Most sheet metal cost problems are designed in before the shop ever sees the drawing. Bending is a forgiving process when a part follows a few rules—reasonable bend radii, flanges long enough to grip, holes kept clear of bends—and an expensive one when it fights them. Here are the rules that matter, in plain terms.
What bend radius should you design for?
As a practical starting point, an inside radius about equal to material thickness bends cleanly in common steels; tighter radii risk cracking and demand special tooling. Designing every bend to one radius—rather than a different radius per flange—also saves setups, because each radius change can mean a tooling change on the press brake.
Why do flanges have a minimum length?
The material must reach across the die opening to form correctly—too short a flange and the part cannot be held for the bend. Short flanges either grow in redesign or get formed with extra operations you pay for. Your fabricator can tell you the practical minimum for a given thickness before the drawing is finished.
How close can holes be to a bend?
Too close and the hole distorts into an oval as material stretches through the bend zone. The safe move is keeping holes a few thicknesses away from the bend line—or, when a hole must sit near a bend, punching or cutting it after forming and saying so on the drawing.
What is bend deduction and why do flat patterns matter?
Metal stretches as it bends, so the flat blank is not simply the sum of the finished faces. Shops calculate the flat pattern from thickness, radius and material. Sending dimensioned finished geometry—rather than your own flat layout—lets the shop’s tooling data drive the blank and keeps responsibility for fit where it belongs.
When should a bent part become a weldment instead?
When bends multiply past what the geometry can nest efficiently, or the part outgrows brake capacity, welding formed pieces together—a weldment—often beats heroic bending. The economical boundary moves with thickness and quantity; it is a quoting conversation worth having early.
Frequently asked questions
On tight bends it can—bending across the rolling grain resists cracking better than bending along it. Shops handle this in nesting when the design allows.
Because true sharp inside corners cannot be bent—every bend has a radius. Drawings showing zero radius get built with a real one; better to specify it yourself.
They are formed features requiring specific tooling—possible, but worth confirming before a design depends on them.
Yes—a short review against bending rules routinely saves more than it costs. Send the model or sketch through the quote request page.
Design the bend, save the money
A & P Fabricating Solutions, LLC forms, welds and machines sheet and plate at our Appleton, Wisconsin shop. Send the part early—the cheapest bending fixes happen on the drawing, not the brake.
