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.

Thursday, 6 September 2012

Oxenham Design truck plant

Although these trucks are one offs, it's starting to feel like all we do is make small vehicles!
For the crane, production already had a mold made from MDF. It was a little strange looking for sure, kind of a cross between a walrus and a clown, and as un-symmetrical as you could get!  Totally not suited to the style of the trucks. The director wanted (needed) something different. Time is now drastically running out. We are at 18 hour days times 2 people, and 10 hours times one person. The time for last minute changes is GONE. I had started early on tackling the crane head, this is the only reason we were able to do something different than what they had supplied.
I measured up the crane chasis and drew the front and side dimensions in Corel draw, using the real world sizes and material thickness. These vectors were exported out to Hexagon for 3d model massing. I wouldn't have bothered doing all this work for the crane, but the director wanted to see something dimensional in order to approve the design. The only full 3d part of the crane would be the grill portion, the rest is all 2d cut styrene panels, so from a fabricating point of view, I really only needed the finished grill portion. As we were standardizing all the construction vehicle eye shapes, I brought in the vectors from Dug the dumptruck as well. I'll use those vectors to mass the crane face for approval.
After a little while, I had come up with this design, which was approved right away.
I quickly exported out the grill into Aspire for toolpathing. The grill and bumper had a total thickness of 1.75", so I loaded up a piece of 2" HDU, and let our Techno cnc expose the finished piece hiding in the material :)
We vacuum formed the final part from 1/16" styrene. The only thing with using 15 lb HDU as a vac mold is that it compresses a very tiny bit under the force of the vacuum, then it expands tightly into the finished part, making it a bit difficult to remove. I wouldn't use HDU for a production run, but it holds up well in the end. None of our HDU molds got damaged at all during the process.
While the grill was machining away, I built up the 2d panels I cut before the 3d run, into the structure of the head.
With the grill firmly attached and the eyebrow arches in place, this guys ready for his spanky new paint job.

I wish I had the final eyes to go in for the final pics, instead of the animatronic eye rings, but the only 2 we have are being used to fit the mechanics on the other trucks at this point.
 While the crane was being built, John was working on the bulldozer, Sandy. He drew this all up in Illustrator, and gave me the files for toolpathing in Aspire. With the model all finished, it was time for paint.

Lookin good!
With the vinyl all applied, and the frame painted up, these are some nice looking trucks!

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