Views: 4 Author: DURMAPRESS Publish Time: 2022-01-07 Origin: DURMAPRESS
High quality hydraulic press brake knowledge of purchase: the first important thing to consider is that you want to produce parts, the point is to buy a can complete the processing task and the shortest workbench, the smallest tonnage of the machine.
Carefully consider the material grade and the maximum machining thickness and length. If the bulk of the work is low carbon steel with a thickness of 16 gauge and a maximum length of 10 feet, the free bending force need not be greater than 50 tons. However, if you are doing a lot of die forming with a bottom, you may want to consider a 150 tonnage machine.
Ok, assuming that the thickest material is 1/4 inch, 10 ft free High quality hydraulic press brake requires 165 tons, and bottom die bending (corrected bending) requires at least 600 tons. If most of the pieces are 5 feet or less, the tonnage is almost halved, greatly reducing acquisition costs. The length of the parts is very important in determining the specifications of the new machine.
Under the same load, the torsion of the table and slider of the 10-foot machine is 4 times that of the 5-foot machine. This means that shorter machines require less gasket adjustment to produce acceptable parts. Reducing gasket adjustment reduces preparation time. Material grade is also a key factor. Compared with mild steel, stainless steel usually requires about 50% more load, and most grades of soft aluminum reduced about 50%. You can always get the machine tonnage table from the manufacturer of the bending machine. This table shows the estimated tonnage required per foot length for different thicknesses and materials.
The bending radius of the part
When free bending is used, the bending radius is 0.156 times of the opening distance of the die. In the free bending process, the opening distance of the die should be 8 times the thickness of the metal material. For example, when forming 16 gauge low carbon steel with a 1/2 inch pitch, the bending radius of the part is about 0.078 in. If the bending radius is almost small to the thickness of the material, it is necessary to carry out bottom concave die forming. However, the pressure required to form a concave die is about four times greater than that required for free bending.
If the bending radius is less than the thickness of the material, it is necessary to use the punch of the front fillet radius is less than the thickness of the material, and resort to embossing bending method. In this way, 10 times the pressure of free bending is required.
For free bending, punch and die are machined to 85° or less (preferably less). When using this set of dies, pay attention to the gap between punch and die at the bottom of the stroke, and to excessive bending sufficient to compensate for springback and keep the material around 90°.
Usually, the springback Angle of the free bending die on the new bending machine is less than or equal to 2°, and the bending radius is equal to 0.156 times the opening distance of the die.
For bottom die bending, the die Angle is generally 86 ~ 90°. At the bottom of the stroke, there should be a gap between the convex and concave dies slightly greater than the thickness of the material. The forming Angle is improved because the large tonnage of the bottom die bending (approximately 4 times that of the free bending) reduces the stress within the bending radius that normally causes springback.
Embossing bending is the same as bottom concave die bending, but the front end of the punch is processed into the required bending radius, and the gap between the punch and concave die at the bottom of the stroke is less than the material thickness. Because enough pressure (approximately 10 times that of free bending) is applied to force the front end of the punch into contact with the material, springback is basically avoided.
In order to select the lowest tonnage specification, it is best to plan for a bending radius greater than the thickness of the material and to use free bending whenever possible. When the bending radius is large, it usually does not affect the quality of the parts and their future use.
The bending accuracy requirement is a factor that needs to be considered carefully. It is this factor that determines whether you need to consider a CNC or hand controlled bending machine. If the bending accuracy is ±1° and cannot be changed, you must look at a CNC machine.
CNC bending machine slider repetition accuracy of ±0.0004 inches, forming accurate Angle must use such precision and good mold. Manual bending machine slider repetition accuracy is ±0.002 inches, and the use of appropriate mold conditions will generally produce ±2 to 3 degrees of deviation. In addition, CNC bending machines are ready for quick molding, which is an unquestionable consideration when you need to bend many small batches of parts.
Even if you have shelves full of molds, do not assume that they will be suitable for a new machine. Wear on each die must be checked by measuring the length from the front of the punch to the shoulder and the length between the shoulders of the die.
For conventional molds, the deviation should be ±0.001 inches per foot and the total length deviation should not be greater than ±0.005 inches. For fine grinding molds, the accuracy should be ±0.0004 inches per foot and the total accuracy should not be greater than ±0.002 inches. It is best to use fine grinding molds for CNC bending machines and conventional molds for manual bending machines.
Side length of bending parts
Assuming a 90-degree bend along a 5-by-10-foot 10-gauge low carbon steel plate, the bender would have to apply an additional 7.5 tons of pressure to lift the plate, and the operator would have to prepare for a 280 pound straight edge drop. Making the part may require several brawny workers or even a crane. Bending machine operators often need to bend long side parts without realizing how hard their work is.
There is now a supporting device suitable for such work in the workshop, which can be modified according to the needs of old and new machines. Using this device, the forming of long side parts only needs one person to operate.
Bending machine CNC system is generally used E200 DA41 DA51 DA53 DA56 DA65 DA66