Thx - MY BAD - somehow I accidentally clkd on New Zealand currency (didn't even know it was there). OK, I' ready to order now.
Two more questions Carl.
I seem to have conflicting photos. I have been following this for a while so obviously some r old - like one has white plates with 8 wheels for the Z axis and one blue with 4 wheels. Can u point me to the newest ones?
I am doing a 12x12 and thinking about putting one screw assy in the front - duplicate the back basically with 1 screw each side and 1 motor with belt drive, instead of the 20x60 piece. Any comment on that idea?

thx much.

 

I used 40% rectangular infill, and so far I've managed to crack every single part, I'm going to have to do them all again with more infill, so I would recommend more than 40%.

I am heavy handed, if I was more careful and had a lighter touch I probably wouldn't have cracked anything, but I like things nice an tight and it's easier to change the infill than change myself.

 

40% seems to be a good number, as Carl, Nick and myself used the same percentage. The PETG parts so far have been strong, but I am only tightening "mock up tight" I also used rectangular infill 3 solid floor and ceiling, S3d doesnt do honeycomb. I did use 4 total perimeters, makes a nice strong cylinder around the screw holes. I am also doing the same Z config, 12x12x20, 3 lead screw on 1 belted motor.

Those 25mm 90 degree corners are nice. I printed a few while waiting on the low profile 8mm's, I may not change them out for the aluminum ones

 

I did run into a small snafu tonight, mounting the older hot end parts. The gantry plates are mirrored in the .stl , one should be duplicated. The belt paths on one side do not line up.

I am about fed up with my mightyclone, I have had nothing but jams for a few weeks now, ABS, PLA, PET. few different thermal barriers, lined, unlined, stepped, straight bore. I may just go bowden on the new bot and get an E3D.

I attached my BOM, has all the parts for my Z stage, fun links to follow and such

 

I think that shells, or perimeters, are the key to strength. I use S3d to slice my models, which gives a nice preview of the toolpath. By using 4-5 perimeters it creates a very strong column to support the bolt head. While increasing the infill will strengthen the part on the whole, it doesn't necessarily make it more resistant to crushing . I over exagerated the shell number for the pics below. When increasing the shell count, be sure to check your toolpath, as sometimes it does funny things to thin walls,

20% 1 shell

20% 7 shell

80% 1 shell

 

I'm having multiple problems as this photo shows.



The large crack, is because I had it all bolted up and then loosed and fiddle with the bar are the front, leverage forced the mount the crack along between the layers, this was caused by stupidity.

The crack across the layers is because I over tightened the bolt and crushed the plastic, extra perimeters would help this.

The crack along the inside of the V, is because it is being pressed into the V which causes it to split, this is what Carl is talking about.

I'll have to try more plastic, less heavy handedness , and hopefully less stupidity.

 

I just discovered that I had the X axis going from left to right (as you look at the bed), so everything is being printed out as a mirror image. So had to moved the X onto the front/back and the Y onto the left/right, as you suggested Carl.

 

I got the dual hot ends sort of working.
Here's a picture of a checked cube.


Notice the ghost cubes on each side that is caused by ooze. I thought I had my oozing problem solved, but looks like it has come back. The cube itself didn't turn out that well as half the plastic is missing..

 

Therein lies the drawback to the bowden setup, no retraction. Also, in my opinion, nothing dual extrudes better then Makerware. As much as I hate to promote anything MBI these days.

Nick, you may also have some layer adhesion issues from the look of that green plastic.

 

I've been lurking for a while now...Just decided yester that I'm going to be building a C-Bot. I believe I've already got all of the v-slot and wheels and I just started printing out the plastic parts last night. While I print out the parts I'm going to be finishing up on a few other little projects.

I'd like to go with dual extruders or possibly a E3D Cyclops. Does anyone know what firmware will support the E3D Cyclops hotend? It's kind of an odd ball since it has only one thermistor and one heater cartridge.

Cheers,
Brian

 

No the heat breaks can't be shortened, Does it make a difference how long the heat break is?

Actually there is a adjustment screw inside the heat break, which allows a little adjustment, but this is only a few millimetres. The intent is that this can be used as a micro adjustment to align the two nozzles. It works, but is a big hassle and I wouldn't want to do it to often. I was thinking of putting each head onto a spring mounted platform for easy adjustment, and also moving one head out of the way it it's not going to be used.

I'm using 8mm retraction, although I only need 6mm. This works fine providing the time after retraction is less than a few seconds, any longer than that and the vacuum holding the plastic disappears and it oozes out. This isn't a issue with the single head, as it is usually less than a few seconds between extruding plastic, but is an issue for dual heads as one head waits for several seconds while the other prints. I might try lowering the temperature and speed, to see if it makes a difference.

 

That makes sense. Thanks!

