I'm thinking in terms oo the PTFE tubing not transferring the heat from the heatsink to the plastic as easily as there is a gap between it and the heatsink plus PTFE isn't as conductive as an aluminum/stainless transition zone.

I don't use Z lift as I find it causes blobbing but I am running 4.7mm retract.

 

Once I remembered you swapped your X and Y axis, it makes a lot more sense to me. Thanks for the pictures. Started wiring the motors in tonight. Got the Z motors going and doing the Z endstop next.

 

Michael, did you ever upload the STL files for your endstops? I would really like to take a look at them.

 

No I didn't but will a little later today with some photos.

 

Elmo - Here are the STLs and some photos of the endstops on my machine. I have to say that I'm not happy with the X-endstop. I should have designed it so that the switch was mounted to the carriage plate and not the Z-bar end bracket as it is now. Looking back, I have no idea what I was thinking when I did it that way. Somehow it just seemed to make sense at the time. I plan to change that as soon as I finish a rework on my i3. Hope this helps.

 

So just to be clear, which is your X axis? The first or second picture?

Also, how is the bolt in the Z axis setup with the spring?

 

The first picture (attachment 8936) is the X axis.

Actually the spring isn't necessary - there is no nut in that part, the bolt threads into the PLA. I just never removed the spring when I realized I didn't need it.

 

If anyone is using A8825 drivers on a Ramps bd I would like to know if u can tell me what temps the heatsinks r running. Mine seem to get to 45°C pretty quickly just doing test moves and homing. I want to know what is "normal" for these.
thx

 

I shrunk the outline by ~ 2" in width so I mounted the X endstop to the back carriage plate and made a small pusher that attaches to the H end under the 5mm mounting bolt on that side - had to use a longer bolt of course.
The Y endstop is mounted in the corner on a simple bracket and the pusher is also mounted to the same H end with a 3mm screw into the empty cavity. Both pushers are adjustable.
The Z endstop is mounted on the frame with an adjusting screw mounted to the platform. It all seems to work well so far.
The total travel of the carriage from H end to H end is just over 335mm (305mm build + 30mm for the dual hotend).
The Y travel is about 317mm so I could have taken another 10mm off that. I like big things in small packages.
My frame is 620mm wide x 512mm deep counting the 2 extruders, one on each side, the screw heads, and the XY motors on the back for a 305x305x305 build area.
I could loose another 40mm in width if I moved both extruders to the same side, which I may do, but the idea was easy access up front. Now if I can figure out this Marlin configuration it will be printing soon though I am still trying to figure out how to print the duct-work for the product cooler. The fan will be mounted to the top of the carriage.

 

Got some pictures to go with that? Working on my own mount that attaches on the carriage that sounds like it might be similar to what you did.

 

talking is easy, documentation is hard.........here u go -- mine is with the idlers at the "front" and it homes in the front left corner.
The pushers may be a little hard to see, except the X one under the red piece (screw was too long).

 

Looks good. Here is what I came up with for the X stop. I took MichaelS' idea and moved the switch to the carriage and added Carl's Z stop bolt concept. I took advantage of the existing mounting holes on the back side of the carriage for mounting the switch.





I might need a longer bolt (next size I had after 16mm was 40mm), but from my testing, this one should work.

Here is the STL files for them.

 

Dang, that's one of those "I wish I had thought of that." Very nice design, I hope you don't mind if I steal that one.

 

No. You may not steal it. Yes, you can use it though.

 

Ha! Fair enough. Thanks Elmo.

 

Whatever works for u. Since I shrunk mine i didn't have the space to work with something like urs and I am planning on mounting the model fan on the top of the carriage. Still have to figure out how to print the parts. Since it doesn't require adj like the Z axis (accurate) I just allowed course pusher movement.

 

Success! Got all the axis motors and endstops hooked up. I was able to send a gcode file to the smoothie board and it started printing it (with that new patented invisible filament). Need to get the extruder hooked up next. Getting closer to an actual print!

 

Came up with this idea for running the cables to the heated bed.







Thinking of gluing up the bottom half to keep it straight. It works as is though. The links came from http://www.thingiverse.com/thing:40918. I also used the end pieces there and modified them with a mount for the v-rail.

 

I probably missed it, but couldn't find the link to those pads in your BOM.

 

here is a news flash - there is a Marlin Developmental v1.0.3 available that does implement QUICK_HOME properly for CoreXY.
https://github.com/MarlinFirmware/Marlin
However the logic for the endstops is reversed (which is easy to change) and I have not gotten it to step if I define 2 extruders. It appears not to see the E1 thermistor. I don't know if it is way I configured it or a bug, but I think my config is the same as 1.0.2 that does work. However, a few things don't quite look the same in the file so I may have missed something.

