Keep Hitting Max Temp

Hi Guys,

I have just got a new geetec all metal hot end, fitted it and started running some test.

This is the hot end:
[www.geeetech.com]

I updated the firmware as there was a change in thermistor on this hot end, and now running setting "8" on the thermistor settings, as you can see in the link above, it uses a 100K NTC thermistor.

Anyway, this thing heats up really quickly, and I don't know if the arduino can keep up with the temp changes, I set it to 220c and it shoots up past that to around 260 then drops back down till its in temp again, then the arduino kicks in another burst of power to the heating element and it shoots up again.

I usually print abs at 230ish and it always hits the max temp (i have this set to 300). Has anyone else had this issue, and is there a way to resolve this?

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Regards,

James Simpson

you need to setup PID

take a look at [reprap.org]

Features
It is assembled with 4.7ohm 8W resistor and 100K NTC thermistor.

How is that 8 Watts?

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_______________________________________
Waitaki 3D Printer

I have tried this, and the most i can get it to stably is 200c, I usually print abs at 220, but anything over 210 and the hot end goes mental...

Its nice and stable increase all the way to 200, then it just jumps 210, 230, 250, 300 and then i hit the max temp limit and it cuts off.

I did the auto tune successfully for 200, but then when i try auto tune 210 and it fails with Autotune failed! Temp too high

I've got my PID settings at:
#define DEFAULT_Kp 20.27 // 22.2
#define DEFAULT_Ki 1.11 // 1.08
#define DEFAULT_Kd 92.67 // 114

as per what auto tune told me to put for the following command: m303 e0 s210 c8

I'm scratching my head now... do i change the the command to m303 e0 s205 c8 and keep building it up that way?

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Regards,

James Simpson