Lowrider CNC

[dkj4linux]

I'm not sure I understand, but won't the bolt block some of the travel ? If I look at the pictures with your fingers undeside, even if the shuttle is at its highest position, the bolts would hit them at the gantry slides sideways.

Would'nt it make more sens to block the bolt on the shuttle, and have the bearings on the gantry ? that way, as the shuttle is lifted, the bolts don't scratch/limit the surface underneath.

The idea here is that the needle cutter/laser/etc doesn't actually require a lot of Z-axis travel in operation... once the business end of the tool is properly positioned above the work piece. Envision mounting the needle cutter so that it's needle guide extends below the heads of those guide rods (bolts)... even at the highest position. Yes, the bolt heads could be positioned quite close to the surface of the work piece but as long as they clear, they clear... they'll never move or interfere with movement of the cutter head over the work surface.

The guide rods could, as you suggest, be firmly fixed to the shuttle and the printed bearings mounted to the carriage body... the guide rods would then move with the tool head and never be in the way. But, in this case, the relatively large/complex printed carriage was developed first... and it was easier, at the time, to simply fix the guide rods to the carriage -- for visualization of range of motion primarily -- and then come up with a shuttle/bearing system to fit.

Remember, I'm just feeling my way along here... :black_eyed:

 

[dkj4linux]

Almost ready to test...

I found a pineapple coupler in my MPCNC junk box, cut a short (~95mm) leadscrew, and completed the leadscrew assembly...



Attached to carriage body... there's just enough room for the coupler...



Lifted the shuttle and used pineapple to thread it onto the leadscrew...



Complete carriage with Z-lift assembly in place... may want to install guide rods (bolts) and bearings on other end of carriage/shuttle for balanced endstop if lower max is ever [inadvertently] reached and/or if binding seems to be a problem...



If I can find a place to attach those wires... it should be ready to test

Looking at it and thinking out loud... I suppose the leadscrew assembly could be inverted (motor sitting where pineapple now sits) and a skirt/saddle-type shuttle fashioned to drape down all sides/ends of the carriage. That could allow a much larger range of motion since the leadscrew and guide rods would point upward... etc.

Not necessary here, though... I'll test what I've got...

-- David

 

[dkj4linux]

Alright... I admit it!

I'm an old man... and I'm easily amused.

Way back when... I was paid for my engineering services and CAD was a 2D thing... that's where virtually all my CAD experience was gained. But all this newfangled stuff -- this 3D stuff -- just blows me away!

I've discovered how to open the McMaster-Carr catalog and download models of their hardware and import it into Onshape. So now I'm playing with Assembly drawings and I'm just discovering how to put things together into a virtual assembly. I'm still really awkward at this point (that'll probably never change at this late date...) but I'm having a blast!





Cool!

 

[jhitesma]

That McMaster catalog is dangerous in a very good way Though...it's also a little dangerous in a bad way - I've found onshape's performance can start to drag on my computers if I start using too many complex models. So I tend to stick to simpler mockup models instead of the actual part models a lot of times. Like instead of importing an 805 bearing I'll just use a quick sketch/extrusion to show the basic dimensions.

Which kind of bugs me. I really want to make REALLY detailed models with each ball in a bearing and the seals all modeled...and I know I can. But I'd rather have quicker performance most of the time

I still get hung up on mates and their relations when I start messing with assemblies. Getting better but much slower than I'm getting better at drawing 2D/3D stuff.

One of these days I need to go back and re-assemble my egg-bot since it has a lot of nice things to join up and make move

 

[moebeast]

Made some changes to my z carriage this morning. Moved the upper bearings to the top, shortened them a bit and stretched the height. Now it really looks like 23mm of travel. I also added a spot for the vinyl cutter/pen holder, but as I am typing this, I realize that the vinyl cutter will not clear the bottom of the needle guide. Whoops. It will still be usable, but the needle and guide will have to come out. I don't know that I'll use it that much. What I want to be able to do is put a pen on it, draw panel lines and other decorations, pull the pen and cut guide holes, flip the board over, put pegs in the guide holes and cut the parts.
It is printing now. We will see.

 

[dkj4linux]

Pretty unspectacular but here it is...

I'm going to populate the other end with guide rods and bearings. I noticed a bit of "tail-wagging" on the unconstrained end... maybe a less-than-straight leadscrew and/or, more likely, a slight shaft misalignment in the pineapple coupler. I couldn't feel/see it on the constrained end though I'm sure it had to be there to some extent.

