#linuxcnc Logs

Oct 29 2023

02:30 AM Deejay: moin
04:40 AM Hermann: Hi i have some servoes setup to step_type 2(quadrature step signal) what are the STEPSPACE and STEPLEN to be set at? Mesa 7i76e
04:56 AM JT-Cave: morning
04:56 AM JT-Cave: Hermann, depends on your stepper driver
05:08 AM Hermann: i cant really find anything in the datasheet(chineese aasd servos) i would to reach 2500 mm/m max vel, the lead is 5mm pitch that equates to 2500/5 = 500 rpm? 500 * 10k steps per rev
05:08 AM Hermann: or am i completely wrong?
05:13 AM jpa-: if it is https://www.machsupport.com/forum/index.php?action=dlattach;topic=33543.0;attach=44811 then it says maximum input pulse frequency 500 kHz
05:14 AM jpa-: which gives you 1000ns STEPSPACE and 1000ns STEPLEN
05:15 AM jpa-: and yeah, 500 rpm is 83 kHz step rate so well within specs
05:16 AM Hermann: thanks jpa-
05:26 AM rmu: does STEPSPACE and STEPLEN even make sense with quadrature inputs?
05:27 AM jpa-: rmu: hmm? to me that manual appears to specify normal step + direction input
05:27 AM jpa-: oh, it has selectable mode
05:29 AM jpa-: i guess stepspace/steplen still make sense in that they specify the maximum frequency of changes
05:29 AM jpa-: but i haven't used quadrature stepgen mode myself
05:31 AM rmu: PCW can probably answer that or a look into the firmware but you dpn't need stepspace / steplen with quadrature signals
05:53 AM Tom_L: morning
05:56 AM Tom_L: 33°F
06:06 AM JT-Cave: 47°F
06:13 AM jpa-: ah, i missed Hermann's first message talking about quadrature
06:15 AM jpa-: no harm setting them though, even if they get ignored
07:22 AM JT-Cave: rooster just crowed in the cold rain
07:27 AM JT-Cave: damn rain is cold
09:02 AM Unlogic: Hi, there seems to be something wrong with the auto login feature on the forum. I've noticed over the past days that even if I tick the checkbox to remember my login it never works after the session has expired.
09:02 AM Unlogic: Today when I visited the forum it wasn't logged in automatically and it displayed a warning about a recent failed login attempt. When I tried to login the forum blocked me and all I get is the following message "Your IP address has been blocked because there were too many unsuccessful login attempts in a short time.". I suspect this is due to the
09:02 AM Unlogic: automatic cookie based login failing silently in the background.
09:04 AM pcw-home: Hermann: The steplen settings still bound the minimum timings in quadrature mode so shoud be set short enough that they do not bound your maximum step rate
01:21 PM -!- #linuxcnc mode set to +v by ChanServ
02:34 PM JT-Shop: nice my GM bi-directional scan tool was delivered today to someone's front porch
02:34 PM roycroft: first test print of the mounting bracket was great
02:34 PM roycroft: the dimensions are spot on
02:35 PM roycroft: i have a little tweaking of the extrusion rate to do, and still haven't done the filleting of the part, but getting dimensions right is always great
02:36 PM JT-Shop: got the front tire changed but I need to rebuild the forks and replace the brake pads before riding oh and the rear tire
02:44 PM solarwind: I have an Oster Classic 76 hair clipper, and I'm fascinated with every aspect of its mechanical design
02:45 PM solarwind: It's powered by a universal motor, has a gearbox with a worm gear drive to oscillate the blade
02:46 PM solarwind: The arm that oscillates the blade back and forth is made out of some kind of translucent polymer and seems to have outstanding wear resistance
02:46 PM solarwind: Any guesses as to what it's made of?
02:46 PM solarwind: https://www.barberdepots.com/wp-content/uploads/2013/10/oster_lever.jpg
02:47 PM solarwind: it has a perfect fit on the metal shaft it rotates on and I've intentionally left this thing turned on for 24h and can see zero wear on this part
02:48 PM solarwind: The square end directly interfaces with a notch in the hardened steel blade to move it back and forth. I'd think for sure this would round off the edges. But nope, it's like new
02:48 PM solarwind: I've replaced the gearbox grease with my own #00 ish grease made from superlube with PTFE
02:49 PM solarwind: From load testing, the motor and gearbox take about 35W while idling and 40W with the blade on. So it's only dissipating ~5W into the blade as friction, which isn't much. But it still feels like this part should wear for how fast the blade oscillates
02:51 PM solarwind: It feels like a very hard material, maybe some kind of thermoset resin. I'm afraid to call it "plastic" because I have no idea what it's made of
03:01 PM Unlogic: I'm still locked out from the forum with the message "Your IP address has been blocked because there were too many unsuccessful login attempts in a short time.". If anyone has the ability to remove my IP from the blocklist it would be very helpful.
03:02 PM Hermann: solarwind could it be made of nylon?
03:09 PM solarwind: Hermann that's what I would guess too, but it feels too stiff to be nylon
03:09 PM solarwind: Entirely possible though
03:10 PM solarwind: I'm really interested in why they chose these polymers for the gearbox. The worm screw is metal, and the static shafts are metal, but the other moving parts are all made out of this polymer and it's well known that barbers use this model every day for many years without having to replace anything
03:11 PM solarwind: So now I'm really interested in the durability of such polymers for structural members/power transmission and how they manufactured them to have such excellent fit on the metal shafts
03:12 PM solarwind: That is, were they machined? Or just somehow injection molded and cured in a mold?
03:13 PM solarwind: The fit is as good or better than any motor shaft brass bushing I've seen.
03:13 PM solarwind: And whatever material it's made out of seems to not mind hydrocarbon oils at all and has low friction
03:14 PM solarwind: Another guess would be POM, but again, don't really know
03:14 PM solarwind: They're cheap enough to purchase, so I don't mind doing a destructive test to figure out what they're made of
05:43 PM JT-Shop: andypugh, https://www.youtube.com/watch?v=1WCaFPWpChg
05:44 PM andypugh: ?
05:45 PM JT-Shop: english bike trip
05:45 PM JT-Shop: I've been watching Simon while waiting for Leo...
08:46 PM solarwind: https://www.youtube.com/watch?v=DVLXsq7pi9Y love videos like this
08:47 PM solarwind: I made a pair of flatstones and stoned my R8 collets. There's a nice shine on all the tapers now
08:50 PM solarwind: The Hardinge collets show the same grind pattern as what his #40 holders are showing
08:50 PM solarwind: The lathe spindle is just perfect though
08:54 PM solarwind: And the mill slideways look as shiny as his polished scraped sample :D
09:25 PM Centurion_Dan1 is now known as Centurion_Dan
10:22 PM Centurion_Dan1 is now known as Centurion_Dan
10:42 PM Unterhaus_ is now known as unterhausen