oh you mean vents? I thought you meant sprue (the thing you pour down)
I thought that was the riser :) which book are we going by here?
[00:02:11] <cradek> http://en.wikipedia.org/wiki/Sprue_(manufacturing)
what is this "book" thing of which you speak?
of course, The Great WP :)
interesting 'SoftPot Linear Membrane Potentiometer - 100mm' http://www.trossenrobotics.com/sparkfun-softpot-membrane-potentiometer-100mm.aspx
>>from advert "Can be used as an accurate positional indicator for CNC head positioning"
not sure thats true, but, interesting
hmm im afraid my pattern will be to small for me to mill to actual size later
it'd be more interesting at 8" than 4"
the size should end up after milling at 20mm ... atm it is 21mm .. with a 6% shrinkage i will be down at 19.74 :/
you should make it oversize to allow for shrinkage of metal. 1/4" per 12" for cast iron iirc
tom3p: depends on the definition of "accurate". Consider a 12-bit ADC, your precision is limited to 100mm/4096=about 41 counts/mm or 1000counts/in, which isn't much.
how thick is a coat of paint?
and accuracy may be much less
that's plenty accurate for a toy cnc
jepler: yep, i got the data sheets, you'd loos more due to nonlinearity.. but, its cool ( they got rotary finger wiper ones too )
you can get 4" sliding pots anywhere tho. faders
MattyMatt, asking me ?
MattyMatt: these would just be like a graphic on the control panel, 'no' thickness, no moving parts. microchip sells a similar eval kit
asking for you :) if paint takes you over 20mm you're OK
tom3p: ah I thought you meant as feedback
MattyMatt, that would have to be 0.25mm of paint ... thats quite thick for a painting :P
it's bulked up
with sand if you want, but I doubt it :)
the stuff Dulux paint lighthouses with
"Aluminum shrinkage factor is usually 3/16" per foot. Or about 2%" http://www.submarineboat.com/lost_foam_casting.htm
i haaate the damn inch system
2% works in metric
in soviet russia, the damn inch system hates you
tom3p, wikipedia says 6%
hate it when pages has differnt numbers
make a .5 meter long mold, cast it
test aimple 100mm bars with 2 holes 50mm apart, check after, get yer own dang numbers
and then measure the shrink
yeah, what tomp said
tom3p, hehe =)
right what toastydeath said ;)
i think lost foam is more suitable for heavier castings realy
where you got atlest 10mm wall thickness
heavier castings are usually done with loam or pit molds
but i might be wrong .)
but i guess that depends on what you consider heavy
toastydeath, im not talking 100kg castings here .. but heavier then something like 5mm wall thickness etc =)
that shape looks made for open face sand mould, IMO, with or without a core for the big stepper hole
or diecasting :)
it'd be worth it. lookit the prices they fetch http://cgi.ebay.co.uk/Nema-23-motor-mount-CNC-XYZ-DIY_W0QQitemZ250534075156
somebody read this article, i think the guys at nist are playing with a reprap type foam printer, but my imagination raced ahead of the printed article http://statusreports.atp.nist.gov/reports/97-02-0055PDF.pdf
foam printer for lost foam casting
that motor mount wouldnt fit on my mill as it stops the table movement to early :)
why not print wax?
giving me only 50% of the table movement
you saw the price and considered buying it?
MattyMatt: dunno, but industry uses foam not wax ( afaik, like in turbines )
MattyMatt, hehe .. no would not buy it for that price either :)
you guys all have mini mills, huh?
I have 2/3 of a wooden dremel pusher
dan1mal_garage: are you trying to make us feel inferior?
and my dremel burned out yesterday
no tom, i was asking because i need one
do you have a small equipment complex? haha
i do need one for engraving
I have a burned out equipment complex
i dont want to tie up the big mill for that
what was that pretty solid alu one?
what are you going to do?
dan1mal_garage: i like this unit 'sable-2015' http://cgi.ebay.com/Sable-2015-CNC-ROUTER-ENGRAVER-mill-PCBs-engraving_W0QQitemZ190354469465QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2c5202b259
get another dremmel, or upgrade?
that's the one :)
dan1mal_garage: depends on how small , 'small' is to you
under bridgeport size is small to me
but i want desktop
dan1mal_garage: I'll lean on my consumer protection rights and keep replacing it until they get suspicious :)
dan1mal_garage: i got one here on the table, and its damn repeatable and zippo backlash. i set it up with 123 blocks and they side into the programmed gaps like jo blox
yeah that sable is real pretty, but too small for most stuff
and dead solid
that's a steal with ball screws and motors
really, a bport is crazy sloppy compare to this thing
is that servo or stepper?
