DIY edge finder
Touching off easily
I just received a second order for AnywhereAmps Alpha. My initial prototype already has a new home, so I’ll be building at least three more copies. All the woodworks done by hand would take 4-5h for each copy, so I decided I want to limit the woodworking stuff to the actual building-it-together process that - hopefully - only takes an hour. I’d like to achieve this by having the custom wood parts milled with a computerized numerical control (CNC) machine.
Such a machine wouldn’t eat the plans I scetched by hand. So I have to familiarize myself with software that is able to transform 2D scetches into a 3D model, and finally another tool to translate the components of the 3D model into paths for the CNC machine to cut my parts. I chose the FreeCAD software to do the 3D work.
But FreeCAD… well, I’ll admit that I’m not a CAD designer or mechanical engineer. But still, this tool is hard to get started with. Luckily, there are some quite good tutorials out there like this: youtube link but to be warned, I needed a couple of hours before I had drawn my first part. Plus, what you can see on the image on the right is still a long way before I was done.
FreeCAD will not tell you how to best work with it. It is a very versatile tool that fulfils many purposes. As I want to use it for drawing 3D parts and/or for G-code generation, I’ll only need a handful of its workbenches.
Of course, the following lines cannot be more than a quick start guide. There are tons of helpful materials out there like a FreeCad wiki, a forum, and many, many tutorial videos etc. at your hands that explain things better and in more detail than I can ;)
Let’s create a central place where we keep all our project’s dimensions. We’ll link them in the drawings, 3D models, and assemblies later so that changing values in the spreadsheet will automatically propagate.
part_description_attributenaming convention for every dimension.
dimensionNameyou entered before
It’s time to create a first sketch of your part using the dimensions you just created. You’ll be drawing so-called master scetches fist which contain all elements of a drawing at a specific view, e.g. on the XY-plane.
masterones, I propose to name them
=or press the tiny round
fxbutton. Enter the name of your spreadsheet (there is auto-completion, luckily) and then the alias of the dimension you want to constraint to reflect.
With your completed master sketches (one each for every dimension), all information is available for any third party service to mill your parts. If you wanted to do that, you could export your sketches to a
dxf file here and you’d be done.
Else: please continue reading.
To create an actual 3D part from your master sketches, you’ll have to create derivative sketches that can be extrudes or cutouts. You’ll have to understand FreeCAD’s way of tree-aligning parts and scetches first: Every pad has an underlying scetch that defines how it looks like. Its extruding direction directly depends on the sketch’s plane. Each part can have one or more datum planes where other parts can be attached to, again forming pads, holes, or pockets on that specific face.
FreeCAD will only display the “last” member of your part’s tree, containing all dependant parts you designed before. To toggle visibility, simply hit the space key.
pad, i.e. your actual 3D part.
create an edge linked to an external geometrytool (hotkey
X) and select the basic pad of your originating master sketch.
pad a selected sketchicon and enter your dimensions.
Hm, your new pad sits right on the master scetch so you cannot see them any more? Don’t panic, just continue reading.
In my opinion, it’s a pain to rearrange parts in the Parts Design workbench. It’s getting much easier if you use the “Draft” workbench for this task. You can clone parts easily here as well and arrange them as you deem fit.
A move consists of two steps: first you have to enter the reference location for your move. Either select the point by clicking somewhere in the 3D view and then moveing the cursor a bit (my recommendation) or enter the reference in the fields on the left, confirming each axis with
Second, is the actual move vs your reference point. I recommend to enter those values using your keyboard because it’s incredibly hard to move to an exact location using the mouse.
Enter, and the move should be complete.
Cool, you now have a dimensions sheet, master sketches that fully specify your parts, the parts themselves as 3D bodies and all properly that’s neatly sorted in your view!
Now, maybe you want to export classic 2D drawings of your part? Luckily, that’s an easy task!
Insert default pageicon.
Insert multiple views of drawable object(s)icon and select the views you want to be present.
turn view frames on/offif vertices overlap your geometries, so you can select them again.
The resulting document might look like this:
Further information regarding TechDraw workbench can be found in the FreeCAD Wiki.
Touching off easily
Strategy and how to
engrave and cut
the struggle to successful builds
Faster Engrave Algo
for CNC: Decision aid
Decision aid, Pros & Cons
3D signs - tutorial
Job preparation and quick demo
of an audio amplifier
From investigation to problem solution
From Pixel to Vector graphics
Symptoms of insufficient spindle power
Beginner CNC issue: Speeds/Feeds
Automatic Z-referencing, Tool length, Tool changes
EdingCNC Settings & Variables
Software/Hardware setup & kinematics
Assembling Sorotec’s Basicline 0607
Switch box setup
Entry-point and questions
Circuit & Application examples
USB-PD power supply explained
Can I use a Metabo/CAS battery for my system?
How to set protective voltage & current limits
Current inrush limiters explained
Electronics knowledge: TVS diodes
Or how to kill your circuits
How to properly talk to VideoLan’s VLC player
Prototype build, issues, improvement ideas for Revision2
How To: First steps with FreeCAD
Professionalizing circuits for AnywhereAmps
AnywhereAmp Alpha’s simple single-supply preamp
Design, folding, stability, amplifiers
Evolving the mobile, foldable instrument combo
Fix ‘ERROR: favicon not found’
Export the instructions from Markdown to PDF! but how?
Why some images display OK locally but won’t on Github
How to make ToC sticky
How to solve issues with disappearing posts
Configure: landing page’s header image, Navigation