#linuxcnc Logs

Nov 29 2021

#linuxcnc Calendar

12:20 AM -!- #linuxcnc mode set to +v by ChanServ
01:37 AM Deejay: moin
03:13 AM randy: morning
04:17 AM Tom_L: morning
05:18 AM JT-Cave: morning
05:18 AM XXCoder: https://youtu.be/Ystj1Y6oxK0
05:18 AM XXCoder: check it out. interesting machine
05:42 AM JT-Cave: bet that is expensive
05:42 AM XXCoder: very likely
07:07 AM unterhaus: the moore I used to use had hydrostatic bearings
07:07 AM unterhaus: could be a pain to maintain it
07:09 AM * CloudEvil wonders about air bearing mouse supplied by the cord.
07:10 AM CloudEvil: Alas almost certainly useless.
07:26 AM unterhaus: it would be better than an oil hydrodynamic mouse though
07:28 AM unterhaus: "the computer is out of oil again"
08:08 AM Loetmichel: *harrrumph* I just checked the Battery voltage of the BMW. 12.4V without ignition... 11,5V idle, 11.7V at 4000RPM... i think that alternator is dead :(
09:04 AM CloudEvil: Loetmichel: Or you have your sick tunez too loud
09:14 AM Loetmichel: CloudEvil: that sholdnt be a problem with a head unit that only has 4*20W ;)
09:23 AM Centurion_Dan1 is now known as Centurion_Dan
10:24 AM bobbytab1es: Loetmichel: It's a BMW so a new alternator is $5k right?
10:37 AM bobbytab1es is now known as bobbytables
11:10 AM solarwind: Hi all, anyone aware of a DC motor servo drive with external amplifier end?
11:10 AM solarwind: What I want is something like this: https://www.geckodrive.com/g320x-digital-servo-drive.html but be able to drive much bigger motors
11:11 AM Loetmichel: bobbytables: the alternator is around โ‚ฌ150
11:11 AM Loetmichel: ... replacing it though... is about dismantling half the engine to get to it...
11:11 AM roycroft: but the labor is $5k :)
11:11 AM solarwind: I can make the power electronics side of it with big mosfets and all, so I just need the control electronics
11:11 AM Loetmichel: :(
11:11 AM solarwind: I wonder if if I can use the gecko G320X armature +/- outputs as a signal source for my power amplifier
11:12 AM solarwind: It wouldn't work if it does back EMF sensing and exotic things like that through the armature +/- outputs though
11:12 AM solarwind: IF it's just a PWM output, it would work just fine
11:12 AM Loetmichel: btw: just had a voltage meter in the cigarette lighter plug on the way home: unless i have the engine above 4000RPM the voltage is slowly falling, above said RPM its slowly rising. So i assume its NOT the regulator but one of the Diodes of the rectifier or one winding shorted.
11:14 AM solarwind: I don't need the step/dir precision. I just need to hold a big DC motor at a certain speed
12:03 PM roguish[m]: solarwind: current, voltage, wattage?????
12:04 PM roguish[m]: solarwind: https://www.ebay.com/itm/265402827947?epid=1613258289&hash=item3dcb3dc4ab:g:PO8AAOSwJr5hjtQr
03:06 PM solarwind: roguish[m] 48V, 30kW
03:06 PM roycroft: folks, i am getting ready to start work on my cnc router, beginning with the z axis
03:07 PM roycroft: a couple months ago i posted a link to a pre-made z axis on amazon, and did not get much feedback from anyone
03:08 PM roycroft: if the one i'm looking at will be reliable and reasonably accurate, i'd really like to just buy it instead of making one from scratch - it will save a lot of time, and probably some money
03:08 PM XXCoder: depends on your time cost
03:10 PM solarwind: roguish[m] thanks for the ebay link, that looks great
03:10 PM solarwind: roguish[m] that actually looks like exactly what I need, solves my problem. Thank you!
