How to calibrate / check the E-Steps?

Markus64
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How to calibrate / check the E-Steps?

Postby Markus64 » Mon Jun 15, 2020 5:57 pm

Hi Guys,
after all the mods I would like to calibrate both extruders. There are many instructions for this on Google. I have an example here:

https://all3dp.com/2/extruder-calibration-6-easy-steps-2/

All of these instructions require printers, which can be fed directly with GCode.
I now wonder how I can implement this on my Pro2. The value for E-Steps is preset to 6640 on my Pro2. And I would like to have checked this value. ;)

Could someone please explain to me which steps, where and how to do it?

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Mon Jun 15, 2020 7:10 pm

You can do it ALL from the control panel.
Simply preheat the extruder, have it in the homed position left front corner.
Lower the bed just to give yourself some extra room.
Get a sharpie marker, and a metric ruler.
Measure 100mm above the extruder entrance of filament and draw a line on the filament.
Ensure the flowrate on the printer is currently set to 100%. This is critical for proper calibration. Flow rate literally tells the firmware to extrude a percentage of any commanded G code filament length, so 100% is 100%.
Using the jog control panel command that extruder 10 times to feed 10mm of filament thus commanding 100mm of filament.
Measure where the line is above the entrance to the extruder.

If less was extruded, slightly increase steps per mm.
If more was extruded, decrease steps per mm.

Steps per mm is under hardware, I think you already know where that is since you quoted it.

THEN after all that, properly do the correct way of extrusion volume testing. https://forum.raise3d.com/viewtopic.php ... fish#p2620
That's how you commission and calibrate a new printer. I can take literally any printer around, do those steps, and calibrate a printer to the limits of what it is capable of.

Just a common sense note here.
Ensure that before making steps per mm adjustments, you know beyond any shadow of doubt that the extruder did not skip steps and was gripping the filament with no slippage. Adjusting steps per mm for skipping steps or slipping iis ill advised. You have fix those issues first as they are variable and unreliable factors you cannot properly compensate for.

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Mon Jun 15, 2020 7:12 pm

If you want to be sure, run that test a few times (extrude 100mm of filament per time, marking a new line each starting test).
That will let you know how consistent the system is before you go adjusting a variable like steps per mm.

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Mon Jun 15, 2020 7:17 pm

Again, when I commission a new printer, no matter what brand, what options, what control panel, there is always a method of performing this test. You might have to hand code gcode, you might have to connect the motion board to a computer or whatever, but again I've yet to see a printer sold today other than something really proprietary this test cannot be performed on.

Raise even makes it nice. While the numbers displayed are not homed or accurate position, they are what distance in mm was commanded by the front panel, so when you command movement of 10mm ten times, you will see the E distance value increment by 100mm indicating you sent the motion board 100mm of commanded filament extrusion. But like I also said, go to the tuning tabe and validate flowrate was 100% before performing the test. This is a flaw really in the system that the slicer often invokes a lower percentage with filament profiles and due to lacking proper ending gcode to reset the system to a known state, the pritn files often leave the printer in a state of less than 100% flowrate.

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Mon Jun 15, 2020 7:25 pm

Again, being honest, I generally advise against changing a commercial printer from a known steps per mm value unless you absolutely have some proven test result showing it to be off enough to justify changing. You are then straying from the baseline and as such setting yourself up for self support. Hopefully this makes sense what I'm saying. You kind of set yourself up as being different, and if you know and understand that, no problem.

Markus64
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Location: Germany

Re: How to calibrate / check the E-Steps?

Postby Markus64 » Mon Jun 15, 2020 9:43 pm

Thanks for the help Jetguy, it worked great!

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Mon Jun 15, 2020 11:50 pm

Out of curiosity, where did you end up?
How close to 100mm was it?

Markus64
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Re: How to calibrate / check the E-Steps?

Postby Markus64 » Tue Jun 16, 2020 4:08 am

I did two tests and both times it was ~ 99.5 mm. I think that's okay.

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Tue Jun 16, 2020 7:51 am

Agreed, 0.5mm is an expected variation of grip based on surface hardness of filament (PLA VS ABS). The teeth bite in differently changing the "effective diameter" of the drive grippe gear thus ever so slightly changing the effective distance moved for a given rotation. This is why filament profiles first started having different flow rate values canned in to compensate for this physical variation.
That said, the stock raise 3D profiles have typically a less than 100% flow rate value as default, and as you just proved, for the filament tested, technically, that rate should have just been over 100% ever so slightly (100.5%) however, it generally only allows whole values (100 or 101%, etc.). That said, minor variation between actual filament wire diameter and the value given to the slicer are also used in the volume calc, so that 1/2 percent issue is compensated for easily.