This was ranging over about 16mm - 17mm... though I was actually commanding about 100 mm of travel. No biggie... I haven't adjusted the Z steps/mm in the firmware yet.

Still playing with Onshape... getting a lot of ideas as I put parts together virtually. Probably means my mind will be going 900 mph tonight when I should be sleeping

-- David

 

[dkj4linux]

Much better!

I added guide rods and bearings to the other end of the carriage/shuttle and it stabilized it immensely. I reran the test from before... 16-17mm of very smooth travel.

I'll not bore you anymore with this... I'm calling it a success.

I plan is to continue fleshing out a real machine using this gantry and carriage. I've got a couple of ideas I want to try...

-- David

 

[rockyboy]

I love these low / narrow Lowriders! I'm far enough along with my stock one that I'm going to finish it up - and I want the ability to work with a router on wood too.

But anyway, I've made some progress recently with getting the torsion box and a rolling frame for it to all sit on.

Next up is assembling the various parts and running some wires around.

 

[rockyboy]

Hooray my Lowrider is mechanically complete and wired up for testing! :applause:



But when I plugged it in, I let out the magic smoke and now I need a new RAMPS board.

I think I know what went wrong, and will give it another shot when the replacement board arrives later this week.

Now it's time to print that smooth 611 Needle Cutter mount...

 

[jhitesma]

Looking good! Sorry to hear about the RAMPS

I'm dying to try mine with the 3D printed wheels...but won't have a budget for the SS tubing until late October or early Nov

I've even tried leaving the parts sitting on the dining room table and telling my wife I need the tubing so I can get them off of there and out into my shop but it hasn't helped

 

[rockyboy]

Hopefully you won't get sidetracked to other projects while you wait and forget to come back to this one

I cleaned up the wiring while I'm waiting for the replacement board tonight.

Here's the overall setup with the shop vac and table saw tucked under the table. Pay no attention to the Albatross. She's new in here and hasn't been bound to a radio yet.



Here's the X carriage with belt installed. The cable wrap is screwed to the carriage to provide strain relief. When in use, the cable will be hanging from a ceiling hook.



Here's the back Y carriage with all the wiring tucked away inside the tubes. Just a little loop of wire left on the inside to enable the 3.5" of Z height travel.



And here's the front carriage. The long white wire on the right side goes to the X carriage stepper via ceiling hook when in use. Again two small loops of wire hanging below enable the Z travel without binding, and the white wrapped wire hanging down in the middle is the main power lead. Right now the plan is for the power box to sit on the shelf below and let the 36" power cord swing around, but I'll figure out something more elegant eventually.



And here's the control panel - which just hangs there waiting to be picked up.




I just finished printing a pen holder for the X carriage and plan for the first project to be drawing the base plate outline for the 611 Needle Mount onto MDF. I'll cut it out on the scroll saw - don't have a DW611 router to install on this thing yet. Yes, I could just print out the base plate outline and use a glue stick like I did for the other MDF parts, but where's the challenge in that?

But I'm printing the needle holder tomorrow too, so that'll be fun! Once I have a working needle cutter, the first plane to cut will be the v2 Mini FW-42 we're designing for the FTFF Challenge

 

[rockyboy]

Some progress... new Arduino clone, RAMPS, and stepper driver boards installed, and things boot up correctly from the external power box now. X axis moves just fine. Z axis just needed the stepper voltage tweaked up a little and it's working happy now. :applause:

But the Y axis steppers just keep jerking around and misbehaving even as I crank up the voltage. These also happen to be the two salvaged steppers from a decommissioned 3D printer. The printer worked when I took it apart, so I don't have any reason to expect the steppers are bad. Need to research voltage setting more precisely on these stepper drivers and give it another go at configuring this weekend before I give up on the hardware and get replacements.

On the needle cutter side, the 611 needle mount printed great and fits on the X carriage perfectly. But I don't seem to have a motor in my junk drawer that will fit the application after all. I'll take a view back through the big thread to see if I can spot a specific motor model, but if someone knows and can post it here that would help too

Thanks!

 

[jhitesma]

Some progress... new Arduino clone, RAMPS, and stepper driver boards installed, and things boot up correctly from the external power box now. X axis moves just fine. Z axis just needed the stepper voltage tweaked up a little and it's working happy now. :applause:

Woo Hoo!

