Migbot Prusa i3 Unofficial Support Thread

Quote
jbehan
I will try a higher nozzle temp, I think I'm at 240 C already, will bump it up 5 C. I do have an enclosure in place and I've been using a bed temp of 110 C, lowering to 90 C after 1 mm. Are you doing anything with the cooling fan?

Thanks for your feedback.

Josh

I had talked to the manufacturer about their stated temp of 230-240 and going above. They said a temp increase even up to 270 could work fine, it really depended on individual extruder and thermistor setup. Thus why I bumped it up to 245 with relative ease.

No fan for me. I don't think I have heard most people using a fan with ABS, I would think that would make it cool too quickly compared to the other layers and warp.

I was keeping my bed temp at 100 because without the enclosure its the only thing that would keep the ambient temp around the model up. Do you know what your temp is in your enclosure at all? Its possible bumping that up a bit for the other layers could help as well, because its not just about the first layer sticking but warping with the other layers.

Edited 2 time(s). Last edit at 08/26/2015 05:11PM by gatorNic.

gatorNic,
Tried again at 245 C and it's better but still had some separation of layers, makes sense about having no fan. I will give it another try tonight without fan. I haven't taken the temp inside my enclosure but I haven't had any warping since I started using it. My enclosure is just some 1/4" foam sheet (FFF foam from HD) taped together with aluminum tape used for duct work. I'm trying to print new X axis parts, specifically the right side with an adjustable belt tensioner. Maybe I have something else messed up, I'm printing at 60 mm/min, 245 C nozzle, 110 C bed, 0.2 mm layer height, 20% in-fill with a 20 line skirt. Does the amount of in-fill affect layer adhesion? Also, I have an in-fill/shell overlap of 18%, maybe that's too high as well....guess this is part of the fun!

Josh

Quote
jbehan
gatorNic,
Tried again at 245 C and it's better but still had some separation of layers, makes sense about having no fan. I will give it another try tonight without fan. I haven't taken the temp inside my enclosure but I haven't had any warping since I started using it. My enclosure is just some 1/4" foam sheet (FFF foam from HD) taped together with aluminum tape used for duct work. I'm trying to print new X axis parts, specifically the right side with an adjustable belt tensioner. Maybe I have something else messed up, I'm printing at 60 mm/min, 245 C nozzle, 110 C bed, 0.2 mm layer height, 20% in-fill with a 20 line skirt. Does the amount of in-fill affect layer adhesion? Also, I have an in-fill/shell overlap of 18%, maybe that's too high as well....guess this is part of the fun!

Josh

Yeah I would put my money on the fan. The fan I would pretty much always use for PLA, and only be using it for ABS if parts look melted or corners are too rounded. Here is a little quote on ABS I found "A fan to provide a small amount of active cooling around the nozzle can improve corners but one does also run the risk of introducing too much cooling and reducing adhesion between layers, eventually leading to cracks in the finished part."

Infill could possibly effect layer adhesion, not sure. I mean correct infill helps in so many other areas...top layers, over hangs, holes in the model, proper connection to the perimeter, etc, I wouldn't be surprised if it does. In theory, I think it certainly would. More stabilizing material inside is only going to hold it together better. I think it would be much less an issue than the fan though. I usually don't run less than 25% infill, and more normally 35% because I think it seems to help the quality of the print in all those other areas. Obviously there is a trade off with print speed, but I think its minor compared to how many times you have to redo a print.

Having some trouble with a brand new build. The electron 3D variant. All the instructions say migbot though.
When I turn it on, the extruder temp reports 358 and I get a MAXTEMP error.
I tried flashing the firmware from the 1st post in this thread and it still behaves the same. Thermistor is plugged in properly. I triple checked.

Any ideas on what I can try next?

How do I confirm what type of thermistor is being used to make sure the configuration,h file is right?

Thanks!

