Finetuning my mendel

I have a mendel with gen3 electronics, a geared adrian's extruder, default firmware,PLA and the reprap host software.

After a few iterations, my printing quality seems to get a bit better. But I still have some problems.

Picture 1 & 2 show the output I had previously. They have a lot of lumps. Mostly cause by the reprap pausing to long at one spot, spitting out a blob of PLA before printing the infill.

Picture 3 shows the next iteration being build. I used 2 shells, and put the E0_steps_per_mm to 3.5. Anything lower than that seems to mess up the outlining, while still spitting out blobs. The 'wall' next to the object being build seems to be quite ok.

As you can see in picture 4&5, the result is a bit hairy, but the outlining is a bit better. Except for the lumps in the smaller part of the object. The height is about the same as the orignal one (2.4 cm). Only all holes are filled up.

What can I do to improve my output?


picture 1
Picture 2
Picture 3
Picture 4
Picture 5

Switching to skeinforge will give you more control over how things are done. This enables you to control the extrusion and application of heat a little more which will result in better prints. Skeinforge also does bridges better, which you will find very useful as you try to print more complex parts. You still need send.py, the reprap host, or something else to actually send the Gcode, but skeinforge will do a much better job of generating the Gcode once you get it configured.

There are a lot of parameters to adjust that might improve your dimensional accuracy, but the basic things to start messing with are flow rate, feed rate, and temperature. Adjusting the extruder reversal parameters and lowing temperatures may also help with cutting back on the strings.

It looks like your part is basically melting in on itself in some spots. Try turning back your extruder tempurature a few degrees. In other areas, it looks like your layer thickness is too high and the layers are not quite pressing into one another. Try lowing your layer thickness and increasing the feed rate to compensate. If you see plastic squishing up towards the extruder after it exits the hot end or starts filling in the part, you are extruding too much plastic for your new settings. Either lower the flow rate or increase feedrate further. Adjust each parameter a small percentage each time. Don't change everything all at once either. Print small objects with enough infill space that you can easily identify infill problems as well as perimeter outline problems. IE, printing really narrow parts with mostly shells is not going to tell you anything about how well your infill settings are working. This snowflake for example would be a bad calibration piece (unless you wanted to see how sharp of a corner you could make). This might be better for basic calibration.

Thanks, I found a tutorial (http://wiki.makerbot.com/configuring-skeinforge) which I might understand. I can try that tomorrow. Do you have any other (better) tutorials for beginning which skeinforge? Like a step-by-step turtorial on printing a object using skeinforge?

You might look at THIS and THAT...

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

Thanks, I will check them out

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reprapworld.com
PLA, ABS, PETG multiple colors (3 and 1.75 mm) €16,49 / kg
Megatronics 3.0 €79.99 / Minitronics €37,19

I spend the whole evening calibrating skeinforge. At first I was cursing it, but now I am kinda loving it. I do think I made some progress. Although the results are far from perfect.

Again some pictures


This picture shows my progress, from left to right.

Picture 1

The last two a bit closed up:

Picture 2

This is a close-up of the last print:

Picture 3

As you can see, there are to much holes in it. Also the shapes are a bit off. The previous one did have a solif infill, but the shapes were almost gone.

Picture 4

I am quite pleased with the layers actually.

Picture 5

Only the corners are off.

Picture 6

I have been playing mostly with the speed settings:

feed rate: 60
flow rate: 70
travel feed rate :100

I also did put infill pattern on grid rectangular

So any help is again much appreciated

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reprapworld.com
PLA, ABS, PETG multiple colors (3 and 1.75 mm) €16,49 / kg
Megatronics 3.0 €79.99 / Minitronics €37,19

I recommend trying ReplicatorG 023 with Skeinforge 35 and print the hexagon.stl example that comes with it. I would slow down the feed rate to 40 and the travel feed rate to 50 and adjust the flow rate to get the the last layer solid. You also need to set the parameters in Dimension to reverse the extruder to prevent ooze. I can't access my Mac right now that I use with the Mendel so I can't send the exact values. Also, I didn't change any settings in the firmware except to turn off acceleration. I'm also building on painters tape (blue 3M) and I found that I need to set the extruder temperature to 205 to get the first layer to stick more reliably. I'm thinking that extruding at 190C would reduce ooze but it doesn't stick to the tape very well.

Thanks I will try your suggestion.

At what value did you set the e0_steps_per_mm in the firmware? Are you be able to share your configuration files?

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reprapworld.com
PLA, ABS, PETG multiple colors (3 and 1.75 mm) €16,49 / kg
Megatronics 3.0 €79.99 / Minitronics €37,19

It's the default value for Adrian's geared extruder: 2.2. Don't have time to upload now so I'll do it later. Meanwhile, here are the important ones:

Speed:
feed rate 30
flow rate 60
travel feed rate 50

Dimension:
Extruder Retraction Speed: 300.0 mm/s
Retraction distance: 85 mm
Restart Extra Distance: 5.0 mm

Seems like a lot of retraction but it gives reasonably little ooze and it extrudes well at start of a line/polygon. The speed is the same as the default in the Reprap host. I went conservative with the feed rate and then adjusted the flow rate using the hexagon example. I'm using this for work and I'm happy with the quality of the prints which I'm not embarassed to compare to one produced on a commercial printer.

After two weeks of tweaking, I seem to have achieved much better results. I was having multiple problems at ones, making it a running target.

Most importantly, the Y-axis has been a pain. The pulley would come lose after a few prints. Some glue fixed that.

Also my lack of knowledge of skeinforge made it difficult. The terminology used in skeinforge is not familiar to me, but after testrun #100, most settings and definitions are quite clear.

So thanks for your help, I have some pictures of my current output:

Picture 1

Picture 2

Picture 3

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reprapworld.com
PLA, ABS, PETG multiple colors (3 and 1.75 mm) €16,49 / kg
Megatronics 3.0 €79.99 / Minitronics €37,19

You might be printing too fast. Since you're only printing one small piece, you may be laying the next layer down while the previous layer is still too soft. Try slowing it down by turning on "Activating Cool" in the "cool" tab and setting it to "Slow Down" with a minimul layer time around 30-60 seconds.