#linuxcnc Logs

Nov 30 2020

#linuxcnc Calendar

01:36 AM Loetmichel: mornin'. GAAAH! Monday morning... first action of the day: put the sharpened putty knife into the left palm... *bleeeed* *2 layers of bandaid* Why me every time? :(
01:43 AM XXCoder: ow
02:12 AM Loetmichel: soo, bleeding stopped. its something ;) *changes bandaid* :)
02:34 AM Loetmichel: soo, new bandaid. all is well.. (hopefully) ... good thing i heal so well... (caution, a bit blood) -> http://www.cyrom.org/palbum/main.php?g2_itemId=17987&g2_imageViewsIndex=1
02:40 AM veegee: I have to figure out the trick to milling by hand
02:40 AM veegee: That is, with a carbide burr and a right angle die grinder
02:41 AM veegee: Certain positions/angles cause it to bite into the material and kick back violently
02:42 AM veegee: climb milling interestingly enough doesn't seem to be an issue
03:32 AM Loetmichel: hehe... $me whisteling along with the radio... Coworker: "maan, you are indestructable, arent you? two hours ago you cut yourself with lots of blood and now you are whistling again?" :)
04:53 AM enleth: veegee: the same applies to angle grinders, you want to "climb grind" at all times for controllability
04:54 AM enleth: veegee: also try a straight die grinder, might be easier to get proper leverage on it
04:55 AM enleth: angle die grinders do not have the side handle like full sized angle grinders do, so it's hard to keep them steady when the forces on the tool try to spin them around the axis of the motor
04:55 AM enleth: there's just nothing to hold onto for proper leverage in that direction
05:01 AM JT-Cave: morning
05:56 AM Tom_L: morning
06:56 AM enleth: was there anyone doing HVAC among regulars here?
09:23 AM JT-Shop: YIPPIE spoke machine is done and proven out so payday this week!
09:56 AM Centurion-Dan2 is now known as Centurion_Dan
10:17 AM veegee: enleth true about the angle grinders. Looks like the most stable position is the one with the sparks/chips flying towards your face
10:18 AM enleth: veegee: one other trick is to try "trapping" the workpiece between the disc and the guard, so that one tries to push it into the other, the tool is then securely latched onto the workpiece and won't do anything stupid
10:18 AM enleth: can't do that with a die grinder, though
10:19 AM veegee: And yeah I used a straight die grinder and it was easier. The shape of the bit makes a huge difference too. A low cutting surface area has much more controllable forces
10:19 AM veegee: Yeah that's what I do with angle grinders
10:19 AM veegee: I always rest it against the guard to get straight clean cuts
10:20 AM veegee: Also because it eliminates vibration and I'm always worried about the cutoff wheel shattering
10:21 AM enleth: I've yet to see the wheel shatter from vibration alone, but I've had many shatter, tear themselves in half or tear off the hub due to kickback and pinching, those are IMO the two things you need to watch out for
10:23 AM veegee: Luckily I've never had an angle grinder tool explode in use
10:23 AM veegee: I pay attention to the expiry date though. Or safety squint real hard if they're "stale"
10:26 AM enleth: I've got a 250mm 2kW Makita grinder that will happily rip/twist the center out of pinched wheels, with a jolt that is only survivable to the operator because the tool itself is so massive it dampens its own movement
10:27 AM enleth: there was this one time when the steel insert in the center got *almost* torn out, I didn't notice, and the whole wheel sans the insert that stayed on the arbor went "I must go, my people need me" when the grinder got up to speed
10:27 AM enleth: skipped across worktables and the floor, embedded itself in some junk on the other side of the place
10:30 AM enleth: other than that, it's almost always kickback that rips a chunk of the wheel out and leaves it unbalanced
10:31 AM enleth: I'm normally using the thinnest possible cutoff wheels for almost anything, not sure if the thicker ones have different failure modes
10:35 AM roycroft: i've never had a cutoff wheel or grinding wheel fail like that, not even remotely
10:35 AM roycroft: all that happens is they wear out over time
10:36 AM enleth: maybe you're just a bit gentler with the grinder
10:36 AM roycroft: perhaps
10:37 AM roycroft: that kind of behavior is something i'd not appreciate, that's for sure
10:42 AM enleth: well, I'm not going mad-300-pound-gorilla on the grinders, but I'm definitely not holding them back either
10:43 AM enleth: as long as the motor isn't struggling, I'll push it
10:44 AM enleth: some people really hold a grinder back, taking ages to make simple cuts instead of letting it cut simply under its own weight
10:45 AM enleth: let alone push it a little
11:34 AM J0ND03: Hello
12:22 PM -!- #linuxcnc mode set to +v by ChanServ
12:53 PM JT-Shop: hi
01:14 PM Eric__: I just discovered home depot's daily deal, could be expensive
01:14 PM Eric__: otoh, their shipping logistics is just silly, my router is taking a scenic tour of the eastern U.S.
