Cookie cutter type of prints... HELP

[canadadrones 1]

Hi guys, have to say I love my Ultimaker 2 and I love Cura (even if I run everything through Netfab first)

So here is my problem... printing files from other users always produce expected results ( I now have an Olson block for nozzle quick change and better thermal qualities)

No under / over extrusions, prints really good speed (need to rerun the speed cylinder test since new nozzle system)

Temperature for PLA good results 190C all the way to 235C ... (I know it's hot)

So my printer is well calibrated and prints well we can establish that.

Now my problem... I am using Rhino 5.0 latest (paid! yes yes) to design simple cookie cutters...

the technique is "simple" I draw a curve, get it doubled and extruded and all so it becomes a mesh that represent the cookie cutter...

The issue is I think on the slicer... or the setting I am using... I need help

Sample file is here, it's a "B" letter

https://dl.dropboxusercontent.com/u/12604183/Letter_B_cookie_cutter.stl

This is the non-repaired STL (it doesn't fix anything on the print if I repair or not in netfab)

when I print it the Ultimaker skip all over the place instead of doing a smooth layer... hard to explain but it's like 1 layer every 2 or 3 layers is just random dots...

results is a lot of garbage on the side of the print that needs to be removed...

Even if I create a plain circle and extrude it for the cookie cutter it will not just spiral down in circle to print it...

So could be the mesh or the slicer that doesn't like my mesh... anyone can help?

Edited June 9, 2015 by Guest

[IRobertI 520]

There is nothing wrong with your model. The problem you're running into is cura trying to fill in teensy tiny areas where it thinks you need infill. This is why you always want to check the layer view (click the button in the top right corner of the 3d view).

The red lines are the "shells" of your print, the outer contours. The tiny yellow dots is the infill and the blue lines are rapid moves that the head will make.

In this case, simply setting infill to 0% will "fix" your issue since the base of the print is thin enough to become solid with the top/bottom layers.

I wrote a few more notes about this here:

http://support.3dverkstan.se/article/30-getting-better-prints#solid-layer-fill

Edited June 9, 2015 by Guest

[canadadrones 1]

AMAZING Robert (as usual!!)

The ZERO infill fixed the jumping around while printing layers but on the last layer there is again strange "spot filling" ... my model should be flat at that point as I was playing with taper edges earlier and did not really produce good results (have to retry as it could be related to the infill too) but that B letter STL file had a flat "top"/final layer so I do not understand why CURA slice it like this

Let me know if you need to see more parameters...

And again, thanks a lot this is really good help and very appreciated!

[IRobertI 520]

I think that's just cura trying to do its best to produce the very thin wall you're requesting (I didn't actually measure how thin they are at the top, but they look very thin). Try fattening up the wall to 0.5mm at the top and see how that goes.

[canadadrones 1]

I am actually trying to make it tapper as it should be "sharp" to cut the cookie dough or cake fondant. the 2 "shells" wide is good but could benefit of having it sharper at the top.

Do you have any experience on how I can make it sharp? If I could have 1mm of 1 shell thickness in between the 2 shells walls it would be so nice. Do you think I am pushing too hard on the resolution? I have printed some stress test models that have very sharp pointy ends so I am confident it can be done. I just don't know how to model it...

[xisle 34]

Using 0.4mm shell in Cura and 0.8/0.5mm walls in Rhino, I was able to get a slightly thinner upper section to print. I did not get the same results with 0.4mm walls.

This is how I did it..

[canadadrones 1]

Guys that is helping a lot... I am trying to program the .5mm top layer in my Rhino script now (as I try to make this transformation happen from curve to cookie cutters.

So for the prints are way better! it's great.

Thanks a lot