Cyclone-PCB-Factory
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CarlosGS
idea for z axis improvement
I had tried to describe an idea earlier here are some pictures
I took the top plate of the tool holder, reversed it and placed it at the top of the axis, added a nut then the bearing then a nut then the gear.
the lm8uu are only to line things up, the smooth rods should butt into place instead, like they do on the x axis carriage so the top plate would be smooth above the rods, Won't need anything to the right of the black line
Side views, can make a raised platform section with an open slot from the back to all the stepper and gear to slip in
at the bottom its a matter of removing the gear, and moving that bearing somehow to the space below the black arrow, or it could go right through to the bottom of the x axis carriage
i think this creates a good solid frame that you could then put a z carriage in with backlash nuts like the other axis.. .
I am finished the basic build now, i have modified it slightly by using 2 more y-smooth rod holders at the back and cutting out the holders that are part of the side frames, it was pretty easy to do. I have centered the tool point at the center of the y-axis distance. Haven't put a work bed on it yet, This give me 13.5 inches of total length on the y-axis and 12 inches on the x-axis. i would say it took me approximately 25 hours to print everything and about 4 hours to lay it all out too this point. Next thing i think is to extend the y threaded rod, i didn't have a piece long enough but my thought is to bring it flush with the front y smooth rod holders.
Hi @ve3sjk i think this is what you want als a top for the z-axis. Its a fixed top in the x-carriage the nut need to be removed and there need to come a place for a radial bearing. And a new z-carriage need to be designed.
pretty close i would have the bearings on the outside, excuse my handwriting maybe this might help you visualize it. this would be a side view from the left side, the upper bearing would have a nut on the inside to prevent it from slipping down, so it would be nut, bearing, nut
the a new z carriage would look something like this, with just a mounting plate facing the front of the machine you could incorporate backlash if you wanted not sure its needed on Z. i know i have seen backlash nuts before there as well
You are right, there is still a lot to do :-) . I think i will try work on the files around Christmas when i have a little more time. But i like the idea that the threaded rod stay in place and not move up or down. If you have more wishes or ideas a bout the z-axis just put them here in this issue.
thank your for working on it, i am good with the idea but bad with open scad, lol. but i am learning fast. On my machine i have offset the x axis to -180 since i have 330mm smooth rods, Its a bit more plastic and it going to need some work, i am printing this part right now, One thing i am having trouble with is where in the code is that Y-smooth rod holder that is attached to the x-frame being built. I built the machine with two extra y-smooth rod holders in the back cutting off the ones that where there, but i like the structure of this frame, i had to offset the bottom back mounting hole in the back of it, as the smooth rod holder just rendered on top of it. This puts the spindle tool tip dead center of the y axis. Still working out how to calculate the new workbed size to max out the working area.
one other thing i have modified is i took the end stop assembly out of the standard parts file and made it standalone, added the parameters for it to the configuration files. I going to use highly VS-15 roller switches instead, this way i can modify the file for different kinds of switches. I am thinking and option in the config file to choose which one you want. Still want to get all 4 endstops on the machine, i think one can be added to the front Y frame for sure then its a matter of getting on on the right X frame.
i noticed you created a v2.1 branch in your repo. Is that for the new version release. I am wondering how i keep my repo up to date with your changes. I forked from yours.
Yes the v2.1 branch is for the new release. Carlosgs released v2 last weekend. I think you need to create a new branch in your repo and than pull my branch in it that way you have my new branch and than you can update that again.
I like the ideas on the revised Z-Axis part. It looks to have similar concepts per the portalcyclone project? Is there value in looking at how that project does this part? From what I can see it seems to be pretty sturdy.
@ve3sjk re the the overall adjustments you are making. I was wondering what length you were using on your X and Y smooth rods? Are you experiencing any "sag" over the longer lengths or did you use 10mm or 12mm diameter rods to counter that possible issue?
Hi @joco-nz thanks for pointing out the portalcyclone. That z-carriage looks very sturdy and i think something like that will make a perfect fit for this project. I will look at it when i have some more time because it need to be configurable for rod diameter and length and bolt size and other parameters.
@D-Byte Agreed - you won't be able to just take it as it is as I think only the STL is published. So you are still going to have to code things up. However having a target shape instead of a blank sheet of paper always helps.
