Print The Porto

A collection of tips about 3d printing.
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How to calibrate your 3d printer Extruder Steps

Step 1

Enter M501 in the control software of your choice. This will show the current stored settings on your firmware.

The section we are looking for begins with, M92. This sets the number of steps which, in turn controls the accuracy of our printer.

To Calculate Accurate Steps

( Distance to Travel / Distance Traveled ) * Number of Configured Steps

For example, on the (40 / 39.90) * 84.40.

This gives new steps of 84.612 ( we only need a few places of accuracy, the real calculation gives more).

Enter this with the command M92 X84.612 (Make sure the letters are capitalized)

If you're using smoothie firmware it's M92 Exxx.xxx

Example of distance traveled:
Mark 120mm from your reference point.
Extrude 100mm.
After extrusion, the mark is now 17mm from marked point.
120mm – 17mm = 103mm actually extruded.

Step 2 Measuring

We need to measure the amount of filament the extruder is pushing through to make sure we don't over extrude. Mark the filament, with a piece of tape or post-it.

Place a flag of tape 100mm above the extruder.

Extrude 50mm of filament.

Measure the distance from the top of the extruder to the 'flag' of tape, to see how much filament was extruded.

Use the formula above (amount told to extrude/real amount extruded) multiplied by Number of steps in firmware.

Type the new value with M92 Exxx

Save all the settings with M500 and M501 to check the new settings.

Repeat until you get the exact extrusion length you asked to print out.

You can also do this with a 100mm, but measure out to 150mm and extrude 100mm of filament to see if it changes, if so, repeat the steps above until it's accurate.

Categories: Calibration, printrbot simple metal

Tags: Calibration

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Calculate and configure Accurate E and Axis Steps for printrbot simple

The section we are concerned with, is the line that begins M92. This sets the number of steps which, in turn controls the print accuracy of a 3d printer.

To Calculate Accurate Steps

( Distance to Travel / Distance Traveled ) * Number of Configured Steps

For example, on the X axis (40 / 39.90) * 84.40.

This gives new steps of 84.612 ( we only need a few places of accuracy, the real calculation gives more).

Enter this with the command M92 X84.612 (Make sure the letters are capitalized)

Do the same for Y axis.

That takes care of X and Y.

On the Printrbot Simple, the Z is an ACME screw, it's number of steps will always be 2020.

For the extruder, we're going to measure the amount of filament, much the same as the amount of travel on X and Y. We mark the filament, with a piece of tape or post-it.

We measure the distance from the top of the extruder to the 'flag'.

We extrude some filament and then measure the new distance from the top of the extruder, to see how much filament was extruded.

Then we use the same formula (amount told to extrude/real amount extruded) X number of steps.

We add this value with M92 Exxx

Then we save all the settings with M500 and check the new settings were saved by invoking M501.

You should have an accurately configured the steps of your printer.

E Steps Fine Tuning

Fine tune e-steps using Triffid Hunter's calibration.

Now, with everything very close to ideal values, we can finally dial E steps in that final little bit!

  1. Find an object with flat tops on a number of levels, such as this cube stack test (scale this object by 250% after loading in Slic3r)
  2. Slice at 95% rectilinear infill. Use the lowest layer height you're comfortable with - the lower the layer height used for this test, the finer your resulting E steps calibration will be. I use 0.2mm for first run, and if I'm feeling ambitious I'll repeat this process at 0.1mm.
  3. Print.
  4. Ignore the first 5-6 layers because they're too sensitive to the exact height of the first layer. If it's obviously over-filling or under-filling, alter E steps or Z=0 point and restart the print.
  5. Observe infill. If you can't see tiny little gaps between the lines, reduce E steps by 0.5% every 2 layers until you can see tiny gaps.
  6. Observe solid top layers. If you can see tiny gaps, increase E steps by 0.5% every 2 layers until there's no gaps in the top.
  7. Send the new E steps to your printer with M92 Ennn without even pausing the print - you will see the result in a couple of layers when the change is this small.
  8. Goto 5 until the infill has tiny gaps AND the solid top layers do not.
  9. Now, your E steps value is extremely fine-tuned! Save this value in your firmware's configuration and flash to make permanent.

Finish

Now print your favourite calibration piece (e.g., ultimate calibration) and see how it measures!

Categories: printrbot simple metal, gcode, Calibration

Tags: Configure Steps, Calibration

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