No worries, I had plenty else to work on It might be a good idea to archive these diagrams in the files section though. I'm sure other modders will get a lot of value out of it as well.

And please don't rush on my account.. I need to clean up my build for the maker faire next month, so I'll probably be pretty conservative on my mod testing until then.

 

Will do on the pics I don't have the diagrams handy at the moment. I can go searching for them later tonight though if you don't get to it before then.

 

Sounds good, but the real test will be with a feeler guage and when your toolhead is installed. Your laptop is most likely more than 1kg in weight, which is a very big print!

Keep us/me posted

 

According to apple

so yea that would be an awfully long print as well I'm bringing the printer to the local 3d printing meetup tomorrow. I got the steppers all wired up and moving. next are endstops and then align the Z. Hotend / extruder are pretty simple and ready to rock so hopefully I'll have it printing this weekend.

I ran some simple Z movements. I'll end up with ~290-300mm on the Z. I could lower the cbeam a bit and maybe squeeze another 10-15mm but not sure I care enough Movement speed with the nema23 was pretty nice - curious what my top z speeds will be. I think the full 290mm move took ~5 seconds so thats plenty fast but gotta know the limits!

 

Got everything printing over the weekend. I still have a big mess of cables that need cleaning up ( sorry its pretty nasty right now! )

I'm going to rig up a bit of an interesting torture test for the Z later this week. I have a 5lb spool of filament which has probably 3.5 on it still. Going to hang it from the front of the forks on the bed mount and then do a tall object print ( thinking a 20x20x50 pillar or something - nothing crazy ).

leveling the bed was pretty simple. I'm using some maybe 1/4" tall springs. Barely had to adjust them to get it level so i guess I got things squared

any thoughts on upper limits of the weight I should put on under the bed? 3lbs ish seems pretty heavy to me in context.

 

Here's the STL created by the generator for the titan extruder. What else should I put on top of it? Those who have a titan already, did you use something to hold the bowden tube up?

 

On my titan, I don't use anything to hold the tube up, but I use the holder from the Rework stls to hold the wiring bits

 

In case folks don't see my G+ Post announcing the next release of the hotend carriage generator see below.

Released! Only on github for now as I have not confirmed thingiverse supports the OpenSCAD functions the generator needs for the 360 fan.
Titan support should be very solid.
BL Touch support should also be.
New fan duct has yet to print cleanly.... More work to be done, test at your own risk.

GitHub - croadfeldt/Roadfeldt_3d_hczf_mount: Parametrized Hot / Cold End, Print Cooling Fan, Z Probe, Servo Mount for various X carriages.

EDIT: It's live on thingiverse as well. No guarantees the 360 fan duct will work there as that needs the updated OpenSCAD.

 

those are nifty but I've had a heck of a time with non lock nuts loosening over time - do those suffer similar?

 

Mine are fairly stiff but kinda short ( maybe 15mm ). I may swap them out but the m3 lock nuts so far are working great but I do wish I could use my fingers to make small adjustments vs a pair of pliers

I'm about 95% done with my build - its printing but working out a few kinks. So far I really like the design! Aside from some fun with the ptfe tube between the titan and the hotend ( *any* backpressure and it fails - fixable ) this frame is just a tank! Thanks for the design / work!

 

I went with the nice knurled nuts with stiff springs as well. I can corroborate that they work well and don't loosen up. Makes leveling so much easier, esepcially on the fly.

 

How often do you have to re-level your printers? I understand that a spring helps in case of nozzle crashes too, but I wonder if a really fixed bed would not require leveling that often?

 

I rarely re-level it now. Only when I swap in a large glass sheet I use to increase the build platform size to support large customer jobs. But it always requires some leveling, mainly due to man handling the bed to remove prints.

For normal operation I rely on the auto bed compensation, which works extremely well.

 

I use autoleveling with plate fixed to the extrusions and rarely have any issues, though I have had a couple bed crashes. Overall I prefer it though, as it also removes the need for a bed support underneath the heated bed.

Ever since I added sliders on the front extrusions I have noticed that the autolevel compensation required is next to nil. In fact, I bet I could turn it off completely and not tell the difference.

 

I have had to level my bed a few times... but they were all my fault, and I'm not using particularly stiff springs.

 

yea, once I get the bed leveled I rarely have to re-do it. I've had some fun issues with endstops not being predictable ( hysteresis or other, not sure ). I've recently switched to a lower pressure endstop for the Z - so far on the cbot its working but I have not been printing on it long enough to know for sure. ( my mendel max 2 printer once in awhile i have to tweak the endstop position but a small ish amount )

For the curious, I switched to SS-5-FT from SS-01D ( omron part numbers, the others are basically the same in terms of trigger force required )

 

Hello Carl,

I have been reading the thread on this build (up to page 23) But I wanted to jump to the end and ask a few questions
1) Does your design have the strength to support a 550x550 silicon headbed with a 3mm (1/8") Aluminum Heat Spreader.
2) On your C-Bot Cut Calc calc.. how much extra is it allowing around the build plate?
3) I am opting right now in my planing phase for the 3 lead screw method for rigidity of moving platform. That said does your design or is there any modifications so the build plate is supported by the main body of the bot? so the screws do the lifting, but the bed moves up and down straight.

