Sqrtm

General Composites Discussions Composites Talk
#1

http://www.compositesworld.com/articles/sqrtm-enables-net-shape-parts
According to the article “In short, SQRTM is designed to produce an autoclave-quality part without the autoclave.” Has anyone seen this method before or use it? Seems like those of use that can’t afford an autoclave could make parts to the same quality or higher? No?

Edit: “Also unique to the SQRTM process is the level of vacuum used, Coughlin adds, pointing out that Radius develops its vacuum pumps to create <0.5 mm/Hg, which is “more vacuum than a standard shop pump can produce.”” What kind of vacuum level is that in inches?

#2

0.5 millimeters = 0.0196850394 inches :rolleyes:

This guy seems to sum up my impression of this method… “‘Our focus is on net-shape parts,’ says Milovich.”

I guess the cost to this is a little higher matrix volume fraction. Then again, I would think a well engineered 2 part mold would still keep the matrix volume fraction pretty low, but I would be curious to hear what values they are getting with this method. It would seem to me, also, that this would only be more effiecent for higher production parts (as they indicate), as you would be at least doubling the price of the mold.

#3

So that would be 29.9803149603" on a digital gauge if a gauge could read out that fare? :embarrassed:

#4

yeah, I mean I guess it would actually be 29.90…"Hg if you use absolute vacuum as 29.92"Hg (from http://www.engineeringtoolbox.com/vacuum-converter-d_460.html).

#5

I’m not sure how this would surpass an autoclaves properties. Even if you pull a perfect vacuum you’ll never be able to match the pressure of an autoclave. Maybe they figured out some combination of resin and fabric that doesn’t need as much consolidation force?

#6

I would think the 100psi that’s used to inject the resin and the clamping force from the press the mold was in would provide the pressure that and autoclave produces. Key word “Think” lol I really have no clue. :confused2:

#7

I don’t think that they are boasting better than autoclave properties, but rather matching. I think they explain the theory is that the higher hydrostatic pressure keeps void forming gases in solution, giving the composite similar quality to autoclaved parts in an out of autoclave environment.

#8

For what I can read it is the disadvantages of RTM and prepreg combined…