#linuxcnc Logs

Aug 16 2021

#linuxcnc Calendar

12:07 AM -!- #linuxcnc mode set to +v by sodium.libera.chat
09:50 AM Loetmichel: *MUHAHAHA* $me just now. "Joerg is sometimes broken" (he made a strange comment/sound) $coworker: "Hey, he studied Astrophysics at the university, he probably always was broken!" Cue Joergs frown and frenetic laughter of the coworkers :)
11:29 AM basilic: hello all, I search a software to generate Gcode from STL or STEP file
11:29 AM basilic: on debian/linux
11:30 AM Tom_L: cura does that ehh?
11:31 AM basilic: cura generate milling gcode?
11:34 AM Tom_L: not a clue
11:35 AM Tom_L: gcode is gcode
11:35 AM basilic: not really, Gocde for adding material and remove from a block isn't the same job
11:36 AM basilic: I want to remove matérial from a wood block to get an object, not print it on my 3D printer
11:38 AM Tom_L: same code different task
11:40 AM Tom_L: printer works from the inside out, mill works from the outside in
12:35 PM foxkid: I have a probably common problem, the solution to which would be something like a 6040 router that can reliable machine hardwood with carbide tooling, mostly 1/8" shank. I'm comfortable wtih electronics, firmware, FPGAs, welding, mechanics, pretty much most of the enabling bits, but I want to do something that is cheap, good for a few months of occasional use, and isn't a full-blown design,
12:35 PM foxkid: build, and program project. Where is a good place to start?
12:36 PM CloudEvil: Budget?
12:36 PM foxkid: flexible. Say $1k +/-.
12:36 PM CloudEvil: (I do not have direct answers, but things get a whole pile easier with another zero when you're not getting parts out of the 'rusty crap' bin.)
12:38 PM foxkid: I have my own rusty-parts bin :) But using those parts requires making CAD models and drawings and design work that takes time. Ideally, there would be a moderate competent Chinese machanism that I would re-electrify if needed.
12:39 PM foxkid: For 10K I can buy something commercial, and bigger than I need. The reason to do anything is to keep a small carvings business going while I re-engineer my bigger, inverted stewart platform machine.
12:42 PM foxkid: It is a machine I built a few years ago, and started doing Etsy-level production on -- before I had really made everything as good as I wanted it to be. Now, a few years later, I'd like to get back to engineering the big machine to be calibrated for 6-axis movements, have a redundant safety system, better kinematics, ... all the things that I hadn't gotten to when it became too useful to
12:42 PM foxkid: take out of service.
12:42 PM CloudEvil: :)
12:43 PM foxkid: The "business" isn't worth dropping 10K on, but I get some pleasure from making special things for people.
12:43 PM Roguish_shop: foxkid, best place to start are your expectations. be realistic. performance, schedule, and cost. 3 legs of any and all projects.
12:45 PM foxkid: Performance in terms of speed is the lowest concern. Repeatability and distortion under cutting loads matters. Schedule -- I'm happy to spend a few days on this as a side project, but not a few months. Cost is more variable, as ultimately it depends on if I think it is "worth it".
12:48 PM foxkid: I guess I got the 1K number in my brain because my som pointed me to the plethora of things on ebay and Amazon. A few hours of investigation brought the conclusion that I have little ability to know what is in each of those boxes, or how difficult it would be to work with... thus the expectation that I'll be replacing the electronics. I've found NO documentation from any of the bottom-feeding
12:48 PM foxkid: suppliers about their interfaces or command sets. There seem to be the "parallal port driven by Mach 3" class of machines, and the "USB driven by some opaque unlicensed binary blob" class of machines.
12:49 PM foxkid: I will scan a few more forums and such to see if there is anything that is dependable information.
12:56 PM rs[m]: foxkid: I would look for "real" used machines of 80ies/90ies vintage
12:57 PM roycroft: thanks, nagios
12:57 PM roycroft: they just sent me a support renewal quote
12:57 PM roycroft: they quadrupled the cost over last year
12:57 PM roycroft: this for upgrade support + 2 email cases/year
12:58 PM * roycroft will finally be spending the time it takes to get zabbix useful
01:00 PM roycroft: the quote is $7995, btw
01:01 PM roycroft: very little software warrants that kind of price for upgrade support
01:06 PM rs[m]: nagios as in nagios.org?
