The model was taller than it was an wide or long (about a 3:1 ratio) - and I couldn't print it with the big side down on the bed because of the joint I was trying to print, which like a mortise and tenon (mortise on one side, tenon on the other) and would have had a long overhang. So printed on it's side, there would be no overhangs. Seemed perfect. I've done a taller project like this in the past, but that overall model was quite large, so still a large surface to adhere to the bed, whereas this one has quite a small surface on the bed (the whole bas is only 7mm x 40mm).
Mid-way in the print - 3 times in a row - at two different scales (I tried bigger to see if that helped - it didn't), the model would come off the bed and stick to the hot end (the extruder). The result was a half-made model with a big glob of PLA as it went for a ride with the extruder for the remainder of the print.
Other things to try in the future:
- Perhaps the 0.15mm layer height was too small, and the extruder was too close to the previously printed layer (sticking to it and dragging it loose).
- Perhaps a "brim" at the bottom of the model would help adhesion.
- A hotter bed temperature may help
- Coating the bed with a glue mixture (I read about this on support forums).
So far - I've had great success simply printing a smaller part - but that won't work for every design. If you have ideas or similar experiences, let me know.