It was some time I didn’t update this blog, I’ve been busy with some projects, and as I’ve finished them, it’s the time to upload the info in my blog.
This has been the case of a person who put in contact with me to build the model of an RC yatch IOM Class, a very famous class with a high level of professionality. Here you have some info about this kind of yatchs: ANVRC
As I already said in this blog, to build a composite hull, we basically need to make a real scale model, get the molds, and then the final part. This model, it’s going to be done cutting the hull by the half, for the middle plane. Once we have the molds, join them and laminate the carbon inside. That’s the reason we make the model in two simetric halfs. This would be the geometry:
The model seems easy, as we only need a rough machining and later, finishing machining. But let’s step by step. First step is get the rough stock. We decided to use a machining resin, very good material for prototyping, easy to machining and sanding. But it’s expensive. The original dimensions are a plate of 1500x500x50 mm, so, we need to think very well how to do the cuts.
After some time to think, this has been the results:
luckily I had access to a saw, so I could cut the plate according with the design, and this cuts should be the most accurate possible, if not we can have machining problems.After cut it, I need to sand to prepare all the cutted surfaces perpendicular.
At this point, I must say that the model is 980mm length, what don’t give me so much freedom , as my CNC has a theoric working space of 1000mm in X axis, but it’s always a bit less. And 980mm means that the tool needs some extra space for approximating paths.. conclusion, it doesn’t fit!
So I had to think it very well to have a limited paths, so I wil remove the extra material by hand later, before the finishing machining.
Maybe someone would ask, why don’t you release the part and make the machining in two steps? I thought about it, but it’s very easy to lose accuracy as you lose the origin, so it’s better not to risk.
When I get the resin, I also get an special glue, made for this kind of resin. Once prepared all the parts over the wood plate, with the best accuracy possible, I glued small cubes of wood to have the correct position before apply the resin glue. So now I can apply the resin glue, and wait until it cure, applying a lot of pressure.
So, we already have the rough stock ready to machining!!