theorb is now known as theorbtwo
[#emc] "This is the #emc channel - talk related to the Enhanced Machine Controller and general machining. Website: http://www.linuxcnc.org/,
wiki at http://wiki.linuxcnc.org/"
[04:52:59] <flyback> http://cgi.ebay.com/High-performance-CNC-Stepper-Motor-Driver-Up-tp-5-6A-PK-/380133899642?pt=LH_DefaultDomain_0&hash=item5881befd7a
$99 to control ONE stepper motor?
no I think it's several
doesn't look like it
oh then it's lame
interesting line: "It can offer servo-like performance."
pjm is now known as Guest87973
G83 the Z is the final depth of the hole and R is the start position for the feed move?
yes, start and retraction depth.
it will pull out to the R value every Q depth of cut
until it reaches the Z final depth
ok, I was confused after reading the manual
what kind of cereal does jesus like?
well, that worked nicely
now to figure out how to do a back side chamfer before parting off...
cradek: how is the 4th?
JT-Hardinge: very carefully?
skunkworks: I didn't work on it last night - still the same state as when I made the silly video
you made a video?
* skunkworks goes looking
[14:18:36] <cradek> http://www.youtube.com/watch?v=kxgSmr01UQg
cradek: how do you handle backlash in the old manual table?
awallin: the worm gear has adjustable engagement - the whole thing is eccentric
aren't we all
awallin: I haven't tested it yet, but it appears to be adjustable so backlash is .001-2" at the outside of the table
cradek: you need to turn a thumb guard for your camera :)
JT-Hardinge: yeah, embarassing
wish I had taken pictures of the mechanical work - to make the shaft from the worm long enough, I spliced it with a pressed-in 2" dowel pin
1/4 x 2"
not as embarrassing as this is http://www.youtube.com/watch?v=G4-lUNa0CpY
sproink! there goes an insert and a little screw...
I did that once too - hit the end of the work (aluminum) though - much softer
it left a mark too
did it hit the collet?
I wonder what kind of trouble I can get into with 4 tons of force...
(actually it would be twice that for the first second...)
depends on how big your tooling is :)
I should make some videos of it splitting logs.. ;)
dad would probably frown on that.
I've used Jr as an arbor press... presses nice and straight
we have a rather large drill press that works great for that also
(and a h-frame hydraulic press that we break out for the big jobs)
I hate it when I don't get what I expect and don't know for sure why...
yeah like getting the chocolate with coconut in it?
kinda like that... I touched off a right hand turning tool to the spindle and added 0.500 (the width of the tool) but when I check it with my material Z0 is not even with the end of the material...
Als is now known as AlSMT
hmmm, the parting tool is off to...
well, where did you touch off? to the newly machined face? Need to touch off all tools right in the beginning unless the program is written with touching off to a previously machined face...
no, I touch off of the spindle always for tools then take any tool and touch off my g54 offset
JT-Hardinge: are you using master or 2.4?
the tools that I use 0.000 for the offset seem correct
do you have the right tool touch off option set?
I'm using tool touch off to fixture
hmmm, my parting tool is off the width of the tool
when I touched it off I put in 0.125 (the width of the tool) so the right edge would be 0.000
and got it backwards :/
should have been -0.125
you were starting to worry me...
JT-Hardinge started worrying me a LONG time ago
I should go and fix the backhoe instead of making parts :)
Has anyone used or tinkered around with car airflow sensors or pressure switches by chance?
does having to replace broken ones count? :)
MarkusBec_ is now known as MarkusBec
Sure, if you know the pinout, voltage and pressure level that it triggers at =)
Or if you know of one that can easily be adapted for other uses =)
something is not correct with touch off when you enter a value other than 0.0000 and use touch off to fixture...
what if you enter zero, then go back and change it?
I have to run to town now... but no matter what I enter other than 0 the Z position of tools that are 0 offset don't match up to tools that have a value in the offset
JT-Hardinge: is g59.3 (fixture coordinate system) zero set to match the reference tool?
when you get back we can go through testing it together - I'm not understanding what you are saying is wrong
Why are there g-codes for tool offsets?