01:21 PM JT-Shop: just a router or a cnc router?
01:26 PM * captain_morgan does the excited to CNC dance
01:26 PM captain_morgan: 2 more weeks!
01:36 PM andypugh: Linky? Let us share your excitement. I could do with some,
01:41 PM * captain_morgan has no links
01:44 PM andypugh: Silly CNC. But it’s interesting at about 9:30 where he mentions stepper drivers with stall detection that can thererode use hard stops to home to.
01:45 PM andypugh: https://youtu.be/FJZa5K6Dk48
01:46 PM captain_morgan: so much post cleanup
01:47 PM gregcnc: workholding appears to be an issue
01:47 PM captain_morgan: heh
01:49 PM gregcnc: workholding was upgraded in the latest video
03:14 PM roycroft: hello, folks
03:15 PM roycroft: i'm coming back around to working on some projects that have been on the back burner for a while, that involve making some custom badges
03:15 PM roycroft: i was originally going to etch the badges using a toner resist method, but my early experiments at transferring the toner to metal sheets let me thinking it would be quite fiddly to do that reliably
03:16 PM roycroft: i then considered engraving the badges, and that's still an option - either with a small end mill or a drag graver
03:17 PM roycroft: but the thought occured to me that i might be able to etch it using a different method - coating the metal with a resist, and burning the resist off with a small laser?
03:17 PM roycroft: er, s/?//
03:18 PM roycroft: would i likely be able to get some fine detail in the etching if i used a laser to do this?
03:18 PM roycroft: for just removing resist, i should think that a low powered laser, such as 5w or less, would suffice
03:19 PM roycroft: and i'd assume the laser and its light path would be fixed, and i'd just need cnc x-y control to do the work
03:19 PM roycroft: is that correct?
03:22 PM enleth: roycroft: yes, you should be able to mount a chinese engraving laser on a 3D printer or something like this
03:22 PM enleth: they do sell complete laser engraving machines for pennies, though - check aliexpress
03:23 PM roycroft: the extruder on my 3d printer does the x-y movement
03:23 PM roycroft: the bed only does z
03:23 PM roycroft: wouldn't it be the opposite with a laser?
03:24 PM enleth: what's the difference?
03:24 PM enleth: small diode lasers are self-contained
03:24 PM roycroft: the laser setups i've seen have the laser source fixed, with mirrors and a lens also fixed to focus the laster
03:24 PM roycroft: laser
03:25 PM roycroft: if i could use my existing 3d printer that would be great
03:25 PM enleth: actually, for those, the "head" with the lens typically moves, as well
03:25 PM roycroft: are these diode sources you're talking about kind of like the laser pointers folks use to torture cats?
03:25 PM enleth: nope, those are single miliwatt lasers
03:26 PM enleth: but you can get 1, 5, I think even 10W lasers in this form factor
03:26 PM roycroft: if i could get one that small it would be trivial to print a mounting bracket to attach it to the 3d printer in lieu of the extruder/hot end
03:27 PM roycroft: and what about resolution?
