Linear Advance with Dual Extrusion

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doenute
Posts: 72
Joined: Thu Jun 18, 2015 7:33 am

Linear Advance with Dual Extrusion

Post by doenute » Fri Dec 07, 2018 8:36 am

Can anyone confirm that I can use two different K values when dual printing--changing back and forth as each extruder is used?

Thanks!

zachah
Aleph Objects | LulzBot
Posts: 52
Joined: Mon Jul 31, 2017 9:20 am

Re: Linear Advance with Dual Extrusion

Post by zachah » Fri Dec 07, 2018 7:26 pm

I haven't tried this myself so I can't 100% verify but you should be able to do this by putting the gcode to set your K values in the Hot End 1 and Hot End 2 Start gcodes.

You can find the hot-end start codes by selecting Settings>Printer>Manage Printers>Machine settings. You'll see there are three tabs. In the Hot End 1 start gcode you would put M900 KXXX and in Hot End 2 start gocde you would put M900 KYYY. XXX and YYY here would be your calculated K value.

doenute
Posts: 72
Joined: Thu Jun 18, 2015 7:33 am

Re: Linear Advance with Dual Extrusion

Post by doenute » Mon Dec 10, 2018 7:36 am

Ok, I'll give it a try. I'm assuming it is OK to use a decimal place like K2.2?

Thanks

doenute
Posts: 72
Joined: Thu Jun 18, 2015 7:33 am

Re: Linear Advance with Dual Extrusion

Post by doenute » Wed Dec 12, 2018 6:15 am

It mainly works.

There is a problem in Cura however for those that sometimes print with a single extruder when the dual extruder head is installed.

If you print with extruder #2 ONLY then Cura will correctly insert the K factor entered in the "Hot End 2 start gcode" into the final gcode file for printing.
If you print with extruder #1 ONLY then Cura WILL NOT insert the K factor entered into the "Hot End 1 start gcode" into the final gcode file for printing.

The workaround for me was to put it into the main PRINTER start gcode, but I don't think this is the correct way Cura should work. I think Cura should execute the gcode in the correct Hot end start gcode regardless of printing with one, two or both extruders.

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