Folding unit is less understanding and application to the press brake machine, for most domestic sheet metal users. The hemming unit is not a substitute for the bending machine, but a good supplement to the bending machine. In this way, the most suitable bending process can be completed selectively on the hemming unit or the bending machine.
Definition of Folding Unit
At present, the main structure of the hemming unit includes a single hemming beam structure, a C-shaped hemming beam structure, and an independent servo-driven double hemming beam structure to meet different application requirements.
The form of the blank holder is also divided into a reversible blank holder double-blade structure and a single-blade structure, with an automatic tool change device and rotary displacement and feed device to realize semi-automatic or fully automatic production.
Folding Unit Features
- Large workpieces only need one or two people to operate
- No indentation and crease for surface sensitive materials
- Correct the blanking size of the board in the first hemming, and control the inner hollow size accurately
- A pair of universal bending tools can cope with most bending needs
- The bending angle accuracy has nothing to do with the material thickness
- No need for skilled bending staff, the bending accuracy is guaranteed by the equipment itself
- Large plates are processed flat, no supporting materials are required, eliminating safety hazards
- This side beam and blank holder tool with a service life of up to 20 years
- Graphical English control system, simulating the bending effect in the whole process, what you see is what you get
- The folding unit is very simple to complete certain processes, such as: arc, bottom bending, etc.
- Put the blanking size tolerance on the unimportant side to compensate the blanking size deviation
- High-precision bending reduces man-hours for subsequent welding and polishing
- With the function of turning the blank holder and folding up and down, one machine completes all the bending processes
- The folding unit adopts an all-electric drive system, which greatly reduces the maintenance workload
Features of Press Brake Machine
- Large workpieces require multiple operations
- Indentation occurs when bending
- The bending dimension error accumulates to the last bend
- Different tools are needed to cope with different bending requirements
- Bending accuracy is related to material thickness
- Bending quality is related to the technical level of the operator
- There are safety hazards in the bending process of large and heavy workpieces
- Bending tools are relatively easy to wear
- It is difficult to set and adjust the parameters, unable to simulate the bending effect
- It is difficult for the bending machine to complete certain bending processes
- Inaccurate material blanking size may lead to material waste
- Insufficient bending precision, which brings a lot of work for subsequent welding and polishing
- Multiple bending machines complete the bending of a workpiece in different processes
- Adopt hydraulic system, bring more maintenance work
Application Scenarios of Folding Unit
- Large plates: more than 2 meters or single-person bending plates that are difficult to locate and ensure accuracy
- Heavy plates: more than 30 kg
- The surface requires no damage: pre-coated plate, stainless steel, aluminum plate, etc
- High requirements for dimensional and angle accuracy: meet the follow-up welding accuracy requirements
- Multi-variety and small batches use universal tools to complete all processes on one machine
- Arc bending, what you draw is what you get
- Need to meet the JIT production model
- Product quality: to ensure high-precision requirements
Working Principle of Folding Unit
The folding unit is for the plate to be placed flat on the worktable, and the position is designated by the back stopper. After the press beam cutter presses the plate, the hemming beam cutter realizes the upward and downward flanging action.
The folding machine is mainly composed of four parts: the back gauge workbench, the blank holder, the bottom beam, and the folding beam.
Application Analysis of Folding Unit
The selection of hemming unit mainly considers the following 10 factors
- The difference between hemming and bending principles
- The base of the expanded graph is different
- Difference in bending dimensional accuracy
- Different angle accuracy of bending
- The problem of scratches and damage on the surface of the material
- Requirements for the skill level of workers
- Tool configuration
- Tool life
- Operating position
- The drive system is different
Different Bending Principles
The bending machine controls the bending angle in order to control the downward pressure of the upper knife. At the same time, when bending, the short side is included, and the operator needs to hold up most of the external materials. When bending large workpieces, two or more More staff assistance.
The working principle of the hemming unit is that after the plate is laid flat on the workbench, the holding beam is pressed down to fix the plate, and the hemming beam is turned up and down to realize hemming. No manual labor is required in all hemming processes of one edge. Participate in multiple positioning and auxiliary turning and positioning work.
Different Design Basic of Expanded Drawing
The unfolded drawing used by the bending machine is set by the K factor, or the corresponding unfolded drawing is obtained by deducting the bending based on the empirical value.
The folding machine is automatically generated by Schroder Unfold software. The bending deduction of each side is a sampling-based on the material characteristics. When the bending length, material thickness, bending angle, flanging height, bending direction change, positioning method, etc. are different. The unfold software will give the corresponding bending Subtract, so as to get the most accurate expansion.
Different Dimensional Accuracy of Bending
The dimensional accuracy controlled by the bending machine is the dimensional accuracy of the short side of the back gauge positioning. After the bending is completed, the final error accumulates to the hollow size, especially when bending large plates, the post positioning and support of the multi-person bending process Material synchronization is difficult to guarantee consistency.
The dimensional accuracy controlled by the folding machine is that after the first hemming is completed, the first edge is used as the positioning reference, and the final controlled size is exactly the inner space required by the customer. Because the plate is processed flat, it is positioned in both directions (side Positioning and post-positioning) and bending reversing work can be easily completed by one person.
Different Angle Accuracy of Bending
The angle accuracy of the bending machine control is indirectly controlled by the amount of pressure on the upper die, which is related to the thickness of the material, and the hydraulic drive causes the angle to change due to changes in oil temperature.
The folding unit is fully electrically driven, and the deflection compensation is based on the sampling of the actual materials used and mathematical algorithms based on experience. For different positioning methods, the height of the flanging, the bending length and the bending position, the central electric deflection compensation system combines the flanging The tilt function of the beam and the blank holder finally realizes the stability and accuracy of the intelligent angle control accuracy.
Problem of Scratches And Damage on Surface
When the bending machine is working, the material will produce relative movement in the lower die, and at the same time, it will leave indentations without surface protection. When bending large workpieces, it needs to be turned and moved many times, and scratches will inevitably occur in the process.
When the hemming unit is working, no matter the blank holder and the hemming beam cutter do not move relative to the material, the surface damage can be completely avoided. When large workpieces are bent, because the plates are processed flat and positioned at the same time, all processing on one side of the workpiece can be completed, completely avoiding surface damage.
Different Requirements of Workers’ Technical Level
Bending machines have relatively higher requirements on the technical level of bending workers.
The folding unit can be programmed intuitively by drawing with fingers or the engineer can use software to realize offline programming and use USB or network connection to import the processing program. After the programming is completed, the worker’s main work becomes simple loading and unloading work No need for skilled bending workers.
When the bending machine realizes some special bending (such as arc) requirements, it needs to change the tool or transfer to another machine to realize it, which increases the transfer and temporary storage of semi-finished products.
The folding unit can be designed with a rotatable blank holder, and two sets of blank holder tools can be installed at the same time to realize a single station to complete all bending procedures. For arc bending or other special bending requirements, there is basically no need to replace the tools. It can be fully realized just by modifying the program.
Because of the relative movement of the workpiece in the die of the bending machine, the tool will be worn and needs to be maintained or replaced.
The folding unit basically avoids relative movement between the material and the tool, and the tool life is prolonged.
The bending machine can only be operated from the front.
According to the size of the workpiece, the hemming unit can be operated both front and back or even at the same time, which is convenient for observation and use.
Factor Driven System
Ordinary bending machines are hydraulically driven, which brings more maintenance work and is susceptible to environmental factors.
The folding unit adopts a fully electric drive design, which reduces maintenance workload and has nothing to do with the use environment. So as to achieve higher bending accuracy.