75 degrees = 68 degrees. No wonder I couldn’t get things to adhere well sometimes.
As a side note, the temp varies wildly along the plate base. An enclosure would definitely help here.
Has anyone else tested the actual temps versus the set/displayed temps and noticed a difference?
Keep in mind IR thermometers are sensitive to the reflectivity/emissivity of the materials they are used on, and the shiny PEI surface can be a bit tricky. Try measuring the temperature of a mirror that your warmed up with your hand and you’ll see a similar problem.
If you want to test more accurately, put some matte tape on the bed and then measure the temperature then.
That said there is also a chance for the heat bed to be a bit lower than target temperature, since the temperature control and feedback occurs at the bottom of the bed where the thermistor is, not at the top, and is separated by a layer of magnetic adhesive and coated metal.
Agree. Thing that matters is consistency of measurement, but thermistors tend to not drift very much. One thing for op to keep in mind is that thermistors tend to be mounted to the bottom of the bed and there will be some temperature difference between the bottom on the top - especially if the printer hasn’t had the opportunity to soak. The other thing to keep in mind is how the terminator is attached to the bed. On my i3 it was just a piece of kapton tape, which meant there was often an air gap between the thermistor and the bed. I’m sure this resulted in quite a bit of weirdness.
The actual number is mostly meaningless. If you have adhesion problems just bump the set temp up by a few degrees. Also the temp will vary across the plate but also vary over time. As the heat soaks into the plate it will be more consistent across it so if there are hot spots now, it’s not a huge deal.
Well, you are supposed to adjust your slicer until you get a temperature where the plastic adheres consistently.
Knowing the real temperature doesn’t actually help, as the performance will vary with coating, printer placement, z-level adjustment, etc.
A lot of printers also heat the bed unevenly, so the temperature could be significantly higher in the centre of the build plate. This video shows it fairly well. You could try adding a few minutes delay to your start gcode after the printer thinks it’s reached the correct bed temp, to let it even out a little.
Here is an alternative Piped link(s): https://piped.video/watch?v=yPy0zDpmc5U
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source, check me out at GitHub.
Adhesion I’d totally recommend cleaning your surface with soap and water (surface depending) and then messing with temps. With abs and petg I’ve found that even a bit of finger print residue is enough to cause a part to come away from the bed, next I’d check first level height. I’ve very rarely found the bed temp to be the reason I lost adhesion.
