Preform with variable fiber density, forming and molding tool and method for forming of composite materials
A method for fabricating a composite panel includes providing a preform including a peripheral edge portion and a central portion. The central portion has a first thickness, the peripheral edge portion has a second thickness that is greater than the first thickness, and a first step is arranged between the central portion and the peripheral edge portion. The method includes providing a tool including a binder defining a second step, an upper punch, and a lower tool; arranging the preform between the binder and the upper punch and the lower tool; shaping the preform using the tool; and injection molding the preform in the tool to create the composite panel.
1. A tool system for fabricating a composite panel, comprising:
a lower tool defining a cavity;
a preform including a substrate including a peripheral edge, a central portion, and a first step arranged between the peripheral edge and the central portion, the first step defining a radially inwardly facing surface, reinforcing fibers attached to the substrate and defining a first fiber density in first regions of the central portion of the substrate and a second fiber density in second regions of the central portion of the preform,
wherein the first fiber density is lower than the second fiber density, and
wherein the central portion of the substrate has a first thickness,
wherein the peripheral edge portion of the substrate has a second thickness that is greater than the first thickness and forms the first step;
a binder vertically moveable relative to the lower tool during preforming and including a first surface defining a second step with a radially outwardly facing surface configured to bias the radially inwardly facing surface of the first step to center and clamp the preform relative to the lower tool; and
an upper punch vertically moveable relative to the binder and the lower tool to center the preform relative to the cavity during preforming, the upper punch and including a fluid passage configured to deliver resin to impregnate the preform arranged between the upper punch and the lower tool.
2. The tool system of claim 1 , further comprising:
a distance sensor arranged on the binder and configured to detect the peripheral edge portion of the preform; and
a controller configured to control positioning of the tool in response to sensing the peripheral edge of the preform.
3. The tool system of claim 2 , wherein the controller is configured to impregnate the preform with resin after confirming a position of the preform relative to the tool.
4. The tool system of claim 2 , further comprising a robot, wherein the controller is configured to cause the robot to deliver the preform to the tool and to remove the composite panel from the tool.
5. The tool system of claim 1 , wherein the second step has a second predetermined height in a range from 6 to 12 mm.
6. The tool system according to claim 1 , wherein the upper punch is configured to move vertically through the binder forcing a portion of the preform into the cavity.
7. The tool system according to claim 1 , wherein the preform includes a first length and the cavity includes a second length, the first length being greater than the second length.