Lets discuss how we can improve layer adhesion and layer adhesion problems between layers.

Der_Muck

Heyho,

I bought the ApolloX from FormFutura in black and started testing for optimal settings in the slicer.
I printed several retraction tests (the one with the 2 towers on a plate) and also broke it.
It was shocking how easy they break and tryed different settings to get the layers better stick together. 
There was no layer seperation at all, the print was looking awesome but the strength isnt there as much as i thought it would be.

I got some tips from FormFutura to turn off the fan totaly and print with 0.15 at a slow speed turned out as the badest print because the part stay weak. I had to stop the print.

After that all, I deside to test ABS in the same way. For my shock it turned out the same, even worser. It was even little easyer to break the towers with one hands fingers.  Again tryed everything, got up to 260°C but it stayed the same.

Is ABS and ASA realy so less bonded between layers? I very often print with PETG and it seems that PETG is muuuuch stronger than ABS in that way, even with PLA I was not able to break the towers with my fingers. Super layer adhesion...

You can try it yourself, try printing the retraction test and than break it, you will see, that its not as hard as you expact to break it.
https://www.thingiverse.com/thing:2450004 

So all in all, ABS and ASA is realy useless for strong parts, I can not understand how i can print parts with it which are strong in every direction... Every test print broke between one layer. If it would be a good layer adhesion, it would break throu different layers.   (I am a mechanical engineering technician and proofed european licensed welder, when i weld, the strongest part of a welded part is the welding itsself. At ABS and ASA prints with that settings, the layer adhesion is the weakest. So how can we turn it to get the best layer adhesion (in generell)

I found a very interesting Video about print speeds, you have to watch it, its realy surprising! Hope it helps you to get strong layer adhesion! https://www.youtube.com/watch?v=8_D9v-HARuY

Richy_T

The layers are always going to be somewhat weaker and you'll generally get a fairly clean break between them. Bear in mind that you're not welding and it's a different process despite superficial similarities. One way to improve layer adhesion is more temperature but that can bring other problems so you have to find the sweet spot (that may even vary between models). You can also increase ABS layer adhesion with acetone vapor baths.

In the end, you have to pick the right material for the job. If that's not ABS, then it's not ABS. I've usually had pretty good luck with it (though I do bear in mind the structural weaknesses).

Der_Muck

Yes, thats also what i thought but in my tests, more temperature even made the adhesion weaker and caused stringing.
Yesterday I only had time for one test print, this time with 70mm/s and it realy worked. The breaking test showed a white surface which was uneven through differnt layers.
It was the best layer adhesion I got at all with ABS.  (Fan off and 245°C) 
For me its not totaly logic why high speeds get better layer adhesions than slow hot once but it seems to be like in the video i posted before.

Printing filament is nearly the same as welding a thermoplast the difference is that the welding material is hot and has to weak the ground that it bond together. In the school we has to weld PVC, PP and PC together manualy with a hot air pistol. On the end we also did breaking tests, pritty the same like with steel now.

But it seems that its not only the best to get hot as hell.
Logical would be to get slow to get as much temp. in the ground but the tests showed that its not purposeful.
Yes, in the end its a mixture of many settings to get not only a good looking print. Surprisingly for only a good looking print its easy to set the printer for that. To get strong parts it needs some tests.

Richy_T

Well, welding us dumping a bunch of very hot material in one area and ideally you try and cut down the stress concentrators. With 3D printing, you are layering material and due to the shape of the extrusion, you have less contact area and the whole thing is basically a stress concentrator (part of the reason vapor baths help). You could try adding another perimeter or two and varying amounts of infill (though I hear that infill has less of a strengthening effect).

Interesting to hear that hotter was weaker. My old printer was not so great so I didn't do a whole lot of experimenting (was happy to get a decent print) and I haven't tried ABS on my A1 yet.

Der_Muck

I had a little chat with an technician from FormFutura and yes its like my tests result.
The time where the filament is hot and is in the nozzle should be as short as it can be. The more time the filament is in the hot area, the more the filament degenerates.
That can be much more a problem with long nozzles like the E3D Volcano. Those nozzles are much longer than the normal E3D once. You can imagen that the extruder has to speed up much more to get the filament stay the same time in the hot area as it would be in a short nozzle. More speed on the extruder means higher printing speeds.

So do not print at to low speed  (under 60mm/s) for sure ABS and ASA will degenerate and cause a bad layer adhesion. With a Volcano nozzle, the minimum speed ofcause is much higher. I think for PETG its the same, with PLA I dont realy know it.

So when you now say ahhh ok I print at 100mm/s and set the nozzle up to 255°C (240°C normal temp.) it would not work, thats simply to much for ABS and ASA. (ofcause for PETG and PLA to) There is a Window for the right settings every setting that gets out of the window cause bad layers adhesion much before you get a bad print. I nealy got every time a good looking test part.