EDIT: I just tested the thermistor with a multimeter. Zero resistant. Does that mean my thermistor is dead? If so, now what?

Edited 1 time(s). Last edit at 08/27/2015 10:17PM by kareem613.

Yes, the thermistor should probably be 100K ohms.

As for ABS shrinkage with infill, more infill (especially lengthwise) will cause more shrinkage lengthwise, because there will be more plastic contracting and pulling inwards, thus pulling up the edges.

Try PET... it does not warp at all, and has no smell.

gatorNic, you rock!
Thanks for the advice, it worked like a charm. No separation of layers, no corner melting....awesome. Thanks for helping me over that little hurdle.245 C nozzle - 110 C bed and no fan.

Josh

Quote
RRuser

Try PET... it does not warp at all, and has no smell.

I'll have to take a look at PET, is it similar to printing ABS?

Quote
kareem613
Having some trouble with a brand new build. The electron 3D variant. All the instructions say migbot though.
When I turn it on, the extruder temp reports 358 and I get a MAXTEMP error.
I tried flashing the firmware from the 1st post in this thread and it still behaves the same. Thermistor is plugged in properly. I triple checked.

Any ideas on what I can try next?

How do I confirm what type of thermistor is being used to make sure the configuration,h file is right?

Thanks!

EDIT: I just tested the thermistor with a multimeter. Zero resistant. Does that mean my thermistor is dead? If so, now what?

Those wires in the thermister are so tiny they easily get pinched or broken. Mine has a small pinch and gives that warning sometimes, but I just fiddle with it and turn off/on again and it works.

Did they not send you an extra thermistor in the migbot box? They did with mine, and I remember somebody else mentioning it too. They are real cheap if not. I would just buy a bunch since the are so breakable.

Quote
jbehan
gatorNic, you rock!
Thanks for the advice, it worked like a charm. No separation of layers, no corner melting....awesome. Thanks for helping me over that little hurdle.245 C nozzle - 110 C bed and no fan.
Josh

Glad it worked! Since I think it was mainly the fan, you can even back the temperatures back down if you want, probably still work. Saves preheat time and energy. Up to you though. Happy printing.

Found out one things with the SD card, after i change the Cable of the SD card and my device can read all card.

HI Josh,

do you have the artwork of the bracket? as i need the hole bigger, as i can't squeeze the stucker inside the hole. so sorry as i really not good in drawing.I'm so sorry for the trouble, & really appreciate your help!

Hi guys!
I've also just finished assembling this printer. Got two problems :/

1. imo my proximity sensor is faulty - light comes up then it's close to plate but it never stops the Z motor :/ ('old' Z endstop does when using with G29). I've tested it from a quite safe height with different aluminum 'targets' - it just keeps going down. I did shorten its original cable quite much but I soldered wires exactly right as they where. Can anyone give me e.g. multimeter reading from working proximity sensor? Thx

2. as I expected with those thin wires I can get my alu plate till ~98C at best (when not printing) and it takes forever. To get ~120C on my old prusa i3 I had to use SevenSwitch to power build plate separately :/ Now when bed is turned on its hardly 10v (where it should be 12v).

They ([email protected]) just now did send me an email asking for review.. looks like I'm gone give not so good (5*) one ..

Drill it out with an appropriate sized drill bit. I no longer have the drawing, sorry.

Josh

Quote
ansisl
Hi guys!
I've also just finished assembling this printer. Got two problems :/

1. imo my proximity sensor is faulty - light comes up then it's close to plate but it never stops the Z motor :/ ('old' Z endstop does when using with G29). I've tested it from a quite safe height with different aluminum 'targets' - it just keeps going down. I did shorten its original cable quite much but I soldered wires exactly right as they where. Can anyone give me e.g. multimeter reading from working proximity sensor? Thx

Might sound dumb..but have you removed the Z endstop? A friend of mine forgot to remove his when setting up his proximity switch and that's exactly what he described. Had both the proximity switch and the Z stop plugged in the board....

