The design needs to consider what exactly is processed before forming and what exactly is processed after forming.
Consider the work production process where bending must be done first and then some of the holes are machined later.
Round holes, square holes, waist round holes, threads, etc., which are very close to the bending edge, need to be processed when the material is placed, and if the material is placed directly according to the unfolding, it cannot be completed in the subsequent processing.
The design needs to consider what can be formed in sheet metal and what cannot be formed in sheet metal.
Minimum bending height to be considered: (as shown below)
To consider the minimum bending radius: The minimum bending sheet metal depends on the bending radius of the sheet metal material, the table below shows the minimum bending radius of the commonly used sheet metal material
1. The bending radius refers to the inner radius of the bending part, and t is the wall thickness of the material.
2. M is annealed state, Y is hard state, Y2 is 1/2 hard state.
Consider whether you can use the machine directly for positioning, if not, set aside two small squares for positioning and remove them after bending.
Consider the direction of sheet metal bending: especially for non-ferrous metals, such as aluminum and copper bending. It is important to look at the direction of the grain of the rolled material and bend it perpendicular to the direction of the grain, not parallel to the direction of the rolled grain, as it is easy to have bending cracks.
To set aside bending avoidance gap: When sheet metal bending wrapped sheet metal parts, the two bending surfaces have the relationship between the wrapped edge and the wrapped edge. The bending avoidance gap should be drawn out when making the unfolding drawing. Because when bending to 90 degrees, the sheet metal has bending rebound, in order to avoid rebound after less than 90 degrees, it is necessary to bend greater than 90 degrees to offset the rebound. Therefore, a gap should be reserved for bending springback avoidance.
Sheet metal multiple bending cumulative error problem: Sheet metal bending
accuracy is not very high, generally controlled within 0.2 mm. The larger the bending height, the lower the bending accuracy. When there are mounting holes, threaded holes, press rivet screws and press rivet nuts on the bending surface, the cumulative processing error should be fully considered. The use of installation over hole increase or installation hole design for waist-shaped holes, etc., to avoid installation errors. To facilitate subsequent installation.
To consider sheet metal riveted screws or riveted nuts, the hole is too small from the bending edge: when bending, there is bending deformation and tensile deformation at the same time. There are holes and notches too small from the bending edge, which will cause holes and notches tensile deformation. Generally when leaving the bending edge is 4.5 times the thickness of the material, there will be no bending deformation problem.
The above is the sheet metal design
needs to consider the sheet metal bending problem. Sheet metal design needs to fully consider the bending process and understand the bending process, the design is to be able to process into products. The limitations of the sheet metal bending process
cannot be ignored.