 

Carl - I love this design. But I can't stop being an engineer...........I am making the platform with 4 rails - using 20x20 for the cross pieces- and placing the screws in the middle of the front and back rail - the ones with the wheel kits on them. The screws will be driven by a single motor and a belt using three 36T pulleys. Since u r the creator, I would appreciate ur opinion on any problems this may create - particularly - will this cause the platform to jam or r the wheel kits sufficient to control this???????

I also want to take all the air out of it that I can- make it as small as possible. I am building to a 12x12 (305x305) platform. I will overhang it by about 1/2" so the base platform will be 320.2x320.2mm. I modeled this in Sketchup - I'm not an expert and it is not complete - and it appears that I can reduce the width by about 20% and the depth about 5% giving me approx 460x460 for the overall XY dimensions reducing the width about 110mm. This is assuming I can get the full end2end travel on the carriage in both X & Y directions. It will also have dual extruders at some point. I am taking the Z drive motor, screw clearance, etc. into consideration. Did I miss anything that will interfere with that????????????
Obviously, I will have to relocate some accessories that are attached to the front verticals.
thx for ur opinions.

bill

 

I may be biased, due to the people that advise me on Z axis construction. By using 4 vertical ways, I feel, that is over constrained and will likely lead to some artifacting. Multiple lead screws, linked by belt to a single motor, should enough to keep the stage in the Z axis. Using 2 vertical ways will contrain the stage in the XY, and lead to less binding. http://www.thingiverse.com/thing:612857/#instructions for some light reading. I plan on mounting two idlers on a cross member for tension, should put about 270 degrees of contact on each of my 36T gears. Similar to the Z on this bot, but I am mounting my crossmember 90 degrees to his and using the idlers for tension, this bot uses the motor mount for tension

 

While my clone is being cranky with the PETG, its printing the ABS like a dream. Chugging along on this mock up, have my Z stage mounted, I have to shorten up a bit, going to move the front and rear lower horizontal up about 8cm. I over estimated the length needed for these leadscrews, combined with the shorter makerbot hotend, although this will give me some room underneath for hiding both PWS.

Because I'm running sailfish I had to mount the X endstop on the gantry plate. I adjusted one of the sliding bar ends, and a little cut and pasting to the gantry plate, not bad for V1. I would like to find a micro switch that is not attached to a PCB and swap that in, but this is what I have at the moment. It looks like the part store has loose switches, as well as the one mounted on the short end of the rectangle might both work well here, recoup the 15 or so mm lost on the gantry plate switch tab.

 

Ahh, I am so frustrated. My cheap prusa i3 is refusing to work correctly. I have been dealing with jamming that caused a stepper to burn out and a bearing break down. I have been working on some new designs for my new printer but have not been able to print them.

 

Sailfish vs Marlin, I found this post pretty much sums it up

Well, Sailfish has a leg or two up on Marlin in other areas. E.g.,
extruder pressure compensation during accel and decel. A non ad-hoc
algorithm for speed changes. Support for hardware to trigger a
recoverable pause (e.g., filament jam detectors such as
https://sites.google.com/site/tunelldev/home/filamentmonitor).
Support for SD cards larger than 2 GB. Ditto printing. Pausing
at preset Z heights. Etc.

Using x3g actually
gives Sailfish a bit of a performance boost. It eliminates some of the
things that the tiny, 8bit, 16 MHz AVR with integer-only arithmetic
would otherwise have to do. E.g., do axial feedrate limits, compute
distances (squares and square roots in emulated floating point arithmetic),
etc. It's just one of the facets which combines to make the acceleration
planner in Sailfish about 5 - 6 times faster than, say, Marlin. (MBI
did their own testing and claimed it was 10 times faster, but I find
that dubious.) The faster acceleration planner helps in surface finish
on parts with lots of small facets. Alternative is to have to slow
down the perimeter speeds even more which is how Marlin deals with
it's slower planner. When the planner is slower, you end up with
moments where no motion is occurring as the motion control waits for
more work to do. Perhaps fine with subtractive manufacturing, but
with additive manufacturing and a slowly oozing nozzle, you get
pimples and zits in the places where motion ceased momentarily

I chose it, because its what I know. Essentially I tell this printer its a Replicator 1. All the hot parts are compatible with my other bot, all the wiring, switches, TC's heaters and such. Sailfish lets me run the mightyboard in CoreXY. I chose the flash-forge mightyboard, as it comes with the ATmega 2560 ( MBI uses 1280 ) , has the cooling fan extra MOSFET soldered in ( i had to manually solder the SMT MOSFET on my current bot ) and a gcode RGB LED driver

 

Any electronics store will have loose micro switches available.

I brought some of these http://www.ebay.com.au/itm/371153579348?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 with the plan to embed them into the gantry bracket so that the switch is level with the end of the gantry.

So your going to set your firmware up to home to max X end stop?