Aerospace Manufacturing Requirements for Sheet Metal Fabrication

A bracket on a ground vehicle can be judged by whether it fits. An aircraft bracket is judged by whether it can be traced, measured and repeated. On this kind of work the requirements usually arrive as a drawing plus a specification stack: material callout, temper, grain direction, heat lot control, bend radius limits, hole tolerance class, edge deburr condition and a first article report. The drawing alone rarely tells the full story.

The practical effect is that a formed part carries more paperwork and more process control than the shape suggests. A 1.2 mm 2024-T3 clip with four holes and two bends may need a heat lot record and a bend angle inspection after forming. That overhead is the point. It is what lets a later batch match the first one.

For a shop, the hard part is not bending metal. It is holding the same result across hundreds of pieces, in different tempers, without letting a burr or a stretched hole turn into a fatigue crack later. Forming is fast. Controlling forming is where the cost sits.

Aluminium dominates thin sheet work: 2024-T3 for fatigue-critical skins and ribs, 5052 and 5083 where corrosion resistance and weldability matter more than strength, 6061-T6 for brackets and chassis parts that will also be machined. 7075 is strong but bends poorly at tight radii, so it usually ends up as a machined part instead of a formed one.

Stainless 301 and 304 appear in clips, shims and heat shields. 17-4PH is used where strength plus corrosion resistance is needed, though it is tough on tooling. Titanium Ti-6Al-4V formed parts are possible but springback is severe and the process window is narrow; many designs convert to machining for that reason alone.

Grain direction is not a detail. Bending across the grain cracks; bending with the grain needs a larger radius. If the drawing does not state grain direction, ask before the material is cut.

Bend angle tolerance on formed sheet typically lands at ±0.5° to ±1°, and bend position at ±0.1 mm to ±0.25 mm depending on part size and tooling. Tighter than that pushes the part toward machining. Springback compensation is done in the tool, not by reworking the part afterwards, because rework leaves marks and changes the material state.

Holes matter more than the outline. Burrs at a hole edge act as stress risers, so deburring is a controlled step, not a cleanup afterthought. Hole diameter and position are checked, and for critical holes the edge is inspected at magnification. A 0.05 mm burr is invisible on the bench and obvious under a fatigue load.

Edge condition covers more than burrs. Laser-cut edges carry a heat-affected zone; on some alloys that zone needs removal before the part goes into service. Sheared edges can micro-crack. The drawing should say which edge finish is acceptable, and if it does not, we ask.

Forming wins when the part is thin, the shape is mostly flat, and the quantity justifies tooling. It loses when the geometry needs deep pockets, tight three-dimensional contours, or wall thickness changes that a press brake cannot produce. Those parts go to 5-axis machining or to a hybrid: formed shell plus machined fittings.

Very low quantities are another boundary. One-off formed parts still need tooling and setup, so a machined part from plate is often cheaper and faster at quantity one. Above a few hundred pieces the tooling cost spreads out and forming takes over.

Titanium and thick 7075 are the usual candidates for conversion. If a designer specifies a 3 mm Ti-6Al-4V bracket with a 1 t bend radius, the honest answer is that the bend will crack. Change the radius or change the process.

Inspection on formed parts is not a single event. It starts with incoming material: mill certificate, heat lot, temper, thickness. It continues in-process with first article checks, bend angle and position measurement, and hole verification. It ends with a final inspection before shipment, and reports can be issued on request.

Traceability is what separates a compliant part from a similar-looking one. If the mill certificate cannot be tied to the sheet that produced the part, the part is not traceable, no matter how good it measures. We keep the material record and the inspection record linked to the lot.

For prototypes and low-volume runs we work from one part up to 10,000+ piece runs with no minimum order quantity. Uploads stay confidential and an NDA is available on request. Quotation and a free DFM analysis come back within 12 hours, and production can start within 24 hours of approval.