03:10 PM roycroft: https://www.amazon.com/dp/B082V3624V
03:10 PM roycroft: that's what i'm looking at
03:11 PM roycroft: and actually, it would probably cost me close to that to buy the parts to make it
03:11 PM roycroft: if not more
03:11 PM XXCoder: roy honestly 150 usd isnt bad
03:11 PM roycroft: i'm just not familiar with those comopnents to know if it's going to be accurate or not
03:11 PM roycroft: yeah - i'm not concerned about the cost at all
03:11 PM XXCoder: whats it say on ballscrew rating
03:12 PM roycroft: other than it's so low it may not work out well
03:12 PM XXCoder: ah c7
03:12 PM roycroft: yes
03:12 PM roycroft: but this is for a cnc router
03:12 PM roycroft: not a high precision mill
03:12 PM XXCoder: yeah c7 isnt bad
03:12 PM roycroft: i'd *like* to hold 0.001", but would be ok with 0.003"
03:12 PM roycroft: but 0.0001" is not even remotely necessary
03:13 PM roycroft: the vertical load is 15kg
03:13 PM roycroft: my spindle will weigh just under 5kg
03:13 PM roycroft: and the motor another kg or so
03:14 PM roycroft: again, i'm looking at probably about that much money just to buy the materials and components
03:14 PM roycroft: not to mention probably 10 hours machining time to make everything fit
03:14 PM XXCoder: indeed
03:14 PM roycroft: if i got that, a vfd, and a spindle, i'd have a z axis for <$500
03:15 PM roycroft: and an hour of assembly time
03:15 PM XXCoder: most of it look strightforward, just dunno on coupler
03:16 PM roycroft: the coupler might not even work with my motor
03:16 PM roycroft: but that's easy to replace
03:16 PM roycroft: and cheap to replace
03:16 PM XXCoder: one complant on garbage bearing
03:16 PM XXCoder: probably usual chineseium thing, chips in bearings. you might want to do a quick rebuild
03:18 PM roycroft: in the end, if it turns out to be crap, i could always get a better one, or build one myself
03:18 PM Loetmichel: roycroft: not to rain into your parade, but play and/or flex is bad. even in a CNC router
03:18 PM roycroft: but i'd prefer to not buy crap if i can help it
03:18 PM roycroft: i'm not parading :)
03:18 PM Loetmichel: i can tell you that you will pay for any of them in broken bits.
03:19 PM roycroft: and sober advise based on experience is not rain, imo
03:19 PM Loetmichel: considering that i operate TWO CNC 6040 i think i am somewhat of an expert in "axis flex" ;)
03:20 PM Loetmichel: that reminds me to buy a new ballscrew/nut for one of the gantrys.
03:20 PM Loetmichel: the older, more worn machine now has twice the bit breaks than the other
03:21 PM Loetmichel: even if they do the same program
03:21 PM roycroft: loetmichel: i'm looking at building a router that can machine parts up to 600mmx1200mm
03:21 PM roycroft: it's going to integrate into an existing router table
03:21 PM roycroft: the plan is to move the gantry way to the back when it's not in use
03:21 PM Loetmichel: hmm
03:21 PM roycroft: and the x axis rails will be flush with the router table top, or slightly below it
03:22 PM roycroft: when doing cnc routing, i would attach a spoil board to the top of the router table and do my thing
03:22 PM Loetmichel: make pivots on the sides of the gantry that you can "unpin" and fold the whole gantry down behind the machine
03:22 PM Loetmichel: so as a suggestion
03:22 PM roycroft: remove the spoil board when done, and i'd be able to go back to using it as a conventional router table
03:22 PM Loetmichel: and use TWO y ballscrews
03:22 PM roycroft: so in my thinking, y is the long axis
03:23 PM Loetmichel: y is the axis which the gantry moves along, yes
03:23 PM roycroft: if i'm standing in front of the machine, x is left to right, and is 600mm wide
03:23 PM roycroft: yes
03:23 PM roycroft: ok
03:23 PM roycroft: so i'm not thinking of using ball screws at all for that
03:23 PM Loetmichel: maybe steal a few ideas from this pic?
03:23 PM roycroft: i'm thinking of a rack and pinion setup for it
03:23 PM roycroft: with motors on both sides
03:23 PM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=11205&g2_imageViewsIndex=1
03:23 PM roycroft: and a ball screw for the x axis
03:24 PM roycroft: yes, that kind of setup is very much what i'm thinking about
03:24 PM Loetmichel: thats a 1700mm by 1200mm by ~280mm travel machine btw
03:24 PM roycroft: and those long ball screws work out ok?
