Beta Production Update

Several beta wheels have sold so far, and the first two to ship should be ready in the next week. So far, all the orders have been for 71″ and 73″ sizes. I’ve decided to limit LED wheel sizing to 2″ or 5cm increments. This simplifies the number of templates I need to have on hand for layout and casting the LEDs into their mounting strip molds. It also simplifies keeping some backstock of replacement parts. By some coincidence, when using 60LED/meter strips, a 71″ wheel has 71 LEDs per strip per section. 73″ wheels have 73 LEDs/strip/section. Other sizes may not work out the same, as the LED spacing is not completely evenly divided over the length of a section. But it’s an easy way of keeping track of LED counts.

Here’s a simplified outline of the build process:
1) mark out tubing on the CNC with LED holes, bolt holes, mounting holes, etc.
2) bend the tubing on the tubing roller to a specific radius
3) manually drill out the marked holes after tubing is bent
4) bend, cut, drill, and tap insert stock
5) cast LED strips and wiring into a form to make the LED mounting strips
6) test fit
7) powder coat and skin the wheel
8) Final assembly with switches, batteries, microcontroller, etc

And here’s a little video showing some of that process:


 

I don’t use the CNC for drilling full through holes. My concern is that drilling fully through before bending will excessively weaken the metal before bending, causing the tubing roller to fatigue the pieces and/or deform them unevenly. So the CNC just countersinks all the hole ositions to give an accurate start point for manual drilling. On a 71″ wheel, there are two rows of 71 holes per section, plus about 10 more holes for bolts, LED mounting, etc. So that’s about 150 holes per section, or 750 holes per wheel that need to be manually drilled first with a pilot hole, then with the final size bit.

So that’s about 1500 individual precision holes to drill by hand, per wheel. At least for now. An important part of my production process is refining the workflow and improving techniques. In my experience, a lot of that just comes with repetition. There’s a feedback loop between product design and production methods that takes place over time. The drilling is just one aspect of production that needs this attention.

I’ve also put some time into rebuilding the 4th axis attachment for my CNC. Initially I threw it together out of spare parts. For a while my 4th (rotary) axis consisted of just a small 4 jaw chuck on the shaft of a NEMA23 stepper motor, and a steady rest made out of scrap steel and spare v-wheels left from building the CNC. The chuck and steady rest individually bolted to the CNC table, requiring re-alignment of both pieces at each use, and limiting the distance between the chuck and the rest to the length of the fixturing table.

Now the chuck and steady rest are bolted to a sturdy steel plate that takes just a couple moments to attach to the table and align. The entire attachment is longer than the table, allowing full lengths of tubing to be cut/marked, engraved at once. I’m still planning to add more supports at midpoints under the tubing, but for now it’s already functioning much better than before.


 

Lastly, I’ve finally gotten steel coupling insert stock milled. There’ll still be some tweaking to the final dimensions, but they’re working great for now. The steel inserts are a huge improvement over the aluminum in terms of rigidity. They’re going to get galvanized as well to cut down on chances of galvanic corrosion between the inserts and the aluminum tubing. Here’s the steel insert stock in all it’s glory:

Leave a Reply

Your email address will not be published. Required fields are marked *