September 02, 2014

3D printed honeycomb material.

PCH is a new generation of material that I've been working on for several months now.
It is a hybrid material made of glass fiber or carbon fiber laid up on a 3D printed honeycomb structure. What makes the strength of the material is actually the printing material. It is what I call PYCABS: a mix of ballistic grade Polycarbonate and ABS.

http://www.stratasys.com/materials/fdm/pc-abs

The result is a bullet proof material that is both very stiff and shock absorbing.
I am quite proud of this as it is the first time that I come up with something as original and high performance as this. As far as I am aware of, this is unique in the industry.

The advantages of this material are the following:

3D printing allows for extremely complex shapes to be created.
The resulting composite structure is light, stiff and shock absorbing.
The full digital production chain enables a fitting tolerance of 0.2 mm.
The production time is short, and material cost reasonable.

The limitations are the fact that the part size cannot be bigger than the printing bed. In my case: 20 cm by 30 cm.

Here is a video of an AD Diamond door structure printing:

An example of a fairly complex door structure designed by CAD:

And the printed result. The glass fiber layup is on the other side of the door and makes the part quite white:

The door attaches to the main strut with CAD designed clips that conform to both the strut shape and match the door reinforcements. The full digital process allows for a fitting tolerance of 02 mm.

I am finishing the Diamond doors kit with this technique first, then I will carry on to the Scorpion, Super Scorpion and Phoenix

The materials used on the pictures above is PYCABS. I am also working on other materials like:

Carbon fiber reinforced ABS
Carbon fiber reinforced PLA
Carbon fiber reinforced PYCABS
New formulated NOVALAC resin based filament ( NEFCAR )

All these materials are more difficult to print and subject to nozzle clogging ( except for the last one ) but will provide amazing results.

Also for information, the university of Harvard is working on a similar project with slightly different techniques but fairly similar results.

Have a look here:
http://www.seas.harvard.edu/news/201...-of-balsa-wood

The honeycomb pattern is controlled and viewed in 3D before printing. A layer-by-layer view of every part is generated for this purpose.

On the picture above, one can see the first two layers ( in blue ) being offset from the next ones ( in red ) to improve gluing performance of the part.

I am also working with mathematicians whohave implemented new 3D honeycomb generation patterns. These exhibit compressibility resistance in 3 directions instead of 1 direction for classical nomex/ paper honeycomb.

The algorithm used can be tweaked to generate a larger thickness ondulation and thus create 3D honeycomb cells exactly similar on x, y and z axis.