Graham, I just PM'ed you my e-mail address.· Looking forward to the CAD drawing.· On the screws that hold the stepper, are the ends of them flush with the mounting plate?· What is the diameter of the lead screw shaft?· I would be surprised if it was the same as the diameter of the stepper shaft.· That means your coupler would have different size holes on each end.
There are four bolts holding the stepper, two go through the larger plate and into the spacer which is drilled and tapped. The lower ones need nuts but I have not added these yet (after several years [noparse]:)[/noparse]), you could tap the plate alternatively.
The spacers are held to the smaller plate by four bolts, these are counterbored into the plate so they do not interfere.
The screws that hold the plate to the end of the axis are countersunk.
The leadscrew is 6mm but the leadscrew does not connect to the coupler my brass adapter does, refer to my webpage I posted earlier.
Graham, I received the .dxf file.· I can open it in a text mode but there is no way I can convert it to a drawing.· Don't worry about it - I'll figure out a way to do it with my limited facilities or I'll give it up.· The screws that hold the end plate on -·are they 3mm screws?
If you want to do dxf editing etc there are some free CAD packages on the web I beleive, some rather good.
You can make the adapter plates with hand tools if necessary, nothing is overly critical as everything is a little adjustable. Another good way to make the brackets is with box section aluminium I think.
Box section might work out quite well, Graham, if I can find the right size.· Probably would not even need spacers if it was thick-walled.· What is the distance between your two plates?
I can measure it but it depends on your couplings you would be better to decide once you were ready for them.
The whole idea of the box section is to be the spacers and end plates all rolled into one, there are many ways to do it which is a problem and a blessing.
THis discussion and googling has me really interested in such a project...
THe foam cutouts, PCB creation, and milling parts (like the legs for a bot)...
The steps from "drawing" to actually milling are somewhat muddy, but from what I gather, you use a CAD (CAM) program to create the object, then
take it's out out and convert it into something usable by the propeller (or bs2) to drive the mill.
is this about it?
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Just tossing my two bits worth into the bit bucket
Graham, I have not measured the shaft diameter on the leadscrew, but if it is truly 6mm, then the diameter would be .236, which is .014 less than the diameter of the stepper shaft.· If I couple them together with a very short length of 1/4" ID thick-wall neoprene gas tubing secured with very small hose clamps, the clamps should center the 6mm shaft in the center of the tubing and they should run pretty close to true.· Do you see anything wrong with this approach?
Steve, I added a couple of finishing touches to my program.· Now, if you are doing manual entry and say Left 100, after the 100 is displayed the screen says:
"Press G to continue or C to cancel"
If I press C the program goes back to Start.· If I press G the program continues.· It will accept only G or C.· Any other key, it just sits there until G or C is pressed.
Sid, yes you can probably get away with that, it sounds like you have 1/4" stepper shafts which is only a gnats whisker bigger than 6mm as you have observed. For PCB stuff the tube will work more than well enough I'm sure.
p.s. Attached is a pic of something I knocked up today on the mill for a friend, a cooling grill in a diecast box. 11 min start to finish. Anyone calls this mill a toy, slap them!
Got everything apart and the end of my leadscrew is only about 5.25mm.· Now I have a problem trying to match a .206 shaft to a .250 shaft.· If I had a good metal lathe I could make a coupler, but trying to do it with a drill press is impossible.· I may have to go back to my slider if I can't figure out a way.· I don't think I could ever squeeze .250 ID gas hose down that much.· In addition, the left end of the hose would have to be up against the leadscrew thrust bearing very tightly, and even with a washer and grease, it would eventually wear and increase the backlash.
You are right it isn't 6mm, looking at my drawings now my shaft was 4.5mm and perhaps I need to check that. It must be the little brass tube that acts as a bearing that is 6mm OD.
For a coupler you should consider buying one, some types (the oldham type) are bought in three parts, the two clamp parts can be for different sized shafts.
You definately need some form of adapter held with the rolled pin otherwise you will have end float in the screw again, it must be in tension. You could make that on the drill press, it doesn't have to be concentric.
And then there is option number two, get hold of some M6 threaded rod. That could be coupled with your tube and you could use a nut on both ends for retention. It is very cheap stuff too.
