Monday, August 8, 2016

More 3D printer play things

The main reason I wanted a 3D printer was to make parts for some of my other projects.  Now that I have a printer, it is time to see what I can come up with.  I have two versions of the cheap Chinese Frequency Counter boards that have been sitting around for a couple of years.  I had been planning on finding cases for them, but I had not done anything with them yet.  They would be the perfect projects to start with, nice and small, need several mounting posts, and holes in the front or rear for connectors.
I have been playing with several versions of design software, and am now trying the 15 day evaluation version of Cubify Invent.  It is less than $50 and I will probably settle on it after the eval. period.  It is much more like some of the 2D CAD programs I have used before.
First thing I did was layout a front panel with built in bezel for the display and mounting posts for the counter board.  I also added a recessed mounting holes for a BNC connector, and the screws that will hold everything together.
Next I designed the rear panel, it has a recess to reduce the thickness. The recess is high enough to allow a 9-V battery holder to be mounted in this recess. I also put in a through hole for a small rocker switch for system power.  It also has 4 recessed holes that will hold glued in 4-40 x 1/4" stand off.

The last thing I needed was to make a case deep enough to hold everything.  This is a simple shell the size of the panels, with 4 through holes for the 2" screws that hold everything  together. 

After it was put together, everything looked nice.  Some of my dimensions were a little off on the front panel, and I had to ream out the holes a little.  I could touch it up with a little body putty and repaint, but I will leave it as is for now.

The only problem I could see with this design was in laying out a new shell for everything I want to build.  Most of my cases are built from Copper Clad circuit board material soldered together. This works well, but it is a pain to get everything cut straight and fitted. 

 I would like to come up with a way to simplify the process.  I tried several versions of corner piece that would allow the case panels to just slide in slots in the corner piece.  This corner piece also has a through hole that you can use to glue in a threaded standoff for mounting the front and back panels.  These can be printed to the length required, or stacked if you need something larger than the print height of your printer. 

 I also designed a slightly different version of the corner bracket to include a slot for a circuit board to slide into.  This would eliminate the need for using stand offs to mount the circuit board.

I modified the design and printed  the front and back panels to fit the larger frequency counter board. Because of what I wanted to use this counter for I put the hole for the BNC on the back instead of the front.  There are also a couple of small holes in the front panel to allow you to get to two push button switches on the board.  I printed up a set of the corner brackets and cut some circuit board material for the top, bottom, and side panels. 

 I assembled it and am very happy with the way it looks. Here are some pictures before I finished wiring the battery holder. You can see the way the copper clad board panels fit into the corner brackets.  Another one shows the printed mounting posts for the circuit board.  I think using the printed corner brackets will make it much easier to build  cabinets for some of my future projects.  Since they can be stacked there is no limit to the size of enclosure that can be made.

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