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3-Axis Stepper Controller


alberto

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If you have checked the time for delay on the pulses and you are confident that this is not the problem, I would check over the connections to the board and just make sure you did not miss something.

Next, are you sure your 1 A power supply is sufficient? Depending upon the stepper, you probably have 4 coils per stepper. 3 steppers? That would be 12 coils at 160 mA. Seems like you need a minimum of 2 Amp. As a general rule, you do not want to run at the minimum. Most devices are engineered at 2X the minimum.

I have always used an old computer power supply for running steppers. If you have access to one, you might want to connect the 12 volt connector to your project to see if you get better results.

MP

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  • 2 weeks later...

You could use the UCN5804 outputs to turn on and off power transistors, but then you could also do this without even using the UCN5804 chip.
It would be hard to relate the rating to oz/in. since the current ratings of the motors are what you actually calculate. Different gear ratios, etc. would give you different results.

MP

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  • 4 weeks later...

I'm glad to see this project still has followers. I've read the whole site and felt a little disappointed to near the end and see posts like the main chip is no longer made. Still I'll have a go and try and find one.
My Project = I want to make a wood cutting router table to cut up to 5mm ply but be able to cut 8' by 4' sheets (probably a little bigger than the average project posted on here). I'm thinking of directly coupling steppers on the end of threaded bar to move a trolley around that has the router mounted on it. Any suggestions as to what size steppers I'd need for this or what I could use as guides to keep it accurate. I envisage an accuracy of 0.1 of a mm to be more than enough. Any plans anyone knows about on the net I could get inspiration from? Anyway excellent site...Thanks.

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This chip would not power steppers needed for such a project. You need something like a L297 and L298 combination to get enough power. Steppers are rated in torque. You should be able to calculate the motors needed from the torque rating if you know what it is. Actually, this is something you will want to figure out before you start this project. Otherwise, you might end up with a completed project that stalls when feeding the wood into it.
As far as keeping with accuracy, I would suggest a lead screw connected to the stepper and a couple of rods with brass bushings to keep alignment. The tolerance of the bushings and looseness of the thread would be your maximum tolerance.

MP

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Thanks for that. I guessed as much. The control circuitry should work all right I'm thinking maybe just a high power buffer on the end of it to power the steppers. I'm at a bit of a loss as to how to calculate what size stepper I'd need. I have access to some that are 3.1A per phase max 70 V but can't seem to find anything similar on the net to gauge if this is big enough or not. I'm not too fussy about the speed of cut Ie if need be I can do multi passes. I don't need to cut the ply in one go. By lead screw do you mean a proper machined screw or a piece of say M10 threaded rod. I'm obviously hoping the threaded rod will be ok but slighly worried about sag or twist over the length. I like the look and the reports on this project and the fact it interfaces directly with dnacam or something similar is just what I'm after.

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Hello All,

I have recently been browsing non stop to find a great CNC stepper controller so i can build my first CNC milling machine for my PCBs to make it slightly easier to make double sided PCBs.

I was just wondering if anyone here from Australia could point me in the right direction to find the UCN chips or similar. I read in this forum that the 5804s can be replaced by the 3967 or3977 chips(not pin for pin) is this correct? I dont mind making heaps of off board connections. Such as im too lazy to order in the resistor network and have way too many 4k7 resistors so ill probably use veroboard with wiring to make similar.

Also just to verify. My motors have 0.66A stamped onto the XY motors and i need another do i need to find another similar motor for the Z axis? I also wanted to know some calculation confusions. Say i had 3 of the 0.66A motors, My current draw would then be something like 4 coild times by 3 motors = 12, therefore 12 x 0.66A = 7.92A. Is this correct? Also if this is correct for the different motor on the z axis could i just figure out the 8 * 0.66A (xy motor) + 4 * (new motors current draw)???

Also with the programs i will be running an old computer with 98 on it.I like the sound of turboCNC but would like to know what people think is best suited for this OS.



Thanks in advance.
Daniel

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I run mine on Win98. Also, I use an old computer power suply for the power source. I felt there was no point in re-inventing the wheel since I had a few old computers sitting around not in use.
What software will you use? I wrote an X,Y type program that I can use for making my own drill files, but it does not optimize the run nor does it read gerber files. Just curious what everyone is using these days. I built my CNC a number of years ago. It does not use the UCN chips. Uses L297 and L298 combinations.