Graham, I measured the end of the leadscrew again this morning and I think 4.5mm is correct.· It is a little bit difficult to get at but I measured about .177 twice so I assume that is correct.· I think I know everything I need· now, so I'm going to put it back together with the slider until I have all the· necessary parts in hand.· I have a friend in Texas who I think can make the necessary parts.
I was looking at the pulsetrain that the Prop sends to my steppers on my USB scope.· I have a 35us pulse occuring every 1350us, which closely matches the pulsetrain the my BS2E puts out.· However, in looking at the instructions that generate this pulsetrain:
It appears that mathematically the pulse low time should be 178 times the pulse width, but this is not the case - the low time is only about 38 times the pulse width.· Can you tell me what is going on.· The 178 was arrived at by adjusting the wait time until the pulsetrain was the same as the Stamp pulsetrain.
Graham, I removed one of the screws from the left plate on the X table and discovered in was a sheet metal screw, not the machine screw I was expecting.· It measured .121 in diameter.· The closest metric size is 3mm - .118.· Did you use 3mm sheet metal screws?
I have been running my program from EEPROM so it comes on when I boot up.· This afternoon I made a small cosmetic change to the program and when I tried to load it, I got an error - "Source register/content can not exceed $1FF", and it highlighted:
Sid, I just bought screws that looked the same but were longer, it isn't crititcal. They are not machine screws because they self tap into the extrusion rather than go into tapped holes, as long as it all feels tight and secure it is fine.
Sid,
I just saw your message about the "source register/content can't exceed $1FF". The message is correct. You've given a negative number (-3 == $FFFFFFFC) for an immediate 9 bit value. Admittedly, there might be situations where this is legitimate, but they're rare. If you look at the description of the instruction, it only uses 5 bits of the immediate 9 bit value. These 5 bits indicate how many upper bits of the result are cleared. The rest of the 32 bit word (32 - source value) gets set to the reversed bits of the original content. From this description, you'd never use a negative value anyway. If you want to reverse the least significant 3 bits, use "rev data,#3".
I think they tightened up the checking of source immediates in the new version, but the old version did check sometimes.
Mike
Mike is·correct.· We had to tighten it up a bit because too many people were making the mistake of thinking they could stuff more bits in the opcode than what is possible.· So now it generates an error when you try to do this.
But, you can still get the same value in there that you could before, with just a little extra code:
rev···· data,#-3 & $1F
In fact, if you look at the Keyboard.spin object that is installed with the v0.98 tool, you'll see it has been updated for exactly this reason.
There are also other new objects provided and updates to previous objects.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ --Jeff Martin
· Sr. Software Engineer ·Parallax, Inc.
Post Edited (Jeff Martin) : 7/16/2006 2:03:36 AM GMT
OK, Jeff.· That worked fine.· The program now loads.· I have the following sequence in my program that worked fine with V0.95:
term.str(string("Press G to continue or C to cancel")) ····· repeat ······· if kb.getkey == "c" ········· start ····· until kb.getkey == "c" or kb.getkey == "g"··
With V0.98, if I hit "c", the program jumps back to start.· However, if I press "g", I have to press "g" 3 times for the program to continue.· I can comment out the whole sequence and the program operates fine, but I would like to keep it in case of erroneous entries.
it is in the repeat loop, getkey is call 3 times before it is allowed to exit the repeat loop, try this. add a temporary variable and
assign the getkey value to that. then test.
repeat
tempvar := kb.getkey
if tempvar == "c"
start
until tempvar == "g"
the == "c" is not needed in the until expression
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Who says you have to have knowledge to use it?
OK - I've got everything working good.· I uninstalled V0.95 and V0.98, reinstalled V0.95 in C:\Prop and V0.98 in C:\Prop98.· Now I can normally use V0.98 and if I develop a problem, I can go back to V0.95 and run the program again to see if I have a problem there.· Thanks to all.
I found a Proxxon MF-70 for $275.00 USD... yes...
I also found the steppers at automation direct, nice ones at $19.00 each...
... and neat bipolar controller chips as well... From allergo (A3983SLP-T) (Sampled for 3...)
SO, this along with a good user interface should come in around $400 USD or so...
(I found a serial touch pad to use...)
I also have a few ideas on making it's data more portable... (IE make it read GCode directly or a Gerber file), but, I have only just started this venture, and someone else will be working on it as well...