(until you hack it )
i wonder what shipping costs
the guy who builds 'em is near the catholic uni in taipei, but he couldnt build up another before i left. mine came boxed up , fully assembled to a hotel in cinncinatti, it ran right away, no probs. (ymmv)
shipping was... i dont recall it being an issue at all, and it had no robs with customs, came via USPS
"no robs with customs" Freudstrike
i did buy the full kit, ps, driver, cables, i bet mine was 500 plus 200 easy. still i wanted soemthing while i moved around.
wow still a killer deal
my whole shop is covered in sawdust now
oh it included MattyMatts 30k rpm dir grinder with collet (singular) and mount
i just hooked up the new compressor, and since it came out of a cabinet shop, there was sawdust in all the nooks and crannies
poof! dust everywhere when it started
aha. I knew it was taiwanese
garage door open, compressor on, sweep out dust ;)
nice, thats exactly what i need tom3p
'finely made in taiwan'
taiwan is lightyears better than china
i lived there tooooooooo long
yeah Draper tools of late have the whiff of some backwoods 1000 miles inland
hmm that doesn't work. Ohio, Cleveland & Detroit are all that far inland :)
i think i'm going to dismantle my lathe's cnc controller so i can take the cabinet to the dump tomorrow
dan1mal_garage: a bandit?
no, GE mark century
but i do have all the stuff from a bandit kicking around
my shizuoka had a bandit on it
i just have to order another 5i20, a 7i33, and a 7i37 and i can start to get my lathe going
or at least just the 5i20
have you retrofitted before? i'm amazed at how capable people in here are.
i did my shizuoka
but it's stepper
my lathe is servo so it'll be all new to me
linear or rotary feedback?
shizuoka = mill
it has resolvers
i had to get the pico resolver to encoder converters
aha Jon Elsons stuff, cool
hopefully it'll work well for me, seems like cradek has a solid machine, and we have the same lathes
since teh resolver is analog ( and thus infinite) and the other end is digital ( and thus finite ), what resolution will you get ?
i havent gotten that far in
whoa is right
[00:49:38] <cradek> http://timeguy.com/cradek-files/emc/screw-vs-scale.png
here is a picture of the resolver feedback vs a scale that I clamped to the axis
cradek, i'm going to gut the GE controller today
any tips before i break out the sawzall?
take lotsa photos, label every wire end, light a candle
don't cut any wires until you are sure where you will mount whatever they hook to
resolver cabling is very special
sheilded i presume
shielded twisted pairs in a shield
yeah each pair shielded I think
and carefully twisted etc
did you reuse the rectangular connectors in the back of the control?
the tach wire is nicely shielded too
identify which end of shield is grounded
good to know
dan1mal_garage: no, I cut them off
hmm i dont think my hoffman enclosure is big enough for the power supply and servo amps
my shizuoka was super easy
this one will be a challenge
if you have a bport and a shizooka and this lathe, what do you want a toy like the sable?
ah, THAT it could do ( hand gun notches done cheap )
i make my own product, and i want to start engraving them
with my logo
bike gears and such right?
but i dont want to tie up my shizuoka with that
cradek, that compressor worked awesome
just wired it up
it draws 25-30 ams
according to the motor
did the lights dim when i kicked in?
no, different circuit
lights come off the main pannel
compressor is on a sub pannel in the garage
you got 3 phase i bet, 220 or higher?
hey, look this http://cgi.ebay.com/DIY-engraving-machine-CNC-router-frame_W0QQitemZ110395098286QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item19b40f84ae
baldor 5hp single phase motor
5hp is too much for my rotory phase converter
cemede: thats very similar to the sable, but moving bridge. i think id like that better for my next project, turn the whole thing upside down over a fixed bed & get more Z throat
dan1mal_garage: single phase 230... you got lots of suff on 1 leg
cemede: that guy happy-ebuy has been around a while as agent for that xiamen factory
yea, my electric bill isnt cheap
it's catching up to the mortgage
this mounted machines seems very interesting
dan1mal_garage: the mini mill cemede posted is also near 500$ mark, i just have no personal experience with it
just 555$ with shipping
and paypal covers all, at least for me
comes with the spindle motor too!
