Saturday, October 13, 2012

The new black

Ever since I heard about 3D-printing many years ago it has been in my mind that someday I would join the wave.

Now it is time for exploring the posibillities of 3D-printing.

I have spent a few hours on the net studying several designs but most of them fails because they are build using 3d-printed components. Chicken and egg problem.

Yes I could go to Ebay and buy a kit but ...

Then I found this Mendel90 design that uses mdf for the basic structure plus (again) lots of 3D-printed plastic parts.By studying the design I soon found out that all the parts can easily be replaced by either wood- or metal-parts.

Basically a 3D-printer is a glue-gun that can be moved in three dimensions so the first challenge is to build a structure for that. The same challenges as for my CNC-machines stable structures with precise movements of a tool..

Here is the very first mockup for my first 3D-printer. A simple T-shabe from two sheets of plywood.

In front of the vertical sheet is some of the parts I will use for the vertical movement of the glue-gun, extruder in 3D-language.

The plywood-sheets is held together with this ingenious "Ikea" screw and nut.
In german the bolt and nut is called "Quermutterbolzen und Rundmuttern". It took me quite a while to find out :-)

Can it be used for miniatures? Maybe.....

3D-printed Queen Anne Chairs in 1:48 scale.

More to come.

Wednesday, October 3, 2012

Hinges (Nightmare)

It is hard to get small hinges in the right size or shape. When I started making miniatures I bought a lot of hinges from several sources because then I just could go to my hinges drawer and select the right hinge for the piece I was working on. Reality is another story :-)

Below is a mockup to see how the hinge fit in the current project. To the right is the smallest hinge I had in my stock and I didn't like it. The hinge is too large.

So I had to make my own. First I draw the hinge parts in the right dimensions and then cut the parts from a piece of  0.1mm brass-sheet using my cnc.  That was an expensive experience because I broke a milling-cutter in the first try. But I made a hinge in the right size.

The hinges was then made using the photo etch technique. Here comes the nightmare :-)
The first sheet I etched from the same 0.1mm brass sheet had parts for 96 hinges but after etching and trying to assemble the first hinge I discovered that the brass was too thin. When opening and closing the hinge it just fall apart. Then I tried etching 0.2mm brass using the same layout.
Doubling the thichness to etch also doubles the etching time and that gives problems with socalled underetching and I haven't thougt about that. So back to the drawing board and after a few more trial and errors I managed to make this sheet of hinge parts.

For assembling the hinges I made this needle nose pliers. It is ground from a cheap fleamarket find (don't take the best from the toolbox).

5 hinges before next step

To ensure that the pin stays in place I decided to solder the pin in place.
Why not glue? Because glue is hard to control in small spaces and can easily make the hinge unusable.
For soldering I use solderpaste normally used for soldering small electronics. The solderpaste contains flux and pewter and can be applied very acurately in small amounts. I got mine from ebay and despite the small container says something about a shelf life of 6 months and cool storage it works well after about two years in a drawer.

Here is some solderpaste on a bottlecap (diameter 28mm) Half of the paste that the red arrow points to is placed on the hinge.

The hinge is placed on a heat resistent surface.
The hinge is heated a few seconds with a heat blower.
Solderpaste before heating
Solderpaste after heating. The solder flows nicely into the hinge,
After the other end of the pin is cut off  the hinge is ready for use.

Have fun