Sheet Metal Bending Technology Ⅰ
Bending process of sheet metal refers to forming process of changing angle of sheet metal. For instance, bend sheet metal, to V shape, U shape and etc. Regularly, there are two bending method: one is moulds bending for complicated structure forming with small size and large quantity process; the other one is press brake bending for large dimension bending production. Mostly, press brakes are widely used in sheet metal bending.
Different bending method, different bending principle, they are chosen according to different production purpose.
1.1.1 Moulds bending
For annual production quantity is more than 5000pcs, and size of parts is not too big of bending (usually 300×300mm), normally, it is better to think about build special punch moulds for processing.
18.104.22.168 frequently-used bending moulds
Frequently-used bending moulds, as figure 1-1 show: in order prolong lift of moulds, it is better to adopt fillet when design moulds.
1.1.2 Press brake for bending process
Press brakes include conventional press brake and CNC press brake. CNC press brake is chosen to bend irregular shape and high accurate works. Its principle is to utilize bending tools (upper die) and V groove (down die), to do forming of sheet metal.
Advantage: convenient to clamp, accurate locating and fast bending speed
Disadvantage: lower pressure, only for bending simple shape, lower forming efficiency, but with advanced CNC press brake, complicated shape can be formed with continuous bending process.
22.214.171.124 basic principle of forming process
For basic principle of press brake, refer to figure 1-2.
1) bending tool(upper die)
shape of bending tools refer to figure 1-3, shapes of bending tools are determined according to actual needed shape of sheet metal.
Figure 1-3 shapes bending tools
2) down die V=6t(t is thickness of sheet metal)
There are many factors to affect bending process, mostly, radius of circular arc of upper die, material, thickness of sheet metal, strength of down die, mouth dimension of down die and etc. Check figure 1-3, left three ones are upper die, and right two are down die.
Basic principle of bending sequence:
1) Bend from inside to outside
2) Bend from small to large
2) Bend special and complicated shape first and then be bend common shape
3) Former bending doesn’t affect latter bending.
Please check figure 1-4 of two common bending formations