Which silicone heater? and Board?

[curious aardvark]

what does it do and why don't I need it ?
Or is there something going on I just haven't noticed ?

[mjf55]

Distortion correction-I had it in spades with my glass bed, not so with the base aluminum heater bed. Distortion correction will map multiple heights of your bed ( using the Map Bed Height tool) and then can automatically correct , during printing, dips and valleys on the bed.
Maybe with PrintBite, you dont need it ( I plan to purchase it soon ) .
Another change I will plan to make ( as long as I am doing it ) is to change the heating profile of the bed. As you noticed and commented on, it takes a long time to get to the last 10 degrees of target. That can be changed in the configuration.h settings ( not eprom) Temperature Control Range (pid_control_range) in which the range where the selected heat manager controls output. Outside this range extruder/bed are heated with full power. HE3D K200 uses 10*, I am planning on changing to 5.

[curious aardvark]

so is the distortion correction eays to use ?
or is it still lots of stupid calculations entered manually that never actually do what the turotial says it will ?

If it's just press a button and it probes lots of spots and then calculates it automatically then, yes I'd like that.

Change the range to 0 if you can. what's the point of slowing down at all before it hits the right temp ?

I have still yet to work out where I get a configuration.h file from.

Would be good to have a look, just not sure where I get it or how i get it back to the printer.

[mjf55]

so is the distortion correction eays to use ?
or is it still lots of stupid calculations entered manually that never actually do what the turotial says it will ?

If it's just press a button and it probes lots of spots and then calculates it automatically then, yes I'd like that.

Change the range to 0 if you can. what's the point of slowing down at all before it hits the right temp ?

I have still yet to work out where I get a configuration.h file from.

Would be good to have a look, just not sure where I get it or how i get it back to the printer.

Welllllll, it's supposed to be easy.......... https://www.youtube.com/watch?v=L9URtv2LqKc But you know the difference between theory and practice ;-)

[Trakyan]

CA, the point of slowing down the heating on the heated bed (your extruder also does this) is to avoid overshoot. If you don't slow it down as it approaches the temperature (and like wise slowly ramp up the power as it cools down past the temperature), you end up overshooting your target temperature and having your actual temperature swing back and forth around the target temperature which isn't good for your prints. It'll cause inconsistent extrusion (if hotend does this) or may cause your parts to become unstuck from the bed due to heating and cooling.

As for the distortion correction, sounds like mesh bed leveling. It can be done manually or if you have a bed sensor, automatically.

[mjf55]

CA, the point of slowing down the heating on the heated bed (your extruder also does this) is to avoid overshoot.

I understand that. It will clearly be a watch and see. Unfortunately, there is only one setting for both the extruder and bed. The bed clearly can use this as it takes a few minutes to reach the last 5 degrees of target ( and thats just with a target of 50. 100* is a loooooong time. So overshoot is not an issue here.
On the extruder, well that may be a different point, but again once it is within 5 degrees of target, the final ramp is more controlled.

Oh, and this is specific to my HE3D K200. YMMV.

[Trakyan]

I was explaining to CA who asked why you would slow it down at all. I find it odd the bed and hotend run on the same pid. If you're willing to do some firmware digging you could probably seperate the two without too much difficulty.

[curious aardvark]

Cheers Trakyan - that make sense.
got no issues with the hotend heating up, that's quick.

It's the bed that's the issue. given that on 50c it usually runs 5-9c hot and on 90c about the same cold. Can't see swing being that much of an issue.

lol that's not what I would call automatic bed levilling.
For it to be automatic you click one button labelled 'autolevel' and it does all that crap by itself.
Anything else just shouldn't be called 'Auto' :-)

[Trakyan]

The issue with the bed is odd, they don't usually run too hot, too cold is fairly common. Does it stay 5-9 degrees hotter than it should be during the whole print or just initially? It could still be a PID issue just of the opposite extreme, hard to say.

And I understand the bed leveling issue, it's why I added the "if you have a bed sensor" clause to cover my butt with that statement
I hear manual leveling on a delta can be painful.