Don't understand this......

I have been trying for hours to successfully print a small gear wheel for my mini lathe and have failed at every attempt. I have attached a couple of pics to show the problems which seem to happen whatever changes I make to the code. The pic named 'top' shows the best two prints to date - both unusable... They were both processed with Slic3r - the one on the left with a fill level of 0.7 and the one on the right with a fill level of 1.0 - I see no difference. In both cases, the inner wall is only connected to the outer wall at the base layer and the teeth of the gears are not filled. I also tried the same thing with Skeinforge but got the same result, but also, the inner wall did not print properly and had many strings across the hole where the filament had not attached properly. The pic named 'side' shows the other problem where the print tapers in towards the top. I wondered if this might be something to do with the top not having support but I also got a similar result when printing the pinion for the Gregs Accessible extruder.

Can anyone shed any light on what is going wrong and how I can correct it please..

Prusa Mendel with heated bed at 60 deg C, PLA filament, Marlin firmware, and using Repetier or Pronterface host software - I have tried both with similar results - (I think I now prefer Repetier)

The next project will probably have to be a filament maker to recycle all the duff gears I now have!!!

Thanks, Ian

Set your perimeters to 1 and the infill will go into the teeth.

Is this my Lathe?

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Hi Sublime, Thanks. No, its not your lathe - I haven't got round to making one of those yet but it is on the list once I get this machine properly under control. This is one of the cheap Chinese 12 x 4 lathes which I need a couple of extra changewheels for to cut some unusual threads.

Do you mean set 'perimeters' to 1 in Slic3r or Skeinforge. If so, won't this make the skin very tin and likely to wear through quickly?

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Thanks, Ian

In Slic3r you set it to 1 and in SF you set extra perimeters to 0

For such a thin gear I would set it to have one perimeter but set the infill to 100%.

Edited 1 time(s). Last edit at 02/15/2012 07:40PM by Sublime.

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FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Thanks, I'll try that tomorrow..

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Thanks, Ian

Hi,

I've been struggling on getting real small gears to print for some time, below is a little howto I have put together:

[forums.reprap.org]

YMMV as I have a 0.35 mm nozzle and no heated bed, but you might get closer to something useful.

Good luck.

I changed the settings in Skeinforge and the pic shows the results - still no use although the infill is a bit better... I have attached also a zip of the skeinforge settings I used.

For some reason, Slic3r didn't want to process the file even though I had run it through Meshlab which I thought would remove any errors from it. I also have another problem with Slic3r, when I try to process the file for the extruder drive pinion, it stops just below the level of the screw hole and apparently doesn't 'see' the rest of the collar. Since Skeinforge does process the pinion correctly, I assume that there is some setting wrong in Slic3r but I can't see what to change - are there settings somewhere other than in the dialogue brought up in Repetier?

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Thanks, Ian

Thanks Tinhead,

I had read your howto already and I had turned the speed down to 10 and set a fan up. My indicated temperature is somewhat higher than yours but this may be due to sensor differences as turning down the temp on my machine makes the PLA come out in lumps....

Your work is impressive and I would love to be at that level of expertise but I still have a way to go as I'm still very new to this technology.

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Thanks, Ian

It occurs to me that perhaps this gear isn't printing right because of some anomaly in the original file and so I have attached it here for comments.
Thanks

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Thanks, Ian

Oh I'm not really an expert I'm only very stubborn


It looks fine sliced with slic3r 0.60, I'll try printing it tonight to see how it comes out on my printer.

I realize slic3r is all the rage these days, but skeinforge still gives you far more control over the print and is still a fair bit more capable. If you have it working, skeinforge is probably worth a try.

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I finally got a half-decent print using Slic3r and Repetier on my linux box. Still a couple of issues with tapering towards the top and stringing in the hole but this one is usable. Thanks chaps.. I also printed a 65 tooth wheel which was fine as far as filling of the teeth is concerned - for some reason, the last couple of layers on this one didn't stick too well but the gear is usable. I guess I need to turn the temp up on the extruder even though it is running at an initial indicated temp of 215deg - I think the temp does drop through a big print and I've seen it dip to an indicated 202deg. I've had the print head off quite a few times recently and so I need to check whether I've disturbed the thermistor. I've also put a 30mm fan blowing on the top end of the hot end to keep the plastic cool and this is making the hot end temp dip quickly when the power to it cycles off.

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Thanks, Ian

Finally found time and printed it!
I used slic3r with the settings in the attached settings.jpg file.
The interface might look a little different because it is from Repetier host.

Edited 3 time(s). Last edit at 02/18/2012 01:52PM by TinHead.

Since you had to adjust the extrusion width modifier I would assume your E-steps per mm are not set correctly so Slic3r can not calculate the width correctly. But I could be wrong.

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FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
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Well I have the E steps setup as good I could measure but I still get too wide width with the auto detection. So for 0.2 mm layers I get about 0.6 mm width when I should get 0.4 according to Sound's calibration guide here: [github.com]

I followed the above until I got the "correct" width

BTW: the Tantillus looks outstanding !

Edited 1 time(s). Last edit at 02/18/2012 02:43PM by TinHead.

Quote
bassman
30mm fan blowing on the top end of the hot end to keep the plastic cool and this is making the hot end temp dip quickly

I fashioned a small shield from heavy foil (baking tray) kaptoned to the lower end of the thermal barrier to keep the fan draught off the heater block..