Sean McColl, our Production Manager,  works closely with the apprentices to explain the importance of our folding capability, something that Sean knows just about everything there is to know.  So Sean has crafted this helpful guide, not only for our apprentices but for anybody who needs to know Folding Knowledge!


Sean puts folding into context: “Precision folding has come a long way in recent decades. What used to be considered ‘precision’ in the 80s wouldn’t pass today. A fabricator might have considered ±1 degree a precision fold; today a precision fold is within a half or even a quarter of a degree. Several factors have driven the market toward greater precision, including pressure to reduce the cost to produce a part, as well as robotics and automation. Although manual welders and assemblers can deal with variability, robots and automation can’t. Therefore, machinery needs accurate parts to function effectively.


“Like many things in manufacturing, press brake technology has advanced significantly over the years, but much of the basic press brake process terms haven’t changed. This is the key language we use and something all our apprentices need to know!”


Back gauge fingers: Stop/gauging devices either on back gauge bar or mounted to the machine.

Back gauge position: The distance from the front of the back gauge fingers or gauging bar to the centre of the “V” opening being used in the die.

Back gauge retraction: Very useful for some particular bending jobs requiring a retraction of the back gauge bar as soon as the punch pinches the plate. This will prevent damage of the flanges previously bent down against the back gauge heads or fingers, that could require gauging with a different level position (higher or lower) in relation to the surface of the die.

Bend allowance: The amount of compensation considered for the stretch of the material at the bending point in order to produce the proper flange dimension.

Bend angle: The angle between two successive flanges of the bent part.

Bending follower for press brakes: Device to support large plate/panels during bending operation. This unit is synchronized to the angular bending speed.

Bending tonnage: The tonnage required to perform a bend.

Crowning device: Mechanical system that compensates automatically the natural deflection of the beams. It can be a set of shims, punch holder or device mounted on lower beam. It can be controlled either manually or by a DNC.

Flange length: The distance on the material from the gauged side end and the next bend side (from inside or outside) centre of the opening of the die to the back stop.

Graphics control: A type of control for the axes of the machine which shows the operator how the part is to be bent, allows for the viewing of the tooling geometry, and simulation of the bending process.

Inside radius: The radius on the inside of a bent part.

Lower die: The lower tool the punch uses to form bend angles.

Mechanical stops: Used in certain types of hydraulic press brakes to assure repeatability in the stopping of the ram. The stopper set inside or outside the cylinder to set the bending depth/stopping position.

Overload protection: (discuss tooling, punch holders weak point, side load): The capability to limit damage by adjusting the tonnage control, or turning off power to engage machine.

Pinch point retraction: The moment that the punch pinches the plate causing the back gauge retraction.

Punch holder: The device used to clamp/hold punch in brake. Punch holder can be part of upper beam or intermediate/separate device. When separate, it is very useful to perform deep boxes with

lower punches (less expensive). Some punch holders have a feature to allow for compensating for the natural deflection of the beams if needed.

Quick clamp punch holder/die holder: A quick release system used to clamp/hold punch tooling or die tooling. Can be mechanically or hydraulically activated.

R1-R2: Independent adjustment of each of two stops of back gauge, up and down.

Repeatability: The accuracy which a beam will move to the same position repeatedly.

Safety Tang: The additional device on the tang to help prevent punch from dropping out when clamp is released.

Throat depth: The distance of the cut-out in the side frame/machine housing that determines the maximum length of flange that can be bent when bending to overall length of machine.

Tonnage control: Capability to regulate the tonnage available for use on the machine, up to its maximum rating.

Twin vee die: Special die combining two different V-openings on one side. It always requires a die holder.

X-axis: Movement of back gauge in and out – front-to-back – (used to control flange dimension).

X-X1: Further, independent movement (offset) of the one stop on back gauge bar in and out.

X1-X2: Tilt of back gauge. Angling the back gauge bar out of parallel with relation to the die

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