Computer numerically controlled (CNC) bending is a manufacturing process that is carried out by CNC press brakes (also known as CNC brake presses). These machines can bend sheet metal work from just a few mm across to sections many metres long on the largest industrial machines. CNC press brakes either have a fixed bottom bed with the V block tooling clamped in place and a top beam which travels under force with the V blade tools this is known as down forming. The opposite is an up forming machine with the bottom bend moving and the top beam fixed. Both process methods will produce the same sheet metal components and there are no restrictions to the design of your component to suit either machine.
We have down forming CNC press brakes (Edwards Pearson PR3 and PR6, Trumpf 7036) and up forming CNC press brakes (Guifil PE6-16). The CNC press brake is basically programmed to accept the sheet metal component flat blank at a given distance which is defined by the programmable back stop, the point where the bend will be formed. The distance that the programmable V blade enters into the V block will define the angle achieved of the final bend, the further the V blade enters the V block the tighter the final V bend will be. The final component can be a combination of different bend lengths and angles generated by the CNC program positioning the sheet metal component blank at defined positions and programmed angles.
The maximum length of the sheet metal component that can be bent up is obviously defined by the length of the CNC press brake bed but the thickness of material is a function of the material tensile strength and the amount of tonnage available from the machine to form the sheet metal. The larger the bottom V block opening the greater the sheet metal gauge can that can be bent for the same tonnage. But, as the V block opening is increased so does the internal radius of the bend on the sheet metal work.
We have a range of standard CNC press brake tooling shown on our Tooling web pages which can act as a guide to the basic limitations on bend size for different sheet material thicknesses.
We have a growing section of case studies within the website which illustrate these design ideas and enable you to fully benefit from the versatility of CNC bending, please take a look to learn more or give us a call if you want to discuss further your particular sheet metal work design needs.