03:24 PM roycroft: my design would be easier and less expensive with ball screws, i think
03:25 PM Loetmichel: yep, they work fine
03:25 PM roycroft: but i was concerned about the length
03:25 PM Loetmichel: only problem is speed
03:25 PM Loetmichel: if you drive them TOO fast they start to oscillate
03:25 PM roycroft: i don't plan on making parts with it
03:25 PM roycroft: i plan on making jigs/fixtures with it
03:25 PM roycroft: so speed is not really an issue
03:25 PM Loetmichel: IIRC critical speed was about 100mm/sec
03:25 PM roycroft: and i should think that the oscillation would mostly be an issue when doing rapids
03:26 PM Loetmichel: yep
03:26 PM roycroft: actually cutting parts it would never move fast enough to be a problem
03:26 PM Loetmichel: and only if the gantry is in the end postions
03:26 PM Loetmichel: in the middle its fine to go faster
03:26 PM roycroft: so even if i were to do small production runs of actual parts, it really wouldn't be an issue
03:26 PM Loetmichel: (shorter "wavelength"
03:27 PM Loetmichel: well, on a table that big you WANT at least 100mm/sec rapits
03:27 PM Loetmichel: or you can drink tea while machining :)
03:27 PM roycroft: the thing is, with my tight space, it would be way better to have the motors on the back end of the machine, inline with the y axis, than having them hang down off the sides, inline with the z axis, which i would need to do with a rack an pinion setup
03:27 PM roycroft: that would allow me to keep the x axis footprint as narrow as possible
03:28 PM roycroft: what is the diameter of your y axis ball screws?
03:28 PM Loetmichel: well, if you look on the picture: the motors on that machine are all INSIDE the machine
03:28 PM roycroft: they look like maybe 18mm?
03:28 PM roycroft: yeah, and inside would not work for me
03:28 PM Loetmichel: 16mmX10mm ballscrews
03:28 PM roycroft: but they could stick out the back end
03:29 PM roycroft: actually, inside might be able to work
03:29 PM roycroft: if i mount them at the rear
03:29 PM roycroft: and my motors are mid-size nema 23
03:29 PM Loetmichel: yeah, same on that pic
03:29 PM Loetmichel: all the steppers are identical Nema23
03:29 PM roycroft: i'm a little concerned that they may not have enough power to direct drive the screws
03:30 PM roycroft: but if i mount them inside and do gear reduction they should be fine
03:30 PM Loetmichel: well, as you can see i even had them geared UP, not down to drive the y
03:30 PM roycroft: so this is great - you've given me some ideas about the y axis that could work out very well
03:30 PM Loetmichel: they had more than enough torque
03:30 PM roycroft: i'll start with 1;1 and see how it goes
03:31 PM roycroft: but did you look at my link to the pre-made z axis?
03:31 PM Loetmichel: yeah
03:31 PM roycroft: is that going to be ok, do you think?
03:31 PM Loetmichel: i am not a fan of "free flying" linear rails
03:31 PM Loetmichel: at least use SBRs
03:31 PM Loetmichel: much more rigid
03:31 PM roycroft: again, it's a 5kg or so 80mm spindle, and a nema 23 motor (for now) that probably weighs another kg
03:32 PM Loetmichel: the problem isnt weight
03:32 PM Loetmichel: its dynamic load/flexing because of mill bit load
03:32 PM roycroft: so it's going to want to twist?
03:32 PM Loetmichel: yes
03:32 PM roycroft: what if i stare at it very very hard and shout *STAY!*?
03:32 PM Loetmichel: and if it can it WILL ripp the mill bit apart because it "digs in"
03:33 PM Loetmichel: dont think that'll work
03:33 PM Loetmichel: and even if it does: do you really want to sit there and stare angry at the machine every time it runs?
03:33 PM roycroft: and i'll probably be using small cutters
03:33 PM Loetmichel: or start it and do something useful while it runs?
03:34 PM roycroft: as they'll work more efficiently for what i'm doing
03:34 PM roycroft: but they're also more easily damaged
03:34 PM roycroft: i actually plan on starting it up and walking away to do other things while it's running
03:34 PM roycroft: because i can't afford to stare at it the whole time
03:35 PM Loetmichel: yeah, i usually order about 20 2mm twoflute tungsten carbide mill bits a month for the two CNC 6040
03:35 PM Loetmichel: when they run all month
03:35 PM Loetmichel: i do mostly alu and brass though
03:35 PM roycroft: this is why i am so interested in installing a light tree on the machine, so i can monitor the status from across the shop
03:35 PM Loetmichel: <- has webcams on his machines
03:36 PM roycroft: i'd like to do non-ferrous metals, but the primary use (initially at least) will be machining manufactured wood products - mdf and plywood
03:36 PM Loetmichel: Its a Linux PC controlling it after all
03:36 PM Loetmichel: ;)
03:36 PM roycroft: my intent is to use a rpi4 to run linuxcnc, with a mesa 7i96
03:36 PM roycroft: hopefully that will work out well
03:36 PM Loetmichel: https://www.youtube.com/watch?v=9u_ChO1AKYY
03:38 PM * CaptHindsight[m] takes solarwind soldering iron away for 2 weeks
03:38 PM roycroft: i'm not sure i need a webcam on it
03:38 PM solarwind: CaptHindsight[m] you mean my JB CD-B? D:
03:38 PM solarwind: JBC* CD-B
03:38 PM Loetmichel: VERY useful to see if anything goes wrong AND work all the while
03:38 PM solarwind: I need to get some more tips for it
03:39 PM roycroft: so you find that the wooden gantry is stiff enough for your router?
