Open Source Electronics Box

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The_ID_of_Ed
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Open Source Electronics Box

Postby The_ID_of_Ed » Sat Aug 10, 2019 2:28 am

This a small Open Source Electronics Box that could be used for any sort of project such as a controller box for a 3D printer, home made power supply, scientific instrument. The project only concerns the electronics box / chassis / cabinet itself. I don’t go into any detail on my particular build of the electronics for my stepper driver system. The motivation was for a control box, which is to help troubleshoot an old all electromechanical calculator repair project.

Image

All of the files are free to download from my Thingiverse account.

https://www.thingiverse.com/The_ID_of_Ed/about

The Open Source Electronics Box files are at:

https://www.thingiverse.com/thing:3800795

I have a video also explaining my project box and its build including the sheet metal work on my YouTube Channel – The ID of Ed.

https://youtu.be/il0gmMonz00

phpBB [video]


To help in the possibility of an open source project I’ve also included the FreeCAD files that generated all the 3D print and G code files.

The Version of FreeCAD that made the Control Box files:

OS: Ubuntu 16.04.6 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16093 (Git)
Build type: Release
Branch: releases/FreeCAD-0-18
Python version: 2.7.12
Qt version: 4.8.7
Locale: English/UnitedStates (en_US)


The assembly files use the Assembly 2 workbench module

The assembly for the generic box is: Control Box – blank.FCStd

Image

This is the most striped down design with no holes or features for any specific project application. This would be the most likely starting point for folks to start their own control box project. The following files makeup the four parts of the generic blank Control Box.

Control Box Front Panel – Blank.FCStd
Control Box Front Panel – Blank.stl

This FreeCAD or 3D print file is the most basic front bezel part of the basic box. There are no control, display or vent features. Its a simple blank slate for a new project box. Be sure to orient the 3D print with the front face down on the print bed, the upper overhanging parts have good angles to print cleanly with no filament drooping. The screw holes will need to be taped for 6-32 nearest metric size.

Control Box Back Panel – Blank.FCStd
Control Box Back Panel - Blank.stl

This version of the back panel is also a simple blank, ready to be modified for a new project.

The next group of files deal with the sheet metal part that ties the front and back panels together and forms the overall chassis of the box.

Cover C section.FCStd
Cover C section Flat PDF Hand drill template.FCStd
Bottom & Short Side Sheet metal chassis Hand Drill & Fold Template.pdf
Long Side & Short Top Sheet metal chassis Hand Drill & Fold Template.pdf

The first of the chassis files is the original FreeCAD file and it uses the sheet metal workbench module that will likely need to be installed from the addon manager if you want to modify it in FreeCAD. The next file is the sheet metal part flattened and used the newer TechDraw workbench to show part dimensions and to make the PDF files to print out the drill and cut paper templates. For the basic generic box version the sheet metal section 7.25” long so the part will at least print on a normal 8.5” X 11” sheet. Its still necessary to print 2 sheets and tape them together to get a full size template for the long fold axis direction. The blank box doesn't have a CNC G code version, use the populated project box version if you want to go with that method and note that its 1” longer. If you plan to do the series of small holes along the fold edges using the paper template and hand drilling, the idea is to space evenly between the bend radius lines depicted in the PDF sheets. The pitch spacing is up to the individual, how much labor verses ease of binding benefit. If you watch my video will can get a feel that at the pitch I used the folding process is quite easy.

The next batch of files deal with the removable sheet metal cover for the blank box

Removable side.FCStd
Top Side Cover Flat Drawing Hand drill template.FCStd
Top & Side Cover Side Hand Drill & Fold Template.pdf

Additional files for the front & rear panels with a few extra features…

Control Box Front Panel - LCD Power Switch & Vents Only.FCStd
Control Box Front Panel - LCD Power Switch & Vents Only.stl
Control Box Back Panel - Vents Only.FCStd
Control Box Back Panel - Vents Only.stl

The above is a versions of the front & rear panels have some cutouts for a LCD, a power switch and some air vents. Not shown in the basic assembly file.


The next section deals with all the files that went into my particular project including mockup parts for trial fitting of the box with components to help in its overall layout.

The assembly file for my presented build project is.

