My Replikeo Prusa i3 Rework Build

Bigger = better! HaHA!

I was thinking about switching over to 1.75mm but I have a few parts to make first and I have to wait for the new jhead to get here. It has shipped already! There's a slight chance I'll have it tomorrow, if not probably Monday. So you're still using the jhead @underthetire?

I was about to make the last part for my new extruder when I broke the jhead. And right after those parts I was going to make this hobbing rig [www.thingiverse.com]

Yes. Well, parts of 2 to make one good one. Had a couple mishaps. The D*#N Replikeo ABS plugged up my nozzle again, so i went to take the thing apart and the aluminum boss broke. Then i was setting up the Replikeo Jhead (finally showed up) and somehow the thermistor came out. (probably my bad eyeballs) and heated up enough to melt the plastic. So, i took all the good parts i could, and stuck one Jhead together. Worked out in the end, the Replikeo Jhead was VERY loose in the extruder body, and the sainsmart one was not. So i have one close to perfect Jhead now, and no more replikeo ABS. I had also ordered a J head from Banggood US, so I did have a backup, but i sold that one to a guy at work.

The 1.75 seems to be easier to get now, at least from Amazon, and for <$20.00 total each roll. Much easier to handle the filament, and it seems like my feedrates increased, ive done a few at 75mm/sec without issues, and a test at 100mm/Sec that looked good.

Still working with a 0.4mm nozzle though? Any thoughts of going smaller?

Still a .4mm. I'm ordering the mk7 parts however, includes a new aluminum heater block, a stainless steel threaded stud with the PTFE liner, and the nicest part, replaceable brass nozzels in various sizes. Probably get a .3,.4,and a .5. Total is only ~12.00, so I may get other sizes as well. I plan on replacing the peak insulator with a machined aluminum one if my dad has the correct grooving tool at his house.

Nice! Mind posting links to where you're sourcing this stuff? I'm thinking of going the replaceable-nozzle route too.

Where I get all my crap I'm not in a hurry for. Banggood. Just type 3d printer in there search.

Yesterday, i tried to test reliability this printer. So i print one big thing, its a dome for my multirotor. It takes 11 hour.

And i found the problem was heat bed cable is the problem as seen on the pictures and the Q3 mosfet was very hot until melt the mosfet terminal.
I changed the cable with silicone cable like this [www.hobbyking.com]

Any one has this problem?

John

Some have reported failures there. I used a good quality #12 soft MTW wire all the way to the table and have my power supply fan blowing on the board. I have not done 11 hours, but close to 7 hours. Also, check your heat bed resistance, I know some are lower than others witch can cause problems.

#16 might be on the small side, that can cause a lot more overheating. I calculated my heat bed to draw~10 amps. I figured #14 was about right, but I had 500ft of #12 available. I'm running #10 from the power supply to the board. With some #16 there during set up, I noticed a 10c rise in wire temp.

Edited 1 time(s). Last edit at 08/02/2014 12:26PM by underthetire.

Yes, i just changed the cable with silicone cable, its important.

What is the normal heat bed resistance?

Mine shows ~1.5 ohm.

1-2 ohm is normal, if it is bellow 1ohm it is problem.

Thanks for the information.

Finally, i got the clue what is the problem that make mosfet burned. my heat bed impedance is below than 1 ohm (0.9 ohm). That is why the cable is warm before i changed with silicone cable.
is it why heating the bed is so long ? to reach 110 degree celcius it takes 15-20 minutes. sometimes its stop before reach 110 degree if i turn on the Aircon. the heat bed is so weak.
I have Makibox (my first 3Dprinter), to reach 120 degree is only take less than 5 minute.

So far i have to replaced the Arduino board, Ramp 1.4 (i can repaired the board if i found the Q3 mosfet in local market), heat bed. I think this 3 component have to spare. I haven't experienced clogging in extruder (im using 1.75 filament and 0.4 extruder).

Any suggestion what else i should buy beside those 3 components ? i need to buy one shoot rather than order one by one, it takes 3-4 weeks from Banggood to my country.

for the moment i have to let the printer take rest for next 3 weeks until my order arrive.

