For a visor that would meet the EN166 European standard as well as meeting the ANIS Z81.1 US standard, the typical design process would as we have done for a number of customers for a number of markers.
As the design of the helmet fit was fixed for product styling needs, POL had to start to optical correct the design to allow the part to be tooled up and manufactured there are a number of key steps that have to be worked through.
The first stage is to change the CAD designed surface into a developed mathematical formula that is a remarkably close fit to the sealing face or the outer edge design to integrate into the styling of the helmet system.
On completion of the rear surface this fit is then analysed to ensure the correct functioning of the fit to the helmet and any hinge units.
Then the work starts to develop the front surface that will correct for the optical view through the visor for the internationally standards we are tasked to meet. As the design cannot be a constant thickness to meet the optical needs, we have to also balance the mouldability of the visor so as not to have a section that is too thick in the middle section while also ensuring the thinner edges are strong enough to withstand the impact needs and ability to fill fully during the moulding cycle.
Following the completion of the design we then simulate the part in optical CAD that shows the effect of moving the visor about over a checkerboard and take a number of key optical measurement in the as used position showing that it will meet the optical standards that we are designing to.
Converting this into a real part the manufacturing processes needs have to be taken into consideration so we develop a feed system that will minimise the stress levels in the material and allow the correct fill path to ensure full and complete moulding.
With the tooling of visors these look to be simple as an open shut tool most of the time, we can add side cores for mounting features for the hinge assemblies. As these are out of the optical areas as long as the flow/fill is not affected to much many things are possible in this area.
Over the years we have developed the tooling process with the key to the finished quality is the machining of the optical surfaces and the quality optical polishing which is why customers come back to POL for the expertise we have in this area.
The final stage is the no-how we have in house to process the material to produce the high quality moulded. POL is then able to offer addition services by having hard coating applied and anti-fog coating.
