Migbot Prusa i3 Unofficial Support Thread

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gotswrv
Uberjay,
Change out the wires as mentioned.

Another thing I've found troublesome is if a fan is is blowing on the hot end. I now have the extruder fan taped up to keep any leakage from getting to the hot end. I couldn't feel the airflow, never would have guessed it was trouble. Ended up accidentally having that fan off once and noticed my temp was rock solid all of the sudden. No more run always ever, had to recalibrate too, so obviously it was a thing.

Thanks ... yes. I'm planning to do just that as soon as I can; however, as I mentioned I may have a kludge in place for now. Also, I'm going to try that fan thing - sounds like an easy tweak.

J

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uberjay

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Ax
Change it to 14 AWG, It's under gauge. Had something similar with the 4th Migbot's bed until I changed out the wire. Made a huge difference. I'm betting the wire's warm when the printer is running.

Thanks... I'll get to that for sure. Did a quick hack to see if I could kludge out the hysteresis calc without letting it dip to low or jump too high:

#define THERMAL_PROTECTION_HYSTERESIS 20 // Degrees Celsius

(default was set to 10)

With the above and a print temp of 210 it was successful. I figure I'm still safe at this print temp - min point should e 190 and max 230 which is (I believe) in the range for PLA and given that my temp variance was a drop not spike.

Anyway.... I plan to:

a) get the larger wire (will take longer to enact for me 'cuz I'm lazy by nature )
b) will also try adjusting the extruder fan's airflow as I've read and is mentioned in another comment / reply here.

Then I just need to dial it in so my print doesn't curl without a brim. .... all in due time though.

Thanks so much for your help Ax....
J

Not a problem, I would change the wire out on both the bed and from the PSU ASAP, they are both under gauge, them getting warm is a fire hazard as they are resisting the flow of current. The bed can be 16 AWG as it's not pulling as much current as the board.

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Ax

Not a problem, I would change the wire out on both the bed and from the PSU ASAP, they are both under gauge, them getting warm is a fire hazard as they are resisting the flow of current. The bed can be 16 AWG as it's not pulling as much current as the board.

So you mean the power and the thermistor wires are under guage?

I'm beginning to think buying this thing was a mistake.... I spent all that money for something advertised as complete and functional and here I am having to fix all their mistakes! I didn't have high expectations for a DIY printer, but I'm thinking my expectations were still a bit high.

Ah well... live and learn.

Incidentally... the thermistor wire temp was only rising about 0.6 degrees during operation; however, I know that that means there is extra resistance and thus inaccurate / skewed readings. I'll keep an eye on the power wire temps too.

Thanks!!
J

No, just the power wires.. the thermistor wires do not carry much current at all. As for buying a $300 printer, the old adage apples. You get what you pay for.

Edited 2 time(s). Last edit at 03/09/2016 08:00AM by Ax.

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Ax
No, just the power wires.. the thermistor wires do not carry much current at all. As for buying a $300 printer, the old adage apples. You get what you pay for.

Thanks... again on the wires/confirmation.

Yeah, I get the cheap printer thing. But I don't agree with vendors that sell it as a package that should work and, well, it doesn't. Also, it hits hard here as that $300 printer that I got was actually $410 after the options I got. For me that equates to over $600 Canadian Dollars. So, not exactly chump change for me anyway. But, yes, if I look at the market of 3D printers I do value the price ... just not the expectation this vendor set that what I would get would be (at least) functional.

Anyway... as I mentioned before, I am very grateful for you and your help. You are very gracious with your time helping all of us who are lost and needy ;-).

Cheers,
J

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spinracing


Go to print parts for the leadscrew conversion.. BLAMMO spaghetti. My y axis stops working and spits out its belt.
Needless to say.. I am going to have to repair the belt holder, and make it functional until I can get the leadscrew parts. But hope to have pics sooner rather than later.

Do you live in the us?

Edited 1 time(s). Last edit at 03/09/2016 10:54AM by Wes78.

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uberjay

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Ax
No, just the power wires.. the thermistor wires do not carry much current at all. As for buying a $300 printer, the old adage apples. You get what you pay for.

Thanks... again on the wires/confirmation.

Yeah, I get the cheap printer thing. But I don't agree with vendors that sell it as a package that should work and, well, it doesn't. Also, it hits hard here as that $300 printer that I got was actually $410 after the options I got. For me that equates to over $600 Canadian Dollars. So, not exactly chump change for me anyway. But, yes, if I look at the market of 3D printers I do value the price ... just not the expectation this vendor set that what I would get would be (at least) functional.

Anyway... as I mentioned before, I am very grateful for you and your help. You are very gracious with your time helping all of us who are lost and needy ;-).

