Prusa i3 - All prints are failing, layers won't line up

[cgmason1986]

I built a prusa i3 from NWreprap a few weeks ago. I got it up and running and calibrated with PLA. After not using it for a few days I tried to switch over to ABS and all of my prints now look like this. This is supposed to be the 5mm thin wall calibration test. The first print was the bottom, and they're getting progressively worse. I am using Slic3r and the only thing that I changed in the settings were the temperatures. Any help you can give would be really appreciated.
failed prints.jpg

[old man emu]

Here's my suggestion:
Using your interface, turn on your extruder heater and set its heat to 200C. Turn your heated bed and set to heat to about 90C When they reach their temperatures extrude about 5mm of filament. Leave the printer turned on and go and make a cup of hot beverage to drink. Back at your desk, don't interfere with the printer, but do something else constructive until your heaters have been operating for 15 - 20 minutes. Then load the file you want to print and give it a run.

What you have done by waiting 15 - 20 minutes before starting your print is to allow the whole of the extruder body to get up to 200C. That means that when you start to print, the filament will become molten all the way through and will flow nicely. Also, since it is the same temperature from edge to core, the laid down layers will cool more evenly and stick together.

Remember, good things come to those who wait.

Old Man Emu

[cgmason1986]

Does this help? Again this is supposed to be a .5mm thin wall calibration box. The layers move all along the x axis in random ways.

IMG_7347.jpgIMG_7349.jpgIMG_7350.jpg
It just seems to get lost during the print.

Here's another one:
IMG_7351.jpg

[cgmason1986]

Thanks for the input but it doesn't seem to be temperature related. The actual movements the printer is taking are wrong. I'm using Slic3r and pronterface. Before the print I checked the layers in pronterface and everything looks ok, which leads me to believe it's either something wrong in my firmware (though I haven't changed anything) or something wrong with the board itself (arduino mega 2560 and ramps 1.4).

[GOC]

...it doesn't seem to be temperature related. The actual movements the printer is taking are wrong. I'm using Slic3r and pronterface. Before the print I checked the layers in pronterface and everything looks ok...

- Looking at your images, it seems to be only effecting the one axis in that one direction. When you say "The movements are wrong". I assume that your referring to the extruder head location versus the GCode line its actually on. If this is the case I concur with Mjolinor:

Your axes seem to be slipping. I think it is mechanical so check pulleys and belt tensions. If they are all OK then slow it right down, maybe you are feeding it pulses too quickly...

I would do the following:

• Inspect the pulley/gear & the belt controlling that axis very thoroughly. If unsure, compare it to the apposing axis components.
• Slow all speeds to or below 40mm/s

- If this doesn't help, you may have to consider that it could be a bad stepper motor or motor driver.

Edit: Another suggestion is to also check the stepper and controller wire connections. A weak connection could be present on the wire controlling that axis direction.

[Mjolinor]

Post a picture of it on the bed before you did anything like remove it.

It is not possible to tell what you are showing here.

[Mjolinor]

Your axes seem to be slipping. I think it is mechanical so check pulleys and belt tensions. If they are all OK then slow it right down, maybe you are feeding it pulses too quickly. Do some measurements with a ruler, tell it to move 50 mm, manually with Gcode and see if it does move 50 mm.

[cgmason1986]

When I manually tell it to move 50mm, it does actually move 50mm.

[old man emu]

Looks like you will have to do a calibration. There are many videos on Youtube showing how to do the calibration. This one http://reprap.org/wiki/Calibration might not be your printer, but the principle is the same for all.

What firmware does your printer use? If your board is an Arduino, then it might be Marlin, which is relatively easy to change settings.

Before you do the calibration test, make sure you do the warm-up procedure I gave you. People have found that doing calibrations with "cold" filament give false results.

OME