MMER1116
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Re: How to calibrate / check the E-Steps?

Postby MMER1116 » Sun Jul 05, 2020 8:54 pm

I followed the calibration steps and found the left extruder consistently only used 96 mm (5 trials) I increased the step by 1.04 x 6640 and retested. It extrudes 100 mm, repeatedly. When I print the test cube .2mm layer, 100% infill, there was a very slight concave surface. Should I also chage the default flow rate from 90% to 100% now that the filament feed length is corrected?

Jetguy
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Re: How to calibrate / check the E-Steps?

Postby Jetguy » Mon Jul 06, 2020 12:29 am

Yes, per the instructions, you slightly adjust flow rate to fine tune final volume.

I guess what I'm trying to get people to understand, I see people beg and beg for "profiles for X filament. Worse, I see some newer person beg and demand for a certified profile from raise3D.
YOU the user STILL have to perform this test and tuning specific to that filament and profile to fine tune it with your spool of plastic, your printer, your measured filament diameter because each tiny error in measurement or factor of that combination (spool of plastic, printer, settings, measurements, errors) works together to "detune" the factory profile. This is the step that takes you from blindly assuming a profile is tuned to actually being a lot more precise and in the process, learning setting and factors of how this works at a fundamental level.

Less than 100% flow rate results in lesser plastic volume.
Greater than 100% flow rate increases total plastic volume.
Suggested tuning in Ideamaker to edit the filament profile as this is the most logical place for different filament types and brands and their individual tuning.
https://forum.raise3d.com/viewtopic.php ... fish#p2620

5.1.4 Calibration Box

To achieve quality prints, start by ensuring that you can print a decent calibration “box” whose top is nice and flat. Producing a respectable box involves calibrating a slicing profile to your printer and choice of filaments. So, until you can print a good calibration box, there is little point in worrying about other printing defects you may be experiencing. Here is the step-by-step procedure for accomplishing this calibration:

1. Obtain a model for a 10 mm high box which is 20 mm on a side. Thing http://www.thingiverse.com/thing:2064 or http://www.thingiverse.com/thing:5573 contains the calibration box as the download file 20mmbox.stl.
2. Use calipers to measure the diameter of the filament with which you will be printing. Be sure to measure in several places to get an average.
3. With the calibration box model in your slicer, slice it at a 0.2 mm layer height, 100% infill, and using the diameter of the filament you just measured. It is critical that you use 100% infill and that you measure the diameter of your filament and input that to the slicer.
4. Print the box.
5. Carefully examine the top surface of the box. While it is easy to see if the top is convex, you may need to use a straight edge to gauge how flat or concave the top is. You are not measuring the box for dimensions with calipers, just trying to visually determine over or under extrusion.
(a) If it is nice and flat, then you are done!
(b) If it is convex, then too much plastic was extruded and your printer is over-extruding. Configure your slicing profile to put out slightly less plastic. How you will do this depends upon which slicer you use. For Ideamaker, the extrusion volume variable is called "Flowrate". In Simplify 3D and other slicers, it's often called extrusion multiplier. As a less precise workaround, you can enter a different filament diameter.
For over extruding, you lower the Flowrate or extrusion multiplier slightly. As a workaround, telling the slicer you have larger filament diameter than actually measured has the same effect.
(c) If it is slightly hollow (concave), then too little plastic was extruded: your printer is under-extruding. In Ideamaker, raise Flowrate, or increase the extrusion multiplier (Simplify3D). As a filament diameter workaround, you tell the slicer you have a smaller filament diameter than measured and this corrects under extrusion.

6. Go back to Step 3, reslicing, reprinting, and re-evaluating the result.



Once you can print a nice calibration box, you are ready to get back to printing. Keep in mind that this calibration process should be repeated for different type of plastics. At issue is the differing hardnesses of the plastics used. The pinch gear in your printer’s extruder feed mechanism bites into the plastic filament. The depth to which it bites depends upon the hardness of the plastic. And the deeper the bite, the smaller the effective turning radius of the gear. With smaller turning radius, less filament is fed per rotation of the extruder stepper motor. This calibration is primarily to address your extruder’s handling of these variations in hardness. For example, ABS is significantly softer than PLA and so significantly different adjustments may be needed for ABS versus PLA. This will, of course, depend upon the geometry of the pinch gear and how capable it is of biting into the filament.


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