Prusa Mendel 2.0 Question

Thanks. It's the Gregsstruder, but I will check that it has what you're describing.

That seems easy enough.

Thanks Nophead.

Here's the extruder I have (Greg's Hinged Accessible Extruder):

[www.thingiverse.com]

I'm not sure if the mounting options are the same as Wade's Geared Nema 17 Extruder:

[www.thingiverse.com]

Would I need to oder wooden mounting pieces from MakerGear?

[www.makergear.com]
(last option)

Building this printer is way hard. It's almost been a year. I just have to get the hot end finished and wire the electronics.

Quote

Would I need to oder wooden mounting pieces from MakerGear?

Not unless you have a groove mount hot end. The mixshop one you linked to just looks like a plain PTFE insulator. The Greg's extruder you linked has two versions. The second one for Wildseyed looks like it would work.

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[www.hydraraptor.blogspot.com]

Thanks for answering Nophead.

So it looks like the plain PTFE insulator will work without any additional pieces.

I didn't fully understand the bit about two versions for Greg's extruder, but I am assuming it has to do with the SCAD code on the instructions of that page.

OK, now I just have to buckle down and finish this sucker.

There are two STL's on the thingiverse page. The second one looks like at has a 16mm hole the insulator and two screw holes to secure it.

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[www.hydraraptor.blogspot.com]

Thanks for anwsering Nophead. I have opted to simply order the Arcol extruder, since I know it will fit on the Prusa 2.0 parts. It seems like I would have to do some "retro-fitting" otherwise.

New questions

How do I wire a plug outlet and rocker switch to this 12V power supply?
(I'm not sure which wires go where on the switch and outlet.)



Also, how do I make sure I wont electrocute myself? There's no plastic housing and all I have is kapton tape.

Edited 1 time(s). Last edit at 07/30/2012 04:14PM by epochapex.

I wired mine temporarily by cutting the end off a mains lead and connecting the wires to the screw terminals as seen here: [reprap.org].

In the UK Live is brown, Blue is neutral and and green / yellow is earth. If you are not in the UK the wire colours will be different.

It isn't safe in that condition because the mains connections are exposed but I like to live dangerously and there are no children or animals in our house.

I took it to a Maker Faire this weekend so I had to make it safe for the public. I printed a cover that goes over the three mains connections and has holes for a panel mounted IEC inlet, STL attached.



To be counted as safe no single fault should create a dangerous condition. That means all main wiring must have two layers of insulation between it and people and between it and the low voltage wiring. Inside the box the mains wires are insulated and the box provides the second level of insulation. The connections to the IEC inlet have heat shrink sleeving over the solder joints and at the PSU end I used insulated ring terminals.

I have seen designs that have one cover over all the connections. That would not be considered safe unless there was something to ensure that if a mains lead came loose it could not touch the low voltage leads.

I also added a link between mains earth and 0V. Electronically it is better to let the 0V rail float as it prevents ground current flowing in the USB cable. The isolation transformer inside the PSU should be certified to be safe with double insulation and separate bobbins for primary and secondary. If you don't trust your life to a random Chinese company then connect the link.

Edited 2 time(s). Last edit at 07/30/2012 03:51PM by nophead.

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[www.hydraraptor.blogspot.com]

Hi Nophead,

Thanks again for the fantastic reply. I think this will be useful for others as well, since I couldn't find much about this. I'll consider your advice in detail. That housing looks awesome thanks for sharing the STL.

I was wondering about connecting an on/off switch as well.
How would I connect the wires from that to the inlet/power supply? I was searching for a long time and didn't find an answer. Do I connect the live to live and neutral to neutral like a DC switch or would I connect the live wire on both sides of the switch? An the middle is ground right? So I should connect that if I don't want to trust my life to a random chinese company?

This one looks close to the one I have:


Sorry I am a total noob to electronics.

Edited 1 time(s). Last edit at 07/30/2012 04:15PM by epochapex.

Switch the live side. One line goes to the center terminal, the other goes to the normally open terminal. Grab a meter to confirm which one this is, its the one which is connected to center with the switch in the on position. Neither neutral nor earth go to the switch, connect them straight to the supply. Use insulated terminals to make the connections and mount it on a printed enclosure similar to the one nophead linked.

Awesome, thanks Andrew!

Here's how my power supply is looking. It's basically wired according to the instructions above. I soldered the wires onto the metal surfaces and then taped the with Kapton tape. The housing is essentially what the voltage meter came in. It's a temporary housing until I can print one out.

Does it look terribly unsafe?

I turned it on and the green LED lights up, but there's no fan sound. Is there supposed to be one?

I don't think that power supply you have has a fan in it, so you shouldn't hear a fan sound. If the green light on the supply comes on, and turns off when you flip the switch, then you did it right. Also, hook up the ground wire to the supply please.

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Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

Hehehe OK great.

I will definitely hook up the ground.

