#linuxcnc Logs

Sep 16 2021

#linuxcnc Calendar

01:03 AM Deejay: moin
01:13 AM TurBoss: good one
01:13 AM TurBoss: morning
04:24 AM Tom_L: morning
05:38 AM JT-Cave: morning
07:24 AM perry_j1987: morning
07:24 AM perry_j1987: well that was a cool launch yesterday at spaceX
07:30 AM JT-Cave: what did they launch
07:31 AM XXCoder: people
07:47 AM perry_j1987: 4 civilions
07:48 AM perry_j1987: for 3 days
08:42 AM -!- #linuxcnc mode set to +v by ChanServ
09:01 AM CaptHindsight[m]: fdarling: using the same exact kernels or different kernels?
09:01 AM CaptHindsight[m]: or what are you actually comparing?
09:02 AM CaptHindsight[m]: perry_j1987 I thought it was a rocket
09:11 AM CaptHindsight[m]: Did schools stop teaching kids how to blend paint colors? I keep getting printing "experts" asking for RGB pigments.
09:12 AM hazzy[m]: Morning Capt
09:12 AM CaptHindsight[m]: how is the show?
09:12 AM CaptHindsight[m]: last day
09:23 AM CaptHindsight[m]: https://www.grid-logic.com/ slow but dumb simple multi-material powder printer
09:24 AM CaptHindsight[m]: with video https://www.grid-logic.com/opl-3d-printer
09:31 AM unterhausen: one of my design class groups designed a way to separate metals. But the company that sponsored them never did introduce a multi-metal printer as far as i know
09:31 AM unterhausen: separate metal powders
09:33 AM unterhausen: That group won the overall competition and also made a nice video, which for some reason paid $500. Winning the competition netted them nothing but a few minutes in the spotlight at the awards dinner
09:34 AM CaptHindsight[m]: HP had two guys standing in front of a picture of their metal binderjet
09:34 AM unterhausen: I tried to talk them into using 80/20, but they used a really fancy erector set-like material which probably cost more and made it look like a toy
09:34 AM CaptHindsight[m]: their plastic powder printer has been out for a couple of years
09:35 AM CaptHindsight[m]: they use a single hopper to spread powders with no way of quickly changing powder between layers
09:35 AM unterhausen: I am not sure how you make money as a printer manufacturer nowadays, the company in Massachusetts went under recently
09:36 AM CaptHindsight[m]: have to sell the printers with a high margin
09:36 AM CaptHindsight[m]: or make it up in material sales
09:36 AM unterhausen: too much competition, I think
09:36 AM CaptHindsight[m]: HP figured out to sell both for high prices leaving little profit margin for the printer buyers
09:37 AM CaptHindsight[m]: it still like the gold rush
09:37 AM unterhausen: that's always the way it has been, held printers back for 20 years
09:37 AM CaptHindsight[m]: you make the fortune selling picks and shovels
09:38 AM CaptHindsight[m]: I keep telling everyone you have to make your own materials or get them to be commodities
09:38 AM CaptHindsight[m]: but few have the skills
09:40 AM CaptHindsight[m]: there was a thermoplastics manufacturer there that said that their prices are too low
09:41 AM CaptHindsight[m]: they were proud that they sell to medical device manufacturer and they will pay any price for the materials
09:41 AM CaptHindsight[m]: the FDA locks them into the thermoplastic supplier when approved
09:42 AM CaptHindsight[m]: they don't change suppliers since it requires a new approval
09:43 AM unterhausen: too bad amazon doesn't have drone delivery, I would deliver a smack on the head to people complaining about the docs on the mailing list
09:43 AM unterhausen: be the change you want to see in the world
09:43 AM CaptHindsight[m]: 3 stooges eye poke
09:43 AM unterhausen: that costs extra
09:44 AM CaptHindsight[m]: many people suffer from an expressive writing disorder
09:44 AM CaptHindsight[m]: so don't expect docs from open source
09:45 AM unterhausen: I hesitate to complain because there are about 3 people keeping this project alive at any given moment
09:45 AM unterhausen: the wiki is a mess though, not that I trust any of the complainers to do anything fruitful about it
09:46 AM unterhausen: it's tough with constant changes
09:48 AM CaptHindsight[m]: I feel that we should adopt a broken English model
09:48 AM CaptHindsight[m]: you learn by do , or similar
09:49 AM unterhausen: I tried to get wine to work on my computer a while back and it's essentially impossible
09:49 AM unterhausen: and their docs essentially pre-blame you for trying
09:49 AM unterhausen: I suggest copy-pasta their docs
09:50 AM CaptHindsight[m]: for some reason linux distro devs have just gone nuts fixing things that weren't broken
09:50 AM CaptHindsight[m]: some mantra about new is better
09:50 AM unterhausen: that's always been a problem with linux
09:50 AM CaptHindsight[m]: different is better
09:51 AM unterhausen: Oh, so you were happy with our old desktop? Desole
09:51 AM CaptHindsight[m]: but if you understand how linux did work and can work you can build systems that actually work very well
09:51 AM CaptHindsight[m]: Gentoo devs tend to get it
09:52 AM unterhausen: sometimes you have to have a vocabulary of a 12 year old instead of the vocabulary of an 8 year old
09:52 AM unterhausen: seems to be the problem on the mailing list
09:52 AM CaptHindsight[m]: lots of Almost Works distros
09:53 AM roycroft: it is a bit annoying that linux devs change things for the sake of change, but at least the linux distros i work with try to continue being useful and functional when they make changes
09:53 AM roycroft: unlike openbsd, which i used for many many years after bsdi went out of business
09:53 AM roycroft: the openbsd philosophy is that functionality is irrelevant as long as the system is secure
09:53 AM CaptHindsight[m]: I skim the ML looking for interesting topics or just the last couple entries where the problem got solved
09:53 AM unterhausen: what changes for the sake of change are you talking about?
