Linear Advance with Dual Extrusion

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doenute
Posts: 74
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
Posts: 65
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: 74
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: 74
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.

b-morgan
Posts: 302
Joined: Fri Aug 11, 2017 8:53 am

Re: Linear Advance with Dual Extrusion

Post by b-morgan » Mon Sep 09, 2019 10:33 am

doenute wrote:
Wed Dec 12, 2018 6:15 am
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.
If Cura executes the appropriate Extruder Start Gcode in response to a T0, T1, etc. command then "normal" Gcode files for a single extruder would not contain any tool change codes and in this case, having the K command in the main printer Start GCode would be correct.

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