03:27 PM roycroft: could i expect sub-mm, even sub-0.1mm resolution?
03:27 PM roycroft: assuming i get everything dialed in well
03:28 PM enleth: roycroft: https://aliexpress.com/item/33043097431.html
03:28 PM enleth: that's a complete machine for close to nothing
03:29 PM enleth: 5.5W is plenty enough to burn away etch resist and it will actually cut some stuff in a useful capacity
03:29 PM enleth: those mirror-and-lens lasers you mentioned earlier are CO2 units, in the 40-1000W range
03:30 PM enleth: above that, fiber lasers are used nowadays
03:30 PM roycroft: yeah, that's almost free
03:31 PM roycroft: and 5w is what i was thinking was the correct size for etch resist
03:31 PM enleth: look for "laser marking machine" or "laser engraving" on ali, either get a full unit or just the laser head for a 3D printer
03:31 PM roycroft: but i still have no idea what realistic resolution i'd get
03:32 PM roycroft: i was looking at vinyl cutters for resist masks, but the manufacturers i spoke with said i should expect more like 1/2" as the smallest text i could cut with one
03:32 PM roycroft: which is ridiculous
03:32 PM enleth: http://www.engraversnetwork.com/support/universal-lasers/laser-how-tos/dpi-vs-ppi-laser/
03:33 PM enleth: and look for the dot size spec in the product descriptions
03:34 PM enleth: internets say 0.1mm is about the best you can get
03:35 PM roycroft: that one whose link you posted has an accuracy spec, but i did not see a resolution spec
03:35 PM roycroft: 0.1mm is probably fine
03:36 PM roycroft: that's ~0.004"
03:36 PM enleth: industrial lasers typically have a very short DOF, so proper bed leveling is critical
03:37 PM roycroft: i'm going to lose some resolution when doing the etching anyway
03:38 PM roycroft: anyway, that one from aliexpress has a pretty decent capacity, and would cost <$200 shipped
03:38 PM roycroft: not bad
03:38 PM enleth: but DOF in a laser directly affects the power density as well as precision
03:38 PM enleth: if you get it wrong, you won't cut through/engrave deep enough/remove the resist completely
03:38 PM roycroft: yeah, so i want to get it right if i want the image to be at all sharp
03:39 PM enleth: you might not get anything at all with bad focus
03:39 PM roycroft: it sounds like that's easier to do than to constantly be fiddling with toner resist, getting it transferred completely, and filling in pin holes and the like
03:39 PM roycroft: as i said, i started doing that and it was just way too time-consuming and unpredictable
03:40 PM enleth: most likely it is
03:40 PM roycroft: i'm good about giving up on ideas quickly when i become convinced they won't work out well
03:41 PM roycroft: the drag knife idea seems like it won't work very well either
03:41 PM roycroft: and i don't want to do direct engraving with end mills
03:41 PM roycroft: so the laser/resist etching method is what i'm currently considering
03:41 PM enleth: I'd expect this to be the best way to do it
03:42 PM roycroft: yeah - i don't know why i did not think of it a long time ago
03:42 PM roycroft: i could use it for pcbs as well
03:42 PM roycroft: which would be really cool
03:42 PM enleth: there is another way a friend of mine is using to etch thin sheet brass for modelmaking
03:43 PM roycroft: what is your friend doing?
