Tips for Choosing a CNC Press Brake - Bhavya Machine Tools

A CNC Press Brake machine is a great option for a company that produces large quantities of finished products. The main considerations for selecting a CNC Press Brake are the complexity of the designs to be created, how many axes will be needed, and the workspace size. Here are some tips for making the best choice.

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CNC Press Brakes Precision

Your Precision CNC Press Brake will not do the job properly if its tooling is not in good condition. The tools are the only machine parts that touch the finished product, so it is essential to invest in good press brake tools. A poor press brake tooling can render a high-quality machine useless.

The accuracy of tooling will directly affect the accuracy of the bent work piece. The upper and lower dies must match in terms of angle and edge. The die compensation device also plays a major role in the accuracy of the work. A numerically controlled compensation device is able to compensate for a wide range of plate positions, whereas a manually adjusted compensation device will require artificial compensation.

Different materials require different bending forces. For example, thick materials need higher bending force, and this will require a higher press brake load limit. The standard press brakes have capacities of 400, 300, 160, and 80 tons. However, if you need to bend sheets with a different thickness, you can use an Adjustable Die System.

A Precision CNC Press Brake also features a deflection compensation system that automatically adjusts the angle between the top and bottom ram. This device also compensates for deformation in the upper ram. This feature improves the accuracy of a precision CNC Press Brake and also lowers labor intensity.

Speed of CNC Press Brakes

CNC press brakes are capable of bending materials with greater precision. These press brakes can be easily operated and feature a user-friendly control unit. They also offer a rigid body frame and high efficiency. Moreover, they are CE-certified and come with a suitable price range. If you have sufficient funds to invest in a CNC press brake, it’s an ideal choice.

CNC press brakes have a smooth speed conversion and can achieve up to 200mm/s. Their synchronization can be adjusted through a proportional electro-hydraulic valve group. They also have grating rulers that allow users to see errors in real-time. In addition to high bending accuracy, CNC press brakes have fast down and return speeds, averaging at 13 or 15 mm/s.

High-speed CNC press brakes are available for the North American and European markets. The frame of these machines is welded steel and has a single oil cylinder. The working table, oil box, slider, and CNC control system are all integrated into the compact frame of this machine. The die is also included in the compact CNC press brake.

CNC press brake machines are highly versatile and can be customized to meet the needs of your specific business. When buying a CNC press brake, consider the number of axes it has, the complexity of the designs, and the size of the workspace.

Springback in CNC Press Brake

The amount of springback in a CNC press brake is dependent on several factors. These include the material tensile strength, tooling type, and bending speed. This makes accurate springback prediction extremely important, especially when working with materials with deep bends and thick, high-strength material.

The angle difference between the tooling and workpiece during the bend process is used to calculate springback. The angle is then divided by the tooling angle to get the total springback. The springback will vary depending on the material and the bend radius. Calculating the initial angle is simple. Double the final angle to determine the desired result.

Conventional press brakes bend sheet metal to a predetermined angle, then spring back the material to a lesser bend than the desired angle. The operator chooses the terminal punch position manually and then reverses the ram’s movement at a predetermined point. This results in the piece being bent to a loaded angle th1, after which it returns to a relaxed position. The process repeats itself until the workpiece is fully unloaded.

The final angle and radius are calculated by using a springback calculator. Although these calculators are not 100% accurate, they help determine the right press brake tools for your needs. Generally, the amount of springback increases with the IR/MT ratio, so the higher the IR/MT ratio, the greater the springback. For example, 1.8 degrees of springback corresponds to a final radius of.510mm, or about 0.2% larger than the punch radius.

Cost of CNC Press Brake

When you are choosing a CNC press brake for your manufacturing business, you have many factors to consider. First, you will need to determine the thickness of the material to be bent. You will need a large bending force for thicker materials. In general, a press brake should be able to handle up to 200mm of thickness. Besides, you should consider the quality of the CNC machine, its accuracy, and the controls.

Other costs that you will want to consider are the operator salary, the hydraulic fluid, and the tooling. The machine will also cost you electrical costs. In addition, you will have to account for the downtime you will experience when performing routine maintenance. These costs can be a major factor in deciding between two machines.

Purchasing a new CNC press brake will cost you a lot of money. Depending on the size of the press brake, you can spend anywhere from $50,000 to $120,000 for it. Of course, there is another option – reconditioning an old press brake. This option is cheaper than purchasing a new machine, but it will cost more than buying a used one.

CNC press brakes can have advanced features that help make manufacturing easier. Many have multi-axis capabilities that can assist you in your manufacturing needs. They can also be equipped with a CNC backgauge for faster bending.