09:54 AM unterhausen: can't go to the last couple of topics because they are talking about how radio stations work or somethign
09:54 AM roycroft: things like systemd :)
09:54 AM CaptHindsight[m]: haha
09:54 AM CaptHindsight[m]: well gene
09:54 AM unterhausen: you can't avoid changes like systemd
09:55 AM unterhausen: never mind, I misunderstood
09:56 AM unterhausen: Gene can't stop himself from posting a user question to the dev list and then has a conversation with himself as he (usually) fixes his problem
09:57 AM CaptHindsight[m]: farm kid in swahili
09:57 AM CaptHindsight[m]: was reading that earlier
09:58 AM unterhausen: the good news is that I don't have to do linux sysadmin much, bad news is when I do I have to look everything up
09:58 AM unterhausen: and the internet is wrong a lot because things change so often
09:59 AM CaptHindsight[m]: writing stuff down is boring, i want to go out and play
10:00 AM CloudEvil: It's a lovely day, go out and play sudoku.
10:01 AM CaptHindsight[m]: https://old.reddit.com/r/CNC/ is interesting since it has lots of non LCNC users
10:02 AM CaptHindsight[m]: Linux is pretty scary to many that are looking at what software to use to run their home built machine
10:02 AM unterhausen: what are grbl users using for stepper drivers?
10:03 AM CaptHindsight[m]: I rarely hear about GRBL and motors >nema17
10:03 AM roycroft: linux is pretty easy to admin, for the most part
10:03 AM roycroft: it's windows that is really difficult to admin
10:04 AM CaptHindsight[m]: so all those tiny stepper drive that plug into RAMPS and similar
10:04 AM unterhausen: linux isn't hard to admin, it's the remembering part that I find difficult
10:04 AM unterhausen: well, on the remora topic on the lcnc forum, there was the blue pill with the converter to attach to a parport bob
10:04 AM roycroft: i started using unix in 1977, and started adminning unix systems in the early '80s
10:05 AM CaptHindsight[m]: I try to avoid software as much as possible but am now doing some development again
10:05 AM roycroft: i've been doing it for a while, which may be a big reason that i don't find it hard to deal with
10:05 AM unterhausen: so they must be hooking up to something that takes step/dir
10:05 AM unterhausen: I did a ton of admin back when I was running a lab with autonomous robots
10:06 AM unterhausen: mostly network stuff
10:06 AM CaptHindsight[m]: unterhausen: all I see with GRBL, I think I have only seen a single youtube with GRBL and servos
10:07 AM unterhausen: oh, it's grblhal, whatever that is
10:08 AM unterhausen: https://forum.linuxcnc.org/18-computer/42276-remora-rpi-software-stepping-using-external-microcontroller-via-spi?start=300#220456
10:08 AM CaptHindsight[m]: they run machines were they don't care about monitoring them while running a program
10:09 AM CaptHindsight[m]: they don't make any changes or adjustments while routing
10:09 AM unterhausen: grblhal looks like a support nightmare
10:09 AM unterhausen: if people thought linuxcnc was hard to set up
10:12 AM CaptHindsight[m]: with LCNC on the Rpi and STM32 or 7i76 and similar the only reason I hear about GRBL is the price of the FPGA cards
10:12 AM CaptHindsight[m]: STM32 blue pill + Chinese BOB is <$25
10:13 AM CaptHindsight[m]: 7i95 is >$100
10:14 AM CaptHindsight[m]: so you have to wonder how low budget are these "cnc machines"
10:14 AM CaptHindsight[m]: usually wooden frames
10:15 AM unterhausen: 7i96, the 7i95 is $250
10:16 AM unterhausen: I suspect a lot of these people drop it quickly or spend a lot of money upgrading
10:16 AM CaptHindsight[m]: the dev that started the Orangepi LCNC project that uses the integrated micro for fast stepping gave up due to the Armbian and u-boot devs making it too difficult to access the memory space for the micro
10:16 AM unterhausen: when it would have been easier to start with a 7i96 and a $25 pc from penn state salvage and surplus
10:16 AM CaptHindsight[m]: so that project just needs a proper u-boot and kernel
10:18 AM unterhausen: remora looks good for my purposes that have very little to do with lcnc
10:19 AM unterhausen: still using lcnc as the motion framework
10:21 AM CaptHindsight[m]: someone was talking about open source automation for factories
10:22 AM CaptHindsight[m]: they didn't understand why a factory would not buy an open source machine or robot
10:24 AM CaptHindsight[m]: https://www.youtube.com/watch?v=V7tgalEHu5g
10:26 AM CaptHindsight[m]: they are all toys
10:31 AM unterhausen: how do I login to libera if I'm already connected?
10:32 AM CaptHindsight[m]: with an IRC client?
10:32 AM CaptHindsight[m]: disconnect and try again?
10:32 AM unterhausen: heh
10:33 AM unterhausen: was trying to avoid that
10:33 AM unterhausen: found it, I think
10:33 AM Rab: unterhausen, you mean like register your username?
10:34 AM Rab: /msg NickServ identify <nick> <password>
10:34 AM unterhausen: I did it, thanks
10:36 AM unterhausen: you don't need the nick if you already changed to the nick you want
10:37 AM Rab: My use case is when libera wigs out and deregisters me and I get stuck with Rab_.
