I have been getting pretty good prints lately so I'm generally very happy with my printer, but I'm starting to look into some of the more niggling issues for which I still have no answers.
I print mostly ABS these days, on an IKEA mirror tile covered with PET tape (the green stuff).
I run the bed at 125C/120C (first/subsequent layers) and my extruder at 235C.
The bed measures between 105C and 110C on the surface (using my IR thermometer) from the second layer onwards, which is still slightly above Tg.
Large objects (or large sets of small objects) print fine at these settings and I have been using them for many months now.
If I print small items however then these settings often give me noticeable (to me!) shrinkage, resulting in sides that aren't straight.
The objects are stuck fast though - even with the bed fan cooling the glass to room temperature I need to snap them off with some effort.
If I reduce the second layer temperatures even a tiny bit (say, to 115C) then the print gets knocked off the bed mid-print.
On the odd occasion that it completes successfully, even the slightest breeze is enough to release the object from the bed.
The sides *are* noticeably straighter though!
What's the cause of this? Should I increase my first layer bed temps? Should I increase/decrease my extrusion temp?
The bed *will* go up to about 135C with a cardboard blanket on top of it during the warm-up phase. I have done this in the past but it takes another 5 minutes to reach that temperature at the start of every print, which is a little annoying (especially as I have to wait for it so I can remove the blanket). I don't remember any marked improvement to adhesion by doing this.
I have tried lots of different filaments now from at least three different sources, and they all exhibit this behaviour. It's as if I've hit some physical adhesion limit of the filament/tape combination.
Luckily it's easy to keep multiple filament profiles when using Slic3r, which is a good enough reason to stick with it even if I have to compromise on output quality.
Printer: Early 2013 Mendel90 kit running Nophead Marlin firmware (with T3P3 changes to drive Panelolu2 LCD).
Mods/extras: Panelolu2, OctoPi, Gantry LEDs
Preferred workflow: OpenSCAD >> STL >> Repetier Host and Slic3r >> gcode
"You can never make anything foolproof because fools are so ingenious"
