Press Brake vs CNC Folder: Which is Right for You?

CNC Press Brake

CNC press brake is capable of fulfilling the requirements of various small-batch products, including thin plates such as car front walls, door lintels, car tops, bottoms, and frames, as well as thick plate products.

CNC Folder

The CNC folder is equipped to handle the demands of a range of small-batch products, including thin plates that require lifting, such as car walls, tops, bottoms, and frames, as well as medium-thick plate products.

Fig.1 CNC Press Brake

Fig.2 CNC Folder

Working Principle of Press Brake and CNC Folder

Working Principle of Press Brake

The press brake has its punch and die fixed on the upper and lower workable surfaces, respectively. It operates through the relative motion of the working table, which is powered by hydraulic pressure, and the interaction between the shape of the punch and die to achieve bending of sheet metal materials (refer to Figures 3 and 4).

Fig.3. Press brake bend forming diagram

Fig.4 Press brake bend car wall

Working Principle of CNC Folder

The upper ram, powered by a motor, presses the metal sheet firmly. The folding beam rotates upward to create the bend in the sheet metal products (refer to Figures 5 and 6).

Fig.5 CNC folder bend forming diagram

Fig.6 CNC folder folding car wall

The Forming Characteristics of Press Brake and CNC Folder

Comparison of press brake and CNC folder in sheet metal forming:

(1) Different forming principles

Press Brake: The angle of bend is controlled by adjusting the pressure of the punch. During the bending process, the short edge is on the inside, so operators must support most of the material from the outside. For bending heavy workpieces, the assistance of two or more workers may be necessary.

CNC Folder: The sheet metal is laid flat on the workbench, and the edge beam is pressed down to secure the plate. The bending beam moves up and down to perform edge folding operations. There is no need for manual intervention in positioning and auxiliary flanging during all folding operations on one edge.

(2) Different bending accuracy

Press Brake: The control of the dimensional precision is based on the short side dimension precision of the backstop material positioning. After the bending process is finished, any final error will affect the size of the inner space. Additionally, since the bending angle is controlled by adjusting the pressure of the top punch, the angle is dependent on the thickness of the material (refer to Figure 7).

Fig.7 The press brake error accumulates to the inner space size

CNC Folder: The dimensional precision control takes the first edge as the reference for positioning after the first fold. The final size control is precisely the size of the inner space as specified by the customer. Additionally, the bending angle is directly controlled by the folding angle and is not dependent on the thickness of the material (refer to Figure 8).

Fig.8 CNC folder control inner space size

(3) The material surface scratch problem

Press Brake: At work, the material undergoes relative motion in the lower die, resulting in indentations without surface protection. When bending a large workpiece, it is necessary to rotate the surface multiple times, leading to unavoidable scratches in the bending process.

CNC Folder: During operation, the edge-pressing beam tool and the folding beam tool remain stationary relative to the material, preventing any surface damage. When bending a large workpiece, all processing can be completed on one side of the plate at the same time as it is laid flat, thus avoiding any surface damage.

(4) The different requirement for worker’s skills

Press Brake: It requires highly skilled workers for bending operations.

CNC Folder: Programming can be performed visually with finger painting or by engineers using off-line software. The processing program can also be imported using USB or network connection. After programming is complete, workers’ main tasks are simplified to feeding and unloading, and there is no need for skilled bending workers.

(5) Punch and die

Press Brake: Products with varying thicknesses and shapes require different top and bottom dies to accommodate their specific bending requirements. In some cases, such as arcs, it may be necessary to switch to a different tool or transfer the product to another machine, leading to increased transfer and temporary storage of semi-finished products.

CNC Folder: The rotatable edge beam and simultaneous installation of two sets of edge beam tools make it possible to complete all bending procedures in a single station. There is no need to switch tools for circular arc bending or other special bending requirements, only to modify the procedure.

(6) Die service life

Press Brake: Due to the relative motion of the workpiece between the punch and die, the tooling will experience wear and tear, which requires maintenance or replacement.

CNC Folder: By avoiding the relative motion between the material and tool, the tool can be used for a long time with minimal wear and tear, thus greatly extending its lifespan.

(7) Driven system

Press Brake: The hydraulic drive system requires more maintenance and is susceptible to environmental factors.

CNC Folder: The full electric drive design reduces maintenance and is unaffected by the environment, resulting in higher bending precision.

(8) Disadvantages of CNC Folder

• The bending radius of the folding machine is larger than that of the press brake due to differences in bending principles.
• Workpieces with both sides turned down cannot be processed due to restrictions imposed by the support platform.
• The size of the workpiece is limited by the top punch compression area, thus workpieces smaller than the size of the compression area cannot be processed.
• The press brake machine is more efficient than the folding machine.
• The press brake has structural characteristics and a diverse range of tooling options that make it easier to realize complex shapes, while the folding machine is less flexible in comparison.
• Edge folding machines are widely used in Europe and the United States, while Southeast Asian countries generally adopt the press brake due to the influence of traditional Japanese processing concepts.

Press Brake vs Folding Machine

In recent years, 30% of sheet metal factories in Europe and the United States have expressed a willingness to invest in the use of folding machines instead of press brakes for bending fabrication. This is primarily due to the fact that the operation of folding machines is more convenient and they offer numerous advantages as a bending equipment.

While both types of equipment have their own unique characteristics, I will compare them based on their working principles for your reference.

Press Brake:

In the entire bending process, the operator must manually hold the sheet material and position it using the back gauge. This method is unsafe for operators handling large and heavy-duty sheets as the weight of the sheet can cause the bending angle to become larger. It is also difficult for a single operator to bend large workpieces.

The bending angle is determined by the depth of the upper die into the lower die, and even a small deviation in plate thickness can result in an inconsistent bending angle. Different plate thicknesses require different punch and die configurations.

The installation and commissioning of the machine require professional knowledge and a long startup time. Additionally, the cost of purchasing, replacing, and maintaining molds is high. The maximum bending width is limited by the upright.

Using a press brake can be more complex and requires trained, skilled workers. Each step in the process also requires a longer work cycle, and the repetition accuracy of the workpiece depends on the operator’s skill and technology.

Folding Machine:

• In the bending process, the sheet material is positioned on the worktable of the back gauge to ensure the correct bending distance and secure the plate.
• By using manual mode, the safety of operators is significantly improved.
• Small variations in plate thickness will not affect the accuracy of bending.
• Bending plates of different thicknesses does not require replacing the mold.
• The skill requirements for operators are low.
• This method provides high bending efficiency.