I used a bowden for about the first half year, but switched to direct drive after Carl released that new design. Immediate quality improvement over the bowden, mainly because there's so much less backpressure in the line causing blobs\drool\zits. I use 1.75mm filament fyi.

I'm also running a volcano that has a much larger hotblock than a normal v6: With my .4mm nozzle on there, it's possible the larger melt zone is allowing the material to come to the correct temp at speed, while a smaller hotblock could limit this. I know that when I was using my 1.2mm nozzle the speed (mm/sec) had to be brought down significantly (I usually printed around 40mm/sec) but the overall volume was huge, and thus faster times overall. I noticed on the volcano the only limiting factor I hit was how fast it could melt the material: It's not that I couldn't make the machine drive faster, it's with that much filament in there, it took longer to heat up, so the faster I went the colder the extrusion got to the point of failure. I think around 60mm/sec was the fastest I ever got it. All that being said, after I switched to the .4mm nozzle I realized I'd been shipped an underpowered heater cartridge for the volcano: Swapping out to a higher wattage one made all the difference, so I look forward to getting a big nozzle back on there and pushing speeds.

Maybe that's happening with your 3mm line? That's a lot more plastic to melt even when extruding out a .4mm nozzle. Just theory. I'd suggest to anyone to switch to a 1.75mm line & direct-drive and just be happy

 

Just a little update on my controller discussion a few days ago. After much thought, I decided to stick with Marlin for the time being and go with an MKS GEN 1.4, but JUST FOR NOW. I'm actually quite interested in the Duet but would rather wait until the new revision comes out. I'd hate to spend that much, only to have it replaced shortly thereafter for the same price. So far, Marlin with OctoPrint does everything I need and most of what I want. It's possible that I could make my current RAMPS work, but it would be a rats nest of wires because of all the workarounds. The GEN 1.4 would neaten that up considerably and it was under $50 CDN. Yes I realize that it doesn't take full advantage of my C-Bot but that will happen eventually with a Duet. Not counting out the Smoothieware platform but I would agree a few others in that there are some deal-breakers for my particular needs. (a shame too because the MKS SBASE 1.3 was only $20 more than the GEN)

 

Is this the MKS BASE or MKS SBASE?

 

Neither. I picked up the MKS GEN v1.4. Should be here tomorrow.

 

Ok, I'm building another C-Bot.... Need to go bigger. I know some of you have already and so I'm looking for feedback. My current setup does 30cm x 30cm x 65cm. I am looking to hit 40-60cm on the XY and keep the 65cm on Z. My biggest issue is the weight of the Z platform. I really really like my aluminum build plate at 6mm. But at that size, I'm thinking little NEMA 17's won't cut it, nor will typical reprap style driver chips. I should be able to wire up larger external drivers, so I can keep using reprap style controllers. So here are my questions.

1. What did you folks use for large build plates? 18inch+
2. How did you heat it? Obvious is a silicone 120 or even 240 volt.
3. What are you driving the Z platform with?
3a. Steppers
3b. Drivers.
4. What gotcha's did you find?
5. What style of Z platform movement did you use?
5a. Lead screw?
5b. Belt driven platform similar to delta?
6. What questions am I missing?

EDIT- I feel dirty asking this... is a large delta better as only the effector needs to move instead of large print? Do we need a C-Bot delta build?

 

My mod for corners makes a huge difference in rigidity. I saw someone is using it for a 700mm build height D-Bot today..

For a build that size I wonder if inverting the Z mechanism to raise the X/Y gantry might be a better way to go? That's almost guarantted to be lighter than your build plate, and a fixed build plate is less of a fire hazard

 

I often wondered this (silently) but how come people don't use Nema23's for the Z given the number of weight issues? I run them on my C-Beam Machine through DRV8825s and a 24V psu. Tons of torque. Just thought that question might be relevant given Chris' plans.

 

@wackocrash5150 - This does seem like a good idea. Definitely keep that as an option if I go the modified C-Bot route.

@Spiffcow - Good call - I was thinking the same thing about moving the item with the least mass.

 

New board is supposed to be announced tomorrow.

 

lol .... go figure. My MKS GEN 1.4 just showed up about an hour ago. Ahh well ...

On the bright side, assembly quality looks good. Programmed fine. Only thing I see missing is a PS_ON pin so it looks like I might have to remap one of the AUX pins. I also figured out (to a degree) how to add menu item in the Marlin LCD display to run a gcode command (eg. lights on/off)

 

Are you running the 4 pin LED lights? If so, I can share my gcode for controlling them via Marlin pin control.