@joco-nz I am using 330mm M8 rods, i don't see any sag that would cause an issue but if it becomes on i will switch to a bigger smooth rod. As a quick test i placed a temp work bed on the system centered on the y-axis. I put two old ide hard drive on it weighing 2.2 lbs. I can't measure any deflection with a micrometer with that on it.
is the captive nut for the z axis that is held in the space on the x carriage supposed to be glued in, from what i can see if it isn't then as soon as the tool pushes down on the circuit board, the z axis threaded rod just lifts out of place at that point making downward pressure unobtainable. Maybe i missed something on assembly
@ve3sjk re the captive nut on the z axis, I don't believe it needs to be glued based on the loads intended for this design, ie PCB milling. With the weight of the spindle/Dremel there should be enough pressure to have a high speed rotating bit cut into a PCB copper layer and substrate with no issues. I have been doing milling tests on mdf with no issues. Milling something harder like aluminium might present more of a challenge but I hope to be in a position in a few more weeks to report on my findings in that space with the v2 design.
@joco-nz I don't think i have ever seen a cnc where the z-axis does that, seems like it would be a better idea instead of having the nut drop in the way it does would to have a slot there to captivate it fully. I understand the concept but in my thoughts, the amount of downward pressure is very dependent on what spindle you use, if the spindle is very light, then its not going to get much downward cutting force. Maybe i can figure out a little clip that pushed onto the tab where the nut goes now to lock it into place.
@ve3sjk Agree hence why I framed my response with reference to the design parameters of the V2 cyclone. i.e. Dremel Spindle. I'm looking into a light weight air powered spindle which will have exactly the issue you have identified due to negligible weight. So we will need to find some form of solution. :-)
I have this nagging feeling that you could probably added a spring/nut backlash system in the hexagonal hole where the threaded rod pass through under where the existing nut sits. I'm at work so I can't test the fit to see if that is viable. But such an approach would at least off some extra pressure while also allow some give if there was an error and too much downward force was being applied? Your clip approach would definitely fix it. Or we look to adjust the design of the x carriage slightly.
@ve3sjk sorry another thought. Of course the whole nut issue would appear to go away once we sort a more solid Z axis design akin to your hand drawings above (good ideas by the way!).
@joco-nz I don't think a spring would do it as the rod needs to thread down in the design so you would need to captive both nuts that way. A full frame would solve it in a new design, in the current design i suppose it just a matter of relocating the nut. Wish i was better at openscad, i think it would be a matter of selecting that front face and putting slot in it the thickness of the nut after removing it from the top.
Pretty well ready to wire it now, variant Cyclone PCB Factory, work bed size is 300mm x 210 mm. X x y axis 330mm rods. Tool holder is a work in progress, i have modified the top plate to fit a Dremel XPR 400 and used two top plates to get it mounted. In the process of modifying the vacuum cleaner attachment to also fix the XPR-400, and getting the wrench slot to render properly. Since the work bed is 12mm thick i have room to mill it smooth when every think is running, although i am pondering the idea of milling some T-slots into it instead.
It looks so amazing!! Thanks for sharing! :D On 14 Dec 2014 20:02, "ve3sjk" [email protected] wrote:
Pretty well ready to wire it now, variant Cyclone PCB Factory, work bed size is 300mm x 210 mm. X x y axis 330mm rods. Tool holder is a work in progress, i have modified the top plate to fit a Dremel XPR 400 and used two top plates to get it mounted. In the process of modifying the vacuum cleaner attachment to also fix the XPR-400, and getting the wrench slot to render properly. Since the work bed is 12mm thick i have room to mill it smooth when every think is running, although i am pondering the idea of milling some T-slots into it instead.
[image: 2014-12-13 20 32 29] https://cloud.githubusercontent.com/assets/7632604/5428841/c0a50124-83a1-11e4-9d38-a08d57818fdb.jpg [image: 2014-12-14 14 52 03] https://cloud.githubusercontent.com/assets/7632604/5428842/c575a7ee-83a1-11e4-87aa-f985d666d88f.jpg [image: 2014-12-13 20 39 29] https://cloud.githubusercontent.com/assets/7632604/5428843/d22aaf2a-83a1-11e4-890f-9c1d5a3cda96.jpg [image: 2014-12-13 20 42 05] https://cloud.githubusercontent.com/assets/7632604/5428844/d490725e-83a1-11e4-8552-f79b74a3255c.jpg
Reply to this email directly or view it on GitHub https://github.com/carlosgs/Cyclone-PCB-Factory/issues/32#issuecomment-66927234 .
@ve3sjk Awesome build! And I love the increased size. You have inspired me to look at how I would "upsize" my build over the summer holidays (winter for you northern hemisphere folk).