THis thread and the other one in the sand box has spirred me into this project... and if my friend goes for it, it will be a real good thing for both of us... [noparse]:)[/noparse]
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Just tossing my two bits worth into the bit bucket
KK, I don't think the Allegro steppers will do the job.· They are rated at 1.5A -2A peak -· and my steppers run at a constant 2A, maybe a tad more.,· Especially the Z axis - going up with the weight of the spindle motor on it takes a bit of power.· Also, you will need a keyboard input, because you will need to select several alpha options, L(eft), R(ight),
U(p), D(rill), and so on.· That is why I use a computer to control my mill.· With the new Propeller program I have a keyboard and a monitor attached.· And my stepper drivers are IB463 - about $165 each.
Comments
Sid
The spacers are held to the smaller plate by four bolts, these are counterbored into the plate so they do not interfere.
The screws that hold the plate to the end of the axis are countersunk.
The leadscrew is 6mm but the leadscrew does not connect to the coupler my brass adapter does, refer to my webpage I posted earlier.
Cheers,
Graham
Sid
It is something I should have done a while ago but I now have the cad on my webpage in DXF and PDF format:
http://www.indoor.flyer.co.uk/millingmachine.htm
If you want to do dxf editing etc there are some free CAD packages on the web I beleive, some rather good.
You can make the adapter plates with hand tools if necessary, nothing is overly critical as everything is a little adjustable. Another good way to make the brackets is with box section aluminium I think.
Graham
Sid
The whole idea of the box section is to be the spacers and end plates all rolled into one, there are many ways to do it which is a problem and a blessing.
Graham
THe foam cutouts, PCB creation, and milling parts (like the legs for a bot)...
The steps from "drawing" to actually milling are somewhat muddy, but from what I gather, you use a CAD (CAM) program to create the object, then
take it's out out and convert it into something usable by the propeller (or bs2) to drive the mill.
is this about it?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Just tossing my two bits worth into the bit bucket
KK
·
Sid
Edited by Newzed - corrected 8mm to 6mm.
Post Edited (Newzed) : 7/13/2006 3:37:19 PM GMT
"Press G to continue or C to cancel"
If I press C the program goes back to Start.· If I press G the program continues.· It will accept only G or C.· Any other key, it just sits there until G or C is pressed.
Sid
p.s. Attached is a pic of something I knocked up today on the mill for a friend, a cooling grill in a diecast box. 11 min start to finish. Anyone calls this mill a toy, slap them!
Got everything apart and the end of my leadscrew is only about 5.25mm.· Now I have a problem trying to match a .206 shaft to a .250 shaft.· If I had a good metal lathe I could make a coupler, but trying to do it with a drill press is impossible.· I may have to go back to my slider if I can't figure out a way.· I don't think I could ever squeeze .250 ID gas hose down that much.· In addition, the left end of the hose would have to be up against the leadscrew thrust bearing very tightly, and even with a washer and grease, it would eventually wear and increase the backlash.
Sid
For a coupler you should consider buying one, some types (the oldham type) are bought in three parts, the two clamp parts can be for different sized shafts.
You definately need some form of adapter held with the rolled pin otherwise you will have end float in the screw again, it must be in tension. You could make that on the drill press, it doesn't have to be concentric.
And then there is option number two, get hold of some M6 threaded rod. That could be coupled with your tube and you could use a nut on both ends for retention. It is very cheap stuff too.
Graham
Sid
what do you do if your board or object is wider than 2 inches ?
caan you split your drawings up ?
dan
I was looking at the pulsetrain that the Prop sends to my steppers on my USB scope.· I have a 35us pulse occuring every 1350us, which closely matches the pulsetrain the my BS2E puts out.· However, in looking at the instructions that generate this pulsetrain:
··· OutA[noparse][[/noparse]thePin]~~···········
··· WaitCNT(cycle + CNT)······ 'cycle = 600
··· OutA[noparse][[/noparse]thePin]~········
··· WaitCNT(cycle*wait + CNT)···· 'wait = 178
It appears that mathematically the pulse low time should be 178 times the pulse width, but this is not the case - the low time is only about 38 times the pulse width.· Can you tell me what is going on.· The 178 was arrived at by adjusting the wait time until the pulsetrain was the same as the Stamp pulsetrain.
