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Six Effective Methods to Choose Best Press Brake

The introduction of press brake

The press brake is a machine commonly used in industrial production to bend metal sheets. As modern industry continues to develop and grow, there is a gradual increase in demand from users for press brakes. However, with this rising demand, there has been a emergence of press brakes of varying quality in the industry. The quality of these machines plays a crucial role in determining the smoothness or challenges faced in the production process in the future.

How to choose best press brake correctly? 

It is advisable to carefully consider the model to purchase based on the primary use of the press brake machine, potential deflection issues, and the bending radius of the parts. When selecting the optimal press brake, decision-makers should delve into the machine’s performance, processing range, processing functions, machining accuracy, and other relevant details. The selection process is not to be taken lightly, as making the wrong choice can result in increased production costs, and the press brake may not be able to recover the expected return on investment.

Workpieces of best press brake machine – specifications and models 

The primary consideration should be a thorough estimation of the standard size, shape, and structure of the parts intended for production. The key focus is on acquiring the most suitable press brake that can efficiently handle the processing task with a compact worktable and minimal tonnage. This approach aims to achieve both practicality and cost-effectiveness in the equipment purchase.

Carefully consider the metal plate as well as the maximum machining thickness and length. If the main product material is low carbon steel, its thickness in 3mm, the maximum length does not exceed 2500mm, then the free bending force does not need to be more than 80 tons. However, if there are a large number of bottom bends during the operation, you may want to consider buying a 150 ton press brake.

In production, if the plate to be bent is low carbon steel, with a maximum thickness of 6mm and a length of 2500mm for free bending, it is advisable to consider purchasing a press brake of over 100 tons. If bending correction is required, a press brake with a higher tonnage is necessary.

On the other hand, if the majority of the bending workpieces are 1250mm or less, the tonnage requirement for the press brake machine can be nearly halved, leading to a significant reduction in the overall purchase cost. Hence, the length of the machined parts plays a crucial role in determining the specifications and model of the press brake machine.

The deflectioncompensation function of press brake

The best press brake in the bending process, especially when bending the long size of the workpiece, will occur deflection. 

The longer the workpiece is, the greater the degree of deflection is. Under the same load, the deflection of the worktable and slider of the 2500mm model is 4 times that of the 1250mm model. 

This means that shorter machines require less gasket adjustment to produce qualified parts, while reducing gasket adjustment shortens preparation time. 

But at present, most CNC hydraulic press brakes increase the function of hydraulic deflection compensation in production design, which reduces the adjustment of equipment by production operators, and improves the bending accuracy and production efficiency at the same time. 

The hydraulic deflection compensation function is controlled by the numerical control system. The hydraulic oil enters the compensation cylinder through the magnetic servo valve to push the worktable up to the top. At the same time, the deflection compensation force increases with the increase of the bending force, thus playing the role of deflection compensation.

Materialbending force

The material of the processed plate is a crucial factor. In comparison to mild steel, stainless steel typically demands approximately 50% more load, whereas softer materials like aluminum often require a reduction of about 50%. Manufacturers provide relevant standard bending pressure parameters, and the table illustrates the bending force per 1000mm length for varying thicknesses and different types of sheet metal.

Bending radiustonnage specification

In the process of bending products, the bending angle radius of the workpiece is a crucial consideration. For free bending, the bending radius is typically 0.156 times the opening size of the V groove. During free bending, the V groove’s opening size should be 8 times the thickness of the sheet metal.

For instance, when bending 1.5mm mild steel with a 12mm V-slot opening size, the bending radius of the part is approximately R=1.9mm. If the bending radius is close to or less than the thickness of the plate, it must be molded under. However, the pressure required for bottom bending is about 4 times greater than that for free bending.

When bending freely, it’s important to pay attention to the gap between the upper die and the lower die at the bottom of the stroke. Utilize compensation springback to maintain the plate overbent at about 90°. Typically, the springback angle produced by the free bending die on a new press brake is less than 2°, and the bending radius is equal to 0.156 times the opening of the die.

Therefore, the die angle for free upper and lower die bending generally falls within the range of 86° to 90°. At the bottom of the stroke, there should be a gap between the upper and lower dies slightly larger than the thickness of the plate.

Accuracy– intelligent numerical control of press brake

Precision in bending is a critical factor that requires careful consideration, influencing the choice between a CNC press brake and a conventional press brake. The selection and procurement of a press brake involve assessing the precision within the mechanical system’s hardness index.

From a scientific standpoint, errors are inevitable and can only be minimized. For workpieces and simple parts where a small range of errors is acceptable, there may be no need to invest in a high-precision press brake. However, for workpieces demanding high accuracy, a press brake with fine precision, such as a CNC press brake, is recommended.

In instances where bending accuracy demands ±0.5° and cannot be compromised, the focus should be on a CNC press brake. The repetitive accuracy of the NC press brake’s slider can generally be guaranteed within ±0.01mm. To achieve accurate forming angles, it is essential to use molds with such precision and high quality.

On the other hand, the repetitive accuracy of the slider in a conventional press brake is ±0.5mm, and even with a suitable die, it may still result in a deviation of ±2 to 3°. Additionally, CNC press brakes come equipped with quick clamps and rapid die-changing systems. Therefore, when dealing with the bending of numerous small parts, opting for a CNC press brake is an unequivocal choice.

Mold– Wear

The bending die significantly influences bending accuracy, making it essential to regularly check die wear. This can be done by measuring the length from the front end of the upper die to the shoulder and the length from the lower die to the shoulder.

For conventional molds, the acceptable deviation per 10mm should be approximately ±0.01mm, with a total length deviation not exceeding ±0.15mm. On the other hand, precision grinding dies should adhere to an accuracy of ±0.005mm per 100mm, and the overall accuracy should not surpass ±0.05mm.

It is recommended to use finely ground dies in CNC bending machines, while conventional dies are suitable for use in ordinary bending machines.

One of the best press brake manufacturers in ChinaRaymax

best press brake manufacturer

Raymax is a professional hydraulic press brake manufacturer and CNC press brake machine manufacturer. Raymax provides many kinds of press brake machines for you to choose for sale which meet your production needs. For the year of 2024 is coming, new press brakes are launched. If you have related needs, welcome to contact us, we will give you customized solution.

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