On the z-frame front. I'm not a bad hand at OpenSCAD so might have a crack at that improved frame. It won't be a flash a bit of coding as what @D-Byte will crank out but I have time on the train each day to work on it so if nothing else it might serve as a raw base for others to work with.
@ve3sjk do you have any views on the vertical dimensions of the solid z-mount?
@ve3sjk and @joco-nz making the Z-nut captive is 10 minutes work ;-) after two weeks of trial and error in OpenSCAD.
Just making the z-nut holder captive was not an option because the linear x axis bearing is behind it.
So i made a option in my settings file where you can chose the alt_z_nut option. That place the z nut under the linear x axis bearing where there is more room.
I don't know if the threaded z rod length allow this also there is the problem of the captive nut holder have some tolerance for printing and fitting the nut. I think this is not a good solution. Maybe you two have a solution for these problems in mind. I think glueing the z-nut or the solid frame is a better solution to this problem.
This or a spring based system which I proved tonight and which can be setup with no reprint needed will stop the threaded rod nut from moving out of its trap. BUT it will not solve the fundamental issue. If you lower the Z axis faster than the rate of cutting into the milling target, as based on the weight of the spindle, said spindle will get left behind as the threaded rod and associated bearing lowers faster than it does until the rod gear is no longer engaged with the motor gear. Until we move to a setup where the Z carriage has a similar captive nut model as used in the X and Y axis along with a similar fixed position to anchor the motor and gearing off this issue will remain. At least that is how it seems to me after moving stuff about and pretending to have just this failed cutting situation and seeing what parts moved and what didn't.
I am trying to figure out the settings for Marlin for the axis steps per mm, If i put 2560 on line 495 of configuration.h it shows a 256.01 on the screen, If i tell it to move 10 mm it moves 1 mm, and if i tell it to move 100 mm i get 10 mm. I am working from a new fork of the latest version of marlin.
I would suggest you look at the Marlin version that ships with Cyclone 2. It has the correct settings in it. These are relevant lines:
#define Cyclone_XY_Gear_Ratio 21.0/21.0 // Number of tooth (motor/rod)
#define Cyclone_Z_Gear_Ratio 8.0/15.0 // Number of tooth (motor/rod)
#define DEFAULT_AXIS_STEPS_PER_UNIT {3200.0/(Cyclone_XY_Gear_Ratio*1.25),3200.0/(Cyclone_XY_Gear_Ratio*1.25),3200.0/(Cyclone_Z_Gear_Ratio*1.25),800} // steps per unit for Cyclone
@joco-nz thanks that did it, just dropped those lines into my fork and it changes to 560 i think in the lcd display, 10 mm is 10 mm now.
@D-Byte I think i am just going to glue mine in for now, i don't really like this way of mounting the dremel i will move to an actual spindle motor as soon as i can. The real solution is solid frame, that way the z-threaded rod is held in solidly held in place between two bearings. The sled that moves inside it can be pretty simple after that, it just needs smooth rod holders and a fully captive nut, i don't think backlash is needed on this axis. I still think a flat surface facing front on the sled with just mounting holes so one could can the tool head easily.
I can see my m8 threaded rods are to be desired, lol. Going to have to source some straighter ones. I am thinking m10 sounds much better for those and maybe even the smooth rods.
My machine has come to life, all 4 limits are in, and my x and y are moving now. I can even get it to follow a board i made some time ago in Cnc-Gcode-Controller after figuring out the proper output from eagle and pcb2gcode. Perfect output no errors or warnings in cnc-gcode.
Need to get the z-axis moving as is for now, wanna see it cut something now that its homing x and y perfectly for a final cutting dimension of 240 x 200, preliminary test make me thing the pin definition for the probe maybe wrong for my build. I think it was 27 in the defines added to the pin.h file, i am wondering if that is something different for the mega 2560. i can trigger my z-min with a ground but i don't think the probe is seeing it.
i got it, sweat and simple a little plate with a slot in the front the size of the M8 threaded rod. Put the captive nut on the z axis in, then acetone the plate in not going to move after that. Just need to project that tab were the nut goes onto a flat surface and print it maybe 1mm thick.
@ve3sjk re probing. From what I can tell the probe function just uses the Z endstop. So if you can home Z correctly then the probe routine should see the Z endstop fine. The only other angle I can think of is that the Cyclone 2 Marlin has tweaked the the probe G-Code in some manner.
I'm using a mega 2560 with the Marlin V1 from the Cycline 2 repo and it "just works". The only tweaks I think I needed to do was on the endstop logic to get correct settings for NC and NO behaviour on the micro switches.