01:17 PM roycroft: nagios.com
01:17 PM roycroft: we use nagios xi
01:17 PM roycroft: but not for much longer, i think
01:18 PM roycroft: you can't jack the price up that much, especially without notice, and expect to retain your customer base
01:18 PM roycroft: i suppose they think they can lose 3/4 of their customers and still generate the same amount of revenue
01:19 PM roycroft: but they won't get any new customers
01:19 PM roycroft: some of the customers whose networks we monitor are governments, with set budgets
01:19 PM roycroft: we can't increase our prices to them until july of next year for some customers, and september of next year for others
01:19 PM roycroft: and we're not going to eat $6k
01:36 PM Tom_L: i wouldn't eat it either, i'd much rather spend it
01:36 PM Tom_L: g'day roycroft
01:37 PM Tom_L: how was the trip?
01:42 PM roycroft: it was very nice
01:42 PM roycroft: relaxing and productive both
02:03 PM * JT-Shop has to do some body work on the deer feeder after a dead tree fell on it
02:04 PM Tom_L: ouch
02:05 PM Tom_L: what is considered a press fit on say a 2" bearing?
02:05 PM Tom_L: i'd consider .001 as an interference fit
02:05 PM Tom_L: .005 - .010" ?
02:06 PM Tom_L: i realize there are alot of bearing specs to consider too but in general
02:21 PM Roguish_shop: .001 is too tight
02:22 PM Roguish_shop: on a 2.0 bearing you could lock the bearing up
02:23 PM Tom_L: say for example on an axle shaft where they use heat / cold to insert the bearing. typically what would they use for tolerance?
02:25 PM Roguish_shop: typically press fits, whether inside or outside are .0005 ish. also depends on the materials.
02:25 PM Roguish_shop: realize that the bearing and shaft or housing are like springs.
02:26 PM Roguish_shop: whose stiffer?
02:26 PM Tom_L: that's kinda what i was thinking on steel, for an aluminum pillow block it could be more
02:26 PM Tom_L: the block would give before the bearing
02:26 PM Roguish_shop: yes, al is 1/3 the stiffness of steel.
02:27 PM Roguish_shop: modulus of elasticity steel 30e6, al 10e6
02:27 PM Tom_L: we did +0 -.0005" quite often on Ti for such things
02:28 PM Roguish_shop: Ti modulus is 17e6
02:28 PM Tom_L: a google search came up wiht the 5-10thou which i wondered about
02:28 PM Tom_L: i forget which site
02:29 PM Roguish_shop: a shrink fit is still equivalent to a press fit. just different method.
02:29 PM Tom_L: yeah
02:31 PM Roguish_shop: shrink fits depend on the temperature difference. but also the coeficients of expansion. which can actually vary with the alloy, not just the base material.
02:31 PM JT-Shop: hmm I need to find a 5x85 screw for the lid of the feeder... I had to cut it in two to get the lid off
02:31 PM Tom_L: 5 x 85 ??
02:31 PM JT-Shop: mm
02:32 PM Tom_L: how long?
02:32 PM JT-Shop: 85mm
02:32 PM JT-Shop: I might just use two short 5mm screws
02:33 PM Tom_L: https://www.amazon.com/Bolt-Base-Tensile-Socket-screws/dp/B00SN3HZN6
02:35 PM JT-Shop: no, I mean find in all my crap lol
02:35 PM Tom_L: that could take months
02:35 PM JT-Shop: but thanks for looking
02:36 PM Tom_L: i was even going for cad plated then SS afterward :)
02:39 PM * JT-Shop wanders over to the nut and bolt department
02:56 PM roycroft: nice
02:56 PM roycroft: i was able to finish the shoji panels for my lamp at lunch today
02:57 PM roycroft: after the glue dries, all i need to do is a bit of finish sanding, applying the shoji paper to the panels, and then the lamp will be finished
02:57 PM roycroft: so i may be done tonight
03:03 PM roycroft: i've found, btw, that while i thought that making all the miter joints using the disc sander and the new jigs i made would be much faster, it's actually a little slower by the time i clean up the fuzzies that the disc sander creates
03:03 PM roycroft: the fastest way to make the joints is to cut the pieces very close to finish size on the table saw, and use the chisel jigs i made a couple years ago
03:03 PM roycroft: not all experiments work out as one would like, i suppose
03:04 PM roycroft: the disc sander is still an amazing addition to the shop, even if i don't use it for its original intended purpse
03:32 PM JT-Shop: how big is the disk sander?
