Extruder motor stops after one or two layers  

Re: Extruder motor stops after one or two layers

Hi Michael

Unfortunately, your post doesn't contain sufficient information to diagnose the problem properly.

What is happening here? Is the extruder motor simply stopping or is your extruder temperature dropping below the minimum temperature for extruding?

What material are you printing with and at what temperature? What slicer are you using or are you printing the gcode files supplied on the SD card? Are you printing from the SD card or from a computer via USB?

Does the extruder fan start when the extruder reaches 50 degrees? Does the print fan start at all?

Peter

Re: Extruder motor stops after one or two layers

Hey Peter,

thank you for answering! So let me give you more information about my problem - I'm printing Prusa PLA at 210°C. So far I haven't noticed the temperature dropping below 200° when trying to print. First I tried the models supplied on the SD card (the PRUSA plate thing and the frog - a couple of times). After successfully printing 1-2 layers the motor stops. I then used Slic3r on a little card holder and tried to print that (again a couple of times). The base is a LOT larger than the frog's, yet the motor stops at about 1.5 layers. I only use the SD card slot, not the USB port.
And yes, the extruder fan starts while preheating at about 50°.
Hope this helps you helping me 😉

Michael

Re: Extruder motor stops after one or two layers

Michael

To me, this sounds like a motor connection/cable problem.

The cables be damaged if the cable ties are too tight, but the cable ties have to be tight-ish to prevent the connectors moving and working loose.

When the extruder motor stops, if you gently hold the filament between finger and thumb at the feed hole on top of the extruder, can you feel it moving at all?

I think you may need to contact support - use the "Live Chat" facility on the shop pages and give them a link to this thread.

Peter

Re: Extruder motor stops after one or two layers

Peter,

it looks like I missed an important detail of the problem. When checking whether there's any filament feed at all (like you suggested) I was hinted at the crumbly surface of the messed up prints. Pretty much like the PLA wasn't melting properly and so I started yet another test print - and voila, the temperature drops from 210° to about 185° within a couple of seconds. Looks like that's why the extruder motor stops working. Mea maxima culpa for not noticing this earlier!
Other than checking the connectors again (which I will do in a minute) do you have any idea on how to fix this?

Michael

Re: Extruder motor stops after one or two layers

Hi Michael

Thanks for the update.

Yes, the extruder is programmed to stop at 190 degrees or below.

So we need to figure out why the extruder cannot maintain temperature. The usual reason for this is the cabling. Can you please remove the extruder heater plug from the RAMBo board and ensure that the wires are properly in the connector and that the screws are nice and tight. Then replace the connector in the socket and ensure that the connector is pushed firmly into the socket.

If you have a multimeter to hand, whilst the heater connector is unplugged, can you measure the resistance of the heater and cable - put the probes across the screws on the top on the connector.

Also, while you are doing this, can you do the same with the heated bed - ensure that the screws are tight and the socket is pushed well into the connector.

Peter

Re: Extruder motor stops after one or two layers

Hi Peter,

I followed your advice, checked the wires (all screws nice&tight), the connectors sit firmly where they belong. I didn't see any molten plastic on the connectors so they seem to work as intended. My multimeter reads roundabout 6Ω.

Michael

Re: Extruder motor stops after one or two layers

Michael

OK, you have checked all that you can and the 6 Ohms is a tad on the high side (equates to just under 24W) so the next thing for you to do is to contact support - use the "Live Chat" facility on the shop pages. Give them a link to this thread and they will be able to sort the problem out.

When your problem is fixed, can you please post back here to let us know what the problem and fix was.

Thanks

Peter

Re: Extruder motor stops after one or two layers

Thanks a lot for your help Peter! I will post the fix to this problem as soon as I find one. Or, well, I'll just print a lot of 2-layer objects and glue them together. 😉

Michael

Re: Extruder motor stops after one or two layers

Problem solved! I received a new hotend 16 hours after pasting this thread into the livechat (thanks a bunch for that guys!) and now everything is printing as it is supposed to. Multimeter measures 4,9 Ohms on the new hotend, quite a difference to 6,2. The pictures below show my very first prints, well, the successful ones. Livechat told me to turn the fan way down and print at 230° while my new hotend was being UPSed. 5 hours later I finally got my USB/SD-Card stand. Works great. The caliper holder and the heatbed...grip thingies were printed with the new hotend.
So thanks a lot for your help Peter! 🙂

P.S.
Two thumbs up for the livechat people - that's what I call super-responsive customer care!

Re: Extruder motor stops after one or two layers

Hi Michael

Great news and thanks for letting us know. As you probably realised, there is a large manufacturing tolerance in the heater cartridges; you happened to get a high-resistance, low-powered cartridge and now you have a replacement which will generate about 30 Watts of heat.

Enjoy your printer.

Peter

Re: Extruder motor stops after one or two layers

Hope you don't mind if I hijack this thread.

I feel like I might have a similar issue. My hotend doesn't get so cold that it stops printing, but I noticed that with standard printer fan parameters out of the box, my hotend reaches 192-190C and the layer adhesion starts to get lousy. I fixed this by setting the print fan in Slic3r to run between 50%-70%, but I feel that it's not good either. Could I suffer the same problem?

I'm not home right now, so I can't measure the resistance, but if I understood correctly, it was simply the resistance measured over the two pins from the heater.

Re: Extruder motor stops after one or two layers

Just in case - the blue cables. Connecting your multimeter to the connector screws should be enough, though. 🙂

Re: Extruder motor stops after one or two layers

Hi Michael

That package looks to have come direct from E3D rather than Prusa Research...

@Sascha - this was a problem with a few Prusa printers a few weeks before Christmas. There are a couple of solutions, including printing yourself a slightly modified part fan housing. The problem is that E3D ship heater cartridges marked as 30 Watt, but with a much lower power output as Michael found. Check your resistance and then if it is rather high, get in touch with support.

Peter

Re: Extruder motor stops after one or two layers

Hi Peter,

you're right, that's just some random picture I used to show what the blue cables look like. And maybe I should point out the fact we DO NOT get the gummibears. So stop searching your Prusa package now. 😉

Re: Extruder motor stops after one or two layers

Ahh, but you do get them with orders shipped from E3D.

Now I wonder what Josef uses to pay his staff??? They do buy quite a few hot end kits from E3d.

Peter

Re: Extruder motor stops after one or two layers

I firmly believe they get a fair share of every 1,000 kits sold!

Re: Extruder motor stops after one or two layers

@Peter

I finally measured the resistance over my heater cartridge and got as high as 6,4 Ohms! So if my calculations are correct, my extruder can only juice out 22,5 Watt. I'm with the live chat right now waiting for an answer, but I guess that's why my temperature dropped so much when my fan hit 100%.

Re: Extruder motor stops after one or two layers

Hi Sascha

Actually it's slightly less than that because at 12V, the RAMBo only generates about 11.7V at the heater terminals, due to voltage drop across the components.

Having said that, you are probably also measuring the multimeter leads as well, which could account for 1 Ohm or so.

Please let us know the result of your Live Chat.

Peter

Re: Extruder motor stops after one or two layers

Hi Sascha

Actually it's slightly less than that because at 12V, the RAMBo only generates about 11.7V at the heater terminals, due to voltage drop across the components.

Having said that, you are probably also measuring the multimeter leads as well, which could account for 1 Ohm or so.

Please let us know the result of your Live Chat.

Peter
I got a new one sent to me. received it today and checked it. The resistance on this one is somewhere between 4,7 and 4,8 Ohm, so a huge difference from 6,4 on the one I got from the kit! Will install it as soon as my current print is completed 🙂