[NickB00]

I broke an endmill once and it went off like a bullet somewhere, so I agree that a box enclosure would be the go. I have some high density foam panels that I could use and maybe line them with some thin ply to stiffen them up. I would need to get some acrylic sheet or perspex for the front door and possibly the top for doing aluminium work. I will also up the feedrate, but it seemed to be cutting nice chips with a depth of cut at 2mm or so. I am not sure how deep a cut I can do with aluminium and what feedrate to use, it was my 1st time. I am hoping to avoid using a coolant by limiting depth of cut even if it takes longer.

Without lube, you are going to break cutters on aluminium. Slower feed rates only make it worse because they promote rubbing instead of cutting which dulls and heats the endmill - you're (unintuitively) better off increasing your feed rate up until deflection becomes your enemy.

I went for the table/enclosure for a number of reasons:
- space in the shed is tight, so I wanted something /just/ big enough without being too big, but sturdy enough to not rattle around.
- I needed somewhere to keep the control box out of the way, and somewhere to put the laptop.
- I knew it would be mostly metal working so there'd be coolant flying around, so it needed to be on a waterproof tray.
- I wanted to control the amount of rubbish flying around. But still see what was going on.
- I wanted to save my face from bits of broken endmill flying at speed when I stuffed up (again).

That said, it ain't perfect. The enclosure adds another two steps (remove/replace front acrylic wall) to every damned tool change. It gets in the way of overhanging stock. It makes life less convenient when doing the cleanup (even though all the walls are just drop in/out, it needs doing and they need somewhere to live when not on the machine) after the job. Oh, and it was considerably more expensive in bucks and time than a dust shoe.

If I was going to do all or mostly wood, well, the top of the enclosure lets dust fly fine, so it woodn't (hurr hurr) be that great - a dust shoe'd be much better. But for metal it's a pretty handy dandy setup and I have no regrets

[NickB00]

Clearing chips especially in a slot is paramount! I can use an air-compressor with gun to give it a clean as it cuts away so good idea. What do you mean by staying at 1 or 2 thou per tooth?

even dry is manageable in most situations, only deep slotting can get sketchy, but you must have at least a strong airblast (a little fan or gust from an aircooled spindle is not even remotely enough). Clearing chips is paramount. It's not too hard to always keep a healthy cut if you try to think in terms of chipload rather than feed. Staying at 1 or 2 thou per tooth avoids rubbing but is still a really light cut. Cutting a real chip also removes more heat from the workpiece, so keeps things a lot cooler, which I like to think keeps aluminum from getting so gummy.

[dharmic]

Chip size, Nick - a factor of number of teeth, RPM of tool and feedrate but it's basically how thick the chips are. Too thin (too slow a feed rate for the RPM and number of teeth) and you get rubbing, 0.001 - 0.002" (0.025 - 0.05mm) chip thickness is a good working minimum.

Something like FSWizard, HSMAdvisor, G-Wizard etc will let you play with these numbers and make some decent recommendations based on materials, tool stickout, depth of engagement etc.

[johncooper]

I'm in process setting up an OMIO X8 2200L USB router. I'm having difficulty with my USB connection and receiving a "No XHC NcUSBPod! " error. I have followed the OMIO instructions for MACH3 installation. The error is intermmitent, so I have been able to verify stepper motor and spindle basic functions. Does anyone have insight on the source of this problem and potential fixes?

[dharmic]

I had the same issue - but it built up over time. Turned out that all I needed to do was ground the frame. If you're similar to me you have a four way power board with the Omio control box, coolant pump and laptop hanging off it. You just need to ground the frame, here in Oz we have earth pins on our power outlets (3 pin) so all I needed to do was undo a bolt on the machine frame, crimp an eye onto a bit of wire and put that under the bolt, and wire the other end of the wire into the earth pin of a power plug which went into the 4th outlet on the power board. Problem solved. For me, anyway

[NickB00]

I use say a 6mm endmill with 2 flutes so not sure what you mean by the number of teeth?

Chip size, Nick - a factor of number of teeth, RPM of tool and feedrate but it's basically how thick the chips are. Too thin (too slow a feed rate for the RPM and number of teeth) and you get rubbing, 0.001 - 0.002" (0.025 - 0.05mm) chip thickness is a good working minimum.

Something like FSWizard, HSMAdvisor, G-Wizard etc will let you play with these numbers and make some decent recommendations based on materials, tool stickout, depth of engagement etc.

[Mmpie]

Nick - as per Dharmic's post, I would recommend getting a feed and speed calculator to start off with. Aluminium isn't as forgiving as wood and having the right feeds and speeds is the difference between having a good time and a bad time, so it will help make your journey a lot smoother and your pockets a bit heavier. It's not gonna pay for itself but it will be worth every penny. Also teeth = flutes.

John - I also had the same problem. If earthing your frame doesn't work, which it didn't for me, I had to shield my spindle cable with a copper braided cable. But I did double the length of my wires.


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[dharmic]

For what it's worth, HSMAdvisor has a free online calculator and there's a free lite version of FSWizard which only has a few materials loaded. Fortunately, these include aluminium

[Stigoe]

I'm in process setting up an OMIO X8 2200L USB router. I'm having difficulty with my USB connection and receiving a "No XHC NcUSBPod! " error. I have followed the OMIO instructions for MACH3 installation. The error is intermmitent, so I have been able to verify stepper motor and spindle basic functions. Does anyone have insight on the source of this problem and potential fixes?

In addition to the other suggestions, if you have access to a multimeter, check the resistance between the shield on each connector on your USB cable. It should be less than 1 ohm. I had a similar problem on my mill every time I enabled power to the stepper motor drivers. Replacing the cable with another one where the resistance between the shields were less than 1 ohm fixed that problem.