I love your design and as far as I can tell its going to be my best option for my Large Format Printer

Thanks,
James

 

I'd say that a 3mm heatspreader is probably a bit thin for such a large print size (assuming you're going to be using it all). As this will be the load bearer for the weight of the print surface (glass?), and print

I'd assume that a NEMA17 would be ample sufficient as mine supporting a 300x300 bed has loads of force behind it. However it is geared down 20T:40T from motor to leadscrew pulleys.

In your last question, are you asking for beefier Z gantry brackets? I would definitely not support a 550x550 bed with only the screws and Z gantry carriage both at the rear of the frame. Cantilever forces would be too much to be stable. Easiest is to add the third leadscrew IMO. Although, if you do beef up the Z carriage brackets, you'd lose max travel in the Z because you'd need to make them bigger in the Z to cope with these forces.

There's loads of good info in the forum, and a lot of discussion about alternative leadscrew setups. You're in too deep now to stop reading I assume! I was!

 

1) I currently use tape on my non-heat bed equipped machines.. and boro with white glue solution on my heat bed machines. I have never heard of PEI but after a quick look that's extremely interesting.Here is a link to the heat bed I'm going to attempt to use. Link
2) Ok I will poke at it with a stick from range. i just want to see my options for dual extruder setup, after getting a Free Replicator Dual clone and discovering water soluble filament its how I print support these days.
3) I assumed i'd need something like that for level lifting.

 

That bed is 12V, 220W. You definitely want to go bigger on both wattage and voltage. I'd avoid mains unless you're really comfortable with mains safety practices.

 

According to Tom Salanderer, you need 0.6W per cm² (go to 5:05). That means 1815W for a 550x550 bed, which is huge if not powered by mains. My 6mm, 320x320 Aluminum bed is heated by a Keenovo silicone heater of 750W (220V) : www.aliexpress.com/item/300X300mm-750W-220V-w-NTC-100K-Thermistor-Keenovo-Silicone-Heater-3D-Printer-Heater-Heatbed-First-Grade/32308797940.html

 

I am not sure how i'll power it but 220V mains are not an option.. i Do not own where I live and the only 220 outlet is for our stove. SO i'm stuck with 110V or 36/24/12 volts... debating now. I wanted originally a 24" x 24" x 24" build area but i've lowered it to 20" x 20" x 20" for the sake of space on my work bench.

Mains Voltage does not bother me.. when i burned my Heat Bed mosfet up on my printerboard rev D I used AC mains via SSR to have heat bed.

 

That's fine. im aware there are lots of lurkers reading so feel like I should drop into any talk about mains to warn that It's not fault tolerant whatsoever and will kill if done incorrectly.

Let us know what you decide to do. I personally would avoid a heated bed altogether, or only heat a central part of the bed, say 250x250 and only use that for abs/PETG/anything that needs a heated bed.

 

Not heating the whole bed is an option i didn't consider. with something like alum over the top i wonder if a small heater could get the middle up to required temps for abs.. that would also leave me with trying to find a coating that would work heated or not for PLA and other such materials. Does PEI work for PLA without heat? I've always run the thought process that a heated bed was just plain better.... i mean i have non-heated machines and i have to be deadly accurate z calibration and even then sometimes the first layers don't stick.

 

From what I've read from other people's experiences with PEI, PLA doesn't stick well unheated, but, you could always use gluestick for PLA, but that's kind of messy. The PrintInZ plates/skins work excellently for PLA, no need for heat, and small PET-G parts will stick ( like 20mm diameter tops kind of small) but PET-G sticks to it well when heated, printed all the C-Bot parts on it with PET-G without a problem once I sorted out a good bed temperature. Printing a single PLA part that takes up your entire plate might cause some sticking issues with the PrintInZ stuff, it'll either stick very well and be hard to remove, or warp around sharp corners. The biggest problem is that the skins/plates are kind of fragile(cold hot end will leave a slight indentation if pressed into it, hot end will leave a deep divot if pressed into it, fairly easy to scratch or scrape parts off with improperly used scraper), and the skins may be too thick for some induction probes. I've never printed ABS on it, nor have I printed with Nylon using heat (cold Taulman Bridge did not stick well, although small parts will stick).

PET-G and PLA on the PrintInZ stuff isn't very sensitive to z height for adhesion. Unheated with PLA is a little sensitive, but it will work in a good range, PET-G sticks very well even when the extruded bit looks like it's just sitting on top like a rope, but it appears to spread out and create an almost solid interface in my experiences.

Also, this is a fairly expensive option, the plate is 77USD for 300x300, and the skin is 30.25USD for the same size