Edited 4 time(s). Last edit at 08/03/2014 01:00PM by flyrobot.

My heat bed also takes a long time. You might want to order an extra end stop and a stepper driver board. If the wire is heating up, you will need a larger gauge wire BTW.

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flyrobot
I have Makibox (my first 3Dprinter), to reach 120 degree is only take less than 5 minute.

Lucky person I had preorder for Makibox too, but I asked refund when they went silent. That is reason why i ordered from Replikeo.

Hi Allnei,

I ordered on july 2013 and got the makibox on may, its nice box small and compact and every plastic parts is injection moulding, but it has problem with filament feeder. In my opinion im more happy to have replikeo. Its more precise and reliable, other thing all the component is easy to get and cheap. But the bad thing is apperance like a toy crash from the tree (its my daughter said )
After all component come and get reliable box, i need to think to get nice case to have better looks.

@underthetire, thanks for the information.

Edited 2 time(s). Last edit at 08/03/2014 11:10PM by flyrobot.

flyrobot i had the same problem with mosfet Q3 burning out. My problem was the heat bed resistance was too low. I replaced the heatbed and put a heatsink on Q3 so far its going alright. Also I am going to put a fan on the RAMPS board to blow on the electronics for good measures.
David

Hi David,

Yes my heat bed resistance is 0.9 ohm its too low. But its running after 3 weeks with a lot of print. its burning out after 11 hour print uninterupted for quite big print.
I think its not only RAMP board but also the arduino board must be blowed by fan. my arduino board also already damage, so we should blow the two board from bottom to up.

what is the resistance of your heat bed?

So because I've been habitually checking the Replikeo site for my order status like a crack addict, I have a bit of an update. I know it's been the weekend and all, so I wasn't expecting much, but I contacted Replikeo through their Facebook (tried via the contact form and no one got back to me.) They said July has been overwhelming for them and that they are stepping up the pace. They told me my order should be shipped out this week, or by the end of next week at the very latest. So at least I got word that it will be shipping... soon...ish. :\ Oh well. I'm just excited and impatient.

On a related note, anyone ever try these guys out:

[www.ebay.com]

I was checking eBay for filament and they came up as a top seller with over 2500 pieces sold. I was wondering if I should place an order for a couple of kg for when the printer gets here.

One of my new prints

So I got myself 80mm fan and printed bracket to attach it to RAMPs board. Now I'm trying to figure where to connect it. Has anyone connected more than one FAN to same connection (i.e. D9)? I want to connect both RAMPS and HotEnd fan to same port.
I also printed autocalibration parts and got me a servo, hopefully I'll get it working with Repetier host.

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Allnei
One of my new prints

That's impressive!

Hi Bratan,

I was thinking the same case about the fan to blow electronic board. If i put the fan into one of mosfet terminal, I am affraid it will make more heating on mosfet.
it will be more safe if i get the source direct from power supply, but i think if I make the fan on power supply position to get near face-to-face with electronic board might be better. this solution will safe the power and dont need to add more fan.

Edited 1 time(s). Last edit at 08/09/2014 01:05PM by flyrobot.

Great review and account of your experiences!

I built my Prusa i3 by sourcing all the parts separately, so I can contrast my experience. Electronics with heated bed and LCD, laser cut frame, stepper motors, metal rods, pulleys and belts, hot end, built extruder, plastic parts, power supply... each of these parts came from different sellers, and altogether, with shipping, my self-sourced Prusa i3 ended up costing about $100-200 dollars more than the Replikeo i3 kit. That said, I ended up buying lots of extra vitamins, a few extra stepper motors, and other extra parts, so I can almost start constructing a second printer. One of the first things I did with my i3 was start printing i3 plastic parts sets so I can start a second printer, and of course so I can help others to build theirs!

