buildung small objects with Geeetech I3 Pro B

[kaestnerw]

I am working with a I3 Pro B since 2 years. I have printed various things like cabinets for elektronics, text, holders for LED....
I am using Verbatim ABS (with 3DLAC for parts which may get hot in the sun) and Verbatim PLA
I am using a nozzle with 0,4 mm, layerhight is 0,25 mm, temp nozzle 230 Grad Temp. bed 60 Grad

One cause why I started with 3d-printing was my model train where I need sometimes spareparts for replacement. And there are the problems at the moment.these parts are small and difficult.
I am using open scad to design my models, then RepetierHost_1_6_0 and Slic3r-1.38.4-prusa3d.
when trying to print some buffers. a buffer for example consits of a cylinder with 5mm diameter, length 0,5 mm, and a cylinder with 2 mm diameter, length 5mm.
the second cylinder makes the problem. the nozzle is going 1 or 2 times around, and then the next layer ist printed - this takes only seconds and therefore the previous layer is still hot and you see what happens - see the picture attached the one buffer on the right side.
therefore I thought I print 2 oder 4 buffers at once -this works the filament is already colder when the nozzle starts to print the next layer, but now I get threads between the buffers. see the problem - see the picture attached the 4 buffers on the left side.

Who has there any advice to these problems:
printing one buffer
threads between the objects
examples for open scad source- buildung a screw, a nut or other example lists to learn how to design things.

[William]

Hello, according to the picture it looks like it was caused by overheating.
Reasons:
1. Insufficient heat dissipation.
2. The printing temperature is too high.
3. Printing speed is too fast
Treatment:
1. Turn on the heat dissipation function during slicing;
2. Properly lower the printing temperature by 5-10 degrees;
3. If the above two solutions do not solve the problem, it means that your printing may be too fast.

[kaestnerw]

Hello William,
thanks for your advice.
I did reduce the temp to first layer 220 and the others at 205 (at first I tried to print with 200 but the printer didnt feed filament anymore so I turned to 205). If I should reduce the temp more, then please give me advice where to set the min. temp. of filament to lower number.
Where to turn on the heat dissipation function, I didnt find in slic3r, but the cooling fan ist set to always on and enable auto cooling, I see that the fan is running all the time.
So the printing turmd to a better result, but the threads between the buffers still remain.
In an artikel about this theme I read that the parameters for retraction should be changed, so I changed
Length to 5, Lift z to 0,7 retraction Speed to 100 but the result remaind not satisfiying - see the foto attached.
the one buffer on the right side is the one printed alone before printing the buffers on the left side.
please could you also proof the version of RepetierHost_1_6_0 and Slic3r-1.38.4-prusa3d are they OK or should I install other versions - if this then where can I get them.
so thanks for your help and sorry for my poor english. greetings from Salzburg Wilhelm

[William]

Hi,try retraction distance 5mm，retraction speed 30-40mm/s.
Is the fan of the cooling nozzle rotating all the time?
You can also increase its speed in the printer control options.

[kaestnerw]

Hello William,
than you for these advice.I changed all 3 things, but the problem still remained.
I found a nother solution: I change the nozzle to 0.2 mm and things turned to useable printings, which I can realy use with my model railway.
thank you Wilhelm

[William]

That's cool!