10:39 AM unterhausen: I guess it does both at once with the nick
10:48 AM CaptHindsight[m]: https://www.tomshardware.com/news/raspberry-pi-pico-alternative-gets-a-screen
11:36 AM unterhausen: too bad they didn't copy the footprint
11:37 AM JT-Shop: craigslist reply lol I want to buy it. are you the original owner and is it your final price? I don't check cl mail so let me know at someemail@gmail.com
11:45 AM roycroft: 99.999% of the time that's a scammer/spammer
11:46 AM roycroft: however, i have some throw-away email addresses that i set up, and when i get those kinds of emails i respond from one of the throw-away accounts
11:46 AM roycroft: which i usually end up deleting after the spam starts
11:47 AM roycroft: i'd say it's about 1/2 spam, 1/2 scam, and if i just ignore the scam replies (which usually involve shipping to some random address after receiving a cashier's check), the scammers stop and i can continue using the throw-away address for another round of cl madness
11:54 AM CaptHindsight[m]: https://www.amerimoldexpo.com/
11:54 AM unterhausen: I think when I sold my mom's van I didn't get any useful responses because my price was too low
11:55 AM unterhausen: everyone thought I was a scammer
11:55 AM unterhausen: I suppose I should have asked low bluebook
11:56 AM unterhausen: I just wanted to get rid of it because virginia has property tax on cars
11:59 AM roycroft: i don't get cl posters/purchasers
12:00 PM roycroft: i'm not a marketing person by any means, but when i post stuff on cl it always sells, usually quickly
12:00 PM roycroft: yet i see the same things posted by others for weeks, sometimes months
12:00 PM roycroft: items similar to what i'm selling, quite often
12:01 PM roycroft: it seems i've figure out how to make cl work, and as i just said, i'm not a marketing person
12:01 PM roycroft: so it must not be too hard to figure out
12:01 PM roycroft: why do so many not ever figure it out?
12:03 PM roycroft: part of it it just coming up with a headline that makes sense, good pictures, and describing the item accurately and succinctly
12:03 PM roycroft: it's the headline that makes me wonder about the intelligence of the average cl poster
12:04 PM CaptHindsight[m]: you set the bar pretty high
12:04 PM roycroft: i would post something like "1-1/2hp Porter Cable router"
12:04 PM roycroft: the average cl post will be something like "router", or "1-1/2hp", or "Porter-Cable"
12:04 PM roycroft: usually partially misspelled
12:05 PM CaptHindsight[m]: spelling correctly, grammar, a picture of the actual item in the proper category, what are people supposed to be geniuses? come on!
12:05 PM roycroft: all i know is that when i post something i want somebody to buy it right now
12:05 PM roycroft: and i try to make it as easy for the person who wants it to find it and to know that it's the thing they want
12:06 PM roycroft: i say to myself "if i were looking for something like this, what would the ad say that would make me know it's what i'm looking for?"
12:06 PM roycroft: and then i write that ad
12:07 PM roycroft: absolutely zero rocket science is involved in this process
12:07 PM roycroft: yet the vast majority of cl posters get it completely wrong
12:07 PM roycroft: i guess cl is one of life's little mysteries that will never be solved
12:07 PM CaptHindsight[m]: nah, tool for sale, does stuff, pic of chair next to tool, money only, calls only, no text, see my other ads
12:08 PM roycroft: and that's the other thing i don't get
12:08 PM roycroft: "no emails - too much spam - but here's my cell number"
12:08 PM roycroft: huh?
12:09 PM roycroft: email spam is way easier to deal with than phone spam
12:09 PM roycroft: like 3 orders of magnitude easier
12:09 PM fdarling: CaptHindsight[m]: with LinuxCNC 2.8 and the exact same kernel and version of Debian, one computer has horrible jitter and another doesn't. The difference is one was installed with LinuxCNC 2.8.0 a few months ago, and this one was installed recently with the 2.8.2 ISO. This is why I was asking if there were any other people reporting issues... I need to do regression testing to figure out at what point things broke
12:09 PM CaptHindsight[m]: I get people that won't take pictures of both sides of something so that I can see what it is
12:10 PM fdarling: I need to do a lot more testing involving booting LiveUSBs, installing older LinuxCNC, compiling newer LinuxCNC on it, etc.
12:10 PM roycroft: at the end of the day, when i post my stuff sells
12:11 PM roycroft: and often i post the same item as someone else at a higher price, but mine still sells, and the other post gets renewed forever
12:11 PM roycroft: and i really don't think i'm all that smart when it comes to selling stuff
12:11 PM roycroft: i'm just not a moron
12:11 PM CaptHindsight[m]: they don't even list or post a pic of the tire size when selling tires
12:14 PM CaptHindsight[m]: "Engine has 0 miles, never run" Can you post a pic of the cylinders through the spark plus holes? NO!
12:14 PM roycroft: i sometimes suspect that many of the cl for sale posts are not even legitimate
12:14 PM roycroft: that they're russian spies passing information back and forth via fake cl posts
12:14 PM roycroft: or something like that
12:15 PM roycroft: that's not paranoia on my part - it's looking for an explanation of posts that are so bizarre they can't possibly be real
12:15 PM CaptHindsight[m]: most of the country folks around me are worried about being harvested for organs when meeting a CL seller
12:16 PM CaptHindsight[m]: they always carry when they go to see the air hockey table for $200
12:16 PM roycroft: well that's bullshit
12:16 PM roycroft: we know that's just an excuse to carry
12:16 PM CaptHindsight[m]: and maybe 1-2 shotguns in the car, in case they run into a shootout situation
12:17 PM roycroft: anyway, i'll continue to be puzzled by cl poster behavior
12:17 PM CaptHindsight[m]: no, they read about it on the internet so it is true
12:18 PM roycroft: but it works in my favor, i think, because i don't have much real competition when i sell stuff
12:18 PM roycroft: i don't have the ebay figured out quite as well as the cl
12:18 PM roycroft: sometimes my ebay listings linger for months before the item sells
12:19 PM roycroft: but that's ok
12:19 PM roycroft: it's actually a feature, in a way
12:20 PM roycroft: just the other day i sold a dozen locking chassis mount receptacles that i listed like 3 years ago
12:20 PM roycroft: they weren't taking up much space
12:20 PM roycroft: and it was some unexpected cash coming in
12:21 PM roycroft: which is kind of how i look at most of my ebay listings - if they don't sell right away i remove the income from my budget
12:21 PM roycroft: and when they finally do sell, it's like free money
01:01 PM roycroft: https://www.amazon.com/R2020X6-20-Pitch-Gear-Rack/dp/B07C8D5RH8
01:02 PM roycroft: is that rack likely good enough for a cnc router, assuming i install an anti-backlash pinion system?
