idea for DIY laminated (lom) ceramic insulator

Hi,

While reading thru all the search results on "ceramic" for my ceramic reprap project I was thinking about a method for producing an insulator with laminated object manufacturing.
To be honest, I have no real idea what this insulator would need to look like since I am new here, do not own a reprap yet and I am a bit to lazy to dig true all the documentation to search for the part although I did for 15 min.
But here's the idea, I have some experience with a ceramic green sheet material called Keralfex [kerafol.de]〈=en
You can cut and shape this material by hand in a very easy manner and they also supply a slurry to glue various components together. It is available in 0.5 and 1mm thick sheets (before firing). After firing (and it stinks big time) you get a solid porcelain object. If the insulator is a tube form you could just roll a sheet with slurry in between the layers. But when it is a slightly more complex shape you could build up the object from hand cut profiles laminated together. Due to the shrinkage when firing it is important to know the tolerance of the part, a very precise and fitting part is definitely harder to make.
I have all of the material available here in the studio to do some tests, is this an idea worth trying? If positive, can somebody point me to the specifications for an insulator (stl file?) and I'll give a try at it. I can send the finished part to anyone who wants to test.

Edited 1 time(s). Last edit at 02/07/2009 01:33PM by unfold.

added some photos of keraflex.

One shows various tests done at FabLab with the Epilog laser, both cutting and engraving. This is pre-baking aka green state on top of a alumina firing plate.
The other shows two examples of lightly bend laminated objects after baking. Two layers glued together with slurry.

Hi unfold,

i did some lom-fabbing with lasercut-steelfoil (see here: [forums.reprap.org]) and knife-cutted ceramic green sheets (from DuPont chemical) for developing and manufacturing microsensors - or search for "viktor laminated" in "all dates" ...

It's a very good method for high-precision-fabbing too when you repeat the steps:
1-cutting contours
2-slurry-laminating next layer
...back to 1 ... until your object is ready.

My smallest samples from ceramic green were 4-layered elements with 0,3mm sheet-thickness and embedded gold-wires and -vias in overall size of 3x0.8x1.2mm (LxWxH) with wires and pads of 0,2mm with and nearly 0,01mm acuracy.

For home-fabbing you can reduce the accuracy to 0.05mm without much problems - my CNC-mill has 0.012mm with halfstep-drivers (but i have some microstepping drivers too when in need for some higher accuracies )

So you'll receive XY-contouring-resolution with the capabilities of your machine and in Z/height of the thickness of your sheets.

For cutting the ceramics (or thin plastic-foils too) i worked with 0,3mm-millheads with my CNC-mill or with a fibercoupled diode-laser with a 0,06mm focus and 1 Watt output-power - both worked very fine

My only actual problem is lack of an appropriate software for cutting an STL-file in the right horizontal sheets or cylindric representations for 'lathe'-lom-fabbing on a rotating axis ...

Viktor

Edited 1 time(s). Last edit at 02/08/2009 05:06PM by Viktor.

Hi Viktor,

Sounds good! Can't you use the reprap software to make the horizontal slices. There's a step in the workflow that does the slicing no? There's also a lot of CAD software that can do slicing, you only would have to rearrange the slices on the same plane for cutting. I would love to try making a usefull part in this technique but have no idea where to look for a suitable part. Guess I'll just make something unusefull
The laser cut green tape tests are in the kiln at the moment, wondering what comes out.

Hi unfold,

i have some CAD's capable of slicing and STL-output, what's working for single-count sheets with manually rearranging the slices.

My problem are highres-objects wits some houndreds slices what's not possible for maually intervention anymore or 'lathe-LOM' with cylindrical slicing/projection.

As i didn't have the reprap-electronics but a more than capble CNC-setup i want to make this with my CNC - here i have to program a converter or some special PP's for aditive fabbing instead of subtractive milling ...

Viktor

Hi Viktor,
Are you doing the laminating itself by hand?

Hi unfold,

... yes low count slices - look here: [builders.reprap.org] for my first approach with my CNC-mill at home.

The steel-lom ( [forums.reprap.org] ) was press-fitting with the "H"-shaped structure and assembled manually - the 'ceramic green' too.

For multi-counts there should be an automated laminating process or simply a transfer from one roll to another as in 'lathe-LOM' with laser-cutting the contours ...

Viktor

Nice, so you glue the uncut material on top of the previous cut layers and then you cut. Laser cut green sheet came razor sharp out of the kils. Yeah for the lazerrr!
Engravings where to low power. Next session will be deeper engraving and lom fabbing.

Hi unfold,

i engraved the ceramic green from DuPont with a 0,3mm millhead (cylindric, two-edged hardalloy, designed for milling PCB and CFK) at 22000 rpm what made excellent results too.

With thin millheads you should have very high rpm's - my actuall mill is capable of 25000 rpm and comercial millheads turn over 50000.

The green sheet is elastic like plastic but brittle when bent over a sharp edge, so it's an ideal material for milling. But you have to vacuum the dust or it will contaminate your working area ...

Viktor

One quick visit to a ceramic atelier and you can see what that dust does in the long run
Is the Dupont green sheet more shapable when you soak it in water? Keraflex is brittle but bends very well when wet.

Attached image of test after firing (twice by accident)

For those of you who are interested in Keraflex, please see www.keraflex.us