my build goal is 305x305x305mm. I posted a side view pic yesturday. I can't say that there were really any problems related to size except where to put it when done. I am not printing yet so that is still open for discussion. I shrunk things down from Carl's 305 sizes. Width including extruders on one side = 570mm, depth including XY motors = ~515mm. To do that I had to rearrange endstops etc, and I have yet to print my ductwork for the fan. I have 2 extruders. My X&Y size is pretty solid but I am down to 295 on Z because of the bed - that may change but it isn't a big deal. The X axis is actually 335 with the 2 extruders. I decided to go this big b/c there was little cost differential and I don't like limits but could not see going to adam's sizing (my house isn't as big as his). Mine has 3 screws, belt driven similar to his. I had an issue with screw alignment but it was a build issue and not related to size. I modeled it all in Sketchup before building to make sure things would fit and had to modify/create a few parts. Frustrating, tiring, but neat learning experience on Sketchup. I can tell u, if u r going to use openbuild lead screws DO NOT use brass nuts. Those screws reflect their price and will work with their delrin nuts only - unless u want to file down all the burrs and defects on the screw faces. Best prices on screws/nuts @ Mr Metric. Cheap, powerful steppers @ Automation Technology. $8.99 for the KL17H248-15-4A, a 76 oz-in unit. 5x = $62.59 >>>> 6x = $67.02 About $4.50 for a spare because of a lowered shipping cost on 6. NICE. Most everything else I bought came from Ebay/China. 2-3 weeks delivery and some were run over by the USPS even one from NY. I am using a Ramps bd and when I am printing will post my config files. There is much to be desired about the documentation.

 

Thanks for the input - I think i'm still leaning towards a 30x30.
One of my issues is that i'm in the UK where you still can't get any of the heated beds you're all using. The only 30x30 beds available over here are the (pricey) flexible silicon ones...so it looks like i'll have to import one from the USA - most likely from Makerfarm as all the other sources i've found so far don't ship to the UK.
Which then means that it will most definitely require its own separate 12v supply as they're rather power hungry.

Adam: I'm trying to reduce the width of my build a little due to available space. Do you think your 3 screw layout would still work OK if the rear Z screws were set inside the heat bed frame & the overall bot width reduced accordingly?

 

have u looked at ebay - from china most r small but I haven't looked lately - make sure u get one with the parts on it led, resistor & thermistor.
have a look at my pic if u want to shrink it. I turned my screws to the side to keep the front clear. I am also using the idler side as the front so the XY motors r out of the way in the "back". The display u see on the right is on the front.

 

I think that the bot could be slimmed down a bit. @ruggb my house wasnt quite big enough. I had spiral stairs to the downstairs, it wouldnt fit. I had to go out the front door, around the house and into the outside celler door to transport. I just drove it across country in my Crosstrek and it it occupied a good 1/3rd of the space.

@Elmo Clarity have you checked the resistance of your board to determine it is a 12V HBP. I dont know about hbp, but I check ohms for every heater core that I buy, especially since mightyboard runs 24v. 40W heatercores 3ish ohms for 12v 12ish ohm for 24v. There are also some dual power HBP, is yours wired correctly?

@craftygeek The closer the lead screw its linear way, the more optimal it is. You could move the leadscrew inside the HBP support. I would also entertain designing a 90d egree bracket(assembling the z stage) that included a nut catch for the acme nut, while keeping the bed support perpendicular and rigid. Personally I wish my leadscrews were wider spaced, I am challenged leveling the bed maneuvering around them, but my hbp and nozzle are almost 2M tall on top of the table.

 

All the resistance checked out properly. Ran the heater bed with an amp meter and it was getting the power that it needed. Switched it over to run the 24V on the 12V connection and it heated right up to 100C. It's looking like it just won't heat up over 45C when ran at 24V. So now I need to rethink my wiring and control. But it is going to have to wait. My Printrbot Simple Metal power to the heater on the hot end shorted out and melted the wiring. Going to have to rewire that guy now before I can work on my new printer.

 

engineering wise, 24v at the same resistance should run at 2x the current. Therefore it should heat 2x as fast and get hotter.
I would measure voltage from 24V return on PS to each connection on the line all the way back to the PS +24v (or the other way round). There is either a bad line/connection dropping voltage (something will be getting quite warm beside the bed) or the PS can't handle the wattage at 24V and is current limiting.

 

Running 24 on the 12 does heat up faster as would be expected. There was minimal voltage loss and the PSU is 14.6A so has the power to run it, as was shown when I switched to 24 on 12. When ran at 24, it started by pulling 5.2A, just as expected. As it heated up, the current draw dropped, again as expected. As far as I can tell, either there is a fault with the board or it just can't do over 45C on 24v.

 

Sorry, I made an assumption and forgot how those bds r made. As I think I recall now (and sometimes I don't recall well) the bd has 2x 12v ckts. Running at 24V puts them in series. Connected for 12v they r in parallel. So the current should actually be about the same since the resistance is doubled. The power should also remain about the same, therefore the heat should be about the same.
If the 24v ohm is 2x the 12v ohm there isn't much that can be wrong with the bd. Any defect should exhibit itself under either connection. What I would do is connect each ckt individually to 12v and verify the output is the same. A intermittent hairline crack in the ckt WOULD be more obvious under 24v but if u had a ammeter on it all the time u should also see the current fluctuate.

 

I measured while heating. I don't think it is the PSU as it was able to provide the much higher current required to do the 24v on the 12v terminal.

I'm just going to go with the 24v to the heater bed and switch back to 12v for everything else.