Yea I did .. also its the sensor - it was not changing state - broken, ordered replacement so will see in few days time thx

Interesting issue is showing its evil head.

Printer is working great. Except when it starts getting to about 14 hrs into a print, then it starts creating stairs in the print, and at exactly 15 hrs 36 minutes (every time) I get a Serial Comm error and it shuts down the print. Any suggestions?

So I just assembled a variant of the migbot, and I have some starting questions. I didn't get auto leveling with the kit, so Ill probably buy this sensor later, now I'm just using an end stop on the z-axis.
It's a good thing this helpful community exists, otherwise I would be dead in the waters.

How do I find out at what height to put the z-axis end stop?
What settings do I need to take a look at in the marlin firmware?
How do I calibrate the printer, specifically how much the motors move?
How do you add the migbot specific settings to the new version of cura?

Edited 1 time(s). Last edit at 09/05/2015 07:45AM by kaffemustasj.

Hi guys,

Read through the thread a couple of times and I'm sure the issues your having will likely happen when I get beyond my first fo-par.

I've finished putting the frame together and wired everything up; I connected the USB cable to my laptop (Windows 10- will see how this pans out soon enough) and the LCD screen comes on.
At the top of the LCD screen, next to the thermometer symbol, it reads 358/0*, and at the bottom of the screen it reads "Err: MAXTEMP".

Is this likely to be a thermistor issue or is there something else I need to check?
Also the square fan doesn't come on at all; is that because of the above issue or likely something else?

Thanks in advance for help anyone can give; it's my first printer so will be a steep learning curve.

Cheers,
David


P.S. OK, I've jus found the potential issue, and possible solution.
I noticed on the hotend of the thermistor that a grub screw holds the cables in place so thought "why not see if pulling the cables out a touch will help?" I did this and suddenly notice, after pulling the cable a couple of mm, that the temperature droped to a more reasonable 17/0*. The error message remained, but a windows restart (turn printer on and off) seems to have sorted it.
Just need to solder the YEnd stop after I accidently pulled one of the cables off, doh!!

Edited 1 time(s). Last edit at 09/05/2015 09:51AM by worthidlj.

Quote
veaceonee
Interesting issue is showing its evil head.

Printer is working great. Except when it starts getting to about 14 hrs into a print, then it starts creating stairs in the print, and at exactly 15 hrs 36 minutes (every time) I get a Serial Comm error and it shuts down the print. Any suggestions?

I dont have a solution but im guessing you are printing with a computer not from a sd-card. First i would try printing from a sd-card. If it works without problems the issue lies in your computer.

Check the usb-hibernation settings and everything that could possibly affect the usb-ports etc..and make sure you have enough processing power on your computer. If the computer priorizes power to high level tasks the printer can start skipping steps if it cant get data fast enough. Printing from a sd-card should fix that problem. Or a faster computer.

Killing all unnecessary backround processes, surfing, and other programs while printing is the way to go with an older computer.

Someone correct me if i am wrong...

And if you are printing with a card, forget all the things you just read

Edited 1 time(s). Last edit at 09/05/2015 01:49PM by w4rdaddy.

Quote
ansisl
Hi guys!
I've also just finished assembling this printer. Got two problems :/

2. as I expected with those thin wires I can get my alu plate till ~98C at best (when not printing) and it takes forever. To get ~120C on my old prusa i3 I had to use SevenSwitch to power build plate separately :/ Now when bed is turned on its hardly 10v (where it should be 12v).

I dont know about others but my migbot has pretty robust cables imho for the bed(maybe 2.0m2 or 2.5m2) but it still took ages (+1h) to reach 100c. Solution was to insulate the underside of the heatbed and before printing put something fireproof on the printbed so that the heat wont dissipate. I use a fire blanket folded, and remove it just before printing. Now its about 15-20min to 110-120c for abs.