01:03 PM roycroft: i go to places like automationdirect.com and look at their fancy helical racks, and feel my wallet going on a crash diet that may well kill it
01:10 PM Rab: "Acme Made" seem to focus on neoprene laptop sleeves, so I would guess the rack is some generic import stuff.
01:11 PM Rab: I see a similar rack from Boston Gear for about twice the price; at least they're a domestic name brand.
01:14 PM Rab: Well, under product details the manufacturer says AMEC. Presumably this AMEC: http://amecind.com/
01:16 PM Rab: Typos all over their site, including in the URLs, but some info for the R2020x6 rack is on the last page of this PDF: amecind.com/pdf/gear.pdf
01:24 PM Rab: Looks like an actual industrial part, possibly made in USA, but not a precision part. You could call AMEC and ask e.g. whether they have a figure for accuracy over 6ft.
01:27 PM Loetmichel: ))()&%"=)$ยง$/&%& MAAAN what a piece of crap car. Just drove 370km in the company beater (Merc E-class station wagon) to and from an exhibition. FOUR times the automatic gearbox crashed and either locked into first gear or neutral until you stop the car, go in park, ignition off, ignition on. VERY funny in roadworks where there is no emergency lane/shoulder. My boss is a cheapass. 20 year
01:27 PM Loetmichel: old car with 300Mm on the odo and no maintenance at all :(
01:27 PM roycroft: with a part like that, inaccuracies would not be cumulative, i should think
01:27 PM Rab: roycroft, say, McMaster has an identical rack for (a few dollars) cheaper: https://www.mcmaster.com/5174T21/
01:29 PM roycroft: but mcmaster would add on shipping to that
01:29 PM roycroft: the amazon link has free shipping
01:30 PM roycroft: but mcmaster have cad drawings
01:30 PM Rab: Complementary gears: https://www.mcmaster.com/racks/metal-gears-and-gear-racks-20-pressure-angle/component~gear/
01:31 PM roycroft: i haven't sorted out the gearing yet
01:32 PM roycroft: this project idea started with belt drive on the y axis, which i felt uncomfortable with from the start, to leadscrew, which is expensive and hard to get in long lengths, and also very slow, to now rack and pinion, which i think is the best choice for a long axis like this (i need 4' of movement along the y, so it will probably be a bit over 5' long total)
01:33 PM roycroft: i'm still figuring out how to set up the drive system
01:34 PM Rab: The Amazon listing is sold by and shipped from "Global Power", which is a storefront name for Beardslee Transmission Equipment Co Inc., who are these folks: https://beardsleetransmission.com/gears/
01:36 PM Rab: So the part seems like it would be legit. You could call Beardslee and ask if they will match their Amazon price+shipping, and that way none of your money will go to Bezos.
01:36 PM roycroft: i might do that
01:36 PM roycroft: i buy from amazon on a regular basis
01:36 PM roycroft: and i feel guilty about it on a regular basis
01:37 PM roycroft: but i like mcmaster, and even though they're a bit more expensive when shipping is calculated, i don't mind paying a small amount more
01:37 PM roycroft: they've always treated me well
01:38 PM roycroft: and it's awesome that they have cad drawings for download for almost all their products
01:38 PM Rab: If this were my project, I would be excited about ripping off Bell-Everman's ServoBelt concept: https://www.bell-everman.com/products/linear-positioning/servobelt-linear-sbl
01:40 PM Rab: McMaster has started showing a shipping estimate, I've noticed. $21.95 for the rack alone, which is 100% more than free but isn't surprising for a 6ft tube going UPS.
01:41 PM roycroft: that's an interesting idea
01:41 PM roycroft: the servobelt, that is
01:41 PM roycroft: and i would be getting two racks, and probably some other parts at the same time
01:42 PM roycroft: the shipping cost would likely amortie out if it were a combined order
01:42 PM Rab: There was a massive thread on PM or CNCzone or somewhere about DIY ServoBelt, with a B-E guy contributing...not sure where that ended up.
01:43 PM roycroft: $25.25 shipping for two racks, for example
01:43 PM roycroft: i'll have a look
01:43 PM roycroft: one of my concerns about a belt drive system is the exposed belt and all the possibilities for disaster with that
01:44 PM roycroft: the servobelt system addresses that problem
01:44 PM Rab: This one, I think: https://www.cnczone.com/forums/linear-and-rotary-motion/59570-forum.html
01:44 PM Rab: Yeah, ServoBelt seemingly solves all kinds of issues with backlash, stretch, belt slap, etc.
01:46 PM roycroft: it will be down to a matter of cost in the end, i suspect
01:47 PM roycroft: even diy servobelt would probably cost more than off-the-shelf rack and pinion, i suspect
01:47 PM roycroft: but i'll spend the time researching it and costing it out before i make any decisions
01:48 PM Rab: Somebody in the thread gave up and went to rack and pinion, so there's that.
01:48 PM roycroft: i started working on this design from the bottom up - the gantry rails and motion control first, then i was going to move on to the gantry, then the z axis
01:48 PM roycroft: but after i started working on it i realised that starting with the z axis and working my way down probably makes more sense
01:48 PM Loetmichel: as long as he didnt go the Chain/sprocket route...
