Brake press folding: what is possible with your part
Folding turns flat plate into a stiff three dimensional component without welding. Most of the design questions people bring us come down to a few rules about radii, flange lengths and tool access.
Bend radius and material
Steel cannot be folded to a sharp corner. There is always an internal radius, and if you try to make it too tight for the thickness the outside of the bend cracks. As a rough guide the internal radius should be at least equal to the material thickness, and more for harder grades and for aluminium.
The radius also affects the flat pattern, because material stretches around the bend. We calculate the bend allowance rather than simply adding up the finished dimensions, which is why a part folded from a hand drawn flat rarely comes out the right size.
Minimum flange length
A flange has to be long enough to sit on the die during the fold. Below that minimum the part slips and the bend is not formed properly. Roughly, the minimum flange is a multiple of the material thickness and the die opening being used.
If your design needs a very short flange, it is usually made by folding a longer flange and trimming afterwards, which adds cost. Telling us the function of the flange often lets us suggest a cheaper arrangement.
Bend order and tool clearance
Folds have to be made in an order that keeps the part clear of the machine. A box with four upstands is straightforward; a box with an inward return on each side may be impossible to fold in one piece and better made as two folded parts welded together.
We check this at drawing stage and will tell you if a part as drawn cannot physically be folded.
Combining with cutting and welding
Most folded parts start as plasma cut blanks. Doing the cutting, folding and any welding in one workshop means the flat pattern, the bend allowance and the final assembly are all controlled by the same people.
Send a DXF or a dimensioned drawing showing the finished part and we will produce the flat and quote it.
Want this priced for your own job? Send us your drawings or a photo and we will come back with a fixed price, usually within one working day.
Common questions
Need this done properly? Talk to the workshop.
Send us drawings, a sketch or a site photo. We come back with a fixed price and a firm lead time, usually within one working day.