Quote
kaffemustasj
So I just assembled a variant of the migbot, and I have some starting questions. I didn't get auto leveling with the kit, so Ill probably buy this sensor later, now I'm just using an end stop on the z-axis.
It's a good thing this helpful community exists, otherwise I would be dead in the waters.

How do I find out at what height to put the z-axis end stop?
What settings do I need to take a look at in the marlin firmware?
How do I calibrate the printer, specifically how much the motors move?
How do you add the migbot specific settings to the new version of cura?

1. "The first layer should be a bit squished to the bed as instructed in almost all of the tutorials about the subject. For me it was trial and error. The sensor provided with the migbot has a LED to indicate when the sensor is detecting the bed, first i just manually adjusted the height about right. Then downloaded a test cube from thingiverse and printed one layer at a time just to test the height of the printhead at the first layer adjusting it little by little. I had a really good picture illustrating how it should be but i did not find it anywhere. I dont remember was it provided with the migbot instructions or did i find it somewhere else but if someone has the picture and knows it is the one i am talking about, post it here so everyone can see." Found the from my other computer : [www.filedropper.com]

2. If you are not familiar with 3d-printers, arduino ide and marlin you probably should look for the migbot original firmware and go from there. Less to tinker with than the stock-marlin from github. If i remember right this thread has a link to the firmwares somewhere, you just need to find it.

3. If you mean the belts/pulleys/rods e-steps the migbot firmware has it ready for you. If your printer have the same belts, pulleys and shafts as the original migbot. If not here is a calculator for most of the parts sold for reprap printers: [prusaprinters.org]

4. I do not have the cura settings for the stock bed that came with migbot but i do have the larger bed (270mm) settings for cura. I attached them to this post.

Hope this helps in some of your problems at least.

Edited 1 time(s). Last edit at 09/05/2015 03:21PM by w4rdaddy.

Quote
w4rdaddy

I dont know about others but my migbot has pretty robust cables imho for the bed(maybe 2.0m2 or 2.5m2) but it still took ages (+1h) to reach 100c. Solution was to insulate the underside of the heatbed and before printing put something fireproof on the printbed so that the heat wont dissipate. I use a fire blanket folded, and remove it just before printing. Now its about 15-20min to 110-120c for abs.

Woah an hour! Mine is not insulated and takes about 10-15mins to reach 105. Although insulation is not a bad idea, it would probably help keep the acrylic from warping on long abs prints.

What did you insulate it with?

read about calibration [reprap.org]

Quote
gatorNic

Quote
w4rdaddy

I dont know about others but my migbot has pretty robust cables imho for the bed(maybe 2.0m2 or 2.5m2) but it still took ages (+1h) to reach 100c. Solution was to insulate the underside of the heatbed and before printing put something fireproof on the printbed so that the heat wont dissipate. I use a fire blanket folded, and remove it just before printing. Now its about 15-20min to 110-120c for abs.

Woah an hour! Mine is not insulated and takes about 10-15mins to reach 105. Although insulation is not a bad idea, it would probably help keep the acrylic from warping on long abs prints.

What did you insulate it with?

on my other i3 I used cork layer ~3mm and alu foil

Quote
gatorNic

Quote
w4rdaddy

I dont know about others but my migbot has pretty robust cables imho for the bed(maybe 2.0m2 or 2.5m2) but it still took ages (+1h) to reach 100c. Solution was to insulate the underside of the heatbed and before printing put something fireproof on the printbed so that the heat wont dissipate. I use a fire blanket folded, and remove it just before printing. Now its about 15-20min to 110-120c for abs.

Woah an hour! Mine is not insulated and takes about 10-15mins to reach 105. Although insulation is not a bad idea, it would probably help keep the acrylic from warping on long abs prints.

What did you insulate it with?

In Finland we have this polyurethane insulator that we use to insulate our Saunas ( [www.taloon.com]) I just cut a right sized sheet of it and taped it under the bed with kapton tape.