Control Box - Stepper Motor Components.FCStd

Image

Image

This is the assembly of the project I built for doing tests on my Mechanical Calculator project. This file in FreeCAD has simplistic models of components used to test fit the assembly design. The internal components are not meant to be actually 3D printed and are simply provided as an illustration of how the CAD software is able to be used for evaluating design ideas.

Control Box Front Panel - Stepper Motor Controls.FCStd
Control Box Front Panel - Stepper Motor Controls.stl

These files are for the front panel version I made for my particular project and has all the component holes. Be sure to orient the 3D print with the front face down on the print bed, the upper overhanging parts have good angles to print cleanly with no filament drooping. This file would always crash Repetier-Host so I had to use my standby for troublesome files of Cura, which worked just fine. Would be interested to know if anyone has any ideas as to why.

Control Box Back Panel - Stepper Plugs Fan.FCStd
Control Box Back Panel - Stepper Plugs.stl

These files make the back panel for my project build. If you happen to have the need, and the components to populate, its generic enough to use as is.

On to the sheet metal cabinet parts…

Cover C section Component holes.FCStd
Cover C section Component Flat fold holes.FCStd
Cover C section with components CNC fold holes1.cnc

The above files deal with the sheet metal part that forms the the majority of the cabinet chassis. The second FreeCAD file is the version that has been flattened and uses the G code workbench module called Path. The last file is the resulting G code for a CNC machine tool to drill a heck of a lot of holes to aid in the folding of the sheet metal and for mount holes. I used a .081” drill bit for all and opened up the various mount holes afterwards on the drill press to avoid doing a tool change on the CNC. The G code is written for Linux CNC. Path as other post processors for other machines. I’m new to the FreeCAD tool path generator and I had a bit of a learning curve from the other G code generators I’m use to. So I freely admit the peck cycle I used is very non optimal. My home brewed CNC is a bit flimsy and a generous peck cycle seemed needed to help it drill into sheet metal.

Next the removable cover….

Removable side 8.25L.FCStd
Removable side Flat CNC Drill fold holes.FCStd
Removable side Flat CNC Drill fold holes.cnc

Same story as the files for the main chassis sheet metal but just for the removable side.

Next are the mockup parts that are inside the assembled model. These are just for reference use and are not meant for any printing. Just for fit and assembly checks.

Power Supply 24V.FCStd

Just a very crude model for the power supply used in my project.

Stepper Driver CMD-50.FCStd

Simple model of a stepper control module I had laying around

Sharp LM20A21 LCD.FCStd
LM20A21 LCD boad Layout.jpg

Simple model of a LCD I had laying around. It may be possible to still buy these…..
I also include a JPG for reference if you happen to have one.

Fan 24V 80X80mm.FCStd

This model of a cooling fan is straight from the McMaster Carr web catalog. All I did was download their Step model. So if you need to model a part that your going to buy, McMaster is great for that.

Fuse Holder 15A 125V AC.FCStd

Classsic fuse holder.

PC HD Power Socket.FCStd

Simple model of the type of power plugs used for old CD, Floppy and Hard Drives. I used them for the power output to my stepper motor.

Power entry socket.FCStd

Scraped out PC bulkhead power entry plug. This one was a has some filter components and thus why its a bit longer that a simpler socket. Just what I had around, not really necessary.
Attachments
Stepper Controll Box Assembly no Cover.png
Stepper Controll Box Assembly no Cover.png (58.36 KiB) Viewed 1656 times
Stepper Controll Box Assembly with Cover.png
Stepper Controll Box Assembly with Cover.png (26.82 KiB) Viewed 1656 times
Blank Controll Box Assembly with Cover.png
Blank Controll Box Assembly with Cover.png (12.6 KiB) Viewed 1656 times
Finnished Stepper controll box - front .JPG
Control box to help troubleshoot an old electromechanical calculator
Finnished Stepper controll box - front .JPG (262.06 KiB) Viewed 1656 times
User avatar
HarryGeier
Posts: 1155
Joined: Mon Jul 10, 2017 12:36 pm
Location: Hof Germany

Re: Open Source Electronics Box

Postby HarryGeier » Mon Aug 12, 2019 7:28 am

Quite nice, will look at it deeper on a next project where it can be used.
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