First Layer Temps.....
Having built my printer over Xmas, I've only been using PLA, which I am happy to stick with for now.
So my prints have always been using PLA, with a 215 nozzle and 60 bed, as per the recommended settings on the printer/slicer. This is throughout the entire print - so for both the first layer as well as the rest of the print.
This is not currently causing any issues. I have good adhesion, no issues there at all, and my layers for the rest of the model seem fine. However, I do notice that my first layer does not always appear 'clean'. For instance, across the first layer I may occasionally have some spots that appear slightly different visually to the rest of the layer (I'll take a pic next time I print!). Even so, the layer it is all sticking to the bed perfectly fine. After the first layer, subsequent layers look spot on. Upon removing the completed print, the underside is smooth as silk - no issues externally at all.
Anyways, I wondered if the first layer should be completed at a slightly lower nozzle/bed temperature?? Or is it normal to leave it on the same temperature throughout?
RE: First Layer Temps.....
As with so many variables in 3D printing, the answer is, “it depends.”
If you’re getting consistently good results with the materials, temps, and models you print, keep doing what you’re doing.
If the first layer anomalies you see are only internal, I wouldn’t worry too much about it. The slicer sometimes does odd things with ‘gap fill’ that can leave an imperfect internal surface in places.
For the most part, and depending on materials, my routine is to increase the bed temperature by ~5* to 10* after the first layer. Some filament profiles include this behavior, others I’ve modified to increase the upper layer temps. My working assumption is that as the nozzle travels vertically, it and the heat block no longer radiates heat into the bed, so an increased bed temp may compensate for the heat loss and improve adhesion for the print duration.
I could be wrong, but this method works for me and I don’t see any downside. As with all things, your mileage may vary.
Cheers