01:48 PM Loetmichel: Chains have unstetic speed
01:49 PM roycroft: and that would give me plenty of time to research servobelt
01:49 PM roycroft: i like rack and pinion because it's so simple and it scales well
01:49 PM roycroft: like scale isn't even a consideration
01:49 PM roycroft: if i needed gantry rails that are 1km long, assuming i could level 1km of rails, it would work as well for that as if they were 1m long
01:50 PM Rab: roycroft, yeah, starting with the spindle and working backwards will let you size everything appropriately for the load.
01:50 PM roycroft: that's what i realized
01:50 PM roycroft: and know what spindle i'll be using, and i know what spindle mounting brack i'll be using
01:50 PM roycroft: so i'll be doing the z axis next
01:51 PM roycroft: which will use a ball screw, because it's a short axis and a ball screw seems the best option for that
01:51 PM roycroft: for x, i'm not sure - i need 2' of working footprint, so it will be ~3' long, and that might be pushing it for a ball screw to be practical
01:52 PM roycroft: but maybe rack and pinion would be approprate for the x
01:52 PM Rab: As long as you have braking.
01:53 PM Rab: Or, I guess, enough hold torque at Z idle.
01:55 PM Rab: But beware the Z axis dropping when the machine is turned off.
02:00 PM roycroft: yes, i'm aware of that problem
02:00 PM roycroft: i think that's more of a problem when using servo motors than stepper motors, no?
02:07 PM JT-Shop: steppers that are not powered up or the coils shorted turn rather easy
03:07 PM Eric_ is now known as unterhausen
03:23 PM unterhausen: I wish they had gotten mint working with python 3, I find debian annoying
03:53 PM roycroft: i don't notice a big difference between debian-based distros, except i'm more used to mainstream debian, and tend to stick with that out of familiarity
03:57 PM Tom_itx is now known as Tom_L
04:05 PM unterhausen: I'm sure if I ever used it a lot I would get used to debian
06:27 PM sync: JT-Shop: motors only produce torque when they move
06:27 PM sync: so shorting them is not a good way to prevent an axis falling
06:27 PM sync: as it will creep
06:28 PM Connor: Motors, or Steppers?
06:28 PM roycroft: that's not true with stepper motors
06:28 PM Connor: Yea. I was gonna say. Shorting out a stepper, will lock them pretty good.
06:29 PM roycroft: that's the basic test to determine which wires should be connected together on a stepper motor
06:31 PM sync: sure, but the same holds true in a bldc motor
06:32 PM sync: shorting only works if the motor generates a current
06:32 PM sync: so it has to be moving
06:35 PM roycroft: that's not been my experience, but ok
06:35 PM roycroft: i'll go relive the experience
06:35 PM roycroft: i may have been on acid when i tested my steppers, and did not know it
06:38 PM sync: if your motor is generating current without moving, you have invented a new source of energy
06:39 PM roycroft: there are magnets in many motors
06:40 PM sync: of course, but having magnets does not give you any current
06:41 PM roycroft: well i'm pretty sure i'm not on acid or any other kind of mind-altering drugs right now
06:41 PM roycroft: if you think otherwise, let me know
06:42 PM roycroft: so if i go get a stepper motor right now and i can short some wires such that it resists moving, then i was likely not on acid when i did that before
06:42 PM roycroft: if there is no effect, then i'm not sure what went on previously
06:42 PM sync: the torque required to move it will increase, but only because it is moving
06:42 PM sync: if it doesn't move, no current is induced
06:46 PM roycroft: so i have a box of stepper motors in front of me
06:46 PM roycroft: each one has four wires - red, black, blue, and green
06:47 PM roycroft: with all the wires hanging loose, i can rotate the motor fairly easily with my fingers
06:47 PM roycroft: if i connect blue to green and black to red i can still turn the motor, but with extreme difficulty
06:48 PM roycroft: if i connect blue to black and green to red i can barely move it
06:48 PM roycroft: if i disconnect all the wires again i can turn it easily
06:49 PM roycroft: i have two other motors in the box - i'm happy to repeat the test with them
06:49 PM Connor: In my experience, DC motors will be braking if you short them out. (Hence a braking resistor). They won't stop a motor dead stop. Steppers, will lock up. I don't know about bldc, probably similar to a DC motor.
06:50 PM Connor: brake, as in SLOW down, or have resistance as the turn, but, not lock up.
06:50 PM sync: they are all the same in the end
06:50 PM sync: roycroft, you simply don't understand
06:51 PM Connor: Whatever. I just know, that short out the leads on a stepper, You can lock it up and keep it from dropping. It's not speculation.
06:51 PM sync: it is, as it has to be moving for it to do so
06:51 PM roycroft: are you telling me i cannot tell the difference between turning almost freely and being almost impossible to turn?
06:52 PM roycroft: i mean, i can understand that my turning the motor by hand is causing movement
06:52 PM sync: no, but you don't seem to understand that the torque you feel is only there because you are moving the motor, if even ever so slightly
06:52 PM roycroft: sure
06:52 PM roycroft: i do get that
06:52 PM roycroft: however
06:53 PM roycroft: the context of this discussion, at least as i understand it, is that a spindle on a z axis can lose position and crash downward due to gravity if power is removed
06:53 PM roycroft: and my response is that it won't
06:53 PM Connor: Right, I think that's all your trying to prevent. Not to maintain accuracy. I would expect to re-home after.
06:53 PM sync: which is not really true, in most cases it will be so slow that you don't notice it, but it will still drop
06:54 PM roycroft: if the dropping of the spindle causes the motor to turn, which induces current that causes the motor to resist the movement, that's fine
06:54 PM sync: _very_ slowly, possibly, yeah, but it still moves
06:54 PM CaptHindsight[m]: move to a lead screw for Z vs ballscrew
06:54 PM roycroft: why?