i like that one
i might buy it
and what about this? http://cgi.ebay.com/CNC-router-engraver-drilling-and-milling-machine-TI_W0QQitemZ110433015035QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item19b65214fb
comes with a chinese control panel xD
not bad, just plug and play basically
but I think that sable unit have a better finish, at least see the pics..
cemede: i know the sable 2015 (500$ plus shipping) , i have no experience with the other.
i believe there's good product out there from china taiwan sg.
i see i did pay more ... $215 for spindle, mount. driver & cables + 500 for machine with motors and cableing to driver. i dunno where the driver is on the xiamen unit.
plus shipping which i cant figger right now
dan1mal_garage you can amortize that machine doing christmas gifts with it and selling them!
engraved jewelry or something
dan1mal_garage: in taiwan, the cyclists i knew came back from a bike show in taipei with a 'bike logger gps' thingy (size of cheap ipod). they plugged the usb into a vista box and google drew their map and altitude plot. such stuff in USA?
MarkusBec is now known as MarkusBec_away
and time too, they were interested in that a lot
we have stuff like that
we even have it so you can measure your wattage
see how much hp you're putting out :)
future of hal gui ? http://cycling74.s3.amazonaws.com/download/tutorialzero.mov
argh! no source arghargh 700$
i picked up a book on hacking iphones just because i saw a diagram using that tool set (lucky it was a library book)
does more voltage make a stepper motor run faster?
yes, but the current must be limited to the max allowed for the stepper..... higher voltage drive will allow the current to rise in the inductive motor coils faster, thus the motor will be able to be driven to the next motor state faster
I'm using a a3979 chip, and am limited to 35V.. so sounds like I'd need a new driver if I wanted to get the motors to move faster
will microstepping it make it slower? so if I goto half or full step it would be faster?
what are the stepper ratings?.... 10x to 25x coil voltage is recommended with high performance drives
for a 3v coil, 30 to 75volts is about the useful range if the driver can take it
steppers with 12v coils can not be expected to work well with normal drives
says 12-24 V 1.5A/phase
what resistance do you measure in one coild?
err says rated voltage 12-48V
phase resistance is 4.4 -4.5
phase inductance is 7.8
Vcoil = 1.4A * 4.5ohms = 6.75v ... this is a high voltage for a stepper....it would really like at least 65v drive with current limited to 1.5a
the a3979 is set to limit at 1.5A, I'm wondering if it could handle 65V
with a gecko drive and about 70-80v supply would get about all the performance you can expect
probably not.... its out of the realm of IC type drives
a3979 -- 2.5A, 35v max... I would not use it with more than a 30v supply
ya I'm doing 32V max
stepper motor can only handle 1.5A so a3979 is set to that
I don't think a higher current stepper is going to help me out for speed
depending on your application, this may be enough performance... else look for lower coil voltage steppers
so say I get a 2.8A/phase with 1.1ohms = 3.08v would run faster at 32V than the 1.4A * 4.5ohms = 6.75V ?
If you would like to experiment, I would buy one gecko drive and make a 70v supply and see how it works
just trying to learn at the moment, going to stick with what I have unless I come across some money
:} I know how that works
so 3.08V would run faster than a 6.75V using a 32V supply?
lower coil voltages typically have a lower inductance for similar sized steppers..... its all related to current rise through the coil inductance
the more resistance the higher the current
if you look at stepper data sheets, they usually make a series of different windings.... best is a balance of rpm required, driver specs, supply voltage available
[04:19:45] <tlab> http://www.linengineeringstore.com/products/product_detail.aspx?proID=3
in a typical stepper coil, you can wind many turns of small wire or a few turns of larger wire.... if you look at the first stepper in that list.... 16.8mH or 1.6mH ... so the high inductance one will typically need 10x the drive voltage
but if you only need a hundred rpm or less, the high inductance may work with a very simple drive... this is typical of floppy steppers
so the first two motors produce the same amount of torque, but require different voltages / current to drive them?