03:43 PM Tom_L: brief shower overhead
03:50 PM JT-Shop: have a bit of rain later in the week
03:56 PM -!- #linuxcnc mode set to +v by ChanServ
04:27 PM roycroft: 12", jt-shop
04:27 PM roycroft: i'd like a bigger one, but real estate is expensive in my shop
04:29 PM roycroft: https://roycroft.us/Sander-Cabinet/Sander-Cabinet-1.jpeg
04:36 PM Roguish_shop: mid 90s here and smoke haze...
04:38 PM roycroft: it's actually fairly nice here - 29 degrees, and the smoke has gone away (for now)
04:38 PM roycroft: i was able to open the big door when i was working in the shop at lunch time, and shall probably do so again after work
04:38 PM JT-Shop: nice setup
04:40 PM JT-Shop: 84°F 50% kinda nice outside in the shade
04:45 PM Tom_L: 77F and cloudy
04:55 PM solarwind: I'm not a structural engineer, but seeing as lumber prices are decreasing, I've been considering a large format CNC router build using wood instead of metal
04:55 PM solarwind: Would that work? Or is it not really a good idea?
04:55 PM solarwind: It would be primarily used for machining 4'x8' sheets of plywood and such
04:57 PM roycroft: lots of people make large format cnc routers out of wood
04:58 PM solarwind: Oh by the way, to the people doubting the UPS driver forging my signature, my door camera caught him leaving the parcel on the front porch. It didn't catch him signing anything, but the fact that no one answered the door and a signature magically appeared is proof enough.
04:59 PM solarwind: The camera is very obviously placed, so the thieves know how to take the package without getting spotted. The field of view isn't the greatest. It caught him carrying it, placing it on the ground, making a phone call and leaving. Parcel itself unfortunately out of view since camera is aimed at face height
05:00 PM solarwind: roycroft would it be rigid enough for surfacing regular milling operations? I was considering buying a cabinet saw, but with a large format router, I think it would render a cabinet saw superfluous
05:02 PM roycroft: i can't see how a cnc router would replace a table saw, but while i don't have direct experience with cnc routers, folks seem to make fairly precise parts with them, including the all-wood ones
05:02 PM roycroft: if you use engineered wood products they can be incredibly strong
05:03 PM solarwind: Speaking of which, 4x4 and 6x6, especially when dry tend to have long cracks along their length. How does that affect their strength?
05:03 PM solarwind: But yes, I'd likely use plywood and such
05:10 PM roycroft: those cracks do weaken the wood somewhat, but i don't know exactly how much
05:10 PM MrHindsight[m]: what are good starting points for milling frozen meat? (feeds and speeds)
05:10 PM roycroft: most carpenters overengineer and overbuild, so it probably dos not matter much
05:10 PM * Tom_L wonders wtf MrHindsight[m] is up to now
05:11 PM roycroft: except some carpenters underengineer and underbuild, but it does not matter there at all either, as all their projects fail no matter what
05:11 PM solarwind: Tom_L not working on his engine dyno clearly
05:12 PM solarwind: I need to build a small one as well. I have some old small engines from snowblowers and such I'd like to test out and tune
05:12 PM MrHindsight[m]: buying meats in low volumes and freezing is lower cost than formulating resins
05:12 PM MrHindsight[m]: so if you want meat in the shape of a particular organ, freeze and mill
05:13 PM MrHindsight[m]: testing MRI and similar equipment
05:13 PM Tom_L: might be a bit hard to fixture
05:13 PM solarwind: MrHindsight[m] HSS, 4 flute. There's so much fat in there, no need for cutting fluid. Also it's frozen, so don't need to worry about overheating the end mill
05:13 PM solarwind: Someone donated me an industrial router table
05:14 PM solarwind: It runs on 600V 3 phase, so I need to make myself a 3 phase alternator. I definitely don't want to get a rotary phase converter
05:14 PM MrHindsight[m]: coat with resin after machining so it holds its sahpe
05:14 PM MrHindsight[m]: like the visible dead guy project
05:14 PM Tom_L: keeping shape while milling could be a problem
05:15 PM roycroft: mummify it
05:15 PM solarwind: Tom_L freeze it super cold, it'll be very stiff
05:15 PM MrHindsight[m]: you can't since it changes the electrical characteristics
05:15 PM MrHindsight[m]: no mummy
05:16 PM Tom_L: contact surfaces would thaw rather quick
05:16 PM MrHindsight[m]: mill and coat with resin to hold its sahpe
05:16 PM Tom_L: build a refrigerated fixture
05:16 PM MrHindsight[m]: shape even
05:17 PM MrHindsight[m]: fill with saline to adjust conductivity
05:20 PM Tom_L: what about using balistic jel?
