This is part of a two-Instructable project on outie (or reversible headphones). The main Instructable can be found here. If you have no interest in headphones but all the interest in parametric wood lamination, my hope is this one can stand alone.

Wood lamination is a fairly messy process. It is difficult to create pieces with critical dimensions, where the functionality is lost if those dimensions aren't met. The end result of the lamination is only as good as the mold/jig you create for it. And if you want to vary the final form even a little bit, you have to create an entirely new mold, usually by hand.

I wanted to explore automatic generation of wood lamination mold and profiles from a parametric 3D model of the finished product. For this I needed:
  • 3D model of the finished product based on critical dimensions (essentially head size for a headphone)
  • 3D model of the mold and wood lamination sheet, automatically generated from finished product

Once I have these, I can:
  • automatically generate cut files for ShopBot and laser cutter for a particular design
  • ensure laminated piece holds to the intended critical dimensions
  • change the critical dimensions in the model for a different head, and automagically generate new molds and profile cut files

The intent is that by going through this process for a simple part, I could gain insight on the process of "automated" wood lamination creation that would later enable me to apply generative art concepts to wood laminates.

Step 1: Headband CAD: robust modeling discussion

In parametric CAD packages (Autodesk Inventor, Solidworks, ProE), making basic models can be a fairly straightforward process. However, making robust models can be much trickier, even for the same shape. If you've ever built something without thinking about it too much, then wanted to go back and make changes, you've probably experienced the pain of spending waaaaaay too much time making the simplest changes. Usually this is because you didn't design your project to be changeable: you made design decisions that were optimized for speed, cost, etc instead. You can do the same thing with modeling. I think of a robust parametric model as one that is easily changed without needing to constantly fix broken parts of the model.

There are many methodologies and best practices for creating robust parametric models. Most focus on the way you create references between your features, since references are the most common thing to break when changing models. The form of a headphone headband can be almost completely described by 2 perpendicular drawings (one from the front view and one from the side). The strategy we'll take is to create 2 base drawings that every feature references directly. This way, whenever we want to change the model, we only have to change the 2 base drawings to update every feature, rather than update every single feature manually.
<p>I would even suggest using just one model for robust assembly design (particularly with AutoDesk Inventor). Model your headphones in one part file, then create new solids as needed for the molds (within that same part)- as you create them you can project geometry from the headphone geometry and Inventor actually works well projecting within the same part file. </p><p>When you get all of your pieces modeled in that one part file, use the Make Components command and you can create a new part from each solid and even place them in an assembly when you execute the command. The parts remain associated to the original part file so that also allows you to make the modifications you want in the original file, and the parts in the assembly will update. It works really well for relationships between holes in parts in an assembly and any other interactions that typically require modifying multiple parts or tying them all to an empty skeleton file or linking them all to a spreadsheet or some other process that doesn't work as well as a single part &quot;assembly&quot;.</p>
<p>Totally agreed! That's how this one was done :)</p>
<p>Sorry, I thought I saw you say two models : P</p>
knockoff beats
Another reason to build my own CNC router. Tremendous learning tool, this instructable!
You killed it, love the future work ideas
pretty cool bro
Awesome job. <br> <br>

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Bio: I tend to have too much energy, so I try to do everything so I can sleep at night.
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