Cheers,
J

Hey J, you must have some 14 AGW wire lying around for one of your RC planes. I forgot to tell you that I changed those wires on mine and a lot of problems went away. I used some silicone coated 14AGW due to the flexibility. A bit more expensive but you saw how I have the wire in the chain guide so it flexes better.

Jeff

p.s. Ax, Thanks for helping J. I was beginning to run out of ideas so I told him he should post here. Forgot about the wire. One of the first things I did months ago so forgot all about it. Yeah, the original wires used to get warm. Cheap Chinese setups. Save a buck without thought to safety.

Edited 1 time(s). Last edit at 03/09/2016 11:14AM by Canadian Geek.

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Canadian Geek
Hey J, you must have some 14 AGW wire lying around for one of your RC planes. I forgot to tell you that I changed those wires on mine and a lot of problems went away. I used some silicone coated 14AGW due to the flexibility. A bit more expensive but you saw how I have the wire in the chain guide so it flexes better.

Jeff

p.s. Ax, Thanks for helping J. I was beginning to run out of ideas so I told him he should post here. Forgot about the wire. One of the first things I did months ago so forgot all about it. Yeah, the original wires used to get warm. Cheap Chinese setups. Save a buck without thought to safety.

Yeah Ax, it's all Jeff's fault that I bothered you ... LOL.

Yes, Jeff, I am pretty sure I have some wire. It's time to disassemble, fix, and reassemble that I'm running short of.

I managed to get a good print, but now I notice my print bed is heating unevenly - +/- 4 degrees on the X axis (warmer the further from the X stepper).

Anyway... yes, lots of todo's for me now. Next time I might be inclined to save up for a higher end model, but for now, I thank you and Ax for all your help. Much appreciated!

J

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Wes78

Do you live in the us?

Yep, Florida.
Kicking myself for not printing extra parts.... resisting doing a Ax and buying another! (Dont have a business need yet.. so cant justify to the wife)

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spinracing

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Wes78

Do you live in the us?

Yep, Florida.
Kicking myself for not printing extra parts.... resisting doing a Ax and buying another! (Dont have a business need yet.. so cant justify to the wife)

I will print you a replacment part if you like and mail it to you. i live in Oklahoma, wouldnt be a problem.
From the github can you give me a link to or tell me what part you need?
and Pm me your address

[github.com]

To those that have said thanks. It's not a problem. Migbots aren't easy to use and aren't a really good first printer unless you're prepared to do a fair bit of tinkering and learning. There are a few parts which really are sub-standard, but there are a few good parts too. They have a lot of quirks and using them on a daily basis you learn how to deal with them. A lot of things are not obvious either. I don't like people struggling having invested a large-ish chunk of money into something they have no clue how to work properly. This is why I help out, I know these printers inside-out, I know their quirks, it's better to have someone with a good knowledge of these printers and a fairly good understanding of the Marlin firmware around to help out, than be left out in the cold. If I knew now, what I didn't back when I bought the first one, I'd have probably looked elsewhere but I didn't, I'm glad I didn't as well, I wouldn't know half as much if I didn't. I guess what I'm saying is you're very much welcome.

As a note, when I finally sort my Mostly Printed CNC out, I'll be modelling out the frame for cutting in Aluminium plate, I will be offering these frames as a replacement for the Acrylic as well as a full Prusa i3 kit, the MetalMig. The MetalMig will be a Migbot, but my style with a metal frame, an E3D Lite6 Hot End and should hopefully just work out of the box.

Edited 1 time(s). Last edit at 03/10/2016 06:32AM by Ax.

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Ax
As a note, when I finally sort my Mostly Printed CNC out, I'll be modelling out the frame for cutting in Aluminium plate, I will be offering these frames as a replacement for the Acrylic as well as a full Prusa i3 kit, the MetalMig. The MetalMig will be a Migbot, but my style with a metal frame, an E3D Lite6 Hot End and should hopefully just work out of the box.

Sounds like I need to start saving up again ;-). Look forward to seeing the MetalMig.

Cheers,
J

Can anyone point me at the how-to to remove the heater element from the hot end so I can put some thicker guage wire on it? Or do I just have to solder it inline on the machine?

I tried just pushing the heating element out of the head, but it's not budging and I don't want to bust it.

Thanks,
J

That wire is fine, you can leave it. It's just the wire from the power supply to the board and the one from the heatbed to the board you need to worry about.

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Ax
That wire is fine, you can leave it. It's just the wire from the power supply to the board and the one from the heatbed to the board you need to worry about.

Ah! Okay then, that makes my life much easier. I was wondering about that.

