well, eyeballing it, it is almost dead on. The other way it was very much out of alignment.
I don't know why mine seem to be more aligned with the back of the plate rather than the center.
Anyway, it needs to be the plate farthest from the motors b/c that is the side the teeth of the belt are facing away from the rail. Since mine is turned around to get the motors out of the way, it works well for me on the front plate.
But u could implement it on the rear also I guess. It becomes more difficult to use that side for tightening though.

 

Hi All,

Quick update on my c-bot build.

Extruder 0 is allocated as the volcano with 1.2mm nozzle. Very different to set-up in comparison to a 0.4mm nozzle with regular size melt-zone. Thanks @AKEric for the simplify3D settings on your blog. Your retraction, speed, and layer first layer settings saved me a lot of headache!

My max volumetric extrude is coming out at about 17 to 23mm3 / sec before my extruder starts skipping. Might have to investigate why that is a bit lower than some figures mentioned in this thread.

First print was a spool holder (pictured) for the side of my enclosure. Done at 0.6mm layer height in clear eSun PETG. Super, super strong print. Absolutely no way i'd be able to bend it by hand. Excuse the lighting. The print is shown without any finishing. Retraction still needs fiddling with to completely remove the small blobs at layer transitions.

As for extruder 1, I'm short on PTFE tubing, and the only length i have left is slightly too short to reach to the (rear left) home position.

Next up is a longer bowden, calibration of the e3D 0.4mm nozzle, electronics enclosures, and some sort of stationary wipe surface to the left and right side of the print bed, attached to the X gantry mounts.

Tool changes, and the volcano nozzle being stationary is going to be a nightmare with ooze. The 1.2mm nozzle oozes about 15mm of excess filament before it goes below the glass temp of PTFE, Better i have a solid tool change procedure with a fixed wipe surface than 1.44mm width ooze walls around each part I print.

Finally, thanks again Carl, and everyone in this thread for their input. Very, very happy with the printer so far!

Austin

 

Idid have to modify my XY bar ends to accept the endstops. I did both sides to allow both a min and max endstop.

 

@Austin Seagers : yah, I'd done a post earlier about mixing and matching two radically different nozzle sizes. Basically, my conclusion was = nightmare.
I could see mounting two extruders just so you could use either one for print A, and another for print B, but not both at the same time. I mean, maybe someone is doing it successfully, but it seems like way more trouble than it's worth for the reasons you've expressed and more. And, IMO, the last thing you want (based on what I've learned by doing it) with a big nozzle is a bowden setup, which is why I switched (very, very happily) to direct-drive, and and am getting much better volcano prints now: so much less stringing and blobbing. 2c

 

Hmm, I can see your point about Bowden not being the best for a volcano nozzle. On the print I showed above, there is a small blob where the layer change happens, but I think I can get rid of that with some fine tuning of my retraction and perimeter settings. That's beside the point though.

Ive read your previous post and I think I replied also. I'm still planning to still go ahead with the design and hopefully mitigate the points you raised by doing the following:

Mixing nozzle sizes and choosing layer heights won't be such a pain if you infill every x layers. I was planning to have my general print settings at 1.5 layer heights, where the normal 0.4 e3d does perimeters, supports; everything except infill, and the volcano does infill. Every 4 layers, the volcano will pass over and do a single 0.6mm layer of infill. Depending on the print, I could probably do slightly more or less layers of infill in one go.

Lots of bottom and top layers will correct any bridging when printing a solid layer on top of the the thick 1.2mm infill.

I therefore don't have the worry about oozing with the volcano whilst printing, as infill is not seen. I just need to get the volcano within the perimeter of the part without oozing on the wall. And to do this consistently.

I did think about direct drive, but mounting even one motor on the tool head gives me the heebee-jeebies. My previous printer had terrible ringing on the axis the motor was mounted to. I wanted to avoid that when going to a new printer. I'd like the e3d to move pretty fast also. And a direct motor will slow that down.

I almost always print parts for projects that need strength. Only so often do I print for novelty, and I don't mind a bit of fixing up afterwards if needs be.

I value your input as its obvious you're very experienced with 3D printing. Your volcano layer settings have already saved me lots of time tweaking. Hopefully this post makes dual extrusion with a volcano seem a bit more viable?

Either way, swapping to a regular e3d from the volcano is easy to do

 

After getting tired of dealing with the two Z axis motors getting out of sync, I am looking at switching over to the single motor/belt combination. I think I remember some conversations about this setup and the reworked Z axis parts look like the new parts are in there. Does anyone have any pictures of this new setup and how the lead screws are held in place?

 

I think @CapnBry did what you are talking about
C-Bot | Page 29 | OpenBuilds

I'm also interested in making the switch; one less motor to buy, driver only needs to power one motor, perfectly synced lead screws.

 

That's what I was trying to find. This thread has just gotten so large it is getting hard to find things.

 

Definitely lots of pages to parse through.

I wonder if it is possible to find a belt just long enough to link the two lead screws together without need for a third gear. That might be wishful thinking or you would probably need a custom length belt loop.

 

Could just add an idler in the loop to adjust the tension? Gives you the freedom of using a slightly over-sized belt

 

Thanks for finding my post for me! I have been out of town for a week so I had lots of posts to look over. If you have any questions about my setup I would be happy to answer them.

