Precision is what counts in aircraft assembly.

It is essential that various individual parts are precisely screwed or riveted together in the assembly of aircraft. Drill jigs are used to ensure that each drill hole is set precisely at the connection points. Any error, no matter how insigificant in itself, can have highly risky and extremely costly consequences. Since these drill jigs hardly wear out, they are in use for decades. This means, that it is not uncommon that they no longer comply with current, stricter ergonomic regulations.

For this reason, Ascent Aerospace wanted to optimize a heavy and unwieldy drill jig. The template consisted of several solid aluminum plates that were conventionally milled and joined. The jig was used to precisely drill holes for the guide rails of landing flaps on the wing spars.

Ascent Aerospace's aim was to make this drill jig significantly lighter and more ergonomic so that the physical strain on the fitters when lifting and attaching the drilling aid would be reduced. At the same time, the template is easier to handle. Other requirements were that the new assembly aid had to be able to be integrated seamlessly into the existing manufacturing process and be available quickly.

As a specialist for additive manufacturing, FIT had the right expertise for additive design and engineering, prividing the perfect solution using ist Rapid tooling solution.

Precision begins with the design

A feasibility check at project start showed that the outer geometry of the drill jig could be optimized, but that alone was not enough to save significant weight. For this reason, we completely revised the design of the template as part of an ADM-E project.

The newly designed drilling aid was constructed in one piece and hollow. The stability required by Ascent Aerospace was achieved by curved sections, angled connecting surfaces, and perfectly vertical hole fits that act as bracing to connect the hollow walls. In addition, the designers at FIT paid meticulous attention to ensuring that the new design could be additively manufactured with as little material as possible and largely without support in a cost-optimized manner.

As an additional element, slots for small mirrors, so-called target holders, were integrated at the corners of the newly designed drill jig, through which the exact fit of the drilling template is verified by means of laser optics.

The special process requirements

The particular challenge in this project was to optimize an existing tool in such a way that it fulfilled its function and the associated technical requirements at least as well as the conventionally manufactured drilling template used to date. In addition, however, it had to be significantly more ergonomic and within budget. FIT succeeded in this by radically optimizing the design. This made it possible:

• to reduce the weight of the drill jig from the original 8 kg to 4.5 kg, which corresponds to a weight saving of 45 %. As a result, the ergonomic specifications were fully met.
• that the drilling template can be manufactured in one piece and thus without any assembly effort.
• to significantly improve the handling of the drill jig, because the hollow handles lie safely and comfortably in the hands of the fitters due to their diameter and ergonomics considering work gloves.

The project was successfully carried out by FIT and has initiated a generation change for the design and manufacture of assembly aids at Ascent Aerospace. The next step is to see if a material change to plastic is possible to further reduce manufacturing costs.

Do you have similar challenges in your company and would like to optimize your assembly aids and jigs? Great. We look forward to getting in touch with you.