Ramps 1.4 Extrusion Speed Issue

I'm having trouble extruding with my ramps 1.4 with pronterface software. Using the extrude 30mm test the literature suggests, I extrude nearly 50mm. However, when I go to print there is barely any filament extruded. In my old gen 3 stuff I could adjust for the type of extruder I was using..ie. wades but I'm not quite sure where to do that in the Marlin firmware. Any ideas ??

thanks

When you extrude 30mm, the firmware requires you to measure the filament going in, not what comes out the nozzle. For example: if you're using Marlin, then you adjust the DEFAULT_AXIS_STEPS_PER_UNIT for E until the filament length matches what you told it to extrude.

Perhaps I didn't explain. I made a mark 50mm above the top of the extruder and then extruded 30mm of filament. At first, when I did this, I used ~50mm of filament. Thank you stephenrc for the code reference, I now have the hot end extruding very close to 30mm. However, when I print something I am still not sure I am getting enough filament to flow as it seems to barely put out filament. I am having some other issues presently and will return to this soon. I would think that if I have a proper measured amount eg. 30mm that all should be fine. At any rate it looks like the command you supplied should be the answer.

Remove the hot end.
Have filament sticking out the bottom of where the hot end is and mark it.

Give the following commands:

G92 E0
G1 F10 E100

Now make another mark and measure the distance.
It should be 100 mm.

If not adjust your E_STEPS_PER_MM value accordingly and repeat the measurement.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Note that it's better to measure that while actually extruding, I've seen some difference in distance extruded when the hotend is mounted and used :

- Heat up your hotend to the usual temperature.
- Move your hotend up above the bed.

The rest just as Bob said, only get sure to use a realistic extrusion speed (F10 is 10mm per minute right ? seems a bit slow IMO).

Also you'll have to remove a big blob from the bed afterwise

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Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

The way I measure the filament is to use a digital caliper. Once the hotend is up to temperature. One end of the caliper sits where the filament goes into the extruder, extend the caliper about 50mm and hold the filament against the moving part of the calipers, zero the caliper and extrude 30mm. I use 30mm/sec, it's not to fast to hold onto. Then read what the caliper shows for the actual feed. Use that number to do the math to get the new E steps and repeat as necessary.