03:39 PM Loetmichel: yeah, its not really "wood"
03:39 PM Loetmichel: its "siebdruckplatte"
03:39 PM CaptHindsight[m]: solarwind: 625A 48V DC servo driver?
03:39 PM roycroft: yeah, i actually bought a miniature easel a year or so ago so that i can use my ipad in the shop for watching youtube videos and the like while i'm working
03:39 PM Loetmichel: basically 13 layer plywood glued with a waterproof resin
03:39 PM roycroft: i could use that to monitor a webcam
03:40 PM Loetmichel: its more fibre reinforced plastic than wood
03:40 PM roycroft: hm
03:40 PM roycroft: i wonder if i could fabricate something like that
03:40 PM roycroft: i have a giant vacuum bag that i use for laminating/bending wood products
03:40 PM Loetmichel: AFAIK its sold as "marine plywood" in the US
03:40 PM Loetmichel: mostly used for truck beds and stuff like that
03:41 PM roycroft: i was going to use aluminium for the gantry sides and the x axis
03:41 PM roycroft: really thick aluminium
03:41 PM Loetmichel: look at the picture again: its not about "thick" its about "boxes"
03:41 PM roycroft: but that is expensive, moreso these days, and a bit harder to work with than wood
03:41 PM roycroft: yes, a torsion box would work well
03:41 PM roycroft: although it would make the x axis wider
03:42 PM roycroft: and that's a bit of a problem
03:42 PM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=11172&g2_imageViewsIndex=1
03:42 PM Loetmichel: same gantry from the back, missing the lid of the box though
03:43 PM Loetmichel: the side walls are also torsion boxes
03:44 PM Loetmichel: and the ground plate has a ton of walls inside
03:44 PM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=4053
03:45 PM Loetmichel: there are reasons for that.
03:45 PM Loetmichel: mainly that this was my eight CNC machine build. "learning by failure" or something ;)
03:46 PM CaptHindsight[m]: polymer concrete/granite's are pretty easy to work with, do people shy away from it since they don't know how to square the machine or just that it's messy?
03:47 PM Loetmichel: CaptHindsight[m]: price probably
03:47 PM Loetmichel: its EXPENSIVE
03:47 PM Loetmichel: also the finshed ting is not "easily moveable"
03:47 PM CaptHindsight[m]: https://www.youtube.com/watch?v=4aBVAbfxLJw for example
03:48 PM CaptHindsight[m]: Loetmichel: ah expense and people want to move the CNC mill around
03:59 PM -!- #linuxcnc mode set to +v by tantalum.libera.chat
04:00 PM Loetmichel: CaptHindsight[m]: well, the CNC in the pictures were about 300kg "wood"... not exactly lightweight either
04:01 PM roycroft: can i assume that gravity is my "anti-backlash" mechanism on a z axis?
04:01 PM roycroft: and did you see my previous questions, loetmichel, or were you split?
04:04 PM Loetmichel: no, i did not
04:04 PM Loetmichel: and gravity isnt a reliable anti backlash at all
04:04 PM Loetmichel: use ballscrews on all axis
04:05 PM aaroncnc: ballscrews are not always zero backlash.
04:06 PM CaptHindsight[m]: roycroft: unless you can move your Z fast enough to float it
04:07 PM CaptHindsight[m]: I've used the polymer anti backlash nuts on Z axis lead screws, it all depends on your requirements
04:08 PM CaptHindsight[m]: https://www.thomsonlinear.com/en/products/lead-screws/xc
04:09 PM CaptHindsight[m]: ^^^ nuts are used here https://i.imgur.com/CN4e4F1.jpg
04:10 PM CaptHindsight[m]: in action https://i.imgur.com/zKNtBAg.mp4
04:12 PM Loetmichel: CaptHindsight[m]: my CNC at home has Acme leadscrews and nylon nuts
04:12 PM Loetmichel: works but has quite a bit of wear
04:15 PM roycroft: yes, my plan is to use a ballscrew on the z
04:15 PM roycroft: anyway
04:15 PM roycroft: the questions i had that you missed
04:15 PM roycroft: 1. did you center the z axis between the front and rear gantry bearings?
