How to setup for easy switching between PLA ABS

[terrypin 3]

I'm returning after a very long gap to my 3D printing with Cura and my Ender 3 V2. But making heavy weather of what I thought a simple task.

 

I've always used PLA. Now I'm trying ABS, but getting in a real mess. Firstly, can someone explain whether this should be set in Cura or on my Ender 3 V2? It seems both are possible, but the Ender 3 V2 itself seemed simple: I just chose the 'Preheat PLA' setting and watched the temps climb from 60 to 70 and 200 to 240, for bed and filament,  respectively. But as soon as I start printing, those temperatures start dropping back to the PLA defaults! Resiult: no ABS gets placed.

 

Am I right that Cura sets this in the Gcode file and that overrules the printer settings? If so, what is the simplest way to set up Cura so that I can simply choose the filament before I create the gCode please?

 

As a separate issue, 70 seems significantly lower than the 90-110 I see recommended on the web? 

 

Terry, UK

Edited yesterday at 03:14 PM by terrypin
typo

[GregValiant 1,365]

Remember that the printer and Cura do not actually know each other.  The only communication is one way and is usually via a gcode file.  Whatever is in the Gcode will override whatever you originally did on the LCD.  You need to set Cura up to print ABS by going through the settings and making sure they are suitable for the material.

 

You are correct that the typical build plate temperature for ABS would be over 100°.  Understand that ABS really requires a "heated build volume" to limit the chances of prints warping and destroying themselves.  Printing ABS gives off noxious fumes and a vent system is advised so the fumes don't build up in an enclosed area.  It isn't something you would want to print in your bedroom on an Ender 3 or an Artillery Sidewinder.

 

M145 sets the material defaults in the printer.

If you were to "print" these three lines (in a gcode file) the material defaults would be changed, and the M500 would save those changes.

M145 S0 H205 B60 F127

M145 S1 H240 B105 F0

M500

You cannot change the material names because they are hardcoded in the firmware.

S0 = "material 1" and is usually PLA

S1 = "material 2" and is usually ABS

H = hot end temperature

B = bed temperature

F = Fan speed in PWM (255 = 100% duty cycle so the 127 indicates 50%)

 

You need to set Cura up for the material you intend to print.  There will be heating commands in the gcode and they will set a new value to whatever pre-condition you did from the LCD.  If you were to set the Feed Rate on the LCD to 125% and then start a print, but you have an M220 S100 in your StartUp Gcode, then when the gcode is printed, the Feed Rate will be set to 100%.  The latest command that the printer/processor sees will be the setting value.