The troubles you've been having are common to all RepRap builds. MOSFETs are notorious for burning up from low-resistance heated beds. Nozzles get clogged or leak. Stepper drivers are tricky to get adjusted to the ideal voltage. Hobbed bolts and cheap filament gears fail to push the filament, or cheap brittle filament gets chewed up by extruders. Calibrating flow and temperature to get good results takes days and weeks, and has to be repeated with each new batch of filament... The list goes on and on. But then, much of the fun of RepRap printers is to build something that does the basic job and to use it as a starting point, to upgrade and improve itself. The Replikeo kit is convenient in putting together all the parts into one shipping package, but beyond that it isn't much easier or simpler than any other RepRap build. There are immediately things you want to fix. After a little while, no two RepRap printers are exactly the same.

In my first year with my i3 I upgraded lots of parts, starting with replacing the heavy NEMA17-based Wade extruder with a light direct-drive compact extruder that I designed in OpenSCAD. I came up with some cool minimal endstop mounts that clip onto the frame and rods, a simple 624-based belt tensioner, a snap-together LCD case, and a few other useful objects, and shared all my best stuff on Thingiverse. (Funny note: The spool holder that Replikeo shows in some of their product images, but which doesn't actually come with the Replikeo i3 kit, happens to be my design.)

I've had a lot of fun over my first year and a half, but I've also had just about every kind of trouble you can imagine. Burning electronics (fixed!), dying stepper drivers, overheating motors, tangled filament spools, crappy brittle filament, clogged nozzles, leaking nozzles... It's definitely the rough and early days of 3D printing. What you get with a Replikeo kit sounds like the real RepRap experience.

Edited 1 time(s). Last edit at 08/09/2014 11:15PM by Thinkyhead.

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Anyone has tried to measure the Q3 temperature? What is normal operating temperature? Mine is very hot approx 140 C. According to Q3 mosfet datasheet, it can handled the heat upto 170 degree celcius and Current upto 55 Amp. But why the mosfet is very hot and i measured the current on the heat bed is only approx. 10Amp.
I still searching the strongest mosfet and coldest for heatbed.
Any idea?

Hi thinkyhead,

This kind of problem with reprap and other opensource project is what we enjoy and the reason we met in this forum. otherwise we buy expensive box like makerbot. But what i like the most with opensource project is i learned many things from all great people in forum.

From your experience, have you modified the Q3 mosfet with other vitamin? I need much stronger vitamin for Q3 mosfet. The heat more than 70 C raised from one or more of the component on any electronic equipments really make me worried and feel not secured.

Edited 1 time(s). Last edit at 08/10/2014 05:41AM by flyrobot.

Quote
flyrobot
Hi Bratan,

I was thinking the same case about the fan to blow electronic board. If i put the fan into one of mosfet terminal, I am affraid it will make more heating on mosfet.
it will be more safe if i get the source direct from power supply, but i think if I make the fan on power supply position to get near face-to-face with electronic board might be better. this solution will safe the power and dont need to add more fan.

Looking at my 80mm fan specs, it only takes 120mA @ 12V. Smaller fan probably takes much less current, so I think it should be safe to put both on same circuit. I didn't know they were driven by mosfet too?

Guys I remember someone posted something about Bed Auto Leveling. I printed this one, it's completely wrong (hotend opening is way too small, screw holes in weird locations). Which one did you use for this printer?

D8,D9 and D10 was driven by mosfet. See this schematic [reprap.org]

This mosfet is too close with mosfet terminal, its better those 3 mosfet is not direct solder to PCB, but put them all to big heat sink and solder it using cable to PCB.

I printed the new x axis carriage with the servo mount built in. It will sit between the hotend and the bottom of the rails. Looks like it will work just fine. I have not had to re level my bed in a couple weeks now afteri made my new Y bed with tapped holes for the hot bed mount, so not in a hurry.

My mossfet is reaching only about 110c.

You should see this [www.electro-tech-online.com]

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Bratan
Guys I remember someone posted something about Bed Auto Leveling. I printed this one, it's completely wrong (hotend opening is way too small, screw holes in weird locations). Which one did you use for this printer?

It was me, who talked about auto bed leveling. What you linked is mount for vanila i3, not Rework that we have.

Use this mount [www.thingiverse.com] and hot glue servo in it. I am not home, so I can´t post you picture of mine. Also you must use it with Marlin FW, because Repetier don´t have good auto bed leveling code.