Installation of CNC Press Brake

A CNC Press Brake is an automated metal-bending machine that produces precision parts. Its automated process eliminates manual work by identifying the correct tooling for each job. The software also determines the proper tooling layout on the machine. This reduces the risk of human error and ensures accuracy and consistency.

Before starting the calibration process, the press brake should be thoroughly cleaned. It has likely traveled long distances and may have been covered in Cosmoline by the factory. It should be checked by staff for loose or broken parts. Then, it can be calibrated. Once cleaned, the machine can be used.

Programming the CNC press brake is a complex process, especially for beginners. It involves setting up the machine, programming the CNC system, and adjusting its parameters. Typically, the ESA CNC controller allows multiple work steps to be programmed. Using the “editor” page of the software, you can input the material, width, thickness, punch, die, and more.

A CNC press brake machine is a useful tool for the manufacturing industry. Whether you need to make complex parts for a mass production, CNC press brakes can provide the accuracy and precision you need to meet production needs. CNC press brake machines are versatile and can be customized to meet your needs.

CNC Press Brakes Maintenance

In order to get maximum efficiency from your CNC press brake, you must regularly perform a series of preventive maintenance procedures. These measures include lubrication and checking the function of the control equipment. For example, you should inspect the longitudinal rulers, electric valves, sensors, and pneumatic valves. In addition, you should check the condition of the matrix mandrels. If they show signs of wear, you must return them to the manufacturer.

The hydraulic oil pipe should be properly tightened. The hydraulic oil circuit should have a good level of hydraulic oil. It is also important to replace the seals in time. If the seals are not properly installed, the press brake may not be able to work correctly. The hydraulic oil should also be filled to the maximum capacity.

It is also important to regularly check electrical connections and switches on your press brake. When performing these maintenance checks, you should always do it with the system turned off. However, there are some maintenance tasks that should be performed with the press brake still under power. When you are working on your CNC press brake, always take precautions. Make sure you do the work in a hygienic environment.

After the press brake is installed, you must conduct a periodic inspection of the hydraulic system. This includes cleaning the hydraulic oil filter and changing the hydraulic oil every three months. Checking the hydraulic oil level is essential to prevent erratic operation of the ram. If the level of the hydraulic oil is low, you will endanger the hydraulic pump and reduce its lifespan.

When customers purchase press brake machine, they are often confused in whether to purchase a CNC press brake machine or a NC press brake machine. Both of the two types of press brake machines bend workpieces to different angles and shapes through different upper and lower toolings.

Actually they have many differences, We analyze from the following aspects:

Usually we name Torsion Bar Press brake as NC press brake, name Electro-hydraulic press brake as CNC press brake. 

1. Different Structure 

The structural principles of CNC press brake and NC press brake are different, so keeping the synchronization of the left and right sides of press brake machine slider are different.

1) NC Hydraulic Press Brake

The entire machine is in fully steel welded structure with stress eliminated by vibration aging technology. The machine mainly consists of the left and right wall boards, working table, oil box, slot steel, synchronizing shaft, sliding block, etc.

It enjoys high accuracy and high strength and can be transported easily. Machine tool have the function of point move, single and continuous, fast and slow area distinguishing slider. Area can be adjusted independently.

Snychro control system:

It also adopts steel torsion bar synchro system with very simple structure but very high accuracy. At both ends of the sliding block, there are 2 synchro folks which make the sliding block movement always parallel to working table. This structure highlights a balanced movement effect during operation. Upper die compensation is used to improve the brake precision.

2) CNC Hydraulic Press Brake

- The whole steel plate of CNC hydraulic press brake is welded and the stress is eliminated by the vibration after tempering sandblasted and sprayed with anti-rust paint.

- The machine frame is processed by imported CNC three-dimensional processing center, which ensures the parallelism and verticality of each installation.

- The CNC hydraulic press brake machine has good rigidity and stability.

- Adopt Hydraulic transmission to ensure stable and reliable operation.

- Use electro hydraulic servo system, full closed loop feedback control synchronization.

- Bending machine throat deformation prevention system to ensure the accuracy of bending.

- Comfortable operation and state-of-the-art technology significantly improve the bending efficiency.

Snychro control system:

The electro-hydraulic press brake machine is equipped with magnetic scale on the slider and the machine wall plate. The CNC controller system can analyze the synchronization on both sides of the slider through the information which fed back by the magnetic scale in real time. If there is an error, the CNC controller adjust the difference through the proportional electro-hydraulic valves ,to synchronize the strokes on both sides of the slider. The CNC controller, the proportional electro-hydraulic system, and magnetic scale constitute the feedback closed-loop control system of CNC hydraulic press brake machine.

