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Topic: Poor Man's Digital Dentist Core XY Build! (Read 5121 times) previous topic - next topic

Qdeathstar

May 08, 2017, 03:03 am Last Edit: May 08, 2017, 03:04 am by Qdeathstar
Hi guys.

LED's got me into Arduino, and Arduino got me into 3D printing. And now that I'm into 3D printing i've found a nice hobby.

Anyway, i am working on a coreXY machine with an approximate build platform of 18" cubed. For those of you who don't know, that is a large format printer. The gold standard prussa i3 has a build platform of around 8" cubed, for comparison.

My design is inspired and almost entirely coppied from The Digital Dentist's build over at RepRap.org. His printer is almost done, but I was so impressed with his build that I took at look at his pictures and I'm in the process of building an approximation.

He has access to a milling machine, and I don't, so had to make some sacrifices to account for this, but over all its looking good.


I thought this might be useful to Travis, since he is building a CNC machine and personally, i think a coreXY design lends itself to CNC as well as 3D printing.







I was able to finish a version of the effector mount. I haven't fully decided on my hotend it yet so there is definitely going to be changes.... im thinking about either dual e3dV6 or i've already a cyclops i modified to have water cooling. I want to do a direct drive (no bowden) system, however. I have might have some Nimble extruders for the cyclops, and if they get here and work that might be OK. The only issue is now i have a big printer and i really need a .8 nozzle or larger to make practical use of it and they are only available with e3d v6.

-Not bowden
-Dual Extrusion
-different nozzle sizes available

Would be my main criteria in that order. If anyone has any ideas on the front i'd appreciate it!





The motor mount didn't have enough "play" to get it to where i need to be in order to make the belts parallel, which is a requirement for coreXY printers, so i've got another one printing down that shifts the upper square over. derp.  You can also see where i've added some mechanical stops to prevent the rail from sliding off the guides. Had that happen to me yesterday. Not again! (not a big deal, the rails have ball bearing retainers).





Thanks to The Digital Dentist for the idea of the belt mount.












Overall, the belts look parallel, which is good news. I'm waiting on the slowboat to get here for the larger pullys for the idler bearings... only option was to get them on aliexpress and wait forever. Well, unless you wanted to pay $15each for them. I've got an old RAMBO board hanging around so once i get the motor spacers reprinted i might fire it up and see how she chootches!. I've made some hole in the effector mount to attach a spare linear rail to so i can try the pencil thing DD did. I think that is a great way to check for backlash/optimum speeds, since you can easily see the ripple. Though, i expect with the hotend attached you might have to run a bit slower because of the added mass.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

travis_farmer

looks pretty neat, though i am a little confused by the miles of timing belt run everywhere. I think i know how it works, but then i look again, and i am re-confused ;)

I see you went with the high-dollar slides... i found those to be a little pricey for my wallet. a little tall to route without deflection, i think. ;)

pic #3, get your dirty socks picked up before posting pictures ;)

Maybe a diagram of the belt layout would ease my confusion. looks sturdy though.

I have revised my slide design to use V-bearings on the edge of angle steel, as i read through the designs on CNCZone. I can get a pack of 20 from VXB on eBay for fairly cheap, and the angle steel i can get at Lowes or Home-Depot. I am going with a larger format, like around 36 X 48 inch, and i will do my best to over-build it to be rigid. I will use steel or aluminum components where needed to make the wood frame more rigid.

so far i have only the ideas in my head, as everytime i draft something up on Fusion 360, i change the design, and have to redraw it again.

~Travis
Current Obsession: My server rack cooler, and my CNC Router
Check out my website, i have my own under-used forum on my hobby server.

Boardburner2

pic #3, get your dirty socks picked up before posting pictures ;)



~Travis
Size calibration reference  :)

travis_farmer

Current Obsession: My server rack cooler, and my CNC Router
Check out my website, i have my own under-used forum on my hobby server.

