A method for forming a thermoplastic panel, comprising: coupling an edge of a skin to a mandrel exhibiting a substantially convex geometry, the skin comprises a first plurality of plies of material comprising thermoplastic resin and fiber ; disposing a second plurality of plies of material in a channel disposed in the mandrel to form a stiffener feature ; heating, via a first heating element , the skin to a forming temperature; moving a thermoforming apparatus with respect to the mandrel ; rolling a first row of rollers of the thermoforming apparatus along the skin in a direction away from the clamped edge of the skin in response to the thermoforming apparatus moving with respect to the mandrel ; rolling a second row of rollers of the thermoforming apparatus along the skin in the direction away from the clamped edge of the skin in response to the thermoforming apparatus moving with respect to the mandrel , the first row of rollers is offset from the second row of rollers ; compressing, via a first spring member , the skin between the first row of rollers and the mandrel in response to the thermoforming apparatus moving with respect to the mandrel , thereby consolidating the first plurality of plies of material and causing the skin to conform to a shape of the mandrel ; compressing, via a second spring member , the skin between the second row of rollers and the mandrel in response to the thermoforming apparatus moving with respect to the mandrel , thereby consolidating the first plurality of plies of material and causing the skin to conform to the shape of the mandrel ; and cooling the skin after consolidating and conforming the skin to the mandrel to a temperature below a recrystallization temperature. coupling an edge of a skin to a mandrel exhibiting a substantially convex geometry, the skin comprises a first plurality of plies of material comprising thermoplastic resin and fiber ; disposing a second plurality of plies of material in a channel disposed in the mandrel to form a stiffener feature ; heating, via a first heating element , the skin to a forming temperature; moving a thermoforming apparatus with respect to the mandrel ; rolling a first row of rollers of the thermoforming apparatus along the skin in a direction away from the clamped edge of the skin in response to the thermoforming apparatus moving with respect to the mandrel ; rolling a second row of rollers of the thermoforming apparatus along the skin in the direction away from the clamped edge of the skin in response to the thermoforming apparatus moving with respect to the mandrel , the first row of rollers is offset from the second row of rollers ; compressing, via a first spring member , the skin between the first row of rollers and the mandrel in response to the thermoforming apparatus moving with respect to the mandrel , thereby consolidating the first plurality of plies of material and causing the skin to conform to a shape of the mandrel ; compressing, via a second spring member , the skin between the second row of rollers and the mandrel in response to the thermoforming apparatus moving with respect to the mandrel , thereby consolidating the first plurality of plies of material and causing the skin to conform to the shape of the mandrel ; and cooling the skin after consolidating and conforming the skin to the mandrel to a temperature below a recrystallization temperature. <EOS>