First completed calibration cube

I just completed printing my first, somewhat successful, calibration cube using my Prusa i3. Currently printing at 172c (175c for the first layer) and .5 nozzle. I slowed down to 20mm/s on the bridges but it still is looking nasty. Also I'm thinking it is extruding too much based on the rough surface...

[app.box.com]
[app.box.com]

Any thoughts or advice on how to print better?



20mm/s on bridges
.22mm layer height
PLA 3mm Filament
Buda 1.2

Calibration Cube: [www.thingiverse.com]

Thanks

Edited 2 time(s). Last edit at 08/22/2013 11:12PM by pcchameleon.

Defenatly extruding too much.

Standard Questions:

1. Have you calibrated your E-Steps?

2. Did you measure the actual size of your filament and enter that into your slicer?

Filament width very not only from different makers but also different rolls from the same maker.

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Komb'
Glankonian Protoforms

1. E-steps have been calibrated. I did a 100mm extrude with no hotend attached to verify and then adjusted for the back pressure after reattaching the hotend but it still seems like too much is coming out...

2. Yes, using a caliper I found an avg of 2.98mm over a couple of feet of filament.

I'll make some adjustments in the extruding factor in Slic3r or go over the E-step calibration again. Thanks for the advice!

What are your retraction settings? Did you by any chance try different retraction settings and see if they make a difference?

By the way, are you having a print quality problem with objects that have bridges like this only? Do you get a good quality (i.e. even layers, no curl ups, and etc) when you print simpler objects?


The questions below are for my own curiosity, probably not related to your issue...

When further adjusted the E step with the hot end attached (after the initial E step calibration extruding 100 mm without hot end), did you also run another 100 mm filament?

Or, did you print something, visually checked the extrusion width, and then made adjustments?

And, did you have to change the E step value quite a bit with the second calibration, or was it a small change?

I wouldn't mess with the extrusion multipler in your slicer until you have your esteps calibrated with the hotend on. I would adivse leaving extrusion multipler at it's default setting until you reach the point where your prints look pretty good and just need fine tuning.

Another thing people often overlook when having over/under extrusion problems is Z steps/mm calibration. If the gcode tells the machine to move up 0.22mm for the next layer and the machine only moves up 0.1mm (for example), it will look like it's over-extruding. It's best to configure X, Y, and Z steps/mm using calculations rather than measurements.

sheck is totally right. Josef has put the formulas into a handy calulator and hosted it on his site.

sheck626 Wrote:
-------------------------------------------------------
> Another thing people often overlook when having
> over/under extrusion problems is Z steps/mm
> calibration. If the gcode tells the machine to
> move up 0.22mm for the next layer and the machine
> only moves up 0.1mm (for example), it will look
> like it's over-extruding. It's best to configure
> X, Y, and Z steps/mm using calculations rather
> than measurements.

Yamster,

The retraction is currently set at 1mm. I have not changed it yet.

I'm have some curls ups but the layer height appears to be correct. For the calibration cube show here is measured right 25mm which was the target height.

Initial E step calibration was done with out the hotend attached. Ran it for a 100mm and measured the actual amount that came out and adjusted accordingly. Then had to do some fine tuning with the hotend attached and running to account for the back pressure of the hotend itself. I guess still working on the fine tuning...lol

Well, I have part of problem. My hotend is leaking. After running it for a couple of prints and getting inconsistent amounts of filament coming out, I found it is was leaking. Im not very happy with the buda-style hotend (G3D v1.2). It used to clog up a lot, so I did a full breakdown and replaced the Teflon tubing and it fixed that issue mostly but now it leaks... Long story short, I have ordered a J Head hotend.

pcchameleon Wrote:
-------------------------------------------------------
> Yamster,
>
> The retraction is currently set at 1mm. I have not
> changed it yet.
>
> I'm have some curls ups but the layer height
> appears to be correct. For the calibration cube
> show here is measured right 25mm which was the
> target height.
>
> Initial E step calibration was done with out the
> hotend attached. Ran it for a 100mm and measured
> the actual amount that came out and adjusted
> accordingly. Then had to do some fine tuning with
> the hotend attached and running to account for the
> back pressure of the hotend itself. I guess still
> working on the fine tuning...lol

You just can't do it like that. You need to measure the amount that goes in to the extruder top, not what comes out the hot-end.

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_______________________________________
Waitaki 3D Printer

Waitaki,

I'll do the 100mm test again this time from the top of the extruder. Im not understanding though if the hotend is not currently attached then it should be the same, right? I manually set the filament flush with the bottom of the extruder and then ran out 100mm of filament, measured, and then adjusted until I got a 100mm of filament everytime I ran it for that.

waitaki, please correct me if I misunderstood or don't explain the procedure properly.

waitaki was concerned about this part of your statement "measured the actual amount that came out". When calibrating the E steps you measure the amount that went in.

(I think you should do this with the hot end on and hot, but there are others who think you can do it with the hot end off, so you choose.)


Make a mark on the filament 100 mm from the top of the extruder and then extrude 100 mm of filament. If the mark stops before it reaches the extruder, you need to increase the E steps value of your firmware. If the mark is even with the top of the extruder, your good. If the mark has disappeared into the extruder you need to lower the E steps value of your firmware.

The hotend has to be attached to get a correct reading - it may indeed extrude 100mm with the hotend removed but the backpressure from the hotend when attached may well influence the actual amount that is fed during use. So do the procedure appdev wrote and you will be on your way.

pcchameleon Wrote:
-------------------------------------------------------
> Waitaki,
>
> I'll do the 100mm test again this time from the
> top of the extruder. Im not understanding though
> if the hotend is not currently attached then it
> should be the same, right? I manually set the
> filament flush with the bottom of the extruder and
> then ran out 100mm of filament, measured, and then
> adjusted until I got a 100mm of filament everytime
> I ran it for that.

---

_______________________________________
Waitaki 3D Printer

Update - Working better now

- New hotend - J Head 0.35 nozzle
- Re-calibrated E Steps with the hotend on


[app.box.com]

No more random hotend cool-downs during the print and no more clogs with the new hotend.

I need to do some more fine tuning but Im happy with these results!

Thanks for the help and advice!

This seems to be a known problem with pla and the G3D V1.2 hotend leaking. The maker suggests using teflon tape to seal the threads before and after the heater.

Jeff.