Thanks
Sid
Sid
I have been running my program from EEPROM so it comes on when I boot up.· This afternoon I made a small cosmetic change to the program and when I tried to load it, I got an error - "Source register/content can not exceed $1FF", and it highlighted:
configure·············· mov···· data,#$F3··············
······················· call··· #transmit
······················· mov···· data,_auto
······················· and···· data,#%11_11111
······················· call··· #transmit
······················· mov···· data,#$ED
······················· call··· #transmit
······················· mov···· data,_locks
······················· rev···· data,#-3····· 'highlighted the " -3 "
······················· test··· data,#%100····· wc
······················· rcl···· data,#1
······················· and···· data,#%111
······················· call··· #transmit
·I tried loading older version of the program and got the same error.· Can you tell me what is wrong and how to fix it?
Thanks very much
Sid
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Who says you have to have knowledge to use it?
I've killed a fly with my bare mind.
http://www.indoor.flyer.co.uk/spitmill.htm
I actually working on a larger conversion too:
http://www.indoor.flyer.co.uk/kt150conversion.htm
Sid, I just bought screws that looked the same but were longer, it isn't crititcal. They are not machine screws because they self tap into the extrusion rather than go into tapped holes, as long as it all feels tight and secure it is fine.
Graham
I just saw your message about the "source register/content can't exceed $1FF". The message is correct. You've given a negative number (-3 == $FFFFFFFC) for an immediate 9 bit value. Admittedly, there might be situations where this is legitimate, but they're rare. If you look at the description of the instruction, it only uses 5 bits of the immediate 9 bit value. These 5 bits indicate how many upper bits of the result are cleared. The rest of the 32 bit word (32 - source value) gets set to the reversed bits of the original content. From this description, you'd never use a negative value anyway. If you want to reverse the least significant 3 bits, use "rev data,#3".
I think they tightened up the checking of source immediates in the new version, but the old version did check sometimes.
Mike
Mike is·correct.· We had to tighten it up a bit because too many people were making the mistake of thinking they could stuff more bits in the opcode than what is possible.· So now it generates an error when you try to do this.
But, you can still get the same value in there that you could before, with just a little extra code:
rev···· data,#-3 & $1F
In fact, if you look at the Keyboard.spin object that is installed with the v0.98 tool, you'll see it has been updated for exactly this reason.
There are also other new objects provided and updates to previous objects.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
--Jeff Martin
· Sr. Software Engineer
· Parallax, Inc.
Post Edited (Jeff Martin) : 7/16/2006 2:03:36 AM GMT
term.str(string("Press G to continue or C to cancel"))
····· repeat
······· if kb.getkey == "c"
········· start
····· until kb.getkey == "c" or kb.getkey == "g"··
With V0.98, if I hit "c", the program jumps back to start.· However, if I press "g", I have to press "g" 3 times for the program to continue.· I can comment out the whole sequence and the program operates fine, but I would like to keep it in case of erroneous entries.
Sid
assign the getkey value to that. then test.
repeat tempvar := kb.getkey if tempvar == "c" start until tempvar == "g"the == "c" is not needed in the until expression
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Who says you have to have knowledge to use it?
I've killed a fly with my bare mind.
Sid
Where did you get your steppers from?
I'm trying to find out how much it would cost me to make a supermill (for someone else)...
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Just tossing my two bits worth into the bit bucket
KK
·
Sid
Sid
I also found the steppers at automation direct, nice ones at $19.00 each...
... and neat bipolar controller chips as well... From allergo (A3983SLP-T) (Sampled for 3...)
SO, this along with a good user interface should come in around $400 USD or so...
(I found a serial touch pad to use...)
I also have a few ideas on making it's data more portable... (IE make it read GCode directly or a Gerber file), but, I have only just started this venture, and someone else will be working on it as well...
THis thread and the other one in the sand box has spirred me into this project... and if my friend goes for it, it will be a real good thing for both of us... [noparse]:)[/noparse]
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Just tossing my two bits worth into the bit bucket
KK
·
U(p), D(rill), and so on.· That is why I use a computer to control my mill.· With the new Propeller program I have a keyboard and a monitor attached.· And my stepper drivers are IB463 - about $165 each.
Sid
For cheap drivers consider those from Xylotex they have a very good reputation:
http://www.xylotex.com/
3-axis for $155 and 2.5A/phase chopper current limited.
And if you want to get machining while you develope your Propeller apps look at:
http://www.dakeng.com/turbo.html (DOS)
and
http://www.machsupport.com (XP)
Graham