How to adjust Steps per E in Printrun?

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banana97 Cura Commander Level: 19 Points: 323
Posts: 33

Posted by
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banana97

Posted Nov 1, 2012 - 11:37 AM  

When extruding through a hot nozzle I am finding a significant difference in the measured vs expected extrusion length. Filament is not slipping but there does seem to be quite a bit of friction in the tube using glow blue filament. How do I adjust the Steps per E in Printrun?

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joergen Level 24 - Tech Head
Posted by
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joergen

Posted Nov 1, 2012 - 1:04 PM

The easiest way during printing is M2210 S100 where the value after S is the amount of extrusion in %

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ddurant Level 23 - Tech Head
Posted by
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ddurant

Posted Nov 1, 2012 - 1:32 PM

Quote by banana97
When extruding through a hot nozzle I am finding a significant difference in the measured vs expected extrusion length.

Do you really mean "extrusion length" here?

The esteps value is how many steps (to the extruder motor) are needed to pull one mm of filament into the drive mechanism - it's not about the length of filament coming out of the nozzle.

Unless the filament is being offset (ie: slipping in the drive) in a very predicatable & consistant way, changing esteps may not be the right way to address this problem.

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banana97 Level 19 - Cura Commander
Posted by
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banana97

Posted Nov 1, 2012 - 2:09 PM

Sorry I don't mean extrusion length. I am measuring the length pulled by the extruded drive.

In print run if I extrude 50mm the actual length drawn is about 46mm.

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fluxline Level 22 - Tech Head
Posted by
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fluxline

Posted Nov 1, 2012 - 2:37 PM

or, once you've loaded the model in printrun, go to the file menu and select edit. Change the second line with the M92 Exxxxx with the xxxxx being the value you want.

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ddurant Level 23 - Tech Head
Posted by
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ddurant

Posted Nov 1, 2012 - 11:02 PM

Quote by fluxline
or, once you've loaded the model in printrun, go to the file menu and select edit. Change the second line with the M92 Exxxxx with the xxxxx being the value you want.

Right.

Also, I dunno M2210 but Joergen is usually pretty clever so you may want to look into that, too.

In print run if I extrude 50mm the actual length drawn is about 46mm.

If you didn't already know, multiply your current esteps value by 50/46 (1.09) then measure again. Keep repeating and adjusting esteps by desired/measured until it starts behaving.

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banana97 Level 19 - Cura Commander
Posted by
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banana97

Posted Nov 2, 2012 - 6:05 AM

Quote by ddurant
Quote by fluxline
or, once you've loaded the model in printrun, go to the file menu and select edit. Change the second line with the M92 Exxxxx with the xxxxx being the value you want.

Right.

Also, I dunno M2210 but Joergen is usually pretty clever so you may want to look into that, too.

In print run if I extrude 50mm the actual length drawn is about 46mm.

If you didn't already know, multiply your current esteps value by 50/46 (1.09) then measure again. Keep repeating and adjusting esteps by desired/measured until it starts behaving.

Thanks - I did this and entered the new value in Printrun, then clicked extrude again - but it didn't change the length much. Out of interest I entered an E value of 850 and 1050 and did the same 50mm extrusion - the length was the same - around 46mm??

When you change the E value through File - Edit, does it only change when you print the model or does it change globally and thus should take affect when you click the extrude button?

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fluxline Level 22 - Tech Head
Posted by
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fluxline

Posted Nov 4, 2012 - 8:00 AM

Sorry for the late reply, spam fog.

It will only change it for that model when you print it. Settings in the menu also has a feedrate of 300 (i think), but it is best to use cura to calibrate for the filament you want to use and keep a list of filamant values that you can replace in the gcode for a model. You can always tweek the number a bit, plus/minus 10?, for what works. I hopes we get a way to store these and use for a print in the next release of Cura. Also, positioning on the print bed at print time. Poor Daid, makes a great product and then people just want more and more ..........

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j.samuels Level 19 - Cura Commander
Posted by
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j.samuels

Posted Nov 4, 2012 - 3:30 PM

You will need to send the commands to the printer in order to change it. Editing the .gcode for a model will only change it when printing that model. There is a box in printrun on the lower right you can use to send individual commands to the printer. You will need to use M92 E to set the new E steps per mm and then send G92 to zero out the extrusion length.

For example, if you have E steps of 865.888 (default), you extrude 50mm and measure 46mm. Then you want to set your new E steps to 941.183 and retest. First send the M92 to set the new E steps value, then G92 to zero out the extruded length.

M92 E941.183 ;sets E steps per mm

G92 E0 ;zero E axis

Now you can retest and it should be very close to 50mm. If not, then you can change it again and repeat. Once you have the correct value then you should re-run the startup wizard in Cura and set the appropriate E steps, so that newly-generated gcode will have the correct values.

One more thing to make sure is that your nozzle is primed for each test, else you will not get a fully accurate measurement.

Also the M221 command as mentioned by Joergen (M2210 is just a typo I'm sure) will allow you to modify the extrusion speed by a % to correct, instead of changing the E steps. In your case I think you can just do M221 S109 to modify the extrusion speed by 109% (50/46 = 1.09 or 109%) which would give you the correct extrusion amount. But I haven't tried it this way personally. It should work, though. I do believe Marlin supports this M code but it's not clear from the reprap wiki.

http://reprap.org/wiki/G-code#M221:_set ... percentage

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banana97 Level 19 - Cura Commander
Posted by
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banana97

Posted Nov 5, 2012 - 7:43 AM

Perfect! Thanks j.samuels - that's exactly what I needed to know.

I will probably do this for the different filaments I have just in case they give different results.

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alaris2 Level 28 - 3D Pioneer
Posted by
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alaris2

Posted Nov 5, 2012 - 8:42 AM

I use M221 myself and it works well.

be aware that it takes a short time to have effect and that small numbers (ie. close to 100) have very little observable effects on the print quality.

I think (not totally sure) that it is accumulative, ie. M221 S200 followed by M221 S100 will not set the values back to the original, but M221 S50 would be required instead. perhaps someone else can comment on that?