Bell Helicopter Textron
Timing is Everything

"At Bell Helicopter Textron’s New Product Development Center, time is the critical issue," says Jim Connally, Senior Test Specialist. "We have deadlines for getting helicopter parts out the door. We also have to get them to the test facilities on time. If we miss our window of opportunity for a test, it might be a year or more before we can schedule another one." 

Bell uses stereolithography (SL) to make vacuum mold and layup tooling. The process begins with a computer-aided design (CAD) file of the tool, which is then sent to a 3D Systems® SLA machine. The SLA system employs SL, an advanced technology that turns a virtual computer image into a physical model. The physical model, or the tool, then functions as a pattern to form parts out of other materials— such as polycarbonates, foam or carbon fiber.

Lane Evans, Group Engineer at the New Product Development Center, says, "A recent project required us to build a glareshield for head impact testing on the Bell Agusta 609 Tiltrotor project. The shield was about two feet by five feet, and we wanted to make it with a vacuum form tool." The project required nine different test specimens, in three different thicknesses, to be built using polycarbonate material.

"To build the glareshield with conventional tooling would have taken six months to a year. Instead, we finished this project in only two months."
                                                                      Jim Connally, Bell
                                                                      Helicopter Textron

“First, we made tooling, and then we formed a polycarbonate sheet over the tool to make the part," explains Evans. By means of heat and vacuum forming, the polycarbonate formed to the shape of the SL tool.

"To build the glareshield with conventional tooling would have taken six months to a year. Instead, we finished this project in only two months," Connally notes.

Since the glare shield project, Bell has made seven additional vacuum forming tools. One is a composite lay-up system that is similar to vacuum forming, except it uses layers of carbon fiber held together with a binder. Extreme heat is generated in this process to cause the fabric to conform to the shape of the tooling.

Previously, Bell used outside vendors to machine wood or metal tooling for its parts. But solid imaging has eliminated the need for outside vendors for the most part. "The glare shield took about two months because it was such a large part," says Evans, "but we can typically turn parts around in as little as two weeks. Quick turnaround makes all the difference in our business."