yes.... usually there are torque vs rpm graphs available... the shapes of the curves will be very different with the same drive conditions
sorry... I dint scroll down the page far enough
oh i c
the 15E model goes to 25k rpm
the high inductance stepper dies in the low 1000's
lots of design tradeoffs ... when working with surplus stuff sometimes the only way to get a feeling for it is to try it
see the files section in http://finance.groups.yahoo.com/group/geckodrive/
there is supposed to be a white paper on steppers.... it is highly recommended reading
thanks will read it
at last, I've seen the battery depicted in the How And Why Wonder Book of Electricity -> http://cgi.ebay.co.uk/Cyclon-2V-25AHr-Sealed-Lead-Acid-Rechargeable-Battery_W0QQitemZ230404622364
a childhood dream fulfilled
Max Discharge Current:1335A
[10:55:28] <Valen> http://www.youtube.com/watch?v=GcDshWmhF4A
MarkusBec_away is now known as MarkusBec
yeey workpiece casted to almost right dimensions and face milled on one side ready for milling the rest, just have to do a new cad of the piece =)
noticed my mill is slightly tilting forward tho
wil have to try and shim that up ...
but the off is like 0.001mm over a 10mm cut
but i can feel it with my fingers .... feel it with my toes
Jymmm: Arduino environment (in linux, at least) is based on avr-libc, with avrdude to upload the .hex to the bootloader. I *hate* their editor, so I'm using a Makefile and Vim editor
Jymmm: Arduino has provisions to make simple stuff easy, but it's limiting. More advanced stuff, you need to read avr datasheets and avr-libc docs
hey all, the shielding of the cable that run from a breakout board to drivers (this case Geck 203V) where should you attached the shielding of these cables. On the gecko's cooling plate or on the Bob's side (0V clamp)
why the hell does heekscad zigzag operation jump over holes etc?
and corners of the piece
i need a way to face mill everything before it starts the actual milling
to cut piece down to size
Ah, hot-air rework station, how did I ever live without you?
Oh yeah, I remember - blowtorch.
i have a huge problem ... with no home limits etc ... how the hell do i position a workpiece that is close to finnished dimensions and just need final milling for it not to be off by to far?
(+- 1mm or so)
[15:19:14] <MrSunshine> http://www.youtube.com/watch?v=quN37YskoaM&NR=1&feature=fvwp
that is THE coolest cnc machine ive seen so far =)
my life for a touch probe :)
probe 4 sides of the extruding part and know the exact center
i can hand probe tho ... take the mill to one side, home it, next side, home it .. measure the piece .. move X and Y to the middle of the extruding part by hand
anyone here know how to set the program entry point mill start point in heekscnc? :)
i need the absolute start to be at 0 0 0
MrSunshine: >>i have a huge problem ... with no home limits etc ... how the hell do i position a workpiece
If you can figure out the touchoff process you can do that without putting the workpiece in the perfect position.
Get close to the workpiece with your tool and then use a drill bit or thick feeler gauge to determine your cutters position to the reference surface on your workpiece and then "touch off" and set the tool position relative to the workpiece in the window. Make sure you use the proper offset system when you do that G54,55, etc. If you touch off and use G54 when your program is using G55,...
...that won't work. :-)
Once you get the process down you can dial your machine into a couple of thousandths without many problems - much better than 1 mm/40 thou :-)
Touch probes are faster, but not cheap typically..
will EMC be sticking with RTAI or are there plans to migrate to Xenomai?
there is no such plan, but anyone can write RTAPI layer for Xenomai
it doesn't have the same api?
each relatime has its own api, emc has RTAPI to be independent of them
xenomai was rtai at one point
there are skins for xenomai
iirc there's a rtai-compatible skin
RTAI does focus more on lowest possible latency
it doesn't matter, what matters is the api
sounds like you are free to install xenomai and use emc as is
most developers I know have jumped to Xenomai, I'm just looking inti it
their reasons are mostly ARM and SH support
sure, if you are going with embedded architectures, the xenomai has always been the only way to go
I see a lot of arm talk on the rtai mailing list lately though
I was considering ARM Cortex8 SOC for a future EMC project, but with mini-itx Atom boards for ~$65 it's too soon to decide
MarkusBec is now known as MarkusBec_away
Dave911, aye thats about how i figured it out ... as not much precision is needed i took the tool to the piece, measured the thickness, and entered Thickness/2 + Tool Diameter, then did the same for both X and Y
so i got the start location in the center of the most important place =)
L84Supper: right, why go through the extra pain at those prices ;)
also moved the piece in heekscnc to having 0 0 0 at the center of the most important piece =)
RTAI claims ARM support
do you think anyone would have a use for a 5v 50A power supply?
and the single rail psu has got to be worth $30-$50?
