This optical bench casting is used as part of a laser range finder and target acquisitioning system on a series of military vehicles. The casting’s primary function is to house and position the optical components of the laser range finder.
Precision Castings of Tennessee worked in concert with our customer in the initial stages of the project to modify the design to improve the optical bench’s ability to be cast while maintaining the part’s functionality.
Due to the complex shape, rapid prototype patterns were produced and cast to verify shrink rates throughout the varying cross-sectional thickness of the casting and ensure that the casting would function properly. The use of rapid prototype patterns allowed the tooling to be designed and built accurately with confidence in the design, therefore reducing the potential for costly tooling rework. The rapid prototyping process also allowed PCT to develop and test the gating design.
Primary Customer Benefits:
PCT improved the customer's manufacturing process by reducing machining, increasing part strength, expanding alloy choice, and meeting the customer's form, fit, and function at a fraction of the cost of similar manufacturing methods. The customer’s manufacturing engineers frequently refer to the performance and reliability of the casting as its key benefits in the field.
Unique Design Considerations:
In addition to the complex design, the part is unique in its package size. The optical bench casting blends a compact and light weight design with the strength and corrosion resistance that are required for the part to serve its function.
Special design requirements and/or process requirements:
The optical bench was designed for functionality and required modification to be a viable casting. Original design features were modified to reduce isolated heavy sections, create areas for gating, and create a part which could be easily tooled and cast while maintaining the integrity of the part and reducing the manufacturing costs.
Precision Castings of Tennessee used fully wax-infiltrated SLS CastForm patterns for the rapid prototype patterns. This wax-infiltrated material performed very well with our casting processes, especially during the dewaxing and burnout stages. Once the shrink rates, the gating design, and the design functionality were verified a hard tool was built. Precision Castings of Tennessee was able to build a semiautomatic tool equipped with an air assisted ejection to maintain the dimensional integrity of the wax patterns.
Precision Castings of Tennessee delivered first articles from the hard tooling within weeks after which additional design changes were needed to allow the part to function properly. The initial design work and cooperation between PCT and its customer set the groundwork for the last minute customer requested changes to be easily implemented and the delivery of production parts to remain on schedule.
Material used (composition of metal of alloy):
IC 17-4 PH (AMS 5355)
Size of part:
The weight of the casting is approximately 5 lbs with outside footprint dimensions of approximately 8”x 6”x 6”.
Secondary operations performed:
Precision straightening, heat treating, nondestructive testing, and machining.