Usually i think people use cork sheets? But i had this polyurethane already and it should take the heat without problems. And it has not burnt or gave any weird smells. Seems to be working just fine.

I could have some burnt coils in the heatbed PCB but like i said its working with my solution for now so i wont be spending any money on it until something breaks totally.

That did it gatorNic. The screw was just over tightened. Thanks!

Quote
gatorNic

Quote
kareem613
Having some trouble with a brand new build. The electron 3D variant. All the instructions say migbot though.
When I turn it on, the extruder temp reports 358 and I get a MAXTEMP error.
I tried flashing the firmware from the 1st post in this thread and it still behaves the same. Thermistor is plugged in properly. I triple checked.

Any ideas on what I can try next?

How do I confirm what type of thermistor is being used to make sure the configuration,h file is right?

Thanks!

EDIT: I just tested the thermistor with a multimeter. Zero resistant. Does that mean my thermistor is dead? If so, now what?

Those wires in the thermister are so tiny they easily get pinched or broken. Mine has a small pinch and gives that warning sometimes, but I just fiddle with it and turn off/on again and it works.

Did they not send you an extra thermistor in the migbot box? They did with mine, and I remember somebody else mentioning it too. They are real cheap if not. I would just buy a bunch since the are so breakable.

Thanks man!
I spent most of yesterday reading up.
I don't have automatic leveling, but I'm planning to buy a cheap sensor on ebay. What is the community's thought on the LJ12A3-4-Z/BY ?

I've read on calibrating the extruder from here: [reprap.org] What program is used to send the "M92 E" commands?

LJ12A3-4-Z/BY is a pnp sensor. You would have to change Z axis logic in marlin from true to false. Get LJ12A3-4-Z/BX which is a npn. No change in marlin. Of course you have to // the min z endstop line. Same price. Hitch + to 12 volt and minus to ground. Then feed output to a 7805 voltage regulator. Output of regulator to Z min on board. No heat sink required. Test output of sensor with metal object. Light should come on and output of regulator should change. Did this with my printers. Gave up on voltage dropping configuration. Now I get output of regulator 0 and 5 volts depending on how close to metal. Don't add any extras to regulator otherwise it will hinder the reaction time. Just output of sensor to pin 1, a ground to pin 2 and pin 3 to board z min.

Edited 1 time(s). Last edit at 09/06/2015 05:37PM by Putzer.

Quote
w4rdaddy

Quote
veaceonee
Interesting issue is showing its evil head.

Printer is working great. Except when it starts getting to about 14 hrs into a print, then it starts creating stairs in the print, and at exactly 15 hrs 36 minutes (every time) I get a Serial Comm error and it shuts down the print. Any suggestions?

I dont have a solution but im guessing you are printing with a computer not from a sd-card. First i would try printing from a sd-card. If it works without problems the issue lies in your computer.

Check the usb-hibernation settings and everything that could possibly affect the usb-ports etc..and make sure you have enough processing power on your computer. If the computer priorizes power to high level tasks the printer can start skipping steps if it cant get data fast enough. Printing from a sd-card should fix that problem. Or a faster computer.

Killing all unnecessary backround processes, surfing, and other programs while printing is the way to go with an older computer.

Someone correct me if i am wrong...

And if you are printing with a card, forget all the things you just read

My computer is an I7-4770 with 12GB RAM on Win7. Dont think it is a computer issue. Will try printing off the SD card, see what happens.

Edit: Just checked Port settings in Device manager, and speed was at 9600, bumped it up to 115200. See what that does.

Edited 1 time(s). Last edit at 09/06/2015 09:19PM by veaceonee.

I can't get the hotend to heat up past around 165. When I remove the fan duct it gets up to the 185 I asked it to.
It appears the fan duct is actually aiming at the hotend instead of below it.

There doesn't seem to be a way to adjust it.
Had anybody else encountered this?