Simple 300 micron sheet 2

[drodrig]

Hi there,

We tried to make a simple plate 300 micron thick sheet using two prepreg layers (SIGRAPREG® C W205-TW2/2-E323/43%). They were pressed with two aluminium plates (15mm thick) and 8 M16 screws. They are 50x40cm2 (20x15 inches2)

The result was insatisfactory. There is a middle strip without resin. It has an interesing pattern: it expands on the ends.

Also, on the "good section" there are small imperfections. There is not a nice glossy surface.

Why is this happenning? too tight? too loose?

Down here some pictures

thanks
regards,

 

[berkshire]

Your plate is bending under load. You need to add more pressure in the middle . Use a thicker plate or put it under a press.
B.E.

You are judged not by what you know, but by what you can do.

 

[drodrig]

ahá

so it is making an arc around the prepreg

interesting

thanks!

 

[Compositepro]

This is why vacuum bags are usually used. The clamping bolts deform the plates, and then resin and air flow toward the centerline. A vacuum bag can also deform the plates if not applied properly.

The hour-glass pattern is due to how resin can bleed out toward the unsealed edges.