03:43 PM enleth: spray-on or stick-on UV-sensitive photoresist film
03:43 PM roycroft: oh, i had thought about doing that
03:43 PM enleth: he prints the design on a transparent sheet and exposes the coated brass through it to UV light
03:43 PM roycroft: actually, i was thinking about silk screening it
03:44 PM enleth: exposed (or unexposed, some photoresists are positive image, some are negative) washes away with water
03:44 PM roycroft: yeah
03:44 PM enleth: his results are excellent and pretty repeatable
03:45 PM roycroft: it looks like i can get focusable 5w lasers for about $75
03:45 PM roycroft: and they're fairly small
03:45 PM roycroft: small enough to work on my 3d printer, i don't know at this point
03:45 PM enleth: but if you can find a proven laser-activated or laser-removable etch resist, you'd probably be better off going with the laser
03:45 PM roycroft: they're bigger, and i'm sure heavier, than the hot end
03:45 PM enleth: it'll be useful for other things
03:45 PM roycroft: yes
03:46 PM roycroft: cutting/burning maker's marks on leather and wood, for example
03:46 PM roycroft: a laser is more versatile
03:46 PM roycroft: besides, if i have one, i can go to people and demand they give me ONE MILLION DOLLARS
03:48 PM enleth: I don't think it's going to be appreciably heaver than a hotend with an integrated stepper
03:48 PM enleth: it's mostly aluminum for heatsinking
03:48 PM enleth: the laser diode itself is tiny
03:52 PM roycroft: well if it is heavier i might just need to run the machine mroe slowly when the laser is mounted
03:53 PM enleth: if even that, really
03:53 PM roycroft: and i assume i can use the 3d printer's control software, as long as i feed it the correct gcode
03:53 PM enleth: sure
03:54 PM roycroft: yeah, this sounds quite doable
03:54 PM roycroft: it would save space, which is precious
03:55 PM roycroft: and be a low investment
03:55 PM enleth: just get yourself a pair of safety glasses for the specific laser wavelenght you buy
03:55 PM roycroft: yup
03:55 PM roycroft: that's the drawback of mounting it on a 3d printer
03:55 PM roycroft: no shielding
03:56 PM roycroft: i don't want to put my eye out!
03:56 PM enleth: those marking machines from aliexpress don't have any enclosures either
03:56 PM enleth: you're just supposed to use safety glasses
03:56 PM roycroft: the $500 ones do
03:56 PM roycroft: my cat likes to wander out in the room where i have the 3d printer
03:56 PM roycroft: i wonder if cat goggles are a thing :)
03:56 PM enleth: 5W is not going to be dangerous to anything other than your eyes, so it's not a huge deal
03:57 PM roycroft: i'd actually build a shielding thing that i'd put up if i eer run the machine while i'm not there
03:57 PM roycroft: which i need to do anyway - i've been lucky so far that she hasn't gotten interested in the 3d printer while it's running
03:58 PM roycroft: one swipe of the paw can destroy a part, or even damage the machine
03:58 PM enleth: also fun fact: for CO2 lasers, that work in far infrared, *any* glasses at all are proper safety glasses, pretty much anything is opaque to 10600nm
03:58 PM enleth: but for a UV diode laser, you have to be a bit more picky
04:00 PM enleth: either coated glass or polycarbonate
04:00 PM enleth: regular glass will let most of it right through
04:00 PM roycroft: creality make a laser module for their 3d printers
04:01 PM roycroft: it's only 500mw though
04:01 PM roycroft: probably not powerful enough for what i want to do
04:03 PM roycroft: but i'm seeing 5w lasers connected to ender 3 printers, which are similar in size to my ender 5
04:03 PM roycroft: they're attached with rare earth magnets, and don't even need for the hot end to be removed
04:04 PM enleth: that makes perfect sense
04:06 PM gigasu_shida: is it true that with induction motors, if the core has higher resistance, the motor will have more torque starting from 0 rpm?
04:15 PM _unreal_: question, trying to figure out the best way to clean up my signal from the motion conroller to the motor controller.
04:15 PM _unreal_: the motion controller has opto isolators but I'm getting a big of signal issues
04:15 PM andypugh: That question makes little sense.
04:15 PM andypugh: Cab you carify where to where?
