Thanks Ian.

I'm only heating to 50 at the moment,

The thermistor is built into the silicone heat pad so I do know the reading is a LOT faster than what the actual bed is at.

And I also agree I do think the pad is a bit over powered. It can easily get the bed over 100c without any effort.

I might have to do some more testing before changing the plate again.

Maybe setting a fixed maximum pwm will solve the problem, just worried that it might cause stability problems at higher temperatures.

Bit of a strange request (and could probably be easily done in gcode or a macro)

But my bed is around 400x400 and 8mm thick the AC heat pad is about 350x350.

The issue I'm having is when heating the bed gets full power and reaches the required temperature within a minute or so. But the outside edges are still cool.

This is causing the bed to wrap really bad.

I've replaced the bed and it was straight. Heated it and again it wrapped.

It would be nice to have a controlled heating curve.

Something like if bellow a set temperature heat at at lower pwm untill a set temperature is reached and so on

Craig

Thanks,
The code is what came directly out of laserweb 4, I might message them and see how I can change the way the gcode is produced,

I'll update my firmware tonight and let you know how it goes.

Thanks again.

Craig

@dc42 thanks for looking into this and glad my info helped find the issue (even more glad it's not something I've done my end!)

By the way my firmware is 2.04RC4 (2019-10-19b1)

Quick question...
You say "You are using both M3/M5 and G1 S parameters, which I wasn't expecting;"

Is using M3/M5 not the "correct" way to control the laser?

@Phaedrux sorry I was half asleep when I wrote that and been playing with a lot of firmwares (on other stuff)

I have the lastest firmware downloaded 2weeks ago, so what ever that is... I'll report back later when I'm home .

settings in my config file:

M307 H2 A-1 C-1 D-1       ; Disable Heater output on H2
M452 P2 I1 S1 R255 F200         ; Enable Laser mode, on output 2 (heater 2), with max intensity being 255, and a PWM frequency of 200

example of some gcode that causes issues (a simple square being cut)

;
; Operation:    2
; Type:         Laser Cut
; Paths:        1
; Passes:       2
; Cut rate:     5 mm/s
;


; Pass 0

; Pass 0 Path 0
G0 X57.57 Y76.11
; Pass Z Height 5mm (Offset: 0mm)
G0 Z5.00

M3
G1 X7.57 Y76.11 S255.00 F300
G1 X7.57 Y9.42
G1 X57.57 Y9.42
G1 X57.57 Y76.11
G1 X57.57 Y76.11
M5


; Pass 1

; Pass 1 Path 0
G0 X57.57 Y76.11
; Pass Z Height 4.8mm (Offset: 0mm)
G0 Z4.80

M3
G1 X7.57 Y76.11 S255.00 F300
G1 X7.57 Y9.42
G1 X57.57 Y9.42
G1 X57.57 Y76.11
G1 X57.57 Y76.11
M5          ; Disable Laser/Spindle
M106 P2 S0 ;turn off laser power

It seems quite random.
in the above case it did the first two lines of the cut before turning the laser off, restarted on the second pass and completed all 4 lines,

I ran the code again straight away and it did all four lines of the first pass, and turned off after the 3rd line of the second pass.

Im running the latest firmware RC4

any update on this? im having the same issue.

M452 is set to sticky in the config but (quite randomly) it forgets the Gcode "stickiness" and only restores after it hits the next G1 Sxxx