Prints Failing after first few layers

Hi,

I was having good success, but now I have nothing but failure. I'm try to print with ABS. I have printed several test cubes and everything was going well. Now not so much. I'm getting the first few layers down well and then the print is going to crap. It seems like I get through 5-6 layers and then it starts gumming up, looses contact and stops printing.

I had printed 2 parts and was trying to be greedy and get a third one done before cooling the bed (it takes so long to heat up). On the hot ends first pass of the third part it contacted one of the other parts and started skipping gears. I hit all stop and reset everything. I tested the unit and everything seemed to be moving fine mechanically.

I also had a power outage while we were away from the during a print. We came back to find a big stringy wad of extruded filament where we expected to find a new part. We cleaned everything up, tested the mechanics and started again. The first layer did not go down well, so I stopped, cleaned and reset.

Here is what I am using:

Hatchbox White ABS 1.75mm filament
Repeiter Host software running on an attached Microsoft Surface. (I tried this print from SD too.)
Repeiter settings:
Feed rate: 90
Flow rate: 105
Hot Head: 255
Heated Bed: 121 (actual surface temp is 110-111)
Top mounted spool real that is spinning freely.

Edited 1 time(s). Last edit at 02/13/2017 12:20PM by CutterNorth.

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Thank you

3D Printer:

Prusa i3 V2 DIY kit by RepRapGuru
Microcontroller: Arduino mega 2560 R3 clone
Print area: 8 x 8 borosilicate glass
Bearing: LM8UU linear bearings; 623ZZ bearings
Heated bed: Dual power 12V/24V (Pre setup for 12V)
Extruder: Mk8/9 Direct drive
Power supply: 360W 12V 30A
Stepper motor: 5 NEMA 17 4.8kg/cm
Belt: GT2
Board: RAMPS 1.4
Stepper driver: A4988
Endstop: Electronic end stop circuits w/ LED (3)

Upgrades:
Plywood mounted

Building my i3 today, but with my delta, I only get prints like that when the nozzle cools off too much by the fan or dust has partially clogged the extruder.

But you said you cleaned up everything. I would try the print again but watch the hotend temps.

Great tips. I did not open up the extruder. With your comment I think I want to make sure there is nothing gumming the inner workings.

Thanks

If you want to print several prints of the same item then it is best to set your slicer to print all at once. It will then print one layer of each item before moving on to the next layer.

If you want to have the printer print one item at a time, when there are several items on the bed, then in your slicer you must tell the slicer the dimensions of your extruder (as far as the parts that are lower than the carriage) so that it can move the nozzle so as to avoid previously completed print items.

Edited 2 time(s). Last edit at 02/16/2017 06:50PM by Supermec.

I thought I had this working. I managed to get a couple of crappy PLA prints done. They had some really weak layers in the middle. Now I'm back to getting only the first 7 or 8 layers done before the print starts to fail. The filament seems to be coming out ok when I manually advance it. I opened up the extruder again, took the gear out and brushed it off again. Still bad printing.

ABS does not like cooling, you should make sure that the print cooling fan is turned off in the slicer and the printer is not situated in a draft. Some people find that they need to put the printer in an enclosure before they can print ABS successfully.

Edited 1 time(s). Last edit at 02/19/2017 12:39AM by Supermec.

OK. Well that was a frustrating handful of days, but I have it solved. I ended up swapping the hot head drive motor out. All of a sudden I can print just fine. It was really clean. I even switched out the drive gear before going for the motor. Once I changed out the motor, my first print was great.