But the Y axis steppers just keep jerking around and misbehaving even as I crank up the voltage. These also happen to be the two salvaged steppers from a decommissioned 3D printer. The printer worked when I took it apart, so I don't have any reason to expect the steppers are bad. Need to research voltage setting more precisely on these stepper drivers and give it another go at configuring this weekend before I give up on the hardware and get replacements.

Have you double checked the wiring on them? My MPCNC was working great as a 2' square machine...but when I expanded it to 3'x4' I had stepper issues that were driving me crazy. Finally tracked it down to the wiring and some poor connections when I extended the wires.

On the needle cutter side, the 611 needle mount printed great and fits on the X carriage perfectly. But I don't seem to have a motor in my junk drawer that will fit the application after all. I'll take a view back through the big thread to see if I can spot a specific motor model, but if someone knows and can post it here that would help too

The motor I designed it around is a jdrones 2830 850kv: http://store.jdrones.com/AC2830_358_Motors_p/ac2830358.htm

But...they measure bell size not stator so most manufacturers would call it a 2212. I have some "angel" 2212's and a Turnigy 2826 that are the same physical size. (The turnigy is a tiny bit shorter - but you could always make the flywheel a little thicker to compensate.)

 

[rockyboy]

Wiring tested fine - and if I only hook up one Y motor at a time they each work fine. But when together and with the voltage cranked way the heck up, I get solid performance on one and stuttery / buzzy / inconsistent crap on the other one. As I kept fiddling with it, I noticed these are two of my salvaged from prior projects steppers, and they don't look like an exact match for each other. I'm pretty fed up with them after tonight, and just ordered a new pair of steppers and some doo-dads from Vicious Circle to replace the pair of these. I'll use these head-ache inducing ones on something in the future where they don't have to be paired up together.

And thanks for the link on the motor - I'll get one of those ordered too.

 

[jhitesma]

And thanks for the link on the motor - I'll get one of those ordered too.

I wouldn't suggest actually ordering the one linked...even though it's the one I designed it around. They're crazy expensive and perpetually out of stock.

But like I said it's a common size. This is the other motor I have that's the same basic size:

http://www.ebay.com/itm/SUNNYSKY-An...612171&hash=item3ae6c59ed1:g:Z1wAAOSw6DtYWNFj

But...I don't think the angels have the threaded prop shaft mounts....so you'd have to go with the prop saver style mount and I'd have to modify the cutter body to accomodate a bit longer of a flywheel. Not a big deal and I can do it if you don't mind reprinting the body.

 

[bigALUSMC]

I love the simple design of this machine. Can this be adapted to change out tooling to say 3d printing and laser applications? This seams like an much easier build to me.

 

[rockyboy]

Thanks @jhitesma!

@bigALUMSC I don't see any problems with doing that - as long as it's able to get the precision you're looking for in X/Y movement, and you don't mind having a lower Z travel height, it should be able to move just about any tool head around that weighs less than a Dewalt 611 router. I installed blind nuts in the X carriage on mine so I can switch tools from the top - initially planning to use both needle cutter and router, but was also thinking about both a drag knife for larger vinyl cutting, and a hot knife for foam slab shapes without the mess of routing.

 

[bigALUSMC]

Thank you Rockyboy. Trying to find a kit that can do it all as I learn.

 

[rockyboy]

Thank you Rockyboy. Trying to find a kit that can do it all as I learn.

Jump on in! The water's fine!

 

[rrc1962]

What stepper drives are you using? What size motors? NEMA17, 23, 34 or 42? What breakout board are you using and how is it connected to the PC? Which CNC software? Mach3? Separate Ethernet motion controller or parallel port to the PC?

You can't just connect one drive to two motors. You can sometimes get away with connecting two drives to the same breakout board output. Depends if the BOB has the current capacity to handle two drives. The proper way to do it is to use one drive for each motor. If you have a Z axis then you'll have 4 motor and 4 drives. X, Y, Z and A. A is slaved to Y in software.

If you're trying to drive a stepper with an Arduino, you won't get stellar results. The Arduino doesn't output a very clean pulse train. It will work, but motion will likely not be steady and the motors will be noisy. With a clean pulse train, the motors will almost be silent.

I can give you list of components that are not terribly expensive, but probably a little more than the garbage littering eBay.

This is what I do for a living. We manufacture CNC plasma machines.