It also infers that BABYSTEPPING will work on a CoreXY by the omission of the error trap if CoreXY is defined.
I'm not printing yet so I can't test it.
Now those r significant changes but it is still DEVELOPMENTAL. test at ur own risk.

 

@adamcooks

as I recall u have 3 screws belt drive - right?
If so can u give me some tips on adjusting them?
Things run almost as smooth as butter from home to 200mm (out of 305mm) then things start jamming up. 305 mm is about 5mm from dead end.
I have tried almost everything, redesigned and rebuilt parts and it has gotten better but I still cannot go smoothly to 305mm. If I loosen things up on the screws i can get it to 305 and I have adjustment leway in the base but to no avail.

 

well according to developer babystepping still doesn't work for corexy - so why did they take the trap out???

 

What needs adjusting? put some pics up, that might help a bit. Mine runs very smooth, my final build area came to 420mm. I think i can stretch another 30mm or so, with some more adjusting but I will most likely leave it, its big enough. I left my bases loose on the frame and run the bed all the way down, mostly tightened, then ran the stage up and down a few times. With no stepper my stage free-falls. 400 steps/mm 1/16 stepping, and i have 36T gears

Are the tops of your leadscrews constrained?

 

tops r loose except for the nut - I am using the brass nuts - what r u using?
I did the same - ran all the way down loose, tightened and it jams. I have the base slotted so I can adjust it in/out but that doesn't seem to help.
If I leave it loose I can run it up/down. If it gets slightly skew the jams. I expect that but when I have it down I would expect I could tighten the stage piece then the base and it would be aligned. Apparently, it has to be perfect but I would think there is some "give". The screws r pretty parallel with the legs eyeballing it.
The top 250mm runs fine except for some vibration at certain points. Near impossible to figure out which screw(s) is doing it. If I put some weight on it it quiets down. I have 800 steps/mm, 1/32 stepping and 36T.

 

How does the stage ride without the lead screws? You wheel layout will require absolutely square frame, have you checked that?

Loosening the lead screw nuts is also a very good idea.

Printer is looking really nice.

 

Since there is only one wheel/corner it doesn't "ride" at all without screws. With the screws it rides pretty well but that needs work.
I keep updating parts. It turns out the rail the nut capture is on was not square. It now goes 305 mm without help sometimes which is better than never. I think I need to rethink my wheel mts. It seems like it runs OK with the wheels loose. And for some reason it appears tighter at the bottom but the frame measures very square. I made the mt 3mm wide == not good. It also sticks up from the bed. Not sure why I did that but it allows the 3mm to flex more. The mt or the slot is also probably a little short. I am thinking I will remake it @ 5mm (I think the mt screw is long enough to catch the nut @ 5). I will also put the mt hole in the center instead of above. Any comment about that?

I also changed the idler to a 608 bearing. I think that helps something.

I got the dev version of Marlin working now so QUICK_HOME works. It does not in previous versions. I also chose the wrong motherboard which caused "EXTRUDERS 2" not to work.

Proof that the last 20% takes 90% of the time. or is it last 10%???????

 

Hi all,

I'm about to take the plunge and start building a C-Bot. I've already printed out most of the plastic parts on my i3 - just need to make a couple of decisions before I get properly stuck in & order the v-slot.

I'm still a little unsure of what bed size to go for - my initial thought was to go for 30x30, but it seems that those of you that have gone that large have been having issues...has anyone had good results this large yet?
I'm now wondering if I should play it safer & stay with a 20x30 as that seems to have been proved as a working size.

Secondly - this may be decided by the bed choice above, but, are you all using 12v rather than 24v?

 

If you want to go 30x30, you might want to look at the Triple C-Bot by adamcooks (http://www.openbuilds.com/builds/triple-c-bot.1757/). He built a 30x30 based on the C-Bot.

As for the bed, I wanted to go with 24v and bought the 200x300 bed from RepRap.Me. It was the only bed I could find that size that supported 24v. However, I am having issues with it getting it to heat up. I can only get it to 45C and that is connecting the bed directly to the PSU. I'm not sure if I got a bad board or if I am doing something else wrong. Not sure how you can directly connect and make a mistake. I may just have to go back to 12v if I can't get a resolution on this with RepRap.me.

 

My bed runs on 12V, bot runs on 24V. I only did that because I already had the PCB. I probably would have run it 24V is I was purpose buying for this bot. I would still have run it from its own PSU using a DC-DC SSR. My 30x30 heats up to 110 in about 3 minutes, with a 4mm glass sheet on top. My Z stage is trouble free. What I need is an aluminum gantry plate to attach my direct drive extruder to.

Theres a link to the manufacture of my HBP in my BOM, they have all sizes.