04:16 PM roycroft: 2. are your y axis linear rails 16mm?
04:16 PM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=14034&g2_imageViewsIndex=1
04:16 PM Loetmichel: I have centered the SPINDLE collet between the gantry bearings
04:16 PM roycroft: since your machine is approximately the size of the one i'm going to build i figure you would have a good idea how to size the linear motion conponents
04:16 PM roycroft: yes, that's what i mean
04:16 PM Loetmichel: hence the "slanted" side walls
04:16 PM roycroft: i consider the z axis the centerline through the spindle
04:17 PM Loetmichel: the SBRs are 20mm
04:17 PM roycroft: and that's what i was planning to do
04:17 PM roycroft: ok, good to know
04:17 PM roycroft: sbrs are not that expensive - i can go 20mm on mine
04:17 PM Loetmichel: yeah
04:17 PM roycroft: what about x and z? are they also 20mm?
04:17 PM Loetmichel: but keep in mind that they are usually NOT straight
04:18 PM Loetmichel: get a good machine ruler and shim them until they are
04:18 PM roycroft: yes, they will have to be straightened
04:18 PM Loetmichel: x yes, Z cant remember
04:18 PM roycroft: i want about 150mm of z travel
04:18 PM Loetmichel: should be ok with 16 or 12mm sbrs for Z
04:18 PM roycroft: more would be nice, but the more z travel, the taller the gantry, and the more wiggling
04:19 PM roycroft: i'm thinking about your torsion box design
04:19 PM Loetmichel: not wiggling but longer lever= more boxes needed to prevent flex
04:19 PM roycroft: a lot of folks who build routers this size use 1"/25mm thick aluminium for the gantry sides
04:19 PM roycroft: and that gets expensive, and is a pain to machine
04:19 PM Loetmichel: yeah, 8mm alu is enough
04:19 PM roycroft: but i could build torsion box gantry sides out of 3/8"/9mm aluminium
04:20 PM Loetmichel: if you make it double and put 30mm of side walls in between ;)
04:20 PM roycroft: two layers thick, with maybe 1"/25mm of side walls
04:20 PM Loetmichel: the inner side isnt getting any forces anyways
04:20 PM roycroft: isn't it getting the racking force of the x axis beam?
04:20 PM Loetmichel: yeah, sounds approbiate
04:21 PM Loetmichel: i meant the hollow INSIDE the side wall torsion boxes dont get any forces anyway
04:21 PM * roycroft would have no problem machining 3/8" aluminium plate
04:21 PM roycroft: oh, yeah
04:21 PM Loetmichel: so why waste material there?
04:21 PM roycroft: the inside
04:21 PM roycroft: not the inner sides
04:22 PM Loetmichel: yep
04:22 PM Loetmichel: my bad
04:22 PM roycroft: you've given me a lot of good ideas today
04:22 PM roycroft: and perhaps i'm a fool, but i think i know you fairly well and trust your judgement in context
04:22 PM Loetmichel: you are welcome
04:22 PM roycroft: i would not say you're "cheap"
04:22 PM Loetmichel: enough if one stumbles blindly around ;)
04:22 PM roycroft: but you're frugal
04:23 PM roycroft: you seem to find the least expensive way to get something done properly
04:23 PM roycroft: you might sacrifice safety at times when doing so, but that's not an issue in this context
04:23 PM Loetmichel: as i said: trial and error
04:23 PM roycroft: yes, and you've done the trials and errors already :)
04:23 PM roycroft: i'm hoping to avoid as much error as possible
04:24 PM roycroft: but i anticipate that my first cnc router build will not be the final build
04:24 PM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=2859&g2_imageViewsIndex=1 <- that was my first CNC built. about '98 or so
04:24 PM roycroft: i just want to get it as close as possible to the final version
04:24 PM Loetmichel: -t+d
04:24 PM Loetmichel: learned a bit since then :)
04:24 PM roycroft: wow
04:24 PM roycroft: proxxon spindle and everything
04:24 PM roycroft: that does look rather dated
04:25 PM Loetmichel: 1998
04:25 PM Loetmichel: it IS dated
04:25 PM roycroft: that predates public availiabity of emc2 even
04:26 PM roycroft: availability, rather
04:26 PM Loetmichel: yeah, it used a dos software called PCNC
04:26 PM roycroft: that word is hard to type toay
04:26 PM roycroft: today
