Carbon composite manufacturing has become a key area of R&D to meet increasing demand for carbon fiber composite materials. This shift is largely driven by industries looking for strong, lightweight, green materials. Manufacturers already using these materials or exploring the materials include automotive, sports equipment, civil infrastructure, and oil & gas manufacturers.
To meet the growing demand, material manufacturers are racing to identify and utilize the most efficient process. There are several different kinds of composite structures and automated composite manufacturing techniques. One such method is Automated Fiber Placement (AFP), which uses robotic arms to dispense layers of tapes of carbon or glass fiber, embedded in thermoset epoxy, thermoplastic material, or the dry fiber (coated with a binderonto a mold. To create a strong bond between these layers one or both constituent layers are heated to the appropriate working temperature and then adjacent layers are sandwiched using pressure from a press or roller. Some of the processes require an autoclave post-process to compact the layers.
Choosing the right heating method is integral to improving the overall efficiency of the process and ensuring the best quality. Current techniques use IR lamps, hot gas, or directed laser beams. IR lamps are widely used across the aerospace industry as this method is the oldest and most tested option. However, laser-based methods using laser diodes are sparking interest from AFP system designers.
Here are a few commonly asked questions from manufacturers as they explore ways to optimize laser-based system processes:
- How much space will the system – specifically the heating head – take up on the tool?
If a compact laser diode is utilized, the result will be a much smaller heating head than comparative technology. This will allow for a smaller, lightweight, more nimble unit.
- Can undesired heating be eliminated?
Reduced parasitic heating is a significant advantage of laser-based AFP. Laser diodes offer increased accuracy in targeting, allowing for proper heating and the elimination of excess heat around the target. Additionally, laser diodes are capable of turning up and down quickly, greatly improving heating consistency with changing speed.
- What type of programming is required?
The startup of IR heaters is very complex and can change as the lamps age, requiring complex, extensive programming. Employing a more reliable heating process using a laser diode-based method could simplify control code to just a few lines.
- How does laser diode technology allow for more accuracy?
Free-space direct diodes can generate high intensity beams with uniform intensity distribution using a beam homogenizer. A beam homogenizer creates a uniform intensity pattern by redirecting laser light using a multi-faceted mirror or a diffractive micro-lens array. Advanced beam homogenizers can distribute beam energy extremely evenly with rapid intensity fall-off at the beam edge.
As laser technology for AFP continues to evolve, its significant advantages develop a solid case for testing in aerospace and new industrial applications. The key for these emerging applications lies in the demand for efficient, accurate, homogeneous heating in a compact and lightweight system.