Getting a belt just the right size is a definite possibility and then having one of the lead screws directly attached to the Z stepper would probably work, but you'd need to raise the pulleys to account for the size of the coupler which would eat up some Z space. The larger problem you'd have with it is getting it assembled with the belt tight. You'd need to loosen one of the Z arms and pull it, the leadscrew and the pulley side mount all at the same time and not have it fall apart on you. It is hard enough to get it all put together with the 3 point configuration and this sounds like it would need another couple sets of hands. With the three point I can get it close then slide the 3rd point (with the motor) slightly off-center to make the belt as tight as I want. It makes turning one lead screw to get them the same height less of a challenge because you can loosen the motor slightly, then use enough force to cause the belt to skip and turn the lead screw, then retighten the belt.

I love this single drive 2:1 geared solution (0.02mm per full step), however I would say the best way to situate it would be with the leadscrews back and front rather than side to side as I have them. There is a slope to the Z arms that makes the rear arms lower than then front by somewhere around 5mm. I can counter this with the bed leveling screws but if you design with front and back motors you don't have to worry about that at all.

 

I've never heard of babystepping but this is pretty sweet. I am always messing with my Z height on my old i3 which for some reason seems to vary 0.4mm one way or the other depending on how it is feeling and how much the head is out of whack. What I do if I don't feel like just canceling and restarting is to reset the Z position on the fly (imagine we're at 0.2mm and want to go up 0.1mm)
G92 Z0.10 ; pretend 0.2mm is now 0.1mm
G1 Z0.20 ; now move to 0.2mm, which is actually 0.1mm higher than we were before

Note that I don't use any feedrates. This is because if you set a feedrate for the Z move, odds are your slicer isn't putting feed rates on all its moves and extrusion moves so by you setting one you're going to override the feedrate on moves in your gcode until a new feedrate is used, which can be a LONG TIME if you're printing slowly on your first layer. I just limit my Z speed with M203 Z2.5 which will effectively set the feedrate of the move.

I totally need to recompile my firmware with this new babystepping though on the old printer.

 

When you say "motors" here, are you referring to the lead screws? Not sure I am following what it is you are suggestion.

Do you have STL files of the mounts you used? I saw that Carl offered to mode some mods for you, but didn't see any follow up.

 

Yes I am sorry I did mean Z lead screws not motors. The two Z lead screws one on the center back, one center front, then the Z motor either on the left side or right side.

I've attached the z bearing mount I used and also Carl's version which is prettier but I have never printed. File format for both is 123dx.

 

Do you have the files as STLs? Never worked with 123.

 

Oh sure. Both in here, but may need to be repaired because I just exported them.

 

Yeah the bearing just sits in there under the weight of the bed pressing down on it. I've printed at least hundred hours on this thing and they're still just sitting locked in place. They will pop out if you turn the whole printer sideways though.

 

Looking at the STL I can see the lip now. Thanks. I think once I wake up more I might play around with it some.

 

There r a lot of sizes available, but u definitely need some way to adjust the tension. If one gear is the motor, u can move that mount and effect an adj. If the motor is driving one screw then u can't move it or the other screw so a 3rd gear is needed.

 

One other question. What was the bearing this part was designed to use?

 

Could i use solid V-Wheels instead of mini ones?

 

The standard flanged 8mm axle bearing, F608ZZ. The set screws on the GT2-40T gear prevent the leadscrew from passing through the bearing. Also in my case the fact that the 8mm leadscrew is slightly larger than the 8mm opening in the bearing. I put the leadscrew in a drill and pushed the 10mm at the end against a piece of 150 grit sandpaper on the table to "turn" it down to fit. Took just a couple of minutes per screw, checking every 10 seconds or so until it fit.

EDIT: I just remembered I actually have a shim between the bearing and the GT2-40T gear as well. I'm not sure it is necessary but it prevents the gear from pressing on the bearing raceway. Not that this is the right way to use a bearing anyway, but hey every bit helps right? :-D

 

Where did you get the shims and GT2-40T? From the original message, it sounds like you got it from robotdiggs. I was able to find the pulley there, but not the shims. But like you said, it probably isn't needed so probably could print my own.

 

I got the shims from openbuilds when I was buying the rest of the parts to build my C-Bot. 3D printed ones would be fine though.

The GT2-40Ts I got from robotdigg along with the right length belt (900-GT2-6 for my 300mm C-Bot in the right/left leadscrew config). I would hesitate to recommend robotdigg, as it took something like a week and a half for my order to ship, then 2 or 3 weeks to get to the US from China. It might cost $3 more each to get them from the US but if you want to build in the next month don't get them from robotdigg.

 

Thanks for the warning. I gathered from your initial post you were not satisfied with their shipping. Will have to find another source. As for the shims, the shipping on just two of those would be crazy. I may have to purchase a new lead screw though because I shortened on to prevent the nozzle from hitting it and now it may be too short for the addition height needed. If I do, will probably just order the shims then.

 

It only took me about six months but I finally finished it. Now to decide which printer to build next.


Edit: More pictures here D-Bot Core-XY 3D Printer by spauda01

 

That really is one of the cleanest builds I've ever seen. She's a beaut!

 

Wow, I had no idea people were making diy sla printers but I guess I shouldn't be surprised.
I'll probably make a Vslot based delta next

 

thats what ive got currently, and i have to say, its...complicated haha the settings and firmware maths are so different, but deltas are also the coolestprinters to watch in my opinion