When I lent my services to a collegue who was working on a film about 12 years ago, I was introduced to the world of cnc. I remember watching this huge machining centre milling out a slab of mdf and turning it into a fantastic set of gears. I knew that it would have taken me hours to achieve the same thing with traditional power tools. I decided then that I would invest in a cnc router for my own business Oxenham Design. At that time I could turn on a computer, but even to check email seemed like a crazy set of operations. I persevered and learned every piece of relevant software I could get my hands on. I am now fortunate enough to be using Vectric's ASPIRE software, and Techno cnc routers, which has helped us to create some amazing projects, both in part, or in full. I thought that this blog would be a great place to share "behind the scenes" adventures with the software, materials and equipment we use, as well as the projects we build.

Tuesday, 27 May 2014

All Them Crazy Tubes!

With the overall shape of the slide approved, I took my low resolution tubes I created in Hexagon, and converted them to hi-poly models. Our Techno would machine all the facets of the low res version if I didn't do this. I also extended the flanges on all sides, and brought everything down to an even base plane.
The model imported into Aspire perfectly! I added a 5 degree draft in Aspire to make releasing the vac-formed shell a whole lot easier.
The only drag at this point, is that Aspire adds a draft to the entire part (shown in yellow)
I can't have any draft on the inside flange, as this will change the angle of each piece, causing the whole slide model to be waaaaaaaaay out of alignment, and size!
The solution was to draw a polyline, that will split the drafted model from the regular version, and then combine the two versions into one.

The result worked great, draft on the outside edge, no draft on the inside edge!

I machined all 5 molds from HDU board, allowing me to zip through the material pretty quickly.
By the end of the day, I had the molds finished, cleaned up, and coated with a 2 part polyester hard-coat. 30 minutes in the sun, and they were rock hard and ready for final sanding.

They pulled really nice! The tight 90 degree molds are quite a bit taller than the rest, so removing the draft from the inside edges made popping the mold out a bit harder than the others. But a little baby powder rubbed onto mold solved most of the release issues.
 By the time we left tonight, we had about 10 parts pulled. Because HDU is a foam insulator, it can retain the heat from the plastic for quite a while, so we have to mix it up a bit by cycling the molds around in order for them to cool down.
Only 60 more pulls to go! No really...........there's 70 sections..........

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