Composites
Custom Manufacturing
In our push to drive the cost of high performance composites down, it almost always becomes necessary to "invent" a new way of doing things. Our twenty plus years of production manufacturing with composites has taught us that the standard methods born of Aerospace and Academic parents simply is not enough when part cost and schedule become the driving parameters. Here are a few examples of how we met our customers expectations by starting at the beginning, and applying an ethos built on hard work, persistence, and innovation.
Modified Diaphragm Forming Process for Sports Applications
Several years ago General Composites was tasked with the challenge of producing a high performance sports component utilizing a brand new thermoplastic composite sheet. A second level of challenge was that tens of thousands of parts had to be fabricated by mid-November…and it was October! Our engineers got to work and combined technology from the Steel Forming, Plastic Thermoforming, and Mass Production Footware Industries to develop a high speed, high pressure, forming process that uses simple open tooling and can attain cycle times of less than one minute per part. A machine was fabricated, technicians were trained, and the deadline was met. We now offer this process as one of our primary capabilities and it is now being used for hockey, backpacking, watersports, and snowshoe applications.
Solid-Cored™ Eutectic Salt Mandrels
One of the challenges of working with eutectic (wash-out) materials is the extremely high shrinkage related to the high processing temperatures and the phase change the material goes through. This can manifest itself as a dimensional problem, a hollow part, or both. Dimensional infidelity is not desired for obvious reasons, but the problem of hollow parts for high performance components is that the reliability of the mandrel is very low for autoclave processing. In other words, parts would "cave in" when subjected to typical autoclave pressures and temperatures and this was unacceptable for one of our aerospace customers. General Composites went on to developed a proprietary and completely different way to fabricate these parts (SolidCore Technology) and has been a continuous supplier of these high quality mandrels for over a decade. We are the only company in the world with this process, and we can apply it to make highly structural "trapped" and dissolvable internal mandrels. The end result is a part with high levels of consolidation and the possibility for very accurate and detailed interior features.
High Through-put Carbon Tow Stabilization
When the carbon shortage hit several years ago, many companies were left with a shortage of stabilized unidirectional materials. This is a primary component in most Resin Transfer Molding (RTM) processes and it left us in a quandary. The challenge here was to develop a machine capable of converting raw 50k-carbon tow to a stabilized format in a low cost, high throughput fashion. In several months we were able to convert our own stabilized unidirectional tape for less than half the cost of commercially available equivalents and were able to pass these savings through to our customers.
Hybrid Prepreg/RTM Fabrication of Critical Medical Components
Because of a requirement to meet stringent cosmetic and structural parameters, General Composites developed a patent-pending process involving the use of both pre-impregnated composite materials and Resin Transfer Molding to meet one medical customers needs around an external fixation device. The end result was a part that exhibited excellent cosmetic features and torsional rigidity, as well as high temperature and long term structural integrity. This process has been in full production for many years since and tens of thousands of components have been manufactured with it.
Injection-Moldable "Metal Replacement" Cascade for Jet Engine Thrust Reverser
Although never put into production, General Composites developed a "metal replacement" molding compound and process based on P150 carbon fiber tow and PPS resin. The challenge was to develop a new process that would force the world to view injection molding in a whole new light. The goal was to develop a material that could be processed traditionally and that would also be low cost yet compete directly with metallic and standard composite components. The outcome was a process with an injection molding heritage (and benefits) and aerospace performance. The specific properties attained exceeded that of aluminum for isotropic modulus and strength and was applied to a sub-scale thrust reverser as a showcase of its properties. At the time, is was considered "too far out there" for a very conservative aerospace prime contractor, but we await the day that the phone will ring and give us the opportunity to unleash this significant application development.
Computer-Aided Resin Transfer Molding (HP-RTM)
As a result of more than a decade of research and over seven generations of equipment, General Composites has developed an advanced Resin transfer Molding (HP-RTM) process whereby precise and preset temperatures, flow rates, flow pressures, and other parameters yield some of the highest performing RTM parts to available anywhere. An additional and equally relevant driver for this need of precise and repeatable control was the fact that our "typical" customer was also demanding lower cost and higher production rates.
HP-RTM Capabilities
- Typical fiber volumes in the 55-65% range with high surface quality
- Production cycles of less than four minutes are possible.
- Annual cycles of over 50,000 parts per tool are possible.
- Unlimited shot volume.
- Computer pressure control of +/- 5 psi, maximum shot pressure of >500 psi.
- Computer control and report of resin temperature, ratio, vacuum and port actuation.
- Full automation capability through de-molding.
- General Composites currently has 12 operational CARTM cells.