MP

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Hello MP,

Thanks for the quick reply. I didnt really expect it to be that quick. As for the power supply ill be using an old ATX power supply retrofitted to be a lab supply with a 10w 10ohm resistor for load. I'm pretty sure i remember that computer supplies only give the neccisary current needed but i would just like to know how to figure out the steppers surrent usage anyway as i like to know for future projects and knowledge. As for the computer i was lucky enough to get a free toshiba laptop from way back (one of the first satellite series) and it has 98 and was thinking of running it on that with turboCNC.

As for the controller i have seen some of the l297,298 chopper controller but it seems to be a bit more difficult to make where as i like the UCN5804 because of the simple layout and size. I have actually sourced the chips finally from an aussie dealer ($22 each) bit heafty compared to the $5 each l297/298 price. If the xyz chopper type controller is better which is the best design cause i have seen a few. Also is anyone willing to do some boards up if im too lazy to etch them myself (of couse ill throw money their way).

Cheers,
Daniel

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Hi Twistedfuse  ,
                          i am australian as well , i was wondering if you could post a pic of your controller ? i would like to see one complete  kinda of a visual guide  .
did you build it exactly the same as the one  on this page :
http://www.electronics-lab.com/projects/pc/008/
i am about too attempt too build this project myself i have managed to source all my parts from Wiltronics here in ballarat ,victoria .

cheers  Thiokol

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  • 3 weeks later...

hello, i'm making my own CNC mill and i was wondering where the schematics for the  UCN5804B motor controller. i saw the schematics but there a litttle scetchy and i was wondering if anyone has pictures of there pc board layout. and i just saw a picture posted on this forum of the bottom of a pc board where he drew i the limit and home switches and i wonder where he got that. thanks ahead

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hello, i'm making my own CNC mill and i was wondering where the schematics for the  UCN5804B motor controller. i saw the schematics but there a litttle scetchy and i was wondering if anyone has pictures of there pc board layout. and i just saw a picture posted on this forum of the bottom of a pc board where he drew i the limit and home switches and i wonder where he got that. thanks ahead



On the project page you'll find the schematic, pcb layout and parts overlay in *.ps format.

Here is my modification, I changed it a bit to suit my needs.

Nikolas
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  • 2 weeks later...

thanks for your version, i got tired of being lazy and got ghostscript so i could view them. i cant find any places that would have the chip "UCN5804B". i dont have a credit card but i can send money order. does anyone have any extra or if i could pay someone to get a hold of one that would be great. the cnc tutorial listed on engadget shows a picture of the circuits and things and it looks like they baught theirs as a kit. if anyone knows of how to get a kit or would be willing to throw it together 4 me its worth 40-50$. sorry for all the questions but i'm only 13.
some close up pictures of your pcb board would  be apreciated.
thanks

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hello averagejoe

  Here you go joe
http://www.alltronics.com/cgi-bin/category.cgi?item=25I001

if you go to there home page and hit the help link it well how to buy with cash
                                              hope that helps
                                                    gogo

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  • 2 weeks later...

Hey my CNC mill is coming along alright... I am still stuck on how to do the electronics. Could someone take some pictures of their CNC electronics just take about 10 close ups of your board. it would help alot. i'm a visual learner. I will post sum pics of my project later today. I will give credit to anyone who helps with my project. I'm entering it into our science fair. thanks alot...
averagejoe

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hello, I just got some pics of my project but my camera battery died so I only have 4 the first two are atached and they are of my (1) my frame and base and the second is just of the threaded rod and hex nut I am using that will allow the first axis to move. You can also see I am using copper pipe and some plastic pipe as sliders. This is all stuff you can get from home depot. I may have to buy a different stepper motor to suit the electronics because this is a four wire motor. And most of the stuff I am seing is for five and six wire motors. My table is pretty large so i don't consider it just a pcb milling table. it's going to be a 3x3x1 <- The 1 is the z axis .

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Here is the other two pictures I have they are both really to bright to view. I had the flash on by accident. no wonder I only got 5 min's of battery life. They are both pictures of my stepper motor and my other hex nut i have on the end so i can connect the motor with the threaded rod. Buy some J-B weld while doing your project it helps with everything you would consider weldng. after that stuff dries it is literally as tough as steal. you can get it at canadian tire.

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post-22181-14279143057017_thumb.jpg

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On mine, I actually use the 12 volt for the steppers and the 5 volt for the digital portion of the circuit. Yes, you just connect the wires to the power lines. If you want to add fuses, it is a good idea. I cut a lot of corners on mine becuase I had to build it fast to get a large number of circuit boards drilled before a deadline. Thus, I did not incorporate fuses, limit switches, or a number of other safety parameters.

I have never used KCAM, but I have been told by other members that it works well with this project.

MP

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