2. Different Accuracy

1) NC Hydraulic Press Brake

The parallelism of the slider will affect the bending angles. NC press brake machine is with mechanical forced synchronization method, and the parallelism of the slider can not be checked and adjusted automatically. In addition, NC press brake is not allowed of eccentric load, the torsion shaft of NC press brake machine force the synchronous mechanism to move, which will make the oil cylinders on both sides up and down moving. If the eccentric load bending for a long time, the torsion shaft will be deformed.

2) CNC Hydraulic Press Brake

The CNC hydraulic press brake machine keep the slider synchronization through the proportional electro-hydraulic valves, and the real-time error feedback by magnetic (raster) scale. If there is an error, the magnetic (raster) scale will feedback in real-time, then the CNC controller will adjust through the proportional valves for keeping the synchronization of the slider.

3. Different Speed

The main factors which can affect press brake machine running speed:

(1) The slider moving speed,

(2) The backgauge moving speed,

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(3) The bending steps

- For NC press brake machine, usually we choose the oil cylinder 6:1 or 8:1, speed is slow. For CNC press brake machine, usually we choose the oli cylinder 13:1 or 15:1, speed is fast. So the idle speed and returning speed of CNC press brake are much faster than NC press brake.

- NC press brake, although has fast descent and working speed, the speed of fast descent and return speed can only upto 100mm/s, and the speed conversion is not smooth. The backgauge running speed is only upto 150mm/s.

- CNC press brake, also has the fast descent and working speed, but the fast descent and return speed can reach 200mm/s, the speed conversion is smooth. The backgauge running speed can reach 500mm/s. All these can greatly improve the production efficiency.

- When the workpiece needs multi-step bending, each step of NC press brake need be set separately, the process is very time-consuming. But for CNC press brake, we can set  and save multi-step as a program, can operate continuously, which greatly improve work efficiency.

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4. Different Operation

NC press brake not equipped with CNC contron system, not with V-axis compensation, When bending new workpieces, the experienced operators only can make trial bendings firstly, if not meet the standard sucessfully, we have to continue to try. This not only waste a lot plates, but also the experienced operators need higher salary.

CNC press brake with CNC control system, also with V-axis compensation, easy operation, and low requirements for workers' experience. The CNC controller with the function of simulating bending, no need to make trial bending, the bending can be performed directly.

5. Different Eccentric Bending 

NC press brake machine, because of the machine own structure, the machine not allowed eccentric load. If bend by eccentric load for a long time, the torsion shaft will be deformed.

CNC press brake machine, because the left and right cylinders (Y1, Y2, two axes) move independently, so the eccentric load bending is allowed. 

6. Different Standard Components

1) NC Hydraulic Press Brake

- Traditional structure by using the torsion bar synchronize Y axis

- Standard X, Y, 2 axis

- ESTUN E21 NC Control Unit

- Motorized Back Gauge

- Upper punch compensation.

- FIRST Valves (U.S.A)

- Full length multi V die, Upper punch with segmentation 835mm

- NOK Seal Ring 

- Side and Rear safety protection

- Mechanical crowning system by Manual

- Electrical cabinet with Telemecanique Schneider, Esautomotion, ABB components

2) CNC Hydraulic Press Brake

- ESA CNC Control Unit S630 (Optional DELEM )

- 4+1 or more axis CNC

- Y1, Y2 precision ram positioning

- Standard X and R-axis

- CNC dynamic crowning

- Large open height/ stroke/ throat depth

- NOK seal ring

- Schneider and ABB electric components

- Siemens motor

- Side and Rear safety protection

- Sheet metal frontal supports

- SUNNY Pump

- Ball screw and linear guide

- Rear backgauge fingers with 3 blocks, and double linear guide

7. Different Applications

1) NC Hydraulic Press Brake

Steel structure industry, rough machining factories, truck manufacturing industry etc…

Due to the structure limitation, Wuxi Shenchong does not recommend customer to choose torsion bar synchronous press brake when they buy model above 400tons.

2) CNC Hydraulic Press Brake

All factories need to use press brake can choose CNC Press Brake machine. 

For different kinds of sheet metal bending process.

- Decoration industry: chassis, cabinets, elevator, doors and windows, curtain wall, etc.

- Construction industry: steel structure, tower, bridge, etc.

- Mechanical equipment manufacturing: environmental protection equipment, animal husbandry equipment, solar energy equipment, heat insulator, transformer, etc.

- Electric appliance and power industry: electrical pole, lamp pole, electrical equipment, electronic device, etc.

- Automobile and ship industry

- Aerospace Industry

If you still have doubts on choosing NC press brake and CNC press brake, please feel free to contact WUXI SHENCHONG at any time.