I'm waiting for a mini-itx or smaller Atom board that only needs a 12Vdc supply vs ATX, similar to the PC Engines Geode based boards http://pcengines.ch/alix1c.htm
i have all the old parts from my giant cnc controller, i wonder what i should dump and what i should ebay
Dave911, and thanks for giving pointers =)
dan1mal_garage: if the emc machine of the future has 100 ARM in it, then maybe :)
RTAI is up to Arm9 last I checked http://www.embeddedarm.com/software/arm-linux-24-rtai.php
50a is a bit overkill for 5v, aint it
Dave911, hard to dial the machine in to a couple of thousands when i only have like +- 0.05 in precision so far (havent done anything about backlash etc yet)
and even then 3.3V would probably be better
i have another power supply that has 12v+ at 10A and 12v- at 5A
not sure what to do with that either
both weigh a good 50lbs
5V one could be ideal for electroplating
sell them before the caps wear out
why didnt i think of that
cant i make a tazer out of the caps? lol
I like this motor, for some reason -> http://cgi.ebay.co.uk/MOTOR-110-VOLT-AC-DC-GEARBOX_W0QQitemZ350286473124
it'd be great for a "this is a servo" display
MrSunshine: +/- .050 ? Wow, that is a lot of slop to deal with..
anybody knows anything about Lorch lathes?
surprisingly i do have one
who was building multi head gantry printers?
old is good
i have a 1910-ish rockford machine tool lathe, that thing is solid
only single phase 1hp and belt driven, but it'll take a hell of a cut
tom3p, do you know the hole spacing and thread of the Sable head? the 8 holes where the tool mount goes. I'm just about to pull numbers out of the air for mine
dan1mal_garage, mine is about from WWII time
belt driven, slave bearings
and small, like tabletop
those are handy
[20:13:38] <dimas> http://www.lathes.co.uk/lorch/page7.html
once you've made the table ;)
like one on the top
is that belt leather? :)
at least thats what mine is i think
the belt and motor are new, but lathe is like pictured one
trying to find pics of mine
[20:17:06] <dan1mal_garage> http://img.photobucket.com/albums/v20/danielwilcox/DSCN0015.jpg
there it is
much cleaner than it is right now
as well as the floor
It'll be a shame to put ugly black steppers on it :)
mine's staying manual
now that IS pretty, dan1mal :)
restored it myself
paint the tailstock
my hardinge is cnc, so no need to convert that one
i just finished gutting my hardinge's controller
the manual feed is on the rack rather than the leadscrew?
the enclosure is already loaded in the truck to go to the dump :)
the rack is for the threading dial
I need all the sheet steel I can get
come to san diego and pick it up!
momma's SS toaster has half-broken at last \o/ that's my SMT oven
i bet she loves you
I could fix it for her, I suppose
she throws SS items in the trash, if I let her
MarkusBec_away is now known as MarkusBec
i found a couple servos for $29 each shipped, but they are small. i was thinking of buying them for the encoders
they are sanyo
do you need the encoders, and are they usable on the hardinge?
i need encoders for the spindle of my lathe and my mill
"worth it" is so subjective :)
lathe has rotating radii large enough to draw an optical encoder with felt tip pen
edge of the faceplate, maybe
or back of it
i think it might have an optical encoder in it of sorts
i gotta eat, i'm starving
Dave911, hehe =)
Dave911, is it? :)
Dave911, i dont realy know if it is that number tho .. thats what ive measured with the means i have on a finnished piece
JustinXJS2 is now known as JustinXJS
Oooh, me back! Spent the weekend moving two old (1930s and 1940s) lathes through a house (an old, empty one, with flagstone floors), across a field (which was easy with a farm-loader thing) and into another workshop. Mainly using crowbars and a chain-block.