Quote
MightyMouth
First layer problem printing ABS
I tried various temperatures between 230c and 260c but the prints show the same problem. My bed is set to 120c but is actually around 100c. I tried increasing the extrusion to between 102% and 105‰. My printer is in a heated enclosure @ 28c.
There are many ways to achieve good first layer adhesion - and many many threads that have talked about it here.
The first thing you need to do is use an actual MM value for the first layer width, not a %.
BTW, I recommend never using % for width in Slicer anywhere - it uses that percentage of the layer height - so you can get an impossibly small extrusion width without realizing it. I don't use auto speeds or % for speeds either - then I know it is printing exactly as I ask it to - easier for me to know why it is printing as it is. Every printer prints differently so auto-anything will only work well by pure chance, and introduces errors.
I recommend a first layer width at least 15% wider than nozzle width. So for instance - if you have a .4mm nozzle width: use at least .46 mm for the first layer width. This will ensure it smooshes onto the bed a bit. Set other nozzle widths to a value that is between 105% and 170% of nozzle width (beware the high end).
Note that first layer height calibration, extruder calibration, and the infill overlap % will also affect the first layer greatly, in that order. A bed probe is critical for good consistency.
2nd - bed prep. You could prepare it with some Auanet super extra hold hairspray (provided you can remove the slab it from the machine to do so) - it works well for me - a very light layer applied to a very clean surface (clean with Windex, acetone) every 10 prints or so, or use thick kapton tape, or another stick on bed surface material, or glue stick. You could place a layer of cardboard over the bed while it's heating to get a slightly higher temp, and insulate under. I use 106 degrees for the bed for ABS.
3rd - the first layer speed. You should do various tests - print just the first layer - to see how slow you actually need to get good adhesion. It should be quite difficult to remove the first layer when the bed is hot. Some use a very slow speed (10mm/sec). I find through testing that I can use 46mm/sec for first layer with a freshly prepared bed. If I haven't printed in a while and I have a big job I will spend the 5 minutes to clean and re-spray the mirror I use - while the bed is heating.
4th - first layer extrusion temp - as long as your hot end can handle it you could use a temp near the high end - 260 for instance. It will allow better bonding for the first layer at a higher speed.
Here are some
Slic3r tutorials and videos you may find helpful.
My printer: Raptosaur - Large Format Delta - [
www.paulwanamaker.wordpress.com]
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