Newbie question: What is the ground wire in this image connecting to? Rats Nest

Just out of interest, I have attached a photo of how the rest of my printer is looking.

Edited 1 time(s). Last edit at 08/09/2012 09:37AM by epochapex.

The ground wire goes to the third pin on the PSU which had an earth symbol on it. If you don't connect it the metal case will be live at half mains potential.

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[www.hydraraptor.blogspot.com]

Thanks. I'll do that.

Hi again,

So I finally tested my motors and there are some issues that I need to resolve.


The X motor is buzzing/pulsing. I read this thread [[url=http://forums.reprap.org/read.php?219,86951]http://forums.reprap.org/read.php?219,86951[/url]] and turned down the potentio meter, but it simply goes from pulsing to buzzing and then back to pulsing when I complete a turn. Touching the heat sink feels like it's overheating. How many times am I supposed to keep turning it?

The Y motor was working fine before, but now it just wont work. I swapped the pololu for the X motor after I stripped the screw, so maybe that caused this new problem?

The Z motor was moving in one direction but not the other. Is this a wiring/soldering issue?

How can I resolve these problems? Your help is greatly appreciate.

randomly adjusting the pots on pololus is a bit hit and miss.

If they are proper pololu drivers you measure volts between the 2 points marked in red on the attached picture and adjust till you hit 400mV or .4V thats a good starting point to then make minor adjustments to the pot to tune it correctly.

[img.photobucket.com]

If they are not true pololu's but copies then try the above, if it doesnt work go all the way down to .050V and start increasing in .025V increments till you get one motor disconnected for the belts adjusted nicely and then adjust the other to the same starting point.

hope that helps,

GaZ

Thanks I will give that a try.

Hi GaZ,

I tried your method, but the increments on my voltage meter are way too small to tell me if it's at .4V. It's a scale up to 300. I'm a total noob at using a voltage meter too.

I checked all the connectors again to make sure they were connecting ot the chip and it got rid of the noise for the most part.

Now the x motor works fine, but the chip gets really hot to touch.

The y motor now seems to have the buzzing/pulsing issue. When I turn the screw it goes from not working at all to sort of jerkiing but only in one direction.

The z motor gets stuck on one side and wont turn properly, but it's not the motor because I feel it getting stuck when I turn it with my hand. So I think that might be because the z axis not straight enough.


Sigh..... I just can't wait till this thing works.

Edited 1 time(s). Last edit at 08/20/2012 10:30PM by epochapex.

For anyone parachuting into this thread, I've done a bit more reading based on my motor problems.

I found a clue to my z-motor problem here: http://forums.reprap.org/read.php?13,32930 I think the motor is actually defective because when I actually turn it while disconnected it gets stuck after a few turns. The guy in the thread above has the same problem. So it looks like I need a new motor or could tinker with the old one.

The x motor seems like the potentiometer is too high and the y motor has a problem with the end stop — it seems the endstop could be connected in reverse. If they're connected in reverse the motor only goes in one direction.

Edited 1 time(s). Last edit at 08/23/2012 04:10PM by epochapex.

Hi again,

I recently recorded my 3D printer on video and posted it on youtube:

https://www.youtube.com/watch?v=1Sing5S8knA&feature=plcp

(The volume is really low, so you're going to have to turn it up.)

I was wondering if anyone can give a me a tip on what's happening to the Z-motors. I've had difficulty troubleshooting them because the problem keeps changing.

First one of the motors had to be replaced, then they were shuddering, then they just didn't work; and now they work, but get stuck.

It seems to be a mechanical problem. Correct?

It looks like your Pots are still off by a little.

Home the Z-axis then enter

g0 z100

into the box on the lower right side in pronterface and click send. While the Z is traveling upward adjust the pot to eliminate the stutter. DO NOT SHORT OUT THE POLOLU - BE CAREFUL. Or it could be $15 down the tubes...

And the bed is the Y-axis, and the X-axis has the extruder.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Hi Akhlut,

Thanks so much for this suggestion. I don't think I would have thought of that or found it easily. I'll give it a try.

It seems like there needs to be a lot of iteration to eliminate problems that might have multiple causes. I've definitely found that to be true. Once this thing works, I'm going to try never to move it. LOL

By the way, what did you mean with the statement below? I'm slightly confused.

akhlut Wrote:
-------------------------------------------------------

> And the bed is the Y-axis, and the X-axis has the
> extruder.

I still can't get my Z motors to work. It's the only thing not working on my setup. I almost had it working, but as soon as I adjusted the pot it's just jittering back and forth or not moving at all.

I tried swapping the connections and the pololu boards.

I think I have some problems with my RAMPS board like this person:
http://forums.reprap.org/read.php?160,112613

Take the guesswork out of adjusting the Pololu trimpots. Use a multimeter to set the reference voltage: 0.4 V gives 1 amps. So, set it to 0.32 V to start with. This should work as long as you can turn the z threaded rods with your hand.

Thanks I'll try it.