04:26 PM roycroft: all words are challenging for me to type any day :)
04:26 PM Loetmichel: and that box under it was a 486/33 IIRC
04:27 PM roycroft: hanging out here for a decade has prepared me fairly well for my first cnc build
04:27 PM roycroft: at least i hope so
04:28 PM roycroft: i have the money to do the build properly
04:28 PM roycroft: but i don't have the money to do it again right after :)
04:29 PM roycroft: using sbr rails would simplify things a lot and lower the cost a lot
04:29 PM roycroft: especially if i mount them directly to the router table, and don't have to add aluminium extrusion side rails
04:30 PM roycroft: sbr20 rails 1800mm long are US$135 each
04:30 PM roycroft: so $270 and i have my y axis done as far as the rails and mounts
04:32 PM roycroft: add another $200 for a pair of ball screws, a bit more for miscellanous stuff, and i should be able to build the complete y axis for $600 or so
04:32 PM roycroft: i already have stepper motors and gecko drives
04:33 PM Loetmichel: dont forget a sync belt to connect the two gantry ballscrews
04:33 PM roycroft: o
04:33 PM roycroft: i'm going to make y a 2 joint axis, and use two stepper motors
04:33 PM Loetmichel: just saying, the last machine i build died when the new owner managed to kill one stepper driver and said belt broke after a while
04:33 PM Loetmichel: gantry ripped apart
04:34 PM Loetmichel: (one side of the gantry moving, the other one not)
04:34 PM roycroft: hmm
04:35 PM roycroft: best to not kill a stepper motor/driver
04:35 PM roycroft: i wonder if i could come up with a sensor to detect that and do an e-stop
04:35 PM Loetmichel: that was not the problem
04:36 PM Loetmichel: the problem was that the cheap fuck was to cheap to call me and just continued to work with one side driven the other side only connected by the sync belt
04:36 PM Loetmichel: until that one broke
04:37 PM roycroft: i'd need double shaft motors to do a sync belt like you're suggesting
04:38 PM roycroft: i've not heard of doing that with two motors on the same axis
04:38 PM roycroft: folks seem to either use a single motor to drive both screws, or two motors that are not connected together
04:39 PM roycroft: the gantry ripping apart would not be a good thing
04:40 PM roycroft: i figured that if one of the motors or drivers stopped working, the gantry would be rigid enough to overcome the resistance of the non-functioning stepper motor, and would just move the other ball screw itself
04:40 PM roycroft: maybe i'd miss some steps
04:40 PM roycroft: but i did not think that the gantry would rack and self-destruct
05:57 PM * JT-Shop disassembles a 1x4 framed table and repurposed it as a small table for the air dryer
05:59 PM CaptHindsight[m]: yeah solarwind:
06:07 PM CaptHindsight[m]: JT-Shop:
06:07 PM CaptHindsight[m]: Mesa US โ€“ CNC Motion Cards in Google search ๐ŸŽ†
06:11 PM CaptHindsight[m]: comes in on top mesaus.com
06:12 PM XXCoder: capt nice hope it means jt gets more customers
06:13 PM CaptHindsight[m]: he has only me to thank
06:13 PM Tom_L: :D
06:14 PM XXCoder: lol ok
06:14 PM CaptHindsight[m]: ๐Ÿคญ
06:57 PM solarwind: Thanks, I'll take a look at their servo driver
06:57 PM solarwind: I want to provide my own power amplifier stage
06:58 PM CaptHindsight[m]: what part are you looking for?
06:58 PM solarwind: So if the servo driver has logic level PWM outputs, or even better, MOSFET gate drivers, that's perfect
06:58 PM solarwind: CaptHindsight[m] just want a basic DC servo driver but without the power mosfets
06:58 PM CaptHindsight[m]: 2 pole or three phase?
06:58 PM solarwind: brushed DC
06:59 PM CaptHindsight[m]: oh so just use a smaller one to drive a bigger one
06:59 PM solarwind: smaller what to drive a bigger what?
06:59 PM CaptHindsight[m]: bi-directional or homo-directional?
06:59 PM solarwind: doesn't have to be bidirectional
07:00 PM solarwind: like that gecko g320x would be perfect if I could provide my own power amplifier stage to drive a 30kW motor
07:00 PM CaptHindsight[m]: how about a Mesa card with PWM out or an LPT card and BOB?