Thanks,
J

Should it come up, I had to replace my heater block because the threads for the barrel disintegrated. Loosening the grub screw and heating the block allowed for the heating element to slide right out.

Well, I'm back to a Thermal Runaway again.

Thought I had that licked... per Ax's recommendation I increased the thickness of the wire from the supply to the control board. Still need to do so for the bed, but I was getting some good prints. Now this... on a tiny 10 minute job.

Any ideas? I know... replace the bed wires... is it really that obvious a fix? I'm just curious because it is the hot end that is failing to hold temp.

Thanks,
Jason.

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uberjay
Well, I'm back to a Thermal Runaway again.

Thought I had that licked... per Ax's recommendation I increased the thickness of the wire from the supply to the control board. Still need to do so for the bed, but I was getting some good prints. Now this... on a tiny 10 minute job.

Any ideas? I know... replace the bed wires... is it really that obvious a fix? I'm just curious because it is the hot end that is failing to hold temp.

Thanks,
Jason.

Okay... think I might have found a possible culprit. I manually turned down the fan speed to ~ 200 out of 244 (using the marlin 1.1 menus) while the hot end temp was declining and had dropped from 197 down to 183. After changing the fan speed the hot end temp climbed back up ... it's now at 188.

I think I saw somewhere maybe that someone was having issues with the stock fan shroud causing too much air on the hot end. Does anyone have a link to a part I can print to replace with a better nozzle?

Thanks!
J

I was using this shroud almost immediately since the one that came with it kept falling apart: [www.thingiverse.com]

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jazzbassNick
I was using this shroud almost immediately since the one that came with it kept falling apart: [www.thingiverse.com]

Thanks!
J

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uberjay

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uberjay
Well, I'm back to a Thermal Runaway again.

Thought I had that licked... per Ax's recommendation I increased the thickness of the wire from the supply to the control board. Still need to do so for the bed, but I was getting some good prints. Now this... on a tiny 10 minute job.

Any ideas? I know... replace the bed wires... is it really that obvious a fix? I'm just curious because it is the hot end that is failing to hold temp.

Thanks,
Jason.

Okay... think I might have found a possible culprit. I manually turned down the fan speed to ~ 200 out of 244 (using the marlin 1.1 menus) while the hot end temp was declining and had dropped from 197 down to 183. After changing the fan speed the hot end temp climbed back up ... it's now at 188.

I think I saw somewhere maybe that someone was having issues with the stock fan shroud causing too much air on the hot end. Does anyone have a link to a part I can print to replace with a better nozzle?

Thanks!
J

This is a modification I made of the same one as mentioned above. I did the modification so I could mount LEDs around the nozzle. Now my old eyes can see what I'm printing: [www.thingiverse.com]

Jeff

p.s. You may want to print it it ABS. I did it in PLA and it has warped a bit since. Nothing too bad but the next time I print it I'll be using ABS.

Edited 1 time(s). Last edit at 03/14/2016 12:04AM by Canadian Geek.

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Canadian Geek
This is a modification I made of the same one as mentioned above. I did the modification so I could mount LEDs around the nozzle. Now my old eyes can see what I'm printing: [www.thingiverse.com]

Jeff

p.s. You may want to print it it ABS. I did it in PLA and it has warped a bit since. Nothing too bad but the next time I print it I'll be using ABS.

Thanks Jeff... I knew you had done something with LEDs. I'm not printing ABS yet. Not sure I want the smell or to build a fume hood/vent just yet. So I'll live with PLA and make a new one if I need to now and then. Unless you want to sell me an ABS one ;-).

J

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uberjay
Okay... think I might have found a possible culprit. I manually turned down the fan speed to ~ 200 out of 244 (using the marlin 1.1 menus) while the hot end temp was declining and had dropped from 197 down to 183. After changing the fan speed the hot end temp climbed back up ... it's now at 188.

I think I saw somewhere maybe that someone was having issues with the stock fan shroud causing too much air on the hot end. Does anyone have a link to a part I can print to replace with a better nozzle?

Thanks!
J

Something isnt right.. as a test i pointed a fan + the cooling fan at my hotend and i dont have any problems with it keeping temperature. changing the fan shroud out may be a way to get by with it but really not the "fix"

I didnt read back to see, so just gonna ask right fast
Out of curiosity... have you done a PID tune on the hotend?
If you have, how many cycles did you run with PID auto tune?
after doing an auto tune, did you input the new numbers and do an auto tune again with the new numbers?
I would recommend doing PID auto tune 8-10 cycles updating with new numbers (kp, ki,kd) each time you auto tune. Auto tune attest 3 times or until you get the Kp,KI,and KD with in 5% of the previously set numbers getting the PID set correctly is VERY important to keep a stable hotend, the hotend "should" be able to over come the fan blowing on it and keep it stable.

there is a possibility that you have a some-what faulty heater cartage,( do you have a way to ohm it?) changing that out would seem like a better idea, maybe try to go up to a 40W one I think the one that comes with it is 30W

and as a last thought, have you made 100% sure you have entered in the FW that right thermometer settings ?

