Custom Heat Pad and thermistor question

Phaedrux

; Z-Probe
M950 S0 C"exp.heater3"                         ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H5 F120 T6000            ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X0 Y0 Z2.5                            ; set Z probe trigger value, offset and trigger height
M557 X15:215 Y15:195 S20                       ; define mesh grid

Looks ok assuming you are using heater pin 3 on the expansion port for the servo control wire. (yellow wire I believe.)

For home Z you need to make some changes. You can basically replace everything in there now with this.

G91 ; relative positioning
G1 H2 Z5 F2000 ; lift z for clearance
G90 ; absolute positioning
G1 X100 Y100 F6000 ; move probe to bed center. Adjust coordinates as needed.
G30 ; probe the bed
G1 X0 Y0 Z5 ; return to origin position

Nothing fancy. Just moves the probe to the center of the bed and probes it and then moves back to a parking position.
You'll need to modify it to move the probe to your actual bed center.

In addition to the changes in config.g you already have you'll need the deployprobe.g and retractprobe.g macros setup if you haven't already.

; deployprobe.g
; called to deploy a physical Z probe
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Wed Apr 14 2021 18:38:44 GMT-0600 (Central Standard Time)
M280 P0 S10 ; deploy BLTouch

; retractprobe.g
; called to retract a physical Z probe
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Wed Apr 14 2021 18:38:57 GMT-0600 (Central Standard Time)
M280 P0 S90 ; retract BLTouch

Then test them by sending M401 and M402 to deploy and retract the pin.

If that works, you can do the tests described here and measure your XYZ probe offsets as well.

https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe

3DPMicro

@wingtip what is the lead on your lead screws? Not apples to apples but 18k mm/m is doable with (the right) .9deg motors, 16x ms, and10mm lead on ball screws tossing around 3kg. Lead screws will be a bit more draggy though.
https://youtu.be/g2fO7k3WzwU
25k mm/m with external 2130's and higher voltage
https://youtu.be/KWK_djAidQs

wingtip

@phaedrux Something isnt working right.. I tried to enter the M401 and 402 and nothing happens. Looking at the pic below, my signal wire (the yellow from the bltouch) is red in this photo on the pwm3 connector. do i need to flip it 180 or is my signal wire on the correct pin for pwm3?

wingtip

@3dpmicro almost everything came from openbuilds.com except a few steppers which i matched to the open builds ones i had and i believe their steppers and leadscrews are only one type (for nema17)... This is just a big experiment so it is what it is at this point lol... its either going to work or be a colossal (expensive) failure.

Phaedrux

Ah ok, so you're using the Duex PWM headers. In that case you'll need to change a line in config.g to use the pin name for that pwm port on the duex instead of the pin on the expansion header (since the duex is using the expansion header).

M950 S0 C"exp.heater3"                         ; create servo pin 0 for BLTouch

Becomes

M950 S0 C"duex.pwm3"                         ; create servo pin 0 for BLTouch

Then M401 and M402 should work if the deploy and retract macros match what I posted above.

If it still doesn't work, check wiring continuity, or try the PWM5 header instead.

wingtip

@phaedrux
The deploy and retract is working via the macros but not by the direct M401 and 402 in the console. Is that normal? What should i test next or have as a macro?

Phaedrux

The macros must be in the system folder for M401 and M402 to work. If you have them in the macros folder only, they won't.

wingtip

@phaedrux So what directory should the two macro's go in? At the moment i have them directly in the macro directory. I do have a BL Touch folder/directory created within the macro directory but havent placed those two files in there yet.

Nevermind i see your last message says in the main directory... but then what is the point of being able to make other directories and keeping things less cluttered?

Phaedrux

@wingtip said in Custom Heat Pad and thermistor question:

but then what is the point of being able to make other directories and keeping things less cluttered?

You still can do that, but the firmware is looking in the /sys folder for the probe deploy and retract macros. That's just the way it is.

In other words, the macros folder is your to do with as you wish, but the sys folder is for the firmware and you must play by it's rules.

wingtip

@phaedrux
Ok, so if the macros are working now from the macro directory then i can leave it that way right? So what should i test or add next to the directory... Thank you for all the help!

Phaedrux

You can leave a COPY of those deploy and retract macros in the macros folder, but if you want the probe to deploy and retract when you send G30, a copy of those macros must also be in the /sys folder.

wingtip

Now working from the console with the m401 and m402. I had to remove a space in the name of the files and now they work. Ok what now?

Phaedrux

@wingtip said in Custom Heat Pad and thermistor question:

Ok what now?

If that works, you can do the tests described here and measure your XYZ probe offsets as well.

https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe

wingtip

Custom heat pad just arrived. 752mm x 522mm, 110vac, 1500 watt.
45c-110c with safety cut at 120c.

In this pic you can just see the heating element pattern

Phaedrux

Looks really good. Not sure if they included instructions for mounting it, but here's what Keenovo recommends. High temp silicone is the way to go. You don't want that thing coming off mid print.

User's-Manual-Keenovo-Flexible-Heaters.pdf

wingtip

@phaedrux
Trust me, it will not come off. I never use self adhesive on my heat pads. There will be the aluminum base, a layer of cork, the heat pad, then the glass layer, the possibly some buildtak or printbite or pei or something all held down by the good ol binder clips. It's always worked for me in the past.

Phaedrux

@wingtip said in Custom Heat Pad and thermistor question:

There will be the aluminum base, a layer of cork, the heat pad, then the glass layer,

Wait, so you're putting the aluminum on the bottom and then cork and then the heater and then the glass on top? That's a very bizarre heated bed sandwich.

The heater should be attached to the bottom of the aluminum so that it can act as a heat spreader. The glass then goes on top of the aluminum. Use the cork to insulated the bottom of the heater pad if you like.

wingtip

@phaedrux Thats the way i setup my FT5 R1 and has been flawless for years. the cork is only a spacer due to having to cut a slot for the thick area of the heat pad where the cables connect and thermistor are installed etc... Why heat up a whole sheet of alum and still have to heat the glass up beyond that? If i had put the heat pad under the alum the heat pad would have to be smaller than the alum to allow room for the mounting screws and nuts/adjustment screws.

I just got the cork and heat pad and glass layed down... about to try to finish the setup steps in the document you listed last night. Still have to wire up the heat pad and the SSR and thermistor. After that i need to print a spool holder. Then decide if i want to print on the plain glass or install pei, buildtak, printbite, or some other printing surface. Havent decided yet.

I did lose some 20mm print area in X axis with the large clips i used to hold the sandwich down lol...

Phaedrux

There's more than one way to crack an egg.

wingtip

Here is the big mac sandwich