07:01 PM solarwind: that may work. This is mostly to hold a large DC motor at constant velocity. Imagine replacing an internal combustion engine with a governor with a DC brushed motor
07:01 PM CaptHindsight[m]: lm555 timer and pot
07:01 PM solarwind: AC induction motor with a VFD would also work
07:01 PM solarwind: Yeah this really doesn't need the sophistication of a servo drive
07:01 PM CaptHindsight[m]: *duino with PWM out
07:01 PM solarwind: This is for a friend who really really wants to use a brushed DC motor
07:02 PM solarwind: if it were me, I'd use an AC induction motor and a VFD
07:02 PM CaptHindsight[m]: I have a bunch of brushed servos with tachometers
07:02 PM solarwind: purpose is to drive a hydraulic variable piston pump
07:02 PM solarwind: so high inertia, slow response time is perfectly ok
07:03 PM solarwind: microcontroller with PWM out should be more than enough actually
07:03 PM CaptHindsight[m]: STM32 blue pill with PWM and PID
07:03 PM solarwind: yeah that's probably what I'll end up making for him
07:04 PM CaptHindsight[m]: glad to of helped since NOBODY else did, ok let me send you my paypal for contributions
07:05 PM CaptHindsight[m]: I have moved to a free question format with guilt on top
07:05 PM * Tom_L gives CaptHindsight[m] credit for just being here
07:05 PM CaptHindsight[m]: guilt and or shame
07:06 PM Tom_L: must have eom bills coming up...
07:06 PM solarwind: I told him I'll make it for him with an STM32 and all that, on the condition that I throw in some triple half bridge configuration 2,300V IGBT modules in the digikey order lol
07:07 PM CaptHindsight[m]: if they have stm32's
07:07 PM CaptHindsight[m]: are they actually in stock?
07:07 PM solarwind: I already have the EE side ready and figured out
07:08 PM solarwind: I have STM32 and PIC microcontrollers on hand. Sooooo many of them
07:08 PM CaptHindsight[m]: best way to get stm32's now is to order them on a small board from China
07:08 PM solarwind: Fun fact: Microchip gives free samples of PIC MCUs
07:08 PM CaptHindsight[m]: PIC, you must be old or foolish
07:08 PM CaptHindsight[m]: well nobody wants to buy them anymore
07:08 PM solarwind: Microchip deserves a gold medal for the quality of their datasheets
07:08 PM solarwind: why?!?
07:08 PM solarwind: I've been using PIC for over 10 years
07:08 PM CaptHindsight[m]: old tech now
07:09 PM CaptHindsight[m]: sure old habits
07:09 PM solarwind: They work perfectly fine and they're very cost effective and highly available
07:09 PM CaptHindsight[m]: have you considered helping with remora?
07:09 PM solarwind: I use STM32 as well, but PIC is great
07:09 PM Tom_L: yeah they had to buy atmel just to keep up
07:09 PM solarwind: Arduino/atmega is worse
07:10 PM solarwind: atmega328p is a piece of junk compared to any PIC
07:10 PM Tom_L: no not really
07:10 PM solarwind: look at the vast array of peripherals PIC comes with vs the atmega
07:10 PM Tom_L: paged memory
07:10 PM solarwind: that's fine
07:10 PM solarwind: I have a C compiler
07:10 PM Tom_L: so did i
07:11 PM solarwind: it's a non issue
07:11 PM solarwind: and MIPS M4K on the PIC32 is nice
07:12 PM Tom_L: all i used was the midrange ones
07:12 PM CaptHindsight[m]: solarwind: which one is the 400w motor vs 350W motor, hint one is Chinese? https://imgur.com/Vo7s0Et
07:12 PM solarwind: PIC18 is a solid chip
07:12 PM solarwind: it does so many things and the pricing is excellent
07:13 PM solarwind: you just need a breadboard and 0.1ยตF decoupling capacitor to get started
07:13 PM solarwind: And the documentation is soooooo goood
07:13 PM solarwind: Linear Tech and Microchip have the best documentation by far. No one else comes close
07:13 PM solarwind: ST is a nightmare
07:14 PM CaptHindsight[m]: not as bad as TI
07:17 PM solarwind: also the piclist mailing list was amazing. Back when I was in university and poor, they donated oscilloscopes and things like that to me
07:17 PM solarwind: I don't think I would have gotten this far without all their help
07:18 PM solarwind: Microchip even sent me a REAL ICE for free. I just called them and asked, it was that easy
07:20 PM CaptHindsight[m]: ๐ŸŽป
07:21 PM solarwind: The big one is the 350W continuous rating motor?
07:22 PM solarwind: Unless water cooled, not sure if the small one can pull off either 350W or 400W continuous
07:22 PM solarwind: I have a 2.2kW spindle on my CNC router and it's very compact, but water cooled
07:22 PM CaptHindsight[m]: ๐Ÿ””
07:23 PM CaptHindsight[m]: you win!
