If you haven’t already, please read Nate’s Blog Post on Failing Fast with 3D Printing (Here). I wanted to take a moment to tell my story on how I failed fast on a design project I finished a few months ago. Back story – every year, I try to come up with a design for 3D Printed trade show give aways (a.k.a. Swag!). I love good swag. Over the years we’ve had pill bottles, door stops, basketball games the size of a business card, and bottle openers. This year before our first trade show, sometime in January or February, I was trying to come up with an idea for our yearly swag. If you’ve been on the internet at all over the last year or two, you’ve probably seen a Fidget Spinner. The idea is a weighted series of lobes mounted to a nice ball bearing and used to “fidget” with (if you’re into that sort of thing).
I was originally going to print a body and buy ball bearings, but this would be expensive to produce them in mass quantities. I have seen printed ball bearings in the past, and wondered if a fidget spinner could be completely printed. I’ve been involved with Additive for a little over five years now and had a good idea on what clearances I would need around the bearing parts. A few extrusions, circular patterns, and fillets in SOLIDWORKS later, I had my first design iteration done (Spinner on the left). Printing time was about 30 minutes on our new F370 printer.
Was it functional? Sure! But there were some weeknesses. You could twist the lobes enough for the balls to pop out. The size of the balls were an issue too. The clearance stackup left way too much room in the race. This first try was Failure #1!
The middle spinner was Failure #2. I increased the thickness of my part and beefed up the lobes to make sure that was correct before rethinking the ball bearing. I also took the opportunity to apply our logo. In adding strength in my design, I also took a step back. I failed to think about design intent. Anyone that has been in our SOLIDWORKS Essentials class will recall getting this drilled into their brain. Design intent is the way we want our models to behave when we make a change. In changing the main design I neglected to check the feature that defined the balls and races, so who knows how they behaved. Actually I do, it FAILED!
After fixing the design intent of my model, I changed the size and quantity of the balls, which helped with the tolerance stackup. I crossed my fingers and hit print. The 3rd attempt was a success! The spinners come out almost perfect every time now and seem to be a big hit at trade shows. Keep an eye out for more stories on the fidget spinner and always remember, two failures do make it right!