Hi, I'm new to this forum. I like to research and learn myself so I don't post, and most of the time the question has already been asked. Thank you everyone who has unknowingly helped me in the past. Lets dive in.
First of all, the system is 24v.
RepRapFirmware for Duet 3 MB6HC version 3.3 (2021-06-15 21:45:47) running on Duet 3 MB6HC v1.01 or later (SBC mode)
Everything is running directly off the main board.
I'm currently trying to replace my hot end (e3d Volcano) with a Nova Hotend with a 100 watt heater. There were no issues with the Volcano when I switched them.
My first try was a standard Auto Tune (m303 t0 s240):
It heated to 240 in about 15 seconds, overshot just barley under the the threshold and continued its journey to which it failed at the end.
Warning: Auto tune of heater 1 failed due to bad curve fit (R=6.652, 1/C=0.0037:0.0108, D=6.6)
I tried throwing those values in (at the time, i didn't know what they represented) and got this:
Error: M307: bad model parameters
I've read in multiple post about people mistakenly getting a 12v heater instead of a 24v. I checked the resistance on the heater and came out with 5.8 ohms. For reference, the company only offers a 60watt in 12V. Following this formula, I calculated:
(P is power in Watt [W], U is voltage [V], R is the resistance in Ohm [Ω])
R=Usqaured/P
R(5.76) = U*U(576) / P(100)
The difference of Actual 5.8 to Calculated 5.76 (in my opinion) is negligible.
I then tried to tune the hot end my self by following the wiki guide
Here are my calculations
Gain:
55 - 120 took 6.07 sec
65 deg in 6.07 sec
65/6.07 = 10.708
Cooldown (Ttarget = Tstart * 0.37 + Tambient * 0.63):
105.8 = (240 * .37) + (27.1 * .63)
No Fan Cooldown 4:49.06 or 289 sec
Fan Cooldown 1:36.5 or 96.5 sec
(Yes, my fan duct is not what I hoped and needs redesigning)
Dead Time:
The best fluctuation i could reach was with D=5. That was with fan on and off and it wasn't that good +- 0.5 deg or 1 deg total. The fan dropped it a couple degrees before it started to rise.
So I ended up with:
M307 H1 R10.708 C289:96.5 D6.6 S1.00 V24.1
To which gave me:
Error: M307: bad model parameters
I thought "well maybe it doesn't know how to control the high powered heater"
I decided to try lowering the PWM to see if could get it to work. That was all a failure. Here are my results if interested.
M303 T0 P0.6 A26.8 S240
Warning: Auto tune of heater 1 failed due to bad curve fit (R=8.030, 1/C=0.0037:0.0102, D=5.8)
M303 T0 P0.4 A23.5 S240
Warning: Auto tune of heater 1 failed due to bad curve fit (R=8.800, 1/C=0.0036:0.0093, D=5.2)
M303 T0 P0.3 A23.7 S240
Warning: Auto tune of heater 1 failed due to bad curve fit (R=8.777, 1/C=0.0035:0.0082, D=4.3)
M303 T0 P0.2 A23.7 S240
Never Completed. Couldn't get to temperature with fan on
At this point, I can't decide if I'm doing something wrong or are there other factors. I would have assumed that lowering the PWM to slow down the heating rate would have achieved something but to no avail. Normally my problems are caused by me doing something wrong. I know other people use this hot end (I've seen it in many videos) and get it to work.
I was going to try using the old Volcano heater (I believe they are the same size) and see what the outcome is and/or buy the lowest wattage heater Nova makes (60w) and try that, but I want to reach out and see if someone has any input on the situation. Maybe I forgot something obvious. Changing out the cartridge is a pain and would rather not swap things in and out. If I have to change it, it'll be while I put on my pouty face and stomp my feet.
I apologize the post is so long, I was trying to make sure you know my steps I tried to figure it out. I'm also sure I forgot to add obvious information that should have been included. Any information or trials will be greatly appreciated.
Thank you in advance,
Pat