Mandrel for processing a composite part and method for fabricating a composite part
A mandrel for processing a part is described that includes a solid mandrel body with an elastomeric material, and hollow micro-particles embedded within the solid mandrel body in a uniform distribution. The hollow micro-particles deform in response to a change in a processing environment resulting in a distribution of voids in the solid mandrel body. A method for fabricating a composite part is also described that includes placing a base composite layer into a cavity of a tooling surface, inserting the mandrel into the cavity, applying a skin to the mandrel and the base composite layer forming a package, enclosing the package in a vacuum bag and curing the base composite layer and the skin such that during curing the hollow micro-particles deform resulting in the distribution of voids in the solid mandrel body, and removing the mandrel from the cavity of the tooling surface following the curing.
1. A mandrel for processing a part, comprising:
a solid mandrel body comprising an elastomeric material, wherein the solid mandrel body comprises:
an internal elastomer core; and
an elastomer skin surrounding the internal elastomer core; and
hollow micro-particles embedded within each of the internal elastomer core and the elastomer skin of the solid mandrel body at respective different uniform distributions, wherein the hollow micro-particles deform in response to a change in a processing environment resulting in a distribution of voids in the solid mandrel body, wherein the hollow micro-particles are collapsible microspheres.
2. The mandrel of claim 1 , wherein the solid mandrel body includes an elongated mandrel body, and wherein the hollow micro-particles are embedded within the solid mandrel body in the uniform distribution axially and along a length of the solid mandrel body.
3. The mandrel of claim 1 , wherein the collapsible microspheres include polymer microspheres.
4. The mandrel of claim 3 , wherein the polymer microspheres include microspheres that crush under a threshold pressure resulting in the distribution of voids.
5. The mandrel of claim 3 , wherein the polymer microspheres include microspheres that melt under a threshold temperature resulting in the distribution of voids.
6. The mandrel of claim 3 , wherein the polymer microspheres include microspheres that melt under a threshold temperature resulting in the distribution of voids with residue of the polymer microspheres remaining.
7. The mandrel of claim 1 , wherein the uniform distribution of the hollow micro-particles embedded within the solid mandrel body results in the distribution of voids being about 10% to about 30% void area in the solid mandrel body.
8. The mandrel of claim 1 , wherein an amount of void area is based on an amount of the hollow micro-particles embedded within the solid mandrel body, and wherein the amount of void area is related to a desired compression of the solid mandrel body.
9. The mandrel of claim 1 , wherein the change in the processing environment includes a change in temperature, and wherein the hollow micro-particles deform based on a threshold temperature applied to the solid mandrel body resulting in a distribution of voids in the solid mandrel body.
10. The mandrel of claim 1 , wherein the change in the processing environment includes a change in pressure, and wherein the hollow micro-particles deform based on a threshold pressure applied to the solid mandrel body resulting in a distribution of voids in the solid mandrel body.
11. The mandrel of claim 1 , further comprising:
a film positioned around an exterior of the solid mandrel body to provide a flexible exterior surface.
12. A mandrel for processing a part, comprising:
a solid mandrel body comprising an elastomeric material, the solid mandrel body comprising:
an internal elastomer core; and
an elastomer skin surrounding the internal elastomer core; and
hollow micro-particles embedded within each of the internal elastomer core and the elastomer skin at respective different uniform distributions, wherein the hollow micro-particles deform based on one or more of (i) a threshold temperature and (ii) a threshold pressure applied to the solid mandrel body resulting in a distribution of voids in the solid mandrel body, wherein the hollow micro-particles are collapsible microspheres.
13. The mandrel of claim 12 , wherein the collapsible microspheres crush under the threshold pressure resulting in the distribution of voids.
14. The mandrel of claim 12 , wherein the collapsible microspheres melt under the threshold temperature resulting in the distribution of voids.
15. The mandrel of claim 12 , wherein the collapsible microspheres range in size from 10 μm to 50 μm in diameter.
16. The mandrel of claim 12 , wherein upon collapse of the collapsible microspheres, the distribution of voids becomes present in the solid mandrel body.
17. The mandrel of claim 12 , further comprising:
a film positioned around an exterior of the solid mandrel body to provide a flexible exterior surface.
18. The mandrel of claim 1 , wherein the collapsible microspheres range in size from 10 μm to 50 μm in diameter.
19. The mandrel of claim 1 , wherein upon collapse of the collapsible microspheres, the distribution of voids becomes present in the solid mandrel body.
20. The mandrel of claim 12 , wherein the collapsible microspheres include polymer microspheres.