05:20 PM unterhaus: Cap'n, what do you do nowadays when you need a stepper and drive?
05:21 PM MrHindsight[m]: ballistic gel just acts mechanically like tissues, it doesn't match electrical specs like permittivity or conductivity
05:22 PM MrHindsight[m]: unterhaus: when buying new I use the integrated stepper motor with driver combos
05:22 PM Tom_L: make molds and freeze hamburger in em
05:23 PM MrHindsight[m]: room temp approach, print mold, fill with meat, enjoy
05:25 PM unterhaus: Cap'n, and specific brand recommendation ?
05:28 PM JT-Shop: https://gnipsel.com/images/wood-working/saw-stop/saw-cabinet-24.jpg
05:30 PM MrHindsight[m]: https://www.automationdirect.com/adc/overview/catalog/motion_control/stepper_systems/integrated_stepper_motors_-z-_drives unterhaus
05:30 PM MrHindsight[m]: https://www.applied-motion.com/products/integrated-steppers
05:31 PM MrHindsight[m]: I've used some off Amamzon from Chinastan with sucess
05:34 PM MrHindsight[m]: unterhaus: https://www.amazon.com/Stepper-Integrate-Position-Encoder-Control/dp/B01MFA87KI/ref=sr_1_15?dchild=1&keywords=integrated+stepper&qid=1629152381&sr=8-15
05:43 PM unterhaus: Thanks, I never noticed automation direct had them
05:44 PM unterhaus: probably because their website is such a pain to use
05:44 PM MrHindsight[m]: the prices have come down so much I don't bother with separate motors and drivers anymore
05:44 PM MrHindsight[m]: they are just quiet and smooth
06:11 PM Roguish_shop: all righty. beer time. finished the 3 parts for a client.
06:11 PM Roguish_shop: another day, another few dollars.....
06:26 PM roycroft: i have shoji paper glued to 2 of the 5 panels
06:26 PM roycroft: with what's readily and conveniently available to me right this minute, i can only do 2 at a time
06:27 PM roycroft: but the glue shouldn't take long to dry
06:27 PM roycroft: although i've never used this glue before, so i'm not totally sure how long it will take
06:27 PM roycroft: i'm estimating 30 minutes to an hour
06:28 PM * roycroft already has a plan for gluing up 10-20 panels at a time in production
08:27 PM roycroft: so the prototype is done
08:27 PM roycroft: https://roycroft.us/Shoji-Lamp/
08:28 PM roycroft: it's not something i could sell, but it's not bad for a first effort, i think
08:29 PM Tom_L: why is it not saleable?
08:29 PM Tom_L: looks like it turned out nice
08:30 PM CloudEvil: :)
08:31 PM roycroft: it has all sorts of flaws
08:31 PM roycroft: and i could have fixed most of them, but this is a prototype
08:32 PM roycroft: i'm not happy with the dimensions, and have already modified my drawings to improve them
08:32 PM roycroft: but the overall look is ok
08:33 PM roycroft: i'd say it's about as good as i expected the first one to be
08:33 PM roycroft: and it's good enough that i'll bring it in the house and use it for a while
08:34 PM roycroft: most of the problems are in the panels, and i can always remake them of those bug me too much