 

Naw .... they're just a simple "daylight" LED strip that I picked up on Amazon. Simple 2 wire that I'll be controlling from a 4 channel relay (and also running through an LM2596 to convert 24v to 12v)

Speaking of, can I use this same relay to control the AC mains while using the other 3 to control DC? (meaning 1 of the 4 channels)

 

Chris
I'm intending to use 4 pin LED lights and any help would be appreciated.

 

@wackocrash5150 - Not sure I follow what you are trying to control via the relay? Do you mean mains power to the whole printer?

@TechGirl - Sure, here is my start gcode that includes the gcodes for controlling the lights. Adjust the pin numbers according to the pins that control each color. I believe I have these ordered in RGB. Remember to use PWM controllable pins!

Make sure you have a proper mosfet setup controlling the actual lights, the amount of current for the light strips is far too high and voltage is also too high for most controller IO pins. If you are using onboard mosfets, then make sure you are using the correct common anode/cathode setup for the mosfets. Most on board mosfets control gnd / return and not supply voltage. So you need to ensure you are using common anode lights for mosfets that control gnd and common cathode lights for mosfets that control VCC.

M80 ; Turn on the power supply
M42 P4 S255
M42 P5 S255
M42 P6 S255

M117 Heating Bed
M42 P4 S255
M42 P5 S0
M42 P6 S255
M190 S[bed0_temperature] ;Uncomment to add your own bed temperature line

M117 Heating Hot End
M42 P4 S255
M42 P5 S0
M42 P6 S0
M109 S[extruder0_temperature] ;Uncomment to add your own temperature line

M117 Bed Compensation
M42 P4 S255
M42 P5 S128
M42 P6 S255

...

M117 Printing...
M42 P4 S255
M42 P5 S255
M42 P6 S255

 

Yes. 5v is acquired via USB from the Pi. Relay would potentially control the mains on the 24v PSU. Similar to this:
Control your 12v/24v power supply with G-Code! by MindRealm

But using a 4 channel relay and it would be inline with the mains cord (and fused as well)

 

That depends on the Current / Voltage limits of the relay primarily. There are definitely relays out there that can do it. My concern would be safety and fire control in the relay itself and corresponding wiring. Personally I would buy a switch purposely built to control mains power via a IO pin or perhaps I2C or SPI or even network control.

If your power supply has a dedicated power on lead, think ATX power supplies, then things become a lot more simple and you may not even need a relay. The caveat is where the control comes from. If you are going the gcode route, then your controller needs to powered on all the time. If you use the Raspberry Pi, then you can power down the controller as well but you won't be able to use gcode to do it.

 

This here is what I picked up on Amazon:
https://www.amazon.ca/gp/product/B0057OC5O8/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I know that the 5v and the 12-24v portions of most controllers can be powered separately. When the 5v is drawn from the USB, the Arduino portion is still on and can still activate pins (eg PS_ON ect.) The relay itself is also powered from 5v, which it draws from the Arduino portion as well. With the PSU off, it simply won't power things like steppers, heaters ect. I'm not actually looking to power down the 5v portion, only the the 24v PSU via a relay and fuse in front of it. I do something similar with my Smoothieboard and Delta although I use an ATX PSU on it. Still, it gets it's 5v from the Pi. The relay falls within specs for the voltages and amperage in question. If it was a 1 channel relay, I'd simply follow those Thingiverse instructions. My main question is running mixed (AC/DC) power to be switched from the same board. (separate relay modules of course)

 

WARNING - IANAEE, I am not an electrical engineer. Below is my opinion only.

I'm familiar with this relay, I am going to use it for my HVAC control system I'm building with OpenHAB. It's a 10amp relay, so if we do the math, assuming %70 efficiency in your power supply. Say 400 watts for the printer itself. (400 / .7) = 570 watts from mains. ( 570 / 120) = roughly 5 amps at 120 volts. In theory this is well within the volt and current limits of the relay. So it SHOULD work, assuming the wiring is done safely and the specs on the relay are accurate. That said, I would still pick up a dedicated mains switch built for mains current with a little headroom built in. A typical, US, home line is 120 volts and from 15-20 amps, assuming you're not running a specialized circuit above 20. The relay is listed at 10 amps, so you already have an imbalance in that the supply line and it's circuit breaker are capable of over driving the relay. So if the relay malfunctions, the supply line with happily supply it with enough current to light it on fire. If I were doing it, I would want the switch itself to be able to hand a higher current load than the circuit, so if it does fail, the circuit break does it's job vs the switch / relay starting on fire.

