Hereís a prototype job I did a few years ago, and it is with kind permission I present some of the story here. I was given a design brief for a new product, something I was not familiar with, and asked if I could turn the idea into a working prototype. I went through quite a few iterations of CAD modelling trying to get a pleasing shape. Once that was achieved, how can it be made in the real world. I had an idea, but it had to be tested as a prototype, I hadnít seen any examples of this before. Thats not to say itís unique, just I hadnít seen it, the design asked for components that could be crimped together.
With the design and a method of attachment figured out, I needed to make the first part for testing. It would need a mould, as I didnít have CNC facilities and basically the design budget wasÖ.. I started to machine the parts in the workshop. This called for some quite intricate curved parts to be made, so the curves needed to be mapped. I didn't want to make form tools as the setup I have isn't that rigid and surface finish was an important part.
Boy, did I wish I had CNC during this part. It was early days in my 3D printing, so that didn't help much as I couldn't produce the accurate parts I can now to use as templates.
A lot of machining later a set of parts for the mould. At this point other than the base they still needed profiling and drilling for alignment dowels.
On with profiling the internal parts and getting the vents in the mould ready. At last a full set of mould parts that all fit together.
Some would say skill, but I would call luck that I made it this far without having to remake any of the parts. All the internal scraping worked out, just a smidge out of tolerance getting things smooth.
The above is a simplified version of the mould to produce the required part. Now its mould time.
First few attempts produced partial casts as I needed to up the mould pre heat and find the sweet spot.
First full cast out of the mould and looking pretty good, till I turn it around. The lead pulled back as it cooled as I expected, just the vent didn't do it's job right.
The inlet vent needed further work, a few minor adjustments and after a few more tests I start getting consistent results.
The initial idea for crimping the parts together was just too fussy and probably would result in rippled edges, so I redesigned the crimp tools.
Now thats the result I was after.
A good crimped surface, the rest of the prototype was completed and several more made for testing. Upon completion of testing it was put into mass production and I am pleased to say tens of thousands have so far been made. This is some of the work I do, normally covered by confidentiality clauses, hence i rarely get to show the real stuff I design and make. My thanks to Mick for letting me share this part of the journey with you all.