Extruder E-step Cal Inconsistent Results

[AbuMaia]

I do that to adjust my flow rate, but not to adjust the esteps. What is your technique?

[orionthunter]

I'm not sure what you mean by adjusting your flow rate. Do you mean the flow % option in Cura (extrusion multiplier ration in Slic3r)? If so this does the same thing as multiplying your E-steps by the same amount. I prefer to leave it at 100% and make the changes in my firmware.

[gmay3]

Hey Drone,

In addition to the normal extrusions to check the calibration of your Esteps, I've found that printing a small box with 100 percent infill has helped me really dial in my extrusion. I described this test in the link below.

http://3dprintboard.com/showthread.p...ll=1#post20845

[Drone]

GMay3- This makes sense also and I will give that a try. How long does that box take you to print and have you tried the box at different feed rates? I think at the end of the day it's about being able to deliver a known volume of liquefied filament over a given time period. This can be changed by a number of different things like nozzle size, motor accuracy, filament slipping, gear lash, and nozzle temp I would think.

I think I am going to try this in steps and try an extrusion test without the hotend attached to test the motor and gears with just a measured filament extrusion. Then I will attach the hotend and try the same test again to see the comparative results. I will try at several feed rates to see why on my printer 65mm FR is repeatable and 100mm is not. Might be a waste of time, but interesting to me none the less.

[gmay3]

The box takes maybe 10 to 15 minutes for me to print.

That's an interesting point about different feed rates. I have not tried these calibrations at different feed rates but that would be an interesting experiment to see if the box's volume changes.

Either way, I would recommend trying to dial in all of your final print speeds and then run the box volume calibration at that set feed rate. I think of the esteps as a course extrusion tuning and the box volume test as a fine tuning. Exactly as you say, the accuracy of the amount of plastic going into the print below is the most important thing. I just adjust the extrusion multiplier in slic3r until the boxes top is perfectly flat.

Yeah definitely try without the hotend if you're interested in doing it for science! I would be interested to see what you find!

[AbuMaia]

To get my extrusion multiplier, I sliced a calibration cube to be hollow with one perimeter. I used the "vase" option in slic3r to make it easy and quick-printing. I set one up for ABS, and another for PLA. Both .gcode files state perimeters should be 0.4mm wide, so I compare printed wall thickness against that number, and set the extrusion multiplier for that filament spool appropriately. It's the first object I print from a new spool. Slic3r is set to treat all filament as 1.75mm, with different multipliers set for each different spool.

[gmay3]

To get my extrusion multiplier, I sliced a calibration cube to be hollow with one perimeter. I used the "vase" option in slic3r to make it easy and quick-printing. I set one up for ABS, and another for PLA. Both .gcode files state perimeters should be 0.4mm wide, so I compare printed wall thickness against that number, and set the extrusion multiplier for that filament spool appropriately. It's the first object I print from a new spool. Slic3r is set to treat all filament as 1.75mm, with different multipliers set for each different spool.

That's a great idea AbuMaia. I would say that's an even more fine tuned test than the solid box volume one. I might try this to see if I can dial my extrusion in even more. Sometimes it's hard to tell if the box is completely flat on top and this gives you direct measurement feedback!

Just curious, how close have you gotten to 0.4mm when you actually go to measure it?

[AbuMaia]

So far my multipliers are between .87 and 1,22, over 5 colours and among both PLA and ABS. I don't know if I've yet gone back and printed the vase-box with the multiplier already set. I'll give that a try and let you know.

Oh, one step I forgot: measure the four sides, toss the largest measurement, add the other three together, and divide by 3 to get the average. Then compare that number to the perimeter width number.

The box walls came out between 0.39 to 0.41

[gmay3]

So far my multipliers are between .87 and 1,22, over 5 colours and among both PLA and ABS. I don't know if I've yet gone back and printed the vase-box with the multiplier already set. I'll give that a try and let you know.

Oh, one step I forgot: measure the four sides, toss the largest measurement, add the other three together, and divide by 3 to get the average. Then compare that number to the perimeter width number.

The box walls came out between 0.39 to 0.41

Great results! I'm definitely going to try this. Thanks for the step by step!

[AbuMaia]

I can't take credit for it. I learned it here: http://zennmaster.com/random-things/...-2-fine-tuning