Edited 2 time(s). Last edit at 03/14/2016 08:58AM by Wes78.

Check to see that your thermister is secure inside the hotend. I found mine was coming out and couldn't get my temps to stay stable. I re-wrapped my hotend with new kapton tape.

Edited 2 time(s). Last edit at 03/14/2016 10:15AM by broy55.

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Wes78
Something isnt right.. as a test i pointed a fan + the cooling fan at my hotend and i dont have any problems with it keeping temperature. changing the fan shroud out may be a way to get by with it but really not the "fix"

I didnt read back to see, so just gonna ask right fast
Out of curiosity... have you done a PID tune on the hotend?
If you have, how many cycles did you run with PID auto tune?
after doing an auto tune, did you input the new numbers and do an auto tune again with the new numbers?
I would recommend doing PID auto tune 8-10 cycles updating with new numbers (kp, ki,kd) each time you auto tune. Auto tune attest 3 times or until you get the Kp,KI,and KD with in 5% of the previously set numbers getting the PID set correctly is VERY important to keep a stable hotend, the hotend "should" be able to over come the fan blowing on it and keep it stable.

there is a possibility that you have a some-what faulty heater cartage,( do you have a way to ohm it?) changing that out would seem like a better idea, maybe try to go up to a 40W one I think the one that comes with it is 30W

and as a last thought, have you made 100% sure you have entered in the FW that right thermometer settings ?

Thanks for the response. Admittedly, I did run the PID tune; however, I can't remember how many times, but I did the recommended 8 to 10 cycles. Also, I did update the firmware with my numbers.

I did check the thermistor setting in the firmware. My thermistor's impedance measured at the plug/board end is ~ 125k. Not sure if that would alter it, because the firmware config talks about 100k.

Anyway, today I have been printing at 75% fan setting with and without the hot bed. (I thought maybe the hot bed was sucking too much juice as I haven't changed the wire guage there yet.) So far, the temp has been solid. So in my emperical testing it seems that the fan may actually be the culprit.

That said, I do plan to rewire the bed at some point and pull the thermistor out and put some thermal paste in there with it. (I think I've read that's a good idea??)

Thanks again!
J

Im glad you got it going well enough to print with it, if memory serves me right its #1 thermistor setting witch is the stranded 100k so thats good.

Defiantly------Defiantly get the wire changed out that needs to be on the top of the todo list for sure.
I strongly recommend doing a pid auto tune with the new pids you have entered. think of it as a "fine tune"


And the fan is only showing you that there is a problem, as the hotend --WILL-- have no problem keeping it hot with a fan blowing on it.
provided-----
1.That its getting the adequate power needed. (amps)
2. properly tuned PIDs (over shooting the set temperature more then 1 or 2c or isolating around the set temperature is a sign of poor pids )
3. "thermistor" rather its going bad, coming out of the hot end or wrong fw settings

Thanks... when things slow down (after an event this weekend) I will definitely attack things as you've recommended. For now, I only print when I'm nearby and babysit it like a nervous daddy ;-). Ie. I'm in get'er done mode as I have parts to get printed on a deadline.

Thanks for all your help. I always am humbled by the generosity of people on these forums.

Cheers,
Jason.

Found this on Kickstarter today: [www.kickstarter.com]

Seems like it would be a good upgrade for the Migbot, thoughts?

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CAlleman
Found this on Kickstarter today: [www.kickstarter.com]

Seems like it would be a good upgrade for the Migbot, thoughts?

depends on what filament you print with and how much printing you do.

there is wear on the brass with just pla but it takes a long time until a replacement is needed
However if your printing with carbon fiber pla ( or any abrasive material) even glow in the dark definitely worth the money
I dont have the Tungsten tip but i do have the hardin metal ( could be Tungsten idk) and i love it.

Edited 1 time(s). Last edit at 03/15/2016 01:09PM by Wes78.

Not to say a tungsten tip wouldn't have merit, but I have issue with some of the claims made. For instance saying that the stainless gets soft. Stainless (304) anneals at around 1000C. Or that higher thermal conductivity is paramount. If so why not aluminum with a pvd coating?
Anyway, I don't see myself printing carbon or peek much.