Revolutionising mobility with investment casting at BraunAbility

Because of the intricate mechanisms needed to allow wheelchair users to enter and exit safely, creating more space requires complex modifications to the vehicle's factory-fitted suspension.

"In the past, Chrysler used a much simpler design, the solid rear axle," says Sajed Dosenbach, a Design Engineer at BraunAbility. "But in the newer design, the independent rear suspension was much more complex."

Ultimately, this meant the company's usual in-house fabrication capabilities simply would not be feasible.

Dosenbach knew investment casting would reduce manufacturing complexity by consolidating parts—not to mention providing greater strength than sheet-steel pressing—so he contacted Signicast.

Design for manufacturability

To implement this new modification, cradle mounts needed to be seamlessly integrated into the Chrysler-designed subassembly beneath the vehicle, similar to the way a trailer hitch slides into a sleeve-like hitch receiver. 

As this suspension had never been attempted before, Dosenbach had to begin the process with only an idea, which he then translated into a CAD drawing. Signicast's role was to help him transform that idea into the components BraunAbility needed.

Before investing the time and cost of tooling for a production run, Signicast needed to verify the manufacturability of this entirely new design and ensure it would meet BraunAbility's rigorous safety and durability testing standards.

In-house prototyping capabilities

After running simulations, Signicast's engineers created CAD models of several design options. Using in-house prototyping capabilities, they transformed 3D-printed patterns into production-intent steel prototype parts—exact replicas of the part—on which BraunAbility could carry out real-world testing.

As Dosenbach explains, "That is the best prototype you could ask for because it accurately replicates the final production part in terms of strength. When prototyping rather than producing a final part, you are essentially changing the manufacturing method."

Preventive prototyping

Most importantly, the ability to revise and improve the idea using Signicast's prototyping capabilities led to a successful, workable design.

For example, some prototype test results showed that the original design would require a greater welding surface area to maintain joint strength. A better solution was to invert part of the design—a far easier and more affordable fix during prototyping than after a production run.

After the new design was prototyped in different versions, BraunAbility retested the part—and it passed. "Going through Signicast's prototyping process was much quicker than developing a completely new original design, and saved us from wasting money on tooling," says Dosenbach.

The roomiest wheelchair-accessible van on the road

The BraunAbility Pacifica is gaining traction as the roomiest wheelchair-accessible van on the road. The suspension clearance project, together with

modifications to the interior floorboard, resulted in nearly 20% more space for wheelchair passengers.

"BraunAbility was able to cut inches off the van floor and fit their new modified floorboard," says Lann Ellis of Signicast. "They have gained extra room and now have the largest cabin space of any modified minivan on the market."

For Dosenbach, Signicast's software simulations, real-world prototypes, part consolidation and in-house machining made the entire project easier to deliver. "The requests I made to Signicast for these parts were very complex on their end. And they always delivered what I needed," he says.

The project also means that wheelchair passengers can now move through a full 360 degrees inside the vehicle.

And for BraunAbility, that translates into a growing base of satisfied customers.