Qdeathstar

I am using iko rails. I got them used on ebay for 30each. The sock is clean afaik, it's just dingy.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Qdeathstar

A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

travis_farmer

There is the belt path.
well that explains things greatly. not sure how it would work for CNC though. I am not sure, but i don't think LinuxCNC would be able to drive steppers in such a configuration...
still pretty neat though, how it moves the X/Y like that. must be some sort of stepper mixing in the software.

how does the Z axis move up and down? seems like it would be a lot of hanging mass when the Z is all the way down. or does the table move up and down?

~Travis
Current Obsession: My server rack cooler, and my CNC Router
Check out my website, i have my own under-used forum on my hobby server.

Qdeathstar

LinuxCNC supports corexy. The advantage of a corexy design is that you do not have to move the x axis motors when changing y position, and that allows greater speed at higher accuracy. My bed moves down for 3d printing,  but you could also mount a motor on the effector to move the z position.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Qdeathstar

#8
May 21, 2017, 08:33 am Last Edit: May 21, 2017, 08:36 am by Qdeathstar
video

chootching away!  Stepper whine is delightful :D



I put in a bigger bearing at the idler mount so the belts don't rub.



Parallel belts :D
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

travis_farmer

i would have to agree that stepper whine is delightful. I bought a small Chinese laser engraver/PCB mill. when it started moving after putting it together, i fell in love with the little machine. :D i can't wait for the moment my big CNC comes alive (swapping the unknown servos for steppers).

looking good on your build, though i am not a fan of sharp corners. they always have a way of attracting bits of flesh as you walk by it ;) but still, looking good :D

~Travis
Current Obsession: My server rack cooler, and my CNC Router
Check out my website, i have my own under-used forum on my hobby server.

groundFungus

Quote
Stepper whine is delightful :D
The bCNC program that I use has, in its tools menu, a program that turns MIDI music into Gcode.  Play tunes on your CNC machine.

Qdeathstar

I filed down the edges so it's not as sharp as it looked. Only having access to a wood table saw and wood band saw the edges are a bit rough... but hey, you gotta piss with the dick ya got.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Qdeathstar

some reason the quote button ain't workin :-/..

but, travis, the mill was delivered already? How do you like it? What have you built with it. Any chance it would cut aluminum very slowly?
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

travis_farmer

some reason the quote button ain't workin :-/..

but, travis, the mill was delivered already? How do you like it? What have you built with it. Any chance it would cut aluminum very slowly?
yes, my mini CNC was delivered within 5 days of purchase. i think somebody must have added nitrious-oxide to the slow boat from China. either that or i have gained expedited service from ordering so much from China ;)

i like it so far. i have done a laser engraving so far. it took about an hour or so to burn a raster image that came out about 2" X 1.5" or something like that. i still have to play with the settings to get more detail, and a faster burn time. I haven't milled with it yet, but i think it would be too small for milling aluminum. it is mainly for engraving plastics, or milling PCBs. I have to play around with it some more to get the Z-axis to lift between cuts. i think it is stuck in laser mode (no lift). i can jog the Z, so i know it works. but i will have to play with it some more before i put a milling bit (about 1/8" chuck).

my big CNC could probably cut aluminum, when complete, but it isn't really built for it (solid T-track table, no coolant/oil sump). I had a chance to buy a metal CNC mill, but i didn't have that kind of money, or any way to transport it.

~Travis
Current Obsession: My server rack cooler, and my CNC Router
Check out my website, i have my own under-used forum on my hobby server.

Qdeathstar

#14
May 22, 2017, 12:00 am Last Edit: May 22, 2017, 12:00 am by Qdeathstar
I think if your CNC can cut wood, it can hack metal :D Good enough for me. Who needs coolant when you got some nice chinese flutes and a couple cans of WD-40!

I got my first print out of my coreXY printer.

a perdy drawing

:D Most complicated 2D printer ever.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

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