 

I'm not sure that actually made sense......"PSU as it was able to provide the much higher current required to do the 24v on the 12v terminal. " what does that mean?

 

Not sure exactly what you are trying to say. The board works out like this:

Across the 24v pads, the resistance is 5.6 ohms. The board will use 4.3A in this mode and that is what I measured. This is 103W and would only go to 45C.

The 5.6 ohms is basically two 2.8 ohm resistors in series and and results in a 1.4 ohm resistance (2.8 in parallel) when connected for the 12v circuit. Running 24v through that requires 17.1A. This is 412W and it goes well over 100C.

Running 12v on the 12v pad requires 8.6A and will produce 103W. Same as the 24v circuit.

The board is listed at 140W so it seems the resistance in the board is a bit higher than it should be. To achieve the 140W, if I did my math right, it should only be 4.13 ohms across the 24v circuit. The specs for the board says the 24v resistance should be between 4.5 and 5 ohms. So based on the specs itself, the best the board could do is 128W (worst is 115W). So there is already a disconnect with the board specs. And my measured values are also out side of specs.

 

It takes more current to run 24v across the 12v circuit than it does to run 24v across the 24v circuit. If the PSU was having problems providing power for the 24v circuit, it would have a lot more problem providing power for the 12v circuit.

 

OK, got it. The difference in numbers is called specmanship. I have not tried mine but @ 1.1ohm that is only 130W. So how much diff will that make? 102W>> ~20° rise..130W should give another 5° maybe or 50°C. I guess I will check that out. 4x the power (412W) yield avoub 4x temp rise - 20° to 80°. interesting!

 

as long as theres nothing wrong with a little OT. Wanhao is entering the reprap market with a i3. Introductory price at 375 shipped in the US. This is an all steel frame, 0 printed parts, HBP. It is really going to be a nice printer, and for 375 you really cant beat it, lots of shiny aluminum where other kits are printed pieces. price good through June 1

 

For that price, I got one just for the ramps experience. Good call on the x belt, no one in the sailfish circles had picked up on that, I see now exactly what you mean.

Anyone going to BAMF this weekend?

 

RE Wanhao, it is hard to tell for sure which side that it is pinned on but it does appear to be the bottom. My 2up looks similar but it is pinned to the carriage on the top where the belt is straight so it has no error. I guess that is the reference to "they easily could of". But at least it's a cute triangle

 

Does anyone have the Ramps fan extender working? If so what did u configure in Marlin?

 

Looks like a great machine. I had been looking at a CTC Makerbot clone for $500 shipped on eBay for printing while my Kossel gets rebuilt(going much larger with 20x40 extrusion) but it's hard to justify not just finishing my C-Bot first. I think building and buying different design printers is becoming an addiction.

FYI, I got my second E3D Lite6 from Matterhackers and it too was missing the fan. The site also still showed Priority mail as my shipping method but was sent first class again. When I call the customer service is great but they seem to be having trouble resolving the small problems I encountered. When I called they thought I was another guy who also had an E3D Lite6 arrive with the fan missing so it's obviously a common mistake. Think I'm gonna wait awhile until they get things under control before I place another order.

Getting close to installing my electronics but still need to pick up 8 M5 60mm bolts and some bed springs. Any suggestions on what size(s) to look for? I'm gonna swing by Home Depot/Lowes in the morning to see if this kit might have what I need as it's in stock locally:

http://www.homedepot.com/p/Unbranded-Spring-Assortment-Kit-84-Pack-15642/202045461

 

Thanks Carl. The 84 spring kit for $5 from Home Depot has four 3.57mm OD springs at 25mm length so I'll try it first.

 

I have it running @ 100% but I can't get PWM to work. If u need that infor let me know. Using Marlin 1.0.3 dev = I am going to go back to 1.0.2 and see if I can get it there, the dev version looks like a major rewrite. A lot of changed/restructure.

 

FAN_PIN has to be changed -- YEAH!!!! -- as I was typing I recompiled and it is running. Hold on............history has just been made
Now I am using a fan extender bd. If u have ur own ckt connected to another output, it has to be an analog pin and u use that pin number instead of 6 or 11.
PWM: 2 to 13 and 44 to 46. Provide 8-bit PWM output with the analogWrite() function

this was my last chg in configuration.h line 747 or there about - uncomment #define FAN_SOFT_PWM -
In pins_RAMPS_13.h change line 87 #define FAN_PIN 11 or 6 whichever u want to use. Now I need to figure out how to use the other output.
assuming there is no conflict - like with servos defined which use 4,5,6,11

Since I have changed a lot of stuff trying to figure this out let me know if it doesn't work for u as there may be something else I forgot I changed.
U can't believe the # of conversations I have had with the developer to get to this point. And he wasn't sure what the answer was. The last change was an off the cuff remark that sounded like a pure guess. He literally did not know how to make it work.
WHY is this so hard??????????????

 

I had to disassemble my hot end mt as I had a bad print. When I reassy I realized I had some s..t luck the first time I assembled this. This time when I tightened the belts the gantry didn't line up square. It is actually a little tricky. When u pull on a belt it twists the gantry. - how do you do it to get it square??

BTW, u don't want to tighten too much as the print will distort under the belt. Might want to look at a little different design here.

 

Also beware of the belt clamp screws dragging on the bar underneath if you tighten them down to far, this happened on my build and caused binding on my first prints.

 

I just posted on thingiverse the slot covers that I made for my C-bot. They are handy for hiding your wires in the rails of your bot.


http://www.thingiverse.com/thing:832077