[NickB00]

OK got it thanks! Good idea!

For what it's worth, HSMAdvisor has a free online calculator and there's a free lite version of FSWizard which only has a few materials loaded. Fortunately, these include aluminium

[johncooper]

FWIW, I made solid progress today, nicely cutting polycarbonate and aluminum. On the USB error issue. I added a ground wire from the router frame to power strip ground (thx dharmic). This didn't resolve my USB issues, but I believe it helped. I rearranged the computer and controller creating the greatest distance between the USB cable and the stepper/spindle motor wiring and this solved the USB communication issue. For today at least.

I'm on the the next tier of issues. I'm cutting at 12,000 rpm. When I raise the spindle above 12k rpm the machine vibrates significantly and becomes very noisy. Any comments or suggestions for operating at higher spindle rates and eliminating the vibration?

The aluminum cuts were in 1/8" thick 6061 al sheet. I tried contours and pockets and they both left a small ridge (~.01") of material protruding form both the top and bottom edge of the contour. Any advice on how to eliminate? I experimented with a finish pass of .02" which gave me a nice finish on the thickness of the cut, but left the ridge as noted.

[dharmic]

Your next step may be to look at shielded cable for the spindle. PITA but some guys have had good results, and it's not as big a PITA as switching to a U400-ETH, BOB, power supply for the BOB etc which is what I ended up doing for other reasons.

Does the machine shake over 12000rpm if there's nothing in the spindle? Take the tool out, the collet and the collet nut and spin it up. Mine's as steady as a rock. If yours isn't you may have a crappy spindle.

[Sterob]

Are you using a PC or a Laptop?

[dharmic]

Who? I'm on a laptop. Which is half the problem as it's a double insulated mains cable (no ground wire) and floating earth. At least on a PC it's clamped to ground - although doing that through the USB earth lead is pretty nasty.

[johncooper]

Your next step may be to look at shielded cable for the spindle. PITA but some guys have had good results, and it's not as big a PITA as switching to a U400-ETH, BOB, power supply for the BOB etc which is what I ended up doing for other reasons.

Does the machine shake over 12000rpm if there's nothing in the spindle? Take the tool out, the collet and the collet nut and spin it up. Mine's as steady as a rock. If yours isn't you may have a crappy spindle.

The USB communication issue arose again last night. I swapped to a new USB cable (swapped out the OMIO provided USB cable) which solved the issue for that session.

I am on a desktop with ground. I've considered shielding the spindle cable, but my issue usually arises prior to powering the spindle, so I haven't pursued this path. Strangely, I'm starting to correlate the issue with night time operation versus daytime. I only have two days/nights of data, so I will continue to monitor.

Regarding the spindle, I will test with spindle only, then add nut, add collet, etc. to determine if the spindle is good and what creates the vibration. From your post, it seems 22k rpm operation without vibration is achievable/expected.

[dharmic]

Sounds like a different issue, possibly, then, to mine.

Mine would run fine for hours then disconnect. At that point, simply starting the spindle would disconnect again and this continued until I left it alone for a day. It was only stuffing around with USB cable swaps etc that I noticed a great big fat blue spark when I plugged the USB cable into the computer. Grounding the frame fixed it (for me) but by that stage I probably had already swapped the cable. Make sure you switch the ferrite beads over from the original cable to the new one, too.

If yours is dropping out regardless of spindle and the frame is grounded then it'll be something else.

Yep, mine runs beautifully at 24k rpm. If yours doesn't run smooth with no nut, collet etc then I'd say it's a dodgy spindle - and you won't be the first to have to deal with this, unfortunately. Someone else got a bum deal with this too and I can't remember whether they replaced bearings etc or just replaced the spindle.

Another point - if it runs smooth with a tool installed too, and only gets crazy when engaging with the workpiece, it could be a case of feeds and speeds and simple tool chatter.

[Sterob]

Who? I'm on a laptop. Which is half the problem as it's a double insulated mains cable (no ground wire) and floating earth. At least on a PC it's clamped to ground - although doing that through the USB earth lead is pretty nasty.

No, the OP..Re: USB issues.
Laptops appear to be more problematic when using USB.

[johncooper]

Tested my spindle for vibration.
Spindle only, spindle with nut and Spinle with nut and collet all perform nicely up to 24k RPM.

I added a 4mm carbide endmill and introduced moderate vibration starting at 12k RPM. Some speeds were worse than others and vibration at speeds above 20k RPM dropped compared to vibration at speeds of 15-18k RPM. All of this vibration was less than yesterday, which corresponds to comparing a higher quality cabide endmill to the HSS endmill that came with the router.

I'm satisfied the machine operates sufficiently well and will experiment with various quality endmills.

I continue to play with the USB connection. It seems it has difficulty when initiating a session and can't recognize the controller. After unplugging/pluggin, reboot etc. it seems the PC recognizes the controller and then all is well. I might buy a PCI to USB 2.0 card and add new USB ports. This is a shot in the dark, since all other devices operate fine with the motherboard USB connections.

[RCaffin]

What you have described sounds a bit like resonance. Could be interesting to test the spindle with a bit of plain ground stock, 4 or 6 mm OD, 75 mm long.

USB - many of us have sworn off the USB method of connection and gone to the ethernet. A benefit of the ethernet is that there is NO electrical continuity over the connections: they are transformer-isolated, and instead of 3 V signals on the USB the ethernet has 15 V signals.

Cheers
Roger

[Mmpie]

There shouldn't be any vibration with the spindle running unloaded. Perhaps something is loose and natural harmonics are causing it? What exactly is vibrating, the entire thing? A video might be helpful if possible.

When I stripped my machine down for the first time I found quite a few loose bolts and holes with stripped threads.


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