06:54 PM roycroft: that's just adding friction and inaccuracy
06:55 PM CaptHindsight[m]: if you really want to stop the Z axis with a ballscrew use a brake
06:55 PM roycroft: i don't think it's going to be an issue
06:55 PM roycroft: because a whole heap of cnc routers have been built with ball screws for the z axis
06:56 PM roycroft: and there are not heaps of reports of the spindle sinking and messing up parts or breaking the router
06:56 PM Connor: It's going to depend on the weight of the spindle, the pitch of the ball screw, and the size of the stepper.
06:57 PM roycroft: i'll agree that the motor has to be sized properly to prevent this
06:57 PM CaptHindsight[m]: lets use 10kg, 5mm pitch and nema23 stepper
06:58 PM roycroft: what i was told earlier today is that if i remove power to the machine and i have a ball screw on the z axis my spindle is going to go crashing down
06:58 PM roycroft: and i don't belive that to be the case
06:58 PM roycroft: i can easily accept that there may be some slipping
06:58 PM roycroft: and perhaps a slow, steady descent of the spindle
06:59 PM Connor: If you remove power, and it's not shorted out. Then, yea, it can creep down. It could pick up speed as it falls..
06:59 PM roycroft: but to say that when i turn the power off the spindle is going to drop like a lead balloon i cannot accept
06:59 PM CaptHindsight[m]: is the Z moving up or down when the power is removed and at what velocity?
06:59 PM Connor: Yea, that's based on resistance of torque on the ballscreew and motor, and the weight of the spindle..
07:00 PM roycroft: as well, any controlled power down/power up will involve rehoming
07:00 PM Connor: and pitch.
07:00 PM CaptHindsight[m]: i say let him learn by trying it out for himself
07:00 PM roycroft: yes, there are some things i'll need to learn by trying them out
07:00 PM roycroft: for sure
07:01 PM roycroft: i do try to educate myself as well as possible ahead of time so i can at least anticipate what may happen
07:01 PM fdarling_guest: I am on one of the problematic LinuxCNC 2.8.2 computers. I have figured out the issue -- LinuxCNC (and therefore latency-test) are running without realtime. I have tested realtime with my own app, and I get the expected low jitter. LinuxCNC is giving the following console message: "cannot gain I/O privileges - forgot 'sudo make setuid'?"
07:01 PM roycroft: and make a good prediction
07:01 PM CaptHindsight[m]: https://www.reddit.com/r/3Dprinting/comments/bu5omm/how_do_i_stop_my_z_axis_from_falling_when_the/
07:02 PM roycroft: but for the most part, i should not be powering down in the middle of doing a job
07:02 PM fdarling_guest: however, I did not compile LinuxCNC from the source -- this is straight off the install ISO. In looking at the Makefile, I can see what the setuid command would do: https://github.com/LinuxCNC/linuxcnc/blob/master/src/Makefile#L553
07:03 PM fdarling_guest: however, the permissions on rtapi_app look correct: -rwsr-xr-x 1 root root 106296 Jul 5 17:39 /usr/bin/rtapi_app
07:03 PM roycroft: so this really isn't a big deal, unless it were true that the spindle would come crashing down immediately when power is removed
07:03 PM roycroft: if i'm missing something, please let me know
07:04 PM fdarling_guest: any ideas on what might be causing this issue? Is it perhaps that the iopl(3) call is failing for some other reason?: https://github.com/LinuxCNC/linuxcnc/blob/827de56d20c5fd3dc0c5a30f1a7e0d8151d59f93/src/rtapi/uspace_rtapi_app.cc#L731
07:04 PM fdarling_guest: this wasn't an issue in the past, something is broken with the latest installer or the latest packages in apt
07:05 PM fdarling_guest: (I am completely up to date by the way as far as apt packages go)
07:05 PM fdarling_guest: I tried running LinuxCNC as root as a quick fix, but it guards against that
07:19 PM fdarling_guest: ...any ideas on how to debug the privilege escalation of LinuxCNC?
07:38 PM roycroft: i've not run into that issue, sorry
07:40 PM fdarling_guest: it's happened on two machines recently, installed by two different people
07:40 PM fdarling_guest: both with the latest LinuxCNC installer ISO
07:43 PM roycroft: andypugh would probably be a good person to address that, but he's away on holidays for a couple more weeks or so
07:49 PM CaptHindsight[m]: fdarling_guest: mebe a message to put on the forums
07:56 PM fdarling_guest: I just compiled LinuxCNC 2.8.2 from git, and had the same issue. I commented out the return statement so that it would ignore the iopl(3) call failing, and now it runs with realtime scheduling: https://github.com/LinuxCNC/linuxcnc/blob/827de56d20c5fd3dc0c5a30f1a7e0d8151d59f93/src/rtapi/uspace_rtapi_app.cc#L735
07:56 PM fdarling_guest: so that call is definitely failing, even though otherwise it's able to run in realtime (using elevated permissions obviously)
08:08 PM fdarling_guest: it's failing with errno = EPERM
08:22 PM Tom_L: roycroft, on a large machine you do need to block the spindle on power down if the brake is going to disengage
08:36 PM unterhausen: every time I have to install debian I think they really should just ask some other distro how to do it
08:37 PM unterhausen: I booted from a usb, but it wants a cdrom. No option to use the media I booted from
08:37 PM roycroft: tom_l: i'll look into that
08:37 PM roycroft: and since i've switched from bottom up to top down design, i'll get the z axis designed first, and will be able to construct and test it before i get the gantry and y axis done
08:37 PM fdarling_guest: https://pastebin.com/T08tZaXe
08:38 PM Rab: unterhausen, there might be a way to point it to where the USB drive is mounted.
08:38 PM fdarling_guest: I created a minimal example of using iopl(3) which fails on a LinuxCNC 2.8.2 distribution installation. You can run it as root, run it with sudo, run it as a normal user, it will fail in all cases. It might have something to do with the fact that secure boot is enabled on this PC...