It would seem to me that would be a config thing, not a per-job thing
you can set and load tool offsets with gcodes
But why would you do that? Shouldn't they always be the same between jobs?
it's true that usually you don't have those gcodes in your part program
sort of - but sometimes you want them different
cradek: I'm not sure what you mean about the g59.3 zero
like jt's parting tool - which side of it should be Z=zero?
JT-Hardinge: you set up the "touch off fixture" by putting your reference tool against it with no TLO, and setting G59.3 to zero there
I didn't do that
then when you use touch off to fixture, you get offsets that compare to that point
I don't know if I'm explaining it adequately
I just took each tool up to the spindle face and one dowel diameter away touched off the Z for the tool as 0 except for the parting tool
that should work fine
that's what I thought too
who cares where G59.3 is, if you don't care exactly what lengths you get in the tool table
do you have an active g92 offset?
I do have a G54 offset for Z
ok, that's normal and should not affect touch-off-to-fixture
I'll do some more testing when I get back from town
hm, I bet g92 should be ignored for touch-off-to-fixture (it is not)
So, anyone have any ideas on car airflow/airpressure switches?
Hey, at 0:43, it that 1.0v per division??? http://www.youtube.com/watch?v=ijK2LsN8ipw
yes.. but he is possibly using a 1:10 probe
If so, then that would be .1v per division?
is there a g-code command which does relative movement to the current position or only absolut movement to 0,0,0?
ah i found it. i have to change to incremental distance mode with G91 than i can do relative movements and after that go back to absolute distance mode with G90
that is the way to do it :)
I never get to answer the easy questions!
cradek: it's a crime to spend you on easy questions :)
How much wood can a woodchuck chuck, if a woodchuck could chuck wood?
hey i need to know somethin
i have a vinyl cutter im fitting to EMC2 with an XYZ and an A he A needs to rotate to keep the blade cutting straight with the direction of travel of the cutter
how would i do that?
by programming the A axis explicitly with each XY move
is there a software that does it automagically
this has been discussed a few times, worth scanning logs
here's a link to a previous mailing list discussion about the topic: http://thread.gmane.org/gmane.linux.distributions.emc.devel/1696
how do i copy?
ok i read through that mailing list... no help at all
DJSprocket: what do you expect? it shows how to modify your gcode
without any explicit help
yeah, thats open-source :D
are you familiar with programming?
if yes, adding this C-Axis-function to 'grecode' my be an option
in c++ a little but not enough to convert the G file into text read it compute the angles and spit out an A co-ordinance
[20:31:40] <cpresser> http://code.google.com/p/grecode
<< this may be a good start
it already has lots of features for gcode manipulation..
what if i needed this running yesterday
then you are fucked up :D
take a lot of money and buy some software/controll which handles this. as sad as it is.. but there may be no ready-to-use solution
i heard that there was someone who already had this working somewhere
unfrotunately I only know the german word for such a tool (schleppmesser), but not the english translation.. so I cant help search :/
its not translating if you called me something...
there should be some cam software that automatically puts in C axis somewhere
I have already seen a lot of such cutters at work. most for simple cartboard
but they all come with commercial proprietary software..
yeah i dont want proprietary i want free as thats all i can afford. i have everything else i need to run this thing except for the rotary axis
another question about stepper motors
my steppers are rated for 5.1 volts can i safely run them overnight at 12 volts for a production run or would i have to put a resistor in line with the V+ on my driver boards?
found a tool: http://www.cnc-club.ru/forum/viewtopic.php?t=35
needs inkscape to run is this the right one? http://inkscape.org/download/
yes. thats inkscape
k thanks that should help. now the stepper question please
but inkscape ist no CAD/CAM tool.. make sure to check if it messes up your cordinates after generation gcode
I mean, make sure a one-inch-line in your DXF-File (or whatever) is also a one-inch-line in the generated gcode
stepper.. I dont know. would have to take a look at the datasheet
ive been trying to track down the datasheets cant find them anywhere
19 year old steppers
custom windings and the whole 9 yards
but the questions is would the resistors absorb the extra amperage and keep the motors from heating up so much
or would the steppers just pull more current
depends on your driver-circuit
ill grab a link
does it drive voltage or currant?
