I have done a few PCBs using the reflow process. To apply the solder-paste using a stencil one requires some sort of fixture to hold the PCB.
So far I helped myself with other PCB Material which I glued on the table to get to the same height. This is okay when only one PCB needs to be made. However, when doing multiple PCBs on after another, the position needs to be constant for every board.
So I designed a simple spring loaded fixture to hold the PCB in place. Its made out of 1.5mm acrylic.
I noticed decreasing performance with my Co2-Laser Cutter. After a short investigation I found one of the mirrors to look like this:
Thats not looking to good, seems like the laser actually damaged the mirror.
Fortunately its not dead center, so I just rotated the mirror a little. Problem solved (for now).
That is how my new HW-0.30-mini Quadcopter Flightcontrol looked prior to the repair:
Since a few of the Pads already were delaminated I decided to do a repair instead of soldering in a new CPU. For a repair I would need to get rid of the expoxy mold to directly acces the pins of the leadframe. Initially I was thinking of using a ‘dreml’ tool to remove the exoxy, but watching the Uncaging Microchips talk at 31C3 taught me that using a CO2-Laser will also work.
Those pictures were taken during the laser-removal:
After lasering, all left to do was attach new wires. I did use a microscope for that. For scale, the wire running on top of the CPU has a 0.3mm diameter.
I ran some quick tests with the software to make sure the repair worked. Then a blob of hotmelt was applied to secure and protect the repaired pins:
Backstory: I am also responsible for breaking the pins. I did solder the CPU at 31C3 without proper lighting using borrowed equipment. The temperature on the soldering iron was set to 450°C, I failed to check that. This lead to some major fuckup. Since I wanted to work with the board, the decision was made to simply cut of the broken pins. At the time I didnt need them.
Recently I bought a 2-Player Starterdeck for the “My Litte Pony” CCG. One of the aspects of the game is managing you ActionsPoints.
The StarterBox did include some counters/tokens made from thin cartboard, but those are not easy to use. I also tried using dice to keep track of the actionpoints, but thats also not optimal.
Thats why I decided to create some tokens:
The material I used is Perspex (color-codes 2TL2 and 4TL1) in 3mm thickness.
The Design is based on My Little Pony Printable Cutie Marks which can be found on Thingiverse. I did some small modifications. The butterfly had some parts which were to small to lasercut; I enlarged those.
You can download the modified .eps files here: MLP.CCG.Tokens
I bought my el-cheapo chinese lasercutter without a pilot laser. They did offer a visible laser for alingment, but that was just a simple laser-pointer mounted next to the main-laser-nozzle. It was kind of expensive (despite the fact that it was a really simple non-coaxial-design) so i decided to build my own.
From ebay i got two laser-modules in a cylindrical housing for about 21€ including shipping which already produce a line (they have a prism build in).
IÂ order to mount them i designed and build a bracket out of 12mm acrylic. Basically its a ring with a slot, i can slide it up the nozzle and fix its positin by tightening a screw. You can see how it looks mounted to the machine in the first picture.
Unfortunately i wasnt able to mount it further down on the nozzle. Now the laser angle is to steep and part of the laser is blocked by the nozzle itself (you can see the laser on the nozzle in the second picture). I managed to adjust it in a way that at least the pilot lasers cross in one point. Alignment in parallel to the working area required a little patience, but somehow i managed:
As a last job i wired everything up and slid the cables through the drag-chain. Since i was already soldering and installing additional wires, i also added two LED-Stripes to the portal to have better illumination while working.
Everyone who has been to a gaming convention/fair has probably seen chessex or q-workshop selling blank dice. I always wanted to use those blanks to create my own dice. Since I now own a lasercutter the time has come to finally manufacture some 😀
I used 16x16x16mm blanks which i got at this years RPC in Cologne. My lasercutter does not have any fixtures, rulers or clamping devices, so I needed to make my own. My simple fixture is a piece of 5mm HDF with a 16mm square cut out at an absoulte position. This allows me to align any futher engraving to those absolute coordinates.
After engraving the only thing left to do was to add some contrast. I used black acrylic paint to cover the engraving. Its quite hard to apply the paint only to the engraved areas, so I decided to rub the paint into the engraved area and remove excess paint after waiting a few minutes for it to dry.
I think it worked quite well 🙂
Now i am looking forward to create one custom dice for each player of my RPG group with a symbol matching their char.
I made this for my niece (currently 16months).
Its made of 5mm HDF wood. I did a google-image-search to find suitable pictures and traced them in Vcarve.
The text and the DIN-Label-Box in the lower right were exported from eagle. I was to lazy to draw them myself.
In the first version i just cut along the vectors which resulted in a really tight fit. The gear was almost impossible to remove and put in again. For the second version i duplicated the lines with an offset of 0.3mm which did result in a larger gap. Now all the parts fall out by themselfes if you turn the puzzle around.
The two sheets were glued together with basic wood-glue. The lower sheet also features ‘eject-holes’ (you can see them under the ruler and nut). That way you can push out the pieces from behind.
