#qi-hardware IRC log for Friday, 2014-08-22

wpwrakwhitequark: nice. drilling holes into the workpiece seems a bit wasteful, though. for PCBs, double-sided tape should be sufficient.05:44
DocScrutinizer51moo06:49
hozerwpwrak: hrrm, I'm obsessing over getting a CNC3020 now12:22
wpwrakwas that for whitequark ? :)12:24
wpwrakand yes he's doing nice things with that mill. i'd be a bit concerned about all the bits he had to replace before it was usable, though12:25
hozererr, yes whoops12:26
hozerstill looks better than stuff like this though.. http://www.mydiycnc.com/content/new-sprite-desktop-cnc-machine-turnkey-system12:31
wpwraklooks a bit diy-ish. but maybe it's not so bad. the "usb solution" sounds interesting12:35
hozerI've only been looking for about 15 minutes but it seems like the cnc3020 is a half-decent spindle and functional12:37
wpwrakit looks a log more solid, yes12:37
hozerand for ~600ish USD I could be milling PCBs12:38
hozernow, how can I get just the CNC part, no control box12:46
whitequarkwpwrak: double-sided tape? not nearly13:59
whitequarkit absolutely doesn't cut it when milling out the PCB, and I'm not even sure about drilling13:59
whitequarkand with stuff like acrylic sheets, holes are really the only way14:00
whitequarkvibration + cutting force = displacement, always.14:00
wpwrakhmm, i fix my pcbs with tape all the time. no problem. tolerance is within about +/- 0.1 mm. that's for cutting the board and drilling. i etch the traces.14:02
wpwrakby the way, some of you may know / have heard of the ottawa linux symposium. that's one of the oldest and highest-profile linux-centric technical conferences. alas, their last conference caused some financial troubles and they're asking for help: https://www.indiegogo.com/projects/ottawa-linux-symposium14:06
whitequarkwpwrak: 0.1mm is too bad already for drilling in my case14:23
whitequarkand cutting board... maybe you have better tape than me?14:23
wpwrakmy tape is whatever they sell in the shop around the corner. i kinda doubt it's high quality :)14:24
wpwrakthat's a stationary shop, so i14:25
wpwrak'm talking about thin tape. not the stuff you use, say, for glueing things to walls14:26
whitequarkwpwrak: same14:26
whitequarkit's some Scotch double-sided tape14:26
wpwrakshould be more than enough. well, maybe you run your mill extremely fast and it just rattles the board too much14:27
whitequarkwhat's your feedrate?14:28
whitequarkI usually do about 200mm/min14:29
wpwrak(0.1 mm) my vias have a hole diameter of 0.254 mm and a copper diameter of 0.76 mm. so 0.1-0.2 mm total tolerance are quite okay. i tend to get a bit more error due to imperfect placement of the toner transfer sheet anyway.14:29
whitequarkalthough I sorta shot myself through the leg here14:31
whitequarknothing glues to HDPE14:31
wpwrak;-))14:31
whitequarkit's both a blight and a blessing14:32
wpwrak(feeed) good question :) all my scripts use "default values". should be around 2 mm/s14:32
whitequarkso, 120mm/min. should be close enough14:32
wpwrakand the mill had a diameter of ~30 mil14:32
whitequarkwpwrak: another thing I dislike tape for is that after 1-2 ungluings, it goes bad14:33
whitequarkand it's pretty expensive, not to mention annoying, to replace often14:33
wpwrakoh, i use it only once14:33
whitequarkand yet another thing is that if the PCB is slightly warped--even 1-2mm over the huge sheet--the tape is not enough to keep it flat14:33
wpwrakit's not meant for multiple use14:34
whitequarkand that adds more error while drilling14:34
whitequarkwell14:34
wpwrakmaybe you need a different kind of tape :)14:34
whitequarkI'm fine with my current setup ;P14:34
hozerwhitequark: what controller do you use14:54
whitequarkhozer: CNC3020T's own14:54
whitequarkheavily modified, because it's shit14:54
whitequarksee http://lab.whitequark.org/notes/categories/cnc3020t/14:54
hozerit was you or somene else I was reading about that blew it up in the first 20 minutes ;)14:55
whitequarkme14:55
hozerwhat do you think of http://probotix.com/index.php?view=product&path=16&product_id=20414:55
whitequarkthat's not a controller14:55
whitequarkapart from CNC3020T's controller, I have an old PC with an LPT port with LinuxCNC14:56
whitequarkyour thing is a replacement for that PC, and it's a good idea to use it14:56
whitequarkin fact, I might someday switch to that board14:56
hozerwell, what I kinda really want is a single beaglebone cape that's got whatever that board has plus the controller 14:56
whitequarkthat's an extremely bad idea14:57
hozerhah, noise?14:57
whitequarkindeed14:57
whitequarkI don't understand this obsession with PCB stacking...14:57
hozerthe cape thing?14:57
whitequarkcape/shield/whatever14:57
hozerits because everyone uses eagle with 2-layer limits14:58
whitequarkhuh?14:58
hozerwell, actually, you can have a beaglebone which is umpteen layers, and make a simple 2-layer board that goes right on it14:58
whitequarkit's a kind of extension headers14:58
hozeryes14:58
whitequarkand extension headers are useful14:58
whitequarkbut there's no reason to try and fit *everything* on a single mile high PCB stack14:59
hozerI like the beaglebone the best of what I've seen (arduino, pcduino)14:59
whitequarkbeaglebone and arduino have different tasks though14:59
hozerno, that's why you need a single beaglebone + daughterboard that has the interface+controller14:59
hozerbut mechanical wise, the beaglebone stacking just looks nice and seems pretty robust15:00
whitequark??? you don't need to15:00
whitequarkjust have two PCBs.15:00
hozerwell, I want a CNC2030 controller for which I can mill the two PCBs I need to make another controller15:01
hozerand stack an arduino/pcduino/beaglebone on top of one of the PCBs and away we go, stand-alone linux CNC15:01
whitequarkwait, you're the one who wanted to make a PoE-powered CNC controller?15:02
hozer;)15:02
whitequarkwhatever... continue. I'm not interested15:02
hozerI'm not going to run a 1kw VFD spindle on POE so I gave up on that15:02
hozerI guess I don't care how many boards it is, I just want to be able get a CNC mill that can mill it's own controller boards15:04
hozerso what's it take to replicate the actual controller part from the CNC you have15:05
whitequarkthere's a bunch of two-layer boards there15:06
whitequarkthe spindle PWM board is single-layer in fact15:06
whitequarkit's not complex at all.15:06
wpwrakmother nature's a bitch, evidence #392: have a few really warm days in winter so the wildlife releases its pollen and you get hay fever. then the temperature will drop and you'll get an evil mix of flu and allergy..19:43
wpwraklet's see if i've figured that evil plot well enough to avoid the mess this year ...19:48
larscgoing on a long vacation?20:04
wpwraknaw, taking anti-allergy pills20:07
wpwrakbeen near-dead for well over a month last year, when that mixture struck the first time. none of the normal anti-flu treatment worked ...20:08
--- Sat Aug 23 201400:00

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