Preparing the printer for >300°C.
Printing polycarbonate and other exotic materials require high temperatures. One of the first steps is getting the heaterblock prepared for these temperatures. E3D can handle that as it is an all metal device.
A second step is getting a termistor/temperature sensor that can handle more then 300°C.
There isn' t that much choice. The one you get with a V6 or Volcano can handle max 295*C.
So I could switch to thermocouple or a PT100.
I choose the PT100. A PT100 is very accurate and has a max temp of 400°C which is more then enough for what I want. For the moment this is max 320°C.
A PT100 requires a converter when using a MKS GEN 1.4 (@csorrows ) and I bought the E3D PT100 converter. This module converts the value measured to a voltage which is send to analog pin 3 of the board.
At the same time I finally cleaned up wiring
Here is the schematic diagram :
I didn't install the RJ45 connectors but left them on the drawing...
A picture of the printhead connection block :
And the MKS GEN 1.4-side :
Required changes in configuration.h :
Thermistor setting :
#define TEMP_SENSOR_0 20 // PT100
#define TEMP_SENSOR_1 0
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_3 0
#define TEMP_SENSOR_BED 1
Temperature limits :
#define HEATER_0_MAXTEMP 350
#define HEATER_1_MAXTEMP 275
#define HEATER_2_MAXTEMP 275
#define HEATER_3_MAXTEMP 275
#define BED_MAXTEMP 150
Changes in pins_RAMPS_14.h
#define TEMP_0_PIN 3 // Analog input on AUX-1 connector
#define TEMP_1_PIN 15 // ANALOG NUMBERING
#define TEMP_2_PIN -1 // ANALOG NUMBERING
For security reasons with the higher temperatures I feed the extruder fan from a separate small 12V power supply.
As a test I left the heater at 335°C for 30 minutes to see how the ABS shrouds behave (part cooler and extruder cooler) and that was ok. I covered the parts of the partcooler faced to the Volcano with aluminium tape to reflect the heat.
Probably one of the first things to print in PC will be a new V6 cooler shroud and a partcooler. PC can handle far higher temperatures then ABS.
Next security steps will include a small arduino project with smoke/heat detection and automatic cutting of the power to the heaters.