My brother used some COVID-time to superpower his garage, finding his DIY inner-zen in the process. To celebrate its completion, I thought I’d make him a sign on my reassembled CNC machine. He was underwhelmed by my first suggestion: He wants a Corona (beer) related sign. Corona, COVID etc.
Bottletop signs are two-a-penny, see below. Pete could just get a Corona one, though he said he could not find one. Probably sold out.
I’ve been watching reruns of the F-word of youtube. I like when Gordan Ramsey says, ‘scrambled-egg….done’ (or whatever he’s just cooked). Its very final. Move on.
I thought if the bottle top was bent, like one cracked off a beer it would be cool. Corona. Done.
Yep! A little post-rationalisation. I just wanted to make a sign which was a bit more interesting.
3d model of an undeformed bottle top is fairly simple. There are a couple of tutorials knocking around online for a head start. I added the glass bottle and a bottle opener. Weapon of choice: Inventor.
You could just do this ‘by hand’ in Rhino btw. I decided to go full Monty.
Option 1: I used Inventor’s inbuilt stress analysis to ‘pop’ the cap. You cannot export the deformed geometry in Inventor. I suspect you can if you use (Autodesk’s heavier duty) Nastran from Inventor. I do not have access to that.
Option 2: I played around with SimScale for a bit (after being wowed by it’s CFD stuff). Cannot recall the issue but I ditched it pretty early on. It may just have been my impatience.
Option 3: So, I returned to my work go-to, Strand7. Setting all the contacts points wot not is not as straight forward as in Inventor (nor I suspect SimScale) both which do a lot of this stuff under the bonnet. Strand7 is a little more hands-on.
I used solid ‘brick’ elements, auto-meshed from imported geometry. A rotation is forced on the bottle opener to lever off the bottle top.
I exported deformed mesh from Strand7 and for post-processing in Rhino in readiness for the CNC:
- The mesh from Strand is triangular. I quad-meshed using Rhino 7/WIP new feature
- Played with some smoothing options (Mesh+, Weaverbird) since the exported modelled has some undulation. Did not get anywhere and concluded I can just smooth out the undulations on the physical model with some sandpaper.
Prepping for CNC