How to choose a suitable bending machine?

If the wrong choice is made when selecting a bending machine, production costs will rise and the bending machine cannot be expected to recover costs. Therefore, there are several factors that need to be considered when making decisions.

Workpiece (Manhattan (Guangdong) CNC Machine Tool)

The first important consideration is the parts you want to produce, which is to purchase a machine that can complete the machining task with the shortest worktable and the smallest tonnage.

Carefully consider the material grade, maximum processing thickness, and length. If most of the work is made of low carbon steel with a thickness of 16 gauge and a maximum length of 10 feet (3.048 meters), then the free bending force does not need to exceed 50 tons. However, if engaged in large-scale bottom concave die forming, perhaps a 160 ton machine tool should be considered.

Assuming the thickest material is 1/4 inch, a 10 foot free bending requires 200 tons, while a bottom die bending (corrected bending) requires at least 600 tons. If most of the workpieces are 5 feet or shorter, the tonnage is almost halved, greatly reducing the purchase cost. The length of the parts is crucial in determining the specifications of a new machine.

Scratching transformation

Under the same load, the deflection of the worktable and slider of a 10 foot machine is four times that of a 5-foot machine. This means that shorter machines require less gasket adjustment to produce qualified parts. Reducing gasket adjustments also shortens preparation time.

The material grade is also a key factor. Compared to low-carbon steel, stainless steel typically requires an increase of about 50% in load, while most grades of soft aluminum require a decrease of about 50%. You can always obtain the tonnage table of the bending machine from the manufacturer, which shows the estimated tonnage required per foot length for different thicknesses and materials.

Bending radius

When using free bending, the bending radius is 0.156 times the opening distance of the concave mold. During the free bending process, the opening distance of the concave mold should be 8 times the thickness of the metal material. For example, when forming 16 gauge low carbon steel with an opening distance of 1/2 inch (0.0127 meters), the bending radius of the part is approximately 0.078 inches. If the bending radius is almost as small as the material thickness,

Bottom concave mold forming is required. However, the pressure required for forming with a bottom concave mold is about four times greater than that for free bending.

If the bending radius is smaller than the material thickness, a convex mold with a front rounded corner radius smaller than the material thickness must be used, and the embossing bending method should be sought. This requires 10 times the pressure of free bending.

In terms of free bending, the convex and concave molds should be processed at an angle of 85 ° or less (smaller points are better). When using this set of molds, pay attention to the gap between the convex and concave molds at the bottom of the stroke, as well as the excessive bending that is sufficient to compensate for rebound and keep the material at around 90 °.

Usually, the rebound angle generated by a free bending die on a new bending machine is ≤ 2 °, and the bending radius is equal to 0.156 times the opening distance of the die.

For bottom concave mold bending, the mold angle is generally 86~90 °. At the bottom of the stroke, there should be a gap slightly larger than the material thickness between the convex and concave molds. The forming angle has been improved because the tonnage of bottom concave die bending is relatively large (about 4 times that of free bending), reducing the stress that usually causes rebound within the bending radius range