i dont know the difference it just puts pulses to the right winding
my guess would be voltage.. current-driver seem odd for steppers :)
its the electrial characteristic of the power-soure.. depending on this, the effect would change
[20:56:26] <DJSprocket> http://store.qkits.com/moreinfo.cfm/QK179
assuming, it is driving just the voltage, adding a resistor would limit the total current
there will also be a voltage drop across the resistor.. burning your additional energy
well i do need to run the steppers off 12 volts thats what my PSU will supply without going into protect mode
my steppers run at 42Volts, but their design is safe for that voltage :)
mine are rated at 1 amp at 5 volts
you sould mesaure the inner resistance of your stepper coils
i'd have to decrease the amperage to get them to stop over heating right?
if 1Amp at 5Volts is right, they would have 0.2Ohms
4.2 ohms to the center tap and 7 oohms across the two outside wires
ah yes.. 5Ohms,. of course :D
dammit.. I inverted that :D
no big deal
so you would add 7Ohms resistors to drop 7Volts at 1Amp
thus burning 7/12 of your total power.. quite a waste :D
the resistors i have are 20 ohms 95 watts
95Watts? how big are they?
4 incches long 1 inch wide .25 inches thick
biggest ive had my hands on
put two in parallel.. it gives you 10Ohms
shouldnt that decreases the resistance in parralel
thus you would have 15Ohms, 12Volt -> 0.8Amp
oh yeh sorry
2x20 in parallel = 10Ohms.. the stepper has 5Ohms in series -> 15Ohms
but you said i need 70 ohms
23:01 < cpresser> so you would add 7Ohms resistors to drop 7Volts at 1Amp
to drop to the voltage of 5
oh 7 ohms not 70
can you put a space between the 0 and the O its hard to read
7 Ohms :D
7 Ohm + 5 Ohm = 12Ohm -> 1 Amp @ 12 V
thats the basic Idea
so the resistors would soak .2 A?
10 Ohms + 5 Ohm = 16 Ohm -> 0.8 Amp @ 12V
yes. you would lose about 20% of your power
which would help to alleviate the heat problem?
just get a 5Volt power supply.. thats easy. plus it doesnt waste energy
i dont have the money plus i would need a 4 amp at least power supply
yeah the steppers heat up alot at 12 volts
at 12Volts, whithout the resisors your steppers run at 2.4Ampere.. thats 240% of the designed spec :)
so yes, the resistors would help.
so what would i need to get it down to 100% just the 2 20's in parralel?
no, you would need a 7 Ohm resistor
i dont have a 7 ohm that wouldnt burn out at the proposed amperage
i guess i should have said below not to
as said above:
cpresser> 10 Ohms + 5 Ohm = 16 Ohm -> 0.8 Amp @ 12V
so 10 ohms is fine
would solve your heat problem, whit little power loss
id rather run them below what they need anyways
would i lose my speed gain by putting the resistors in?
sorry, cant answer that, since I dont know :)
just test it :)
i will in a bit
most likely you will only loose torque, since speed is controlled via the step-rate
gotta go upstairs and do some soldering first
their 100 ounce inch steppers lol
* cpresser is gone for now. bedtime :)
* flyback bbl, bathroom break
JT-Hardinge: did you figure out the offset problem? I fixed something (that was not affecting you) but otherwise my testing showed that it is working right
no I think the problem was PEBKAC or however you spell it, I was correct with my offsets for the parting tool etc. but something else was wrong
dunno just went back from the start and set all the tools offset from the spindle face and checked the position in G54 and all was I expected
thanks for asking
and I just made a nice part, but I should have used cutter comp on the angled parts :/
how do you set X offset? I use the spindle for Z, but don't know how to do X well
only 25 thou deep 45 so it really don't matter this time
is it still mounted? a file is good for that...
usually a test cut
ah I suppose you don't have any X work offsets, so you can still use 'fixture'
it came out fine just some chamfers on the front and back sides of the part
I didn't even think about fixture for X
and I didn't think about lathes when I wrote it...
but it seems fine
seems to work here just fine
I think I'll make an extra one just for fun now :0
now where are the M4x0.7 socket setscrews? oh - nowhere - right
grr - off to the hardware store
good luck at the hardware store finding that
it's a decent one - usually I'm lucky
oh, I wrote a comp for an elapsed time meter, works pretty cool
2 min 12 seconds to make that part :)
* JT-Hardinge heads inside now