Sheet metal is the one fabrication route where prototypes and production parts can be made by exactly the same process, because laser cutting and press braking need no part specific tooling. That makes prototypes fast and cheap, and it hides a trap: a design that is easy to bend one at a time may be awkward to produce in quantity, and nothing in the prototype will tell you.
Why prototypes are so cheap here
A laser or punch cuts the flat blank straight from the file, and a press brake folds it with standard tooling. There is no die to cut and no lead time beyond the queue. That is why a fabricated prototype often arrives faster than a printed one and why several iterations are affordable within a single design week.
Design choices that keep the price down
One material thickness throughout so one setup does the job. One bend radius so one punch and die set does every fold. Flanges long enough for the brake to grip. Holes far enough from bends not to distort. And a part that can be bent without a fold colliding with the machine, which is the constraint a designer is least likely to have imagined.
What the prototype does not tell you
Nothing about whether a progressive die could make it, whether the nesting is efficient, or whether the bend sequence that works by hand can be automated. If the production route is stamping, ask the fabricator or the toolmaker to review the part against that route while the prototype is still cheap to change.
Finishing and hardware
Prototype fabricators will usually deburr, insert self clinching hardware, weld, and send parts out for plating or powder coating. Each of those adds days rather than hours, so decide early whether the prototype needs its production finish or whether bare metal answers this week's question.
Questions people ask about sheet metal prototype
How fast can a sheet metal prototype arrive?
Often within a few working days for cut and formed parts in stock material, because there is no tooling to make. Plating and painting add time.
Do I need a flat pattern?
No. Send the folded model and let the fabricator unfold it using their own bend allowances, which are tested against their tooling and material. A flat pattern you generated may not match their brake.
Can prototype and production use the same process?
Yes, and often they should. Laser and brake fabrication scales reasonably well, so many products never move to stamping at all.
What is the most common prototype problem?
A bend that cannot physically be made because a previously formed flange collides with the tooling. A quick review of the bend sequence before ordering prevents it.