This week we had a first try with the resin infusion process of the spheres. The purpose of this test is to see how the molds work and to get familiar with the process. The high temperature resistant resin we were supposed to use turned out to have too high viscosity for this process, so we quickly decided to change to another one just for this test. There was a lot of preparatory work to be done before we could infuse the resin with the vacuum pump. The idea we have is to brush the thicker resin, instead of infusing, to the layers of glass fiber and suck the excess with the vacuum pump. This will be tried later in the week.
Soon there will be pictures of the first glass fiber spheres! But meanwhile you can check these out.
Hej! In the next few days the mechanical team will receive the moulds for the manufacturing of the hemispheres of the FFUs (Free Falling Units).
The process used will be the Resin Infusion. In the following video you can see how does the process work.
As mentioned in previous posts the fabric used will be glass fibers. For what concern the kind of fabrics we decided to go for a very thin 8h satin. This kind of fabric has a very good drapability so it will be easier for us to obtain the right shape.
There are still some uncertainties on which type of fiber glass we will use.
The D-type would be the best since it has the lowest dielectric constant (good for radio transparencies) but unfortunately it is not very common and it will be hard to get it.
Right now we are investigating the possibility to use S2-type or E-type. Those types have a higher dielectric constant but also higher strength. In this way we might need a less thick hemisphere (0.6-0.7 mm instead of 1 mm), so the effect of the higher dielectric constant can be reduced.