sub 3g 3d-printed tiny whoop frame

There are many 3d models of tiny whoop frames available at thingiverse.com but they are rather heavy  (about 5-7g).

Common PLA and ABS plastics are brittle when parts are bulk, but much more flexible when thickness is smaller than 0.5 mm.

This is an attempt to 3d print custom tiny whoop frame with weight similar to commercially available well-known frames like Indictrix, Eachine or BladeFpv. The idea is to make thickness thin enough to withstand stresses with flexibility (elasticity).

If we try to make a g-code with slicer and will use default (auto) settings for extrusion width, or “common sense” settings equal to nozzle diameter, we will see “holes” (not printable areas) if thickness of the model is close to the nozzle diameter. Here is an example:

The model is a set of walls with the thickness of 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1.0 mm.

 

linewidth.png

And here is a result of 3d printing (0.4 mm nozzle) in dependence on extrusion width (0.19 mm, 0.29mm, 0.33 mm, 0.39 mm, “auto” (from left to right)):

P1080454.JPG

Minimum possible wall thickness we can print with “auto” settings of the extrusion width is 0.5 mm (the model), actual thickness will be even thicker.

In contrast, with 0.19 mm extrusion width we can print 0.2 mm walls (though nozzle diameter is 0.4 mm). It does not mean that actual thickness will be equal to 0.2 mm, but slicer can produce g-code without non-printable areas and wall thickness is significantly thinner than default settings. Moreover, playing with the extrusion width we can change thickness of the wall even if the wall is printed with single line.

Here is a video:

 

Finally, I was able to print sub 3g frame, and other parts to have weight compatible to commercially available best frames. May be it is not very practical if “standard” tiny whoop is to be built, but opens a way to produce custom frames with desired motor/type/propeller size.

Few more tips:

  1. Print in 1 line thickness, vary extrusion width to get desired thickness.
  2. Include support structures in the model, typically, slicer cannot do it well for such delicate printing
  3. Do not try to reduce temperature of the extruder, or use extra fans, as we usually do when are trying to print detailed models. Indeed, it can produce more details but makes inter-layer adhesion weaker. With single line printing, adhesion is more important than more details.
  4. Make layers along stress direction. That is why the battery holder is printed “vertically”.

 

Experimentally I found that the best results I can get if extrusion width is set to 0.24 mm for all parts but battery holder, which has 0.33 mm extrusion width. Technically it is possible to print even thinner and lightweight frames, but to me they are not strong enough.

The  STL model is available at:

https://www.thingiverse.com/thing:2731056

 

 

 

 

 

 

 

 

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