04:16 PM captain_morgan: roycroft jumping way back up, I've had good success with lasering off black spray paint
04:16 PM captain_morgan: some of my best PCBs were etched using that method
04:17 PM captain_morgan: that was using a K40 laser, but I've heard of people using the small 5W lasers for this too
04:17 PM captain_morgan: but if the focus on your laser is *really* good, you can direct expose too, but I dont' have hands on experience with that
04:20 PM roycroft: interesting
04:20 PM roycroft: black spray paint is cheap and ubiquitous
04:20 PM roycroft: both of which are good
04:21 PM roycroft: i'm really thinking seriously about getting a 5w laser and mounting it to my 3d printer
04:21 PM roycroft: if that works, then great
04:22 PM roycroft: if not, then the laser itself is not a big investment, and i can repurpose for something else
04:22 PM roycroft: maybe build a little dedicated laser cutter/engraver machine
04:22 PM roycroft: i don't mind if it's slow - this would not be an industrial/production application
04:23 PM roycroft: if it takes 3 hours to etch a badge or pcb, that's fine
04:24 PM gigasu_shida is now known as gigas_cedar
04:31 PM * JT-Shop guesses it will get easier to change the belt on the drum sander after his finger prints are all gone
04:31 PM Tom_L: may as well trim your nails too
04:32 PM JT-Shop: lol
04:32 PM Tom_L: i was wrong about save as, it's save management
04:33 PM JT-Shop: ok thanks
04:33 PM Tom_L: just opened it to look at something
04:34 PM _unreal_: andypugh, hi sorry
04:34 PM _unreal_: from the motion controller TO the motor controller
04:34 PM _unreal_: this is the mach3 usb motion controller
04:34 PM _unreal_: going to the stepping motor controller
04:34 PM * JT-Shop has been chasing his tail all day and not getting much done :(
04:34 PM _unreal_: the setepping motor controller has opto isolators
04:34 PM andypugh: My fault. I can’t read.
04:34 PM _unreal_: but I think there is some NOISE being picked up on the stepping control wires
04:35 PM _unreal_: what would be a good way to clean it up?
04:35 PM Tom_L: shielded wires
04:35 PM _unreal_: I'm using twisted pair with one side grounded on each lead
04:35 PM JT-Shop: 5' short of 1 1/2" channel to finish the gates... can't just get a $15 chunk of steel delivered so I had to add on till I got above $40
04:35 PM _unreal_: the wires are only like 10" long at most
04:35 PM andypugh: You know that the conventional wisdom is that USb can naver work right?
04:36 PM Tom_L: _unreal_, how long is your cell phone antenna?
04:36 PM andypugh: Just to get that over with.
04:36 PM Tom_L: andypugh, he goes against all conventional wisdom
04:37 PM andypugh: So is it possibly USB latency adding noise? ie the positions are correct, but the times are not?
04:37 PM * JT-Shop can only imagine which he your talking about lol
04:37 PM _unreal_: cell phone?
04:38 PM _unreal_: I put the new stepping motor controller in and it seems to be picking up noise I think?
04:38 PM _unreal_: I dont know its just wierd
04:38 PM Tom_L: iirc gloops or somebody had a bob that wasn't grounded properly
04:38 PM Tom_L: might check that
05:07 PM JT-Shop: roycroft, what do you set the belt speed at for end grain?
