Very bad layer bonding - Problem

Hello everyone.

I'm having a big problem with my Prusa i3.

The problem is when I'm extruding it looks almost perfect. Just the way i want an object to look like from a printer like this. But after a few minutes the print begins to crack/delaminate.
i have tried raising my temperature on hot end and the bed but nothing seems to really help just make it worse.

Heres my settings:
Prusa i3
E3D Hotend with 0.4 Nozzle
Aitripper Bowden.
Blue ABS 1.75mm from RRW

Layer height: 0.25
First Layer: 0.20
Perimiters: 3
Extrusion multiplier: 1
Cooling: No
Speed: 60-70mm/s
Hotend Temp: 235
Bed Temp: 105

Anyone got any advise for my problem ?
Pictures added below from my Google Drive.


[drive.google.com]
[drive.google.com]

What is your extrusion width? Your extrusion width should be about twice the size of your layer height, if not a little more. I used to specify 220% as the ratio in Slic3r, but I've since moved back to using slic3r defaults, it is giving me a ratio of 280% - my layer height is 0.2, and my resulting extrusion width is 0.56. Having a wider bead increases the top and bottom surface area making for a stronger inter-layer bond.

Quote
jbernardis
What is your extrusion width? Your extrusion width should be about twice the size of your layer height, if not a little more. I used to specify 220% as the ratio in Slic3r, but I've since moved back to using slic3r defaults, it is giving me a ratio of 280% - my layer height is 0.2, and my resulting extrusion width is 0.56. Having a wider bead increases the top and bottom surface area making for a stronger inter-layer bond.

Slic3r extrusion width is blank, that means its default or?

But good fact to know, im still a beginner. I just Got it printing nicely now. Now i need bonding to be fixes so i Can print parts that Can actually hold something

If you specify nothing, slic3r will use its defaults. You can look at the G code it produces with any text editor. Slic3r produces a block of comments at the beginning of the file that gives, among other things, the extrusion widths it is using.

I see. I tried with 0.5 but didnt seem to get that much syringer , next time i print ill try 0.6 or maybe i should write in percentage?

I think a percentage is better because if you ever change your layer height and you specify an exact value here, then you need to remember to go back and recalculate. Using a percentage does that automatically for you.

In looking at the pictures again, you might be under-extruding a bit. Also, is your Z calibration off? If you tell the printer to lift, for example, 1 mm, and it actually lifts 1.1 mm because the calibration is off, then you will see weak layer-to-layer bonding.

Så What to use as percentage ? 200-300?

After i mounted my bed with springs i have had a hard time leveling my bed maybe thats the problem?
But im using m5 screws and the calculator says 4000 for m5 and it doesnt seem wrong.

As an extruder om using an Mk8 drive gear, with 125 e steps , maybe thats too low?

Edited 1 time(s). Last edit at 04/26/2014 09:40AM by TRoager.

UPDATE: i found out that i was under extruding. my e steps were 125 for my MK8 Drive Gear but than i calculated it and it were 40mm off, so i recalibrated it and now its 150,7 e steps and it works perfect in room temperature and 230 degrees on Hotend.

Thanks for your help