Hand lay-up combined with autoclave curing is a composite manufacturing technique which is still widely used in the aerospace industry. The main reasons are the confidence in this well established process and the high fibre volume fractions and low void contents which can be achieved due to the high pressures used in autoclaving. However, autoclaving mainly depends on the manual mould lay-up of prepreg material. Manual lay-up of high-curvature products is complicated and most of all a time consuming process. Consequently, the manufacturing costs are high and the process is unsuitable for large series. Many alternative processes are being developed among which automated tape laying, fibre placement and resin infusion are the most promising techniques. Another process which may offer improved cost efficiency is diaphragm forming of thermoset prepregs. This technique offers the possibility of layup and consolidation of flat prepreg stacks onto a high-curvature mould in a single step. Furthermore, product quality improves as manual lay-up is avoided. In combination with automated tape lay-up, diaphragm forming of thermoset prepreg could offer a significant reduction in part cost compared to conventional techniques
OBJECTIVE design and develop a medium volume method of producing continuous fiber reinforced thermoplastic composite components to lower the cost of capital investment, fast cycle times, low cost single sided tooling, no solvent emissions, and automated/low labor.
Discussion on Manufacturing Method
Diaphragm forming is a thermoforming process which was origanally develop for forming of thermoplastic composite.It will laminate between two foils and it was clamed onto a mould after which in between a vacuum is applied (figure1). Figure 1
This package is placed in an autoclave and heated to the process temperature. After reaching this this temperature a hydrostatic pressure difference is created, which forces the laminate into mould