What is going on with this print?

Prusa Mendel i2
Sanguinololu/Sprinter
3mm PLA filament
0.5mm J Head extruder
Heated bed
slic3r
No fan (yet)

First layer: 200C ext, 80C bed
Other layers: 185C ext, 60C bed

I have been struggling a bit with more precision printing, trying to determine what could be affecting print quality.
Example: I printed three gear spools, and while the general shapes turned out well, the gear definition and other detailed features are poor. Picture attached. What am I missing here?

Thanks in advance!
Rob

More info on my settings:
Layer height: 0.3mm
Ext width: 0.48mm

The little blisters are often indicative of too much filament being driven through the extruder. When there's too much plastic coming out it has no place to go but out the sides. It will also wreak havoc on your surface finish. Make sure that you extruder is properly calibrated (if you tell it to extrude 10mm of filament, it actually pulls 10mm of filament into the extruder).

Starting temps seem a wee bit too high for PLA..

Thanks for the input! This is definitely getting me on the right track. In reviewing my parameters, I did a few things:
1) Recalibrated my extrusion steps/mm setting in sprinter
2) Found that I had my extrusion multiplier set to TWO (whoops) when it should be around one.
3) Reduced my post-first layer temps to 175C ext/ 55C bed.

Doing these yielded a much improved result - take a look at the attached photo.

I still think I can get better definition on the teeth and other finer details - what's left to change? Speed of the print? My current speed is 30mm/s on post-first layers.

Thanks,
Rob

What are your retraction settings?

have you tried to calculate the E-steps value? On my printer everything went from OK to fantastic in less than 2 minutes! use this guide: http://reprap.org/wiki/Triffid_Hunter's_Calibration_Guide

Even so, when printing pulleys Use the M92 command to lower the E-steps a bit further, to prevent the small blobs at the end of each tooth.

Hope this helps

is the base of the gear round, on the photo it looks like it's a bit wobbly? If so, this could be the result of an improperly tensioned x and/or y belt. If it's to loose you'll get a lot of backlash. Also check if both axes travel smoothly from end to end

Hi all -
Here is the latest. As I was going through the Triffid Hunters Calibration Guide above, I noticed that instruction was to have 95% infill while using the calibration model. My setting was 25%. For a SMALL part. Here are some pictures of my print using 95% infill as suggested (to start). Wow - very nice. Apparently small parts need a higher infill percentage. That may be obvious now, but it wasn't to me yesterday.

The melting at the top is I believe due to the fact that I only printed one and have no cooling. Easily solvable problem. I am doing another run of my gears with a higher infill percentage this time.

Thanks,
Rob

Okay, I am getting noticeably closer to a precision print - very exciting.
I have calibrated all motors (including E-steps), and prints are better for it! I am thinking my e-steps are a little low because of the following phenomenon: exterior surfaces look great, but interior ones look like they don't have enough filament. Look at the attachment. Is that what is causing this? If not, what? Thanks!
Rob

It could be heat buildup on the interior. Did you install the fan yet?

A fan usually makes a great improvement in small parts. Just make sure it doesn't cool down your nozzle so much that you get extrusion problems onstead. Been there done that . took me a while to figure out.

Edit: Also, the reason your interior spaces don't llok good is good old fashioned stringing. Numerous ways exist to handle this problem:

• Retracting filament when making travel moves.
• Lower printing temperature.
• Lower printing speed and higher travel speed.
• Using "wiping" slicing algorithms, that "wipe" the nozzle on a surface before travel moves. I believe KISSlice has this option.

Edited 1 time(s). Last edit at 01/21/2013 05:37AM by Speedsoda.