07:23 PM solarwind: I can see a permanent magnet motor of that size being able to do 400W continuous
07:24 PM solarwind: AC induction? Unless very high efficiency design, not sure if they can pull it off
07:25 PM solarwind: oh my bad, it is a DC motor. Brushed right?
07:26 PM CaptHindsight[m]: both are brushed DC
07:27 PM solarwind: Yeah no way in hell the small one is actually 400W continuous. Does it even have permanent magnets?
07:27 PM CaptHindsight[m]: Chinese power watts
07:28 PM CaptHindsight[m]: https://i.imgur.com/kXfWYsx.jpg
07:28 PM CaptHindsight[m]: I forgot how I even got it
07:28 PM CaptHindsight[m]: it must have come with something else
07:28 PM solarwind: The water cooled induction spindles are decent though
07:28 PM solarwind: It came with my 6040 CNC router
07:29 PM solarwind: For the price I paid for the whole kit at the time, it's all very good
07:29 PM CaptHindsight[m]: I have a Chinese router motor at 225W that is 3x the size
07:29 PM solarwind: Don't even need to pump water through the spindle for light tasks like routing PCBs
07:30 PM CaptHindsight[m]: i have a bunch of 300-500W brushed DC servos with tachs on them
07:31 PM CaptHindsight[m]: i think they are all old machine take offs
07:32 PM solarwind: Yup, old, big, overbuilt always worth saving
07:32 PM solarwind: That 1969 allis chalmers original engine... the fact that it still starts up on the first crank even in winter amazes me.
07:33 PM solarwind: I mean you needed to manually choke, but I put a servo on the choke and a stepper motor on the mixture control connected to my onboard computer.
07:34 PM solarwind: It works every time. I'll probably make it EFI with exhaust gas sensors this summer.
07:36 PM CaptHindsight[m]: rusefi is already done
07:36 PM solarwind: Yeah that's the plan
07:36 PM CaptHindsight[m]: uses stm32
07:37 PM solarwind: as long as it's not arduino
07:38 PM solarwind: I really need to put one of those webasto coolant heaters on my Jeep. I hate these Canadian winters
07:39 PM solarwind: it's manual, so it doesn't have auto start. A coolant heater should also eliminate any engine startup wear and let me use 10w-30 instead of 5w or 0w
07:42 PM CaptHindsight[m]: if you moved to Mexico ....
09:35 PM roycroft: i know it's the middle of the night in the uk, so most of the brits will be sleeping, but i wonder if anyone knows if tumico calipers are decent quality or not
09:40 PM Tom_L: Scherr-Tumico is a Minnesota company
09:41 PM Tom_L: https://www.hobby-machinist.com/threads/repair-of-scherr-tumico-dial-caliper.21440/
09:43 PM roycroft: that's interesting, as all the used tumico calipers i've run across are in the uk
09:43 PM Tom_L: not on the top 10 best list
09:44 PM roycroft: i don't know that i need this, but i'm thinking of ways to ensure that the two rails on the y axis of my cnc router are parallel
09:44 PM roycroft: a 36" caliper might be a useful tool for that
09:45 PM roycroft: and i'm finding used tumico calipers for about 1/3 to 1/2 the cost of used starrett
09:45 PM Tom_L: sounds expensive
09:45 PM roycroft: vernier, not dial
09:45 PM roycroft: but yes, they're expensive
09:45 PM Tom_L: go no go might be just as good with a feeler gage
09:45 PM roycroft: i can get a 36" tumico for <$150 delivered
09:45 PM roycroft: which makes it a possibility
09:45 PM roycroft: used starretts go for $400+
09:46 PM roycroft: not worth it
09:46 PM roycroft: but yeah, there are other ways to ensure parallelism
09:46 PM Tom_L: i'd make a tool and use feeler gage
09:46 PM Tom_L: basically free
09:46 PM roycroft: yes
09:47 PM roycroft: a 36" caliper may come in handy in the future, though
09:47 PM roycroft: if it's of decent quality
09:47 PM Tom_L: i've never had a need for one
09:47 PM Tom_L: and takes up space
09:48 PM Tom_L: i do have some decent rulers but still not 36"
09:48 PM roycroft: well i'm not looking for an excuse to get one
09:48 PM roycroft: i'm just looking at options
09:48 PM roycroft: i have a 36" starrett rule, and a 72" spi rule
09:49 PM roycroft: and i've used each several times
09:49 PM roycroft: the 36" starrett on a regular basis
09:50 PM Tom_L: other option is to float one side of the rail
09:51 PM Tom_L: one side cradled in a channel and the other not
09:51 PM roycroft: that is something to consider