- This topic has 2 replies, 2 voices, and was last updated 8 years ago by
.
-
Posts
-
Dieci anni fa si concludeva una fase della ricerca per la costruzione di specchi per telescopi di grande diametro in fibra di carbonio, abbinata a materiali alveolari di supporto, con il resoconto di fabbricazione descritto nel seguente documento PDF.
Da allora non si è più saputo nulla, e la curiosità almeno da parte mia, è rimasta piuttosto alta.
la realizzazione sembra sia avvenuta per tre specchi:
Un 150F6,3; un 408F4 con corredo di test ottici Hartmann e Ronchi; e uno specchio da 1 metro con raggio di curvatura di 6 meters, e quindi con rapporto focale risultante di F3Non ne sapevo nulla di questa tecnologia, mi chiedo anch’io se è stata portata avanti e con quali risultati o se è stata abbandonata.
Certo che di ricerche su materiali alternativi per gli specchi ne sono state fatte tante, ma a quanto sembra, ancora non si riescono ad eguagliare le prestazioni del vetro.The "Never say never" for the use of CFRP in mirrors “do-it-yourself” lies in the current difficulty of simply and economically making the parabolic surface. As with the technology described in the linked documents, it requires the construction of a glass mirror with positive curvature on which to pour the surface resins and the CFRP laminates, and therefore it is certainly not an interesting method if not for a large series production.
At present, there is still a lack of ingenuity raised by someone who studies a simpler and easier way to obtain a parable within the amateur's reach..
The only thing that can already be experimented with now would be to create a resin positive by casting on an existing amateur parabolic mirror, on the surface of which to obtain first the convex and then the new definitive concave mirror in CFRP.
On this front it is already very interesting that the special carbon fiber prepared for end use is also known, which is the TORAY type M46J, of which all the characteristics are known (see here:
http://www.toraycfa.com/pdfs/M46JDataSheet.pdf).Which constitutes the product sold in tape with carbon fibers coated on a face with a certain thickness of epoxy resin ready to copy in convex shape the shape and the concave surface finish of the mirror, to be subsequently copied in a concave form by overlapping under pressure against what is currently the mold and with heating by polymerization at 120 degrees, (from my ancient experience of working with epoxy resin castings I think you will certainly need a non-stick liquid for the mold that normally the resin supplier recommends) leaving a surface described as directly aluminizable.
The application technology of carbon fibers for the creation of the most diverse robust and lightweight products, it is by its nature suitable for “do-it-yourself” because it does not require machinery. And already today a lot of that production, prototypes included, it is made by hand according to the best “Do it yourself”.
- You must be logged in to reply to this topic.