FOLD THE ARC WITH A COMMON KNIFE
First, select the 0.2R ordinary upper die and select the lower die according to the die selection standard, and then calculate the arc length. Secondly, calculate how many knives to complete the arc according to the length of the arc and the thickness of the material. Finally, calculate the bending angle of each fold according to the arc angle and the number of folding knives, and perform the bending. However, the process of forming the arc is formed by several knives or even dozens of knives, so the size range of the bending arc is limited by the knives. When choosing a tool, it depends on the processing method.
In general, the scope of processing is as follows:
1）Forming a 90-degree arc: Arc forming larger than R12.
2）Forming an arc above 120 degrees: All R arcs are larger than the tool limit.
BENDING ARC WITH R MOLD(FOLD ARCS WITH ROUND RODS AND ARC CUTTERS)
The arc R angle is formed according to the inherent R angle of the tool. When choosing a mold, if the forming is smaller than the R12 arc, you can choose the upper and lower molds with processing specifications for one-time forming. Because the R mold is a standard mold, the size of the R specification is limited, so the size of the processing arc is limited.
Standard mold specifications include the following:
1) The R angle of ordinary knives is R3.0.
2) The specifications of round rods are R 3.0, R4.0, R5.0, R6.0, R8.0, R10, and R12. If the required processing R is not within the standard mold specifications, you can increase R by adding material to the periphery of the R mold. If the forming is larger than the R12 arc, it also needs to be formed in several cuts. The processing conditions are the same as those of ordinary knife-folding arcs.
The advantages of bending arcs with R mold have just made up for the disadvantages of ordinary knife bending arcs. The first type has a good bending effect and can process products with strict appearance requirements.
PROCESSING PRECAUTIONS
1）When folding arcs with R molds, we must first pay attention to the selection of molds according to the selection criteria. However, when the mold is processed at 90 degrees, the arc of 90 degrees cannot meet the requirements due to the rebound of the sheet metal parts. Therefore, during the processing, the staff needs to push by hand to ensure the processing angle. Under the premise of having an 88-degree lower die, it should be the first choice when processing a 90-degree arc.
2）When processing arcs, the operator needs to use tools for detection to ensure the appearance and size of the product.
3）When processing corner arcs, we generally use program modeling or manual processing.
Select the V-groove width standard of the lower die when bending arcs
（1）When bending a 90-degree arc, select the V-groove width of the lower die to be: V>2(R+T).
（2）When bending a 135-degree arc, select the V-groove width of the lower die as: V>1.5(R+T).