08:38 PM fdarling_guest: however, this isn't any apparent way to disable secure boot in the BIOS
08:38 PM unterhausen: it's a very bad gui with about 10 options, none of which are the usb
08:38 PM * roycroft finds debian to be one of the easiest os to install of any he's ever used
08:39 PM unterhausen: roycroft probably burns a cd
08:39 PM roycroft: i don't know for gui installs of debain
08:39 PM roycroft: i actually install most things in virtual machines
08:39 PM fdarling_guest: I have definitely had the Debian installer fail with being unable to find packages from the repository, not having drivers, setting up GRUB incorrectly, etc.
08:39 PM unterhausen: I think installing lcnc in a vm is a bad idea, but that's just me
08:39 PM roycroft: but i use proxmox pve as my hypervisor, and that is debian based, and i install it from a usb thumb drive
08:40 PM fdarling_guest: you can usually fix it from the console, but the frustrating thing is they skimped on command line utilities, I guess they had to save a few megabytes!
08:40 PM roycroft: i would not install linuxcnc as a vm if it were going to actually control a real machine
08:40 PM unterhausen: I think you just said it was easy to be annoying
08:41 PM roycroft: no, i did not mean to be annoying
08:41 PM roycroft: sorry if i came off like that
08:42 PM unterhausen: the mint install they had set up was fine, just click on an icon on the desktop
08:42 PM unterhausen: I don't think I have ever seen a live cd that didn't have that option
08:44 PM roycroft: i'd have to go check my changelogs, but iirc my linuxcnc installs on computers that i intend to control real machines were done by installing a stock debian from usb thumb drive, then building a real time kernel, then installing linuxcnc
08:44 PM unterhausen: it looks to me like this might be lcnc specific installer
08:45 PM roycroft: that could be, and i don't know that i've ever installed that way
08:45 PM snakedLX is now known as snaked
08:50 PM roycroft: i'll likely be doing a linuxcnc install on a rpi 4 soon - that might prove interesting
08:50 PM XXCoder: yeah
08:52 PM unterhausen: the rpi install was very easy
08:52 PM unterhausen: if you can write an sd card, that is
08:52 PM unterhausen: as soon as I ask what I'm missing about this install on the forum I'll figure it out
08:53 PM unterhausen: standing next to the mill without internet is less than ideal
08:56 PM roycroft: the internet is a pretty flower that smells bad
08:57 PM Tom_L: iirc you will want to uninstall linuxcnc on that rpi iso since it may still be a pre release
08:57 PM Tom_L: then install the newer one from the .deb file
08:58 PM roycroft: i should probably order the rpi before i attempt the install
08:58 PM roycroft: it might work better if i do
08:58 PM Tom_L: you can do the image without it
08:59 PM Tom_L: then plug it into the rpi
08:59 PM roycroft: sure
08:59 PM roycroft: but it would not really gain me anything
09:00 PM roycroft: my primary interest right now is seeing if i can reasonably run linuxcnc on a headless rpi using x11 tunneling over ssh
09:04 PM roycroft: wow
09:04 PM roycroft: now we're forecast for rain starting tomorrow, not friday
09:04 PM roycroft: but 23mm of rain tomorrow, starting at 1pm
09:04 PM roycroft: and another 26mm on saturday
09:07 PM unterhausen: the solution to my problem has been the same for at least a few versions, when it can't read the cd rom, take the usb drive out and reinsert
09:07 PM unterhausen: the devs involved must know about this, it's ridiculous
09:07 PM unterhausen: took a couple of tries, but it worked
09:08 PM roycroft: kyle proved this years ago, when he rebooted the internet
09:08 PM unterhausen: we really need to shut it down until we know what's going on
09:09 PM roycroft: https://www.youtube.com/watch?v=ckIMuvumYrg
09:09 PM unterhausen: the installer has to know what device it's running from
09:20 PM unterhausen: thanks for coming to my ted talk
09:21 PM unterhausen: the livecd also locks the screen without making you set the password, which is very silly
09:35 PM roycroft: i would recommend ditching the livecd at this point
09:35 PM roycroft: it sounds like the current version is not quite ready for prime time
09:41 PM Bleepshop: XXCoder: Got the make/model off the big CNC. It's a Limtech Orion 510. And it's like driving a Rolls... Once you turn on the main bus, fire up the extractor cyclone and air compressor, turn on the CNC power, boot the CNC and then let it spend a couple of minutes homing. LOL
09:44 PM XXCoder: lol
09:45 PM XXCoder: interesting
09:45 PM XXCoder: some picture has it with SBRs
09:45 PM XXCoder: some with MGNs
09:47 PM unterhausen: I got it installed on the hard drive, but the bios is giving me a little trouble
09:50 PM Bleepshop: XXCoder: ?
09:50 PM XXCoder: SBR is supported bar rails
09:50 PM XXCoder: MGN well forgot what full name is but basically rail with flat block on it
09:51 PM Bleepshop: XXCoder: Almost square rail with air bearings.
09:51 PM XXCoder: air bearings interesting. sounds like variant of MGN
09:52 PM XXCoder: https://sc01.alicdn.com/kf/HTB1l96qLpXXXXXtXXXXq6xXFXXXW/222224644/HTB1l96qLpXXXXXtXXXXq6xXFXXXW.jpg_.webp
09:52 PM XXCoder: standard bearing balls one
09:52 PM Bleepshop: At least I'm assumming they're air bearings. Machine won't even come out of E-Stop without 50PSI available.
09:53 PM Bleepshop: That's the rail.
09:53 PM XXCoder: might be postive air pressure brakes let go
09:53 PM XXCoder: ie if no air, it cant get out of braked mode
09:54 PM Bleepshop: I dunno I grabbed a throwaway stain brush from the fininshing department and gave all the rails a going over. Basicly learning what shoud be where.
09:55 PM XXCoder: ypour new job machine correct?
