Today, we'll teach you how to choose a bending machine based on the characteristics of these six points:

One: Partwork - A key consideration is the components you plan to manufacture. The highlight is to purchase a machine capable of completing the machining tasks with a compact worktable and low tonnage. Carefully consider the material grade, as well as the thickness and length of the material. If most of the work involves 16-gauge low-carbon steel with lengths up to 10 feet, the bending force need not exceed 50 tons. However, for extensive bottom-die forming, a machine with a 160-ton capacity may be more suitable.

Alright, assuming.Please provide the Chinese content that needs to be translated into American English.Thick materials are 1/4 inch thick, requiring 200 tons for 10 feet of free bending, while bottom-dished mold bending (corrected bending) necessitates at least 600 tons. If most parts are 5 feet or shorter, the tonnage is roughly halved, significantly reducing purchase costs. The part length is quite important in determining the specifications of the new machine.

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

Material grade is also a critical factor. Compared to低碳钢, stainless steel typically requires a load increase of about 50%, while most soft aluminum grades reduce the load by approximately 50%. You can always obtain a tonnage table from the bending machine manufacturer, which shows the estimated tonnage required per foot of length for different thicknesses and materials.

Three, Bend Radius of Parts: When using free bending, the bend radius is 0.156 times the distance of the die opening. During the free bending process, the distance of the die opening should be eight times the thickness of the metal material. For example, when forming 16-gauge low-carbon steel with a 1/2-inch die opening distance, the part's bend radius is approximately 0.078 inches. If the bend radius is nearly as small as the material thickness, bottom die forming is required. However, the pressure needed for bottom die forming is about four times greater than that for free bending.

If the bending radius is less than the material thickness, a punch with a rounded corner radius less than the material thickness must be used, and the embossing bending method should be employed. This requires 10 times the pressure of free bending. For free bending, the punch and die should be machined at 85° or less (slightly less is preferable). When using this set of molds, pay attention to the clearance between the punch and die at the bottom of the stroke, as well as the degree of overbending to compensate for springback and maintain an angle of approximately 90°. Typically, the springback angle on free bending dies on new bending machines is ≤2°, and the bending radius is 0.156 times the opening distance of the die. For bottom die bending, the mold angle is generally 86° to 90°. At the bottom of the stroke, there should be a clearance slightly greater than the material thickness between the punch and die. The forming angle is improved because the tonnage for bottom die bending is larger (about four times that of free bending), which reduces the stress within the bending radius range that usually causes springback.

The embossed bending is similar to bottom die bending, but the front of the punch is machined to the required bending radius, and the clearance between the punch and die at the stroke bottom is less than the material thickness. Sufficient pressure (about 10 times that of free bending) is applied to force the punch front to contact the material, basically avoiding springback. To select lower tonnage specifications, plan for bending radii greater than the material thickness, and aim to use free bending as much as possible. Larger bending radii often do not affect the quality of the finished product or its future use.

Four: The bending accuracy requirement is a factor that needs to be carefully considered. It is this factor that determines whether you need to consider a CNC bending machine or a manual bending machine. If the bending accuracy requirement is ±1° and cannot be altered, you must focus on a CNC machine.

The CNC bending machine slider has a repeat accuracy of ±0.0004 inches, and precise forming angles require this level of precision along with good molds. The manual bending machine slider has a repeat accuracy of ±0.002 inches and typically results in ±2~3° deviations when using appropriate molds. Furthermore, the CNC bending machine is prepared for quick mold changes, making it an undeniable consideration when bending many small batch parts.

Five, Molds: Even if you have a full shelf of molds, don't assume they are suitable for your new machine. It is essential to inspect the wear on each mold by measuring the length from the front of the punch to the shoulder and the length between the shoulders of the die.

For standard molds, the deviation per foot should be approximately ±0.001 inches, and the total length deviation should not exceed ±0.005 inches. As for precision ground molds, the accuracy per foot should be ±0.0004 inches, with the total accuracy not to exceed ±0.002 inches. Precision ground molds are used for CNC bending machines, while standard molds are used for manual bending machines.

Six, Bend Piece Length: Assuming a 5×10 feet 10-gauge low carbon steel sheet is bent 90°, the press brake would likely need to apply an additional 7.5 tons of pressure to lift the sheet, while the operator must be prepared for the 280-pound straight edge to fall.