EDIT - I see you are going to use a fuse as well, that changes things a bit obviously. Just make sure your point of failure, i.e.; the fuse, works and won't start a fire itself.

 

Awww Chris! You're taking out all the fun!! lol
Yeah, I planned on installing a fuse to be first in line.
So the 4 relays on one unit are essentially isolated from one another and doesn't matter if I use 1 of 4 for AC and the remainders for my DC fans and lights?

 

It's all good man.

Yep the 4 relays are separate from each other. So in theory there shouldn't be any issues. BUT here again, I wouldn't mix voltages or dc / ac on the same board. Should something short the supply / feed wires between relays or the board not have proper spark gaps, etc.... the magic smoke might come out of everything. For the cost of a dedicated switch for mains, it would bring peace of mind.

 

Funny you should mention that, as I happen to have a couple single channel ones in a drawer (same specs). I was just trying to keep parts to a minimum but, your advice is sound. The spark gap makes sense.

 

Just a quick little video demonstrating the menu changes and the relays. They're not actually switching anything yet. Kinda proud of myself in a silly way ... lol

 

Don't mean to be a party pooper, but I'd argue some of those traces look too close to be safe at mains voltages. In the UK. (230Vac mains) Mains traces should be standard clearance of 2.8mm to achieve CE marking. At least one looks more like 1mm on that board. That might be OK in the US, but that board is marked as being OK at 230Vac, which it most likely is not.

I'd also make sure that those relays don't require any heatsinking to take their upper current limits.

Mains can, and will get you given the first chance. The terinal pins and pads on the underside of that board will be exposed mains contacts. Make sure you enclose that board so you or anyone else can't get to it accidentally.

Also, not many MCU's will happily give 15-20mA on more than a few pins. You may need a buffer for each relay on that board

 

So I have a couple of questions that I would like to ask to all of you who have built the C-Bot.

I built a D-Bot, I saw it and said I like that design I'm going to build it. After it was built I didn't care for some of the design options, mainly the Z motors attached to the rails that hold the print bed, I like them better on the back Z rail that is attached to the frame. I like the direct drive option instead, I bought a pancake stepper just for this actually. and a few other things.

I'm going to reprint some parts from the Cbot reworked set but I had a couple of questions hopefully someone can answer. On the direct drive back plate I don't see a spot to hold the current type of mechanical end stop, and from the build guide i can't see where they go. can someone show me a picture of the rear where the x end stop is so I an see it?

I have other questions but im pressed for time at the moment. I'll be back thanks!

 

It attaches to the rear plate. Original rework uses collision switches (where the screwdriver is pointing) or another uses spiffcow's design C-Bot direct drive backplate with cheap endstop mount by spiffcow like what I used on mine.
Like spiffcow, I did not fee like waiting 5 weeks for switches to show up from China. Luck would have it, they showed up less than 2 weeks after printing it. Oh well. lol

PS I also used the bracket referenced in his Thingiverse summary,

 

So...... whatever happened to that forum idea? This list is about to hit 100 pages. I feel like it's going to collapse under its own weight.

I know there were a lot of ideas floating around, and I don't know anything about setting up a forum (nor am I volunteering to, and beggars can't be choosers), but even just a single bucket with topics would be better than this... not that I don't now have a deep, emotional attachment to this thread at this point

Or how about a Google Group, like (for example) 3D Printer Tips, Tricks and Reviews (no, this is not an 'adult' site, they just ask you if you're an adult before you enter...)
Or a Google+ page, like (for example) 3D Printing - Community - Google+
Google+ is nice since you can make sub-categories.

2c

 

I personally think google groups are a horrible format for anything other than public-facing email chains, as that's effectively what they are.

There are loads of forum hosting services that have a free model, where ads are placed in pages to pay for hosting. They're also extremely easy to get started and eventually customise if needs be.

 

Right on, I would agree.

I'd be up for setting up whatever we want. It's not my day job, but I've done enough of it for various teams / communities in the past to get it done. The results from the last poll where to move most of it to github.

I can look into the options again and will spin up a test or two.

 

Do not move it to github. Github is not a forum site but a source code revision site. We could have the files saved in github, but discussion needs to be on a true forum.