09:55 PM Bleepshop: I do know not to turn the spindle air all the way up unless I want to chase the loc-line tip. LOL
09:55 PM CaptHindsight[m]: https://www.youtube.com/watch?v=l2B12U6NtQw
09:56 PM CaptHindsight[m]: https://www.youtube.com/watch?v=lOTWx69mghM
09:57 PM XXCoder: cool video
09:57 PM XXCoder: whats loc-line tip
09:58 PM Bleepshop: XXCoder: Yeah, Ended up fixing a finish sander when it when on the blink. I dunno if it was a test or if I was really the only one that noticed that one of the sanding belts was misaligned and the LED was glaring past the edge of the belt onto the sensor.
09:59 PM Bleepshop: XXCoder: https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Ftse1.mm.bing.net%2Fth%3Fid%3DOIP.AB7viG-9fvgbV795KPUe4gAAAA%26pid%3DApi&f=1
09:59 PM XXCoder: oh yea
09:59 PM XXCoder: i always forget name of those
10:01 PM Bleepshop: Yeah, I'm pretty much wowwing them over there. I've been pointing out shit that is about to break, fixing shit that is broke and today I suggested stuffing a CANBUS sniffer up the damn sawmill because it keeps wanting to be reset.
10:01 PM XXCoder: honestly, i would just ignore "was this a test" views, and just fix things best as you can
10:01 PM XXCoder: ie just do job :)
10:03 PM Bleepshop: XXCoder: I don't really care either way. It was the owner of the place running the machine for a prototype project and I was in "Get 'er done!" mode. LOL
10:03 PM XXCoder: indeed lol
10:06 PM Bleepshop: It was funny, PLC on the machine refused to init, he got a call, I started popping cleanout access panels looking for jammed shit/etc. Found the belt off track and then had to argue with him that it miight be the problem. "Just try it damn it!" He reseated the belt and boom it was happy.
10:08 PM Bleepshop: I'll be working it over next. The PLC is acting wonky. Might be bad caps, might be full of sawdust, might be full of spiders. LOL
10:08 PM Bleepshop: Thankfully the shopvac will deal with either of those. xD
10:09 PM XXCoder: or iron powder
10:09 PM XXCoder: conductive, can screw with things yet look like dust
10:10 PM Bleepshop: XXCoder: This is a production wood milling operation. Not much iron/steel/aluminum gets cut unless somebody fucks up badly.
10:10 PM XXCoder: true
10:12 PM Bleepshop: Although I may change that in a few weeks when I start making new equipment parts. >:)
10:13 PM XXCoder: i wonder if you could call for 3d printer too
10:13 PM XXCoder: to print some parts
10:14 PM Bleepshop: I've already designed a sanding belt cleaning frame to deal with the fact that they are using the forks on the forklift to stretch the belts around and then having to clean them with the pressure washer section at a time.
10:15 PM XXCoder: sounds very awkward
10:15 PM XXCoder: is your idea automatable?
10:15 PM XXCoder: ie it just slowly rotates though belt though pressure wash line
10:16 PM XXCoder: just open enclosure, place belt on wheels and close
10:17 PM Bleepshop: Yeah, 2 rollers, belt stretched over them, Foot pedal On/Off, Several inches/min feed rate where the guy can peel the bad spots easilly
10:18 PM XXCoder: foot pedal sounds not automated enough'
10:18 PM XXCoder: id add door detect and just a button. its on timer to run though entire belt however many times needed plus little bit more
10:18 PM Bleepshop: We're in a desert. it's cheaper to pay somebody to not waste the water than to pay for the water. LOL
10:19 PM XXCoder: it should be able to reuse water
10:19 PM XXCoder: so only loss is vapor lopss
10:20 PM Bleepshop: Pressure washer would choke, smoke and die on recirulating what comes off these belts. The runnoff is being used to pave a section of the yard.
10:21 PM XXCoder: dont just do plain recycle, filter it and such first
10:21 PM XXCoder: first being sock of fiber filter, then bit more refined
10:21 PM Bleepshop: Large amounts of disolved resins/etc.
10:23 PM Bleepshop: Pine sap is hell on machinery. Microfine White Oak dust is hell on machinery, Ironwood is hell on machinery, Lots of this stuff is just annoying. LOL
10:24 PM XXCoder: lol yeah though is it filterable?
10:24 PM XXCoder: even using water 2 or 3 times longer means large savings, in desert in least
10:24 PM Bleepshop: And then there's the cat demanding attention and trying to hang from my collar.
10:26 PM Bleepshop: Like I said, the runoff is being mixed with sand and sawdust as a paving material. And it's a hell of a lot cheaper than asphalt. LOL
10:26 PM XXCoder: fun
10:27 PM Bleepshop: Part of it is the runoff is used for fire prevention as well. Keep high risk areas damp to keep dust/static down.
10:28 PM Bleepshop: I could fill a dump truck 12--14 times with sawdust if I could find a place to 'lose' it. xD
10:29 PM XXCoder: turn it into fire logs
10:30 PM XXCoder: sell em
10:31 PM roycroft: sawdust is "organic art powder"
10:31 PM Bleepshop: And there's enough bark slabs for several hundred feet of rustic fence and trim waste from the resaw mill where I could roast an elephant every weekend. Lots of wood.
10:31 PM roycroft: advertise it as such and sell it on cl
10:32 PM XXCoder: honestly all you need is fire-safe glue use small amount and build a steel pipe strong welded bottom, and permatics rammer to compact it
10:33 PM XXCoder: boom, production. though maybe bottom should have rammer too so it can push rods of wood out
10:33 PM Bleepshop: Hmm.. I wonder if we could sell it to the Screaming Trees as 'Screams of Trees' ? ;D
10:34 PM XXCoder: lol whatever makes money
10:34 PM Bleepshop: It's "'Certifiably 100% Organic" xD
10:35 PM Bleepshop: Except for the sand and dirt. LOL