven bits and they caused more drag and more tear out than Ryan’s bits did. They were dual flute 1/8" endmills even, so I’m definitely not trusting the hd special bit, but it’s too easy to blame that, really.
Did you hear it skip steps? Mine sounds like rubber gears grinding when it skips.
You can also try an “air cut” or cut in HD foam. If it’s something in the machine, it could show even without any resistance.
Thanks. I’ll dial it down and see what happens.
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Gyday Guys
Iam having a similar problem, with the X axis, using Estlcam controller to a ramps board , on a machine I made myself, not bad for a 77old fart!
the X axis Jerks and misses steps when traveling from cut to cut? the cut-outs are good and steady. it seams to me that the speed is too fast, have tried to alter the settings, but some weird results?? am using these settings ,see screen shot.
can any one explain in layman’s language how this screen works.
As far as I know Ramps is no longer supported on estlcam control. It would be easier for most of us to help you if you used marlin on your ramps.
Thanks Ryan
am using Arduino/ marlin
see screen shot of setting that I am using, it works but it isn’t correct.
Lloyd
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The screen shot you are showing is estlcam control, it will overwrite marlin. If you want to use it even though it is not supported I have an old post where I detail the settings and math involved.
Otherwise I suggest you start here, https://www.v1engineering.com/assembly/software/
Ok Guys
in my original statement I quoted:
the X axis Jerks and misses steps when traveling from cut to cut? the cut-outs are good and steady.what does this??
Lloyd
