need help, Fine tuning and problems with small gears...

I've been banging my head against this prusa for a few month now.

My prints are close, but not quite there. Usable but not Quality.

I'm currently using Sfact->Pronterface->Sprinter.

Sfact settings:
Filiment Diameter 2.8
Nozzle Diameter .35 (J-head)
Layer height .25
Extrusion width .43
E-Steps adjusted through calibration, and then some...

Results printing the Sfact calibration object 40x10.stl, wall width .51-.38 averaging to .4225 from 6 mesured points...

The 20mm cube prints nicely, but does show the lower fill if lighted just right.

At this point, I'm not sure if I should adjust E-Steps to get closer to .43 or change to .42 and adjust E-steps that way...

With these settings, and a fill of 35%, my small hering bone gears have globs in the teeth as the nozzle shovels extra plastic overboard...
The bases on them look fantastic though.

I've tried Slic3r, however, I get an overstuffed 20mm cube with that. I tried moving the E-Steps across, to no avail.
However, I may be missing something in the configuration as I'm editing the ini/conf file directly as I can't seem to get a gui on my Linux.
I can post my set-up for printing the cube if you like.

I've been unable to get a photo of the gears to show how rough the tops are.

Any help, sujestions, etc... most welcome.

I really want this thing producing my next week, as I have someone asking me to create some custom gears for there project.

Thanks,

Might want to consider switching from Spinter to Marlin. Most people report better quality prints from the frimware switch.
The guys in my local RUG swear by the change of firmware.

I'm thinking I would apreciate the change to Marlin more after I have my slicing configurations properly set.

marlin vastly improved my prints with no other changes to the slicing mechanism (in my case, slic3r).

Interesting.

I looked into it, and noticed that Sprinter had an update, so I tried that first.

Rounds are now ... Round rather than sectional.

The infill is now more cosistant and the sound more pleasent.

Temp on head now controlled by variable resistance(or something) rather than on/off. Making the hot end more stable less swing in temp. I may have to lower my set temp to compensate.

Endstopping actually slows down notcably on 'bounce' to stop. Both more sane and better acuracy.

I tried the Sfact bridging test object. Only 3 strings snapped. the body showed clearly spaceing in the infill. (Will have to fix that)
And the rectangular post on top edge came out clearly, although it was over stuffed and glossy compared to the rest of the object.
(Guessing lower temp may improve the look, not sure about stuffing.....)

Will post a pic later, and update with new settings for better fill.

Ok, I think this might be a problem.

My latest test started looking like the filiment was stripping.

However, when I femoved the filiment, if didn't show the usual big gouge/gouges where the stripping happened.

Also it was showing stress (white) marks where the bold bit into it.

So, being curious, I snapped a pice off at the stress mark.

Right there, in the middle of the filiment, was a void! An air bubble.

Now I'm not sure what to do with the rest of the roll...

I'm thinking I need to find better palstic.

Slowing down, and if possible active cooling the part during the print (fan) is a great help for little and/or detailed parts.

For tiny gears you might also want to use a single perimeter, so that the infill actually reach the inside of the teeth.

Also if you want to print a single one (you probably must have a fan for that) you can disable retraction (and verify skeinforge's comb module is enabled). No reason to retract when your head won't leave the single shape you have, and retraction can produce tiny blobs on the surface when it stops to retract.

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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.

There's some good advice.

Don't have a fan hooked up as of yet.

The gear I took a photo of was a set of 4.

perimiters set to 2.

I had previously done a single solid fill, 2 perimiter with slightly better results.

Will try single perimiter.

Don't know how to slow down...

Tinkering with Slic3r currently...

Will post with something soon,

Thanks.

Update!

While reading another thread, I decided to check my filiment width.

After seening the numbers, I realised, I hadn't checked the filiment width when I switched from PLA to ABS. I had just assumed it would be silular. (Same source.)

Turns out the ABS is closer to 3.2 average vs 2.8. (Doh!)

Plunking that into Slic3r, produced some promising tests.

So, I tried the 4 small gears with a 35% fill. Single wall this time.

See attached pics. The left is the previous batch right is new print.

Still some bumps in the teeth, but those seem to be the infill overlapping the perimiter rather than over fill being shoveled out.
The top serface is quite nice.

I will try again with double wall to contain the infill.

Also, I must say I like the way Slic3r moves the head. The way it moves and makes discreat floors for the openings seems a lot saner than what I'm used to.

I may try Marlin firm ware on my next machine, but I'm happy enough with what I'm seeing now.

Edited 1 time(s). Last edit at 04/04/2012 10:36PM by Komb'.

Sorry for my advice of using a single perimeter, I didn't check your nozzle size. With a 0.35 it might not be needed, 2 could get better result.

Are you still using retraction ? It might be another source of surface blobs, and not needed if you print one gear only - you'd only have to ream the middle hole, which you will need to do anyway.
Mmm I realise this last one may not apply as you're using slic3r, and not skeinforge with "Comb" activated.

---

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

I was just printing those same gears and also had some problems. After putting down the perimeters, there was too little and too oddly shaped space for the infill and it didn't get drawn properly. So, I set perimeters to one and solid layers to 1000 (so every layer had 100% infill). This was with Slic3r and Marlin, 0.5 nozzle, 0.25 layers. After that I finally got some really good gears.

Edit: I wouldn't recommend one perimeter with sparse infill, but with solid infill it worked really well.

Edited 1 time(s). Last edit at 04/05/2012 04:46AM by ttsalo.

Final Update. (Probabily... )

With 2 perimiters and retract still active.

The bases where about the same while filling.

The teeth however, had very little space after the two primiters. The result was a nearly 100% fill. I did notice the occasional hole in the fill, but for the most part it was close enough to 100%.

As you can see from the pic, the result is Beautiful. Well to me anyway.

I wish to thank all who posted and hope this helps someone else.

Nice work.. I will be very happy when my heringbone gears look like that. See pitiful attempt attached.

As bad as this looks, this is my first print on the printer also attached, built from discarded bits of ply from under my work bench and you have no idea how excited the family was to see something printed.

I will be using your calibration settings today to see if I can get mine as good as yours.