05:21 PM roycroft: there's an inkscape plugin that generates gcode for a laser directly
05:22 PM roycroft: that makes everything a lot easier
05:31 PM CaptHindsight: roycroft: http://www.scorchworks.com/index.html
05:32 PM CaptHindsight: http://www.scorchworks.com/Gcoderipper/gcoderipper.html this one is especially helpful with non-planar surfaces
05:35 PM roycroft: thank you
05:35 PM roycroft: i'm laser shopping at the moment
05:35 PM CaptHindsight: it's easily adapted to work with cutting tools, lasers and even an airbursh https://i.imgur.com/EAF5oPj.jpg
05:35 PM CaptHindsight: an early test on non-planar https://imgur.com/a/NYNWYAX
05:35 PM roycroft: most of the lasers are 12v, and my 3d printer has a 24v power supply, but i decided that i might not always use the laser on that printer, so i think a 12v laser with a power converter is the most flexible thing for me
05:38 PM CaptHindsight: you might want to think about PWM for the laser as well to adjust it's power
05:38 PM unterhaus: I have had a dremel flex shaft for 25 years and never used it before today. Worked for a while and then shaft doesn't engage both ends at the same time
05:38 PM CaptHindsight: it's/its
05:42 PM roycroft: https://www.ebay.com/itm/143221385068
05:42 PM roycroft: i'm looking at items like that
06:27 PM unterhaus: Gene spends more money saving money. I think he could have bought a used high-end router spindle by now
06:28 PM XXCoder: unterhaus: probably can rebuild it to be more proper spindle? lol
06:28 PM unterhaus: Trying to use the $300 ones to machine metal isn't going to work
06:29 PM XXCoder: ie add your own better bearings
06:29 PM XXCoder: redesign casing around it
06:30 PM unterhaus: I have some Moore grinder heads I wish I knew how to run. 30k, 60k, 80krpm
06:30 PM unterhaus: I have the amp too
06:31 PM unterhaus: you swap modules to make them run different speeds
06:32 PM XXCoder: ah misread what you said lol nm
08:25 PM roycroft: well, a laser just shipped to me
08:26 PM roycroft: so that should be interesting and fun
08:26 PM XXCoder: you got good proper NM range goggles?
08:31 PM roycroft: not yet
08:31 PM roycroft: the laser is shipping from china
08:31 PM roycroft: it will take a while
08:31 PM XXCoder: ok. its well worth buying
08:32 PM XXCoder: one that come with laser is bullshit really
08:32 PM roycroft: i need to get some goggles and a power converter, which i'll have plenty of time to do before it arrives
08:32 PM roycroft: my eyes are bad enough as it is
08:32 PM roycroft: i don't want to risk making them any worse
08:32 PM roycroft: so no worries, i'll definitely have good eye protection in time
08:32 PM roycroft: i need to sort out what kind to get still
08:33 PM serp: what kind of laser did you get
08:33 PM XXCoder: :) yeah does it list nm?
08:33 PM roycroft: it's 450nm
08:34 PM roycroft: 4.5W output
08:34 PM XXCoder: so its blue like mine
08:34 PM roycroft: https://www.ebay.com/itm//143138770486
08:34 PM roycroft: that's what i got
08:34 PM roycroft: yes, it is blue
08:35 PM serp: are you building something to run it or attaching it to something already
08:35 PM roycroft: the initial plan is to put it on my 3d printer and see how well it works there
08:35 PM serp: what's the firmware on your printer?
08:37 PM roycroft: marlin
08:37 PM roycroft: folks do this all the time
08:37 PM roycroft: they use the fan control to control the laser
08:38 PM roycroft: my printer is 24v, so i need a 24v to 12v converter, but that's no problem
08:38 PM roycroft: there's an inkscape plugin that will generate the gcode
08:39 PM roycroft: and there are other third-party apps that will generate gcode for lasers connected to 3d printers
08:39 PM roycroft: but if that doesn't work out well for me i'll build something
08:39 PM roycroft: i'm hoping it does, though, so that i can save space
09:19 PM unterhaus: that was nice, the ebay vendor I bought a scale from gave me the pinout for my dro that I bought without looking at the manual which doesn't have a pinout
09:52 PM veegee: Just got this beast from a government surplus auction: https://www.gcsurplus.ca/ic-ci/images/FS530185-963363.jpg
09:53 PM veegee: https://www.gcsurplus.ca/ic-ci/images/530185-963368.jpg
09:53 PM veegee: They don't make em that sturdy anymore
09:53 PM veegee: At least not that I can find for a reasonable price. And definitely need it to be 3 phase
09:55 PM veegee: Also, if anyone is in the giving mood, I know what I want for christmas: https://www.bkprecision.com/products/power-supplies/MR25080
10:49 PM XXCoder: found any interesting cyber monday sale?