Press Brake

CNC Press Brake Slider Deformation Problems And Solutions

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CNC Press Brake Slider Deformation

The CNC press brake is mainly used for the forming and straightening of carbon steel and stainless steel products. It is used frequently and is the main production equipment in the workshop. The equipment is composed of a bed, slider, column, deflection compensation mechanism, workbench, back gauge device, safety protection device, hydraulic system, electrical system, etc. The equipment body has only one basic movement—the slider reciprocating up and down (driven by hydraulic cylinders on both sides), the production site is equipped with various molds of different shapes to bend the sheet into various shapes and angles, at the same time it will make CNC press brake slider deformation.



CNC Press Brake Slider Deformation

Estimated reading time: 7 minutes

Slider Deformation Phenomenon

After long-term use will make CNC press brake slider deformation, the bottom of the slider body undergoes a certain degree of plastic deformation, resulting in varying degrees of gaps between the upper mold clamp, the slider, and the upper mold. It can be measured with a feeler gauge that the openings at various positions are not the same, and the gap in the middle of the slider is the largest, causing the flatness and straightness of the fitting surface of the fixture at the bottom of the slider to fail to meet the fixture installation requirements. The fixture cannot effectively clamp the mold,

which eventually leads to a slight displacement of the mold during the molding process, and the plate is processed with a large forming error, which not only makes the subsequent process impossible to assemble but also causes a great waste of manpower and material resources for rework and repair.

Operators usually fill thin copper of different thicknesses in places with large gaps Slices, to a certain extent, eliminate the activity gap for temporary use. But this will create a piece of Certain equipment hidden dangers that may not only increase the wear of the slider but also affect the fixture and mold performance. CNC bending machine slider interface CNC Press Brake Slider Deformation

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Analysis of the deformation principle

CNC press brake slider deformation is the most complex large-scale component in the bending machine. Often use Q235, The steel is welded. When bending, the oil cylinders on both sides exert a downward bending force on the slider. The slider is connected to the piston rod through the spherical block. On the back of the slider, there is The pressure block and the guide block to provide plane constraints for the up and down movement of the slider.

The work of the bending machine The table and the oil cylinder are the main load-bearing parts, and the center of the workbench and the center of the oil cylinder is the In the same plane, according to the principle of action force and reaction force, the action force is applied between the slider and the joint surface of the oil cylinder is vertically downward and evenly distributed. When the slider is working, the plate will The reaction force of the slider acts on the bottom surface of the slider, vertically upward and evenly distributed.

Use ANSYS finite element analysis software to simulate the whole bending machine, and establish a corresponding finite element model. The deformation of the slider forms a symmetrical distribution, and the middle position at the bottom of the slider has the largest deformation, and the deformation gradually decreases from the middle to both sides CNC Press Brake Slider Deformation

Treatment scheme for slider deformation

Due to the high cost of the overall replacement of the slider, often as high as hundreds of thousands of yuan, and the long processing cycle, it is difficult to meet the needs of the production site in time. To deal with the CNC press brake slider deformation, and combined with various factors such as reducing costs and improving stability, it is possible to consider processing the fixture mounting surface of the slider. After many times of practice and consideration, a total of 3 optimization and transformation schemes are proposed. CNC Press Brake Slider Deformation

Grinding fixture installation interface
The solution is to use a high-precision gantry boring and milling machine to finish the original fixture installation interface after the entire slider is disassembled. When processing, it is necessary to select a reference plane. First, use a dial gauge to measure the actual deformation degree of each contact surface of the slider installation interface, and then process the slider according to the deformation.

After the processing is completed, it needs to stand for a while to ensure that the stress is released. , to ensure that the flatness of the plane can be controlled within 0.1 mm, which can meet the requirements. If there is a higher requirement for roughness, it needs to be ground on a grinding machine. In addition, it is necessary to ensure the depth of the fixture installation groove and the width of the mold installation groove during processing,

to avoid the fixture cannot be installed, or the mold cannot be clamped when pressure is applied due to uneven processing. Although the maintenance cost of this solution is low, and the processing cycle is short, it can be used in the short term,

but the overall thickness of the fixture installation interface becomes thinner, the strength here decreases, and the working center is along the X-axis throat during the bending process. The inner side is offset, and the resulting torque will accelerate the deformation of the slider interface, and the service life cannot be compared with the original size interface. This solution is suitable for situations where it is required to restore the equipment to production in a short period, while also retaining the possibility of further modification CNC Press Brake Slider Deformation

Cut off the original interface and reprocess
This solution is to cut off the original fixture installation interface as a whole, and process a new fixture installation interface on the slider according to the standard size of the equipment factory. The maintenance cost of this solution is relatively low, and no other material costs are required. However, after the installation interface is removed, the interface position needs to be moved up by nearly 120 mm as a whole.

After on-site calculations, the slider of this type of bending machine can only continue to descend 90 mm in the vertical direction before reaching the lower limit position of the oil cylinder, and the working stroke of the oil cylinder cannot meet the requirements. In addition, if considering raising the lower workbench of the bending machine as a whole (including but not limited to increasing the thickness of the workbench) to deal with the problem of insufficient stroke of the oil cylinder,

it is derived that the lifting axis of the rear profiler needs to be raised synchronously to position the workpiece, In this case, the stroke of the screw of the lifting shaft is also limited, and this transformation plan does not apply to this type of bending machine CNC Press Brake Slider Deformation

Cut off the original interface and install a new transition block
The solution is to make a new set of transition blocks for the CNC press brake slider according to the standard size of the equipment to connect the fixture and the slider after cutting off the original fixture installation interface. The transition block and the original slider are connected by high-strength bolts, and the installation holes are set on the transition block at intervals of 500 mm to form a uniform distribution. At the same time, a flat key is provided on the transverse center line for longitudinal positioning to ensure high standard positioning accuracy (In this working condition,

there is no need for keys to transmit torque and large loads, so the keys are difficult to wear and fail). Based on the bearing capacity requirement of not less than 142 t/m, to improve the strength and wear resistance of the slider interface, the production material was re-selected. The mechanical properties of the material have been greatly improved.

The advantage of this scheme is to retain the original structural design, and high reliability, the transition block can be processed directly according to the drawing, the machining accuracy is easy to detect, the control is precise, the transition block produced has high precision, and is processed from this material at the same time It is difficult for the transition block to undergo plastic deformation,

which greatly prolongs the service life, but the disadvantage is that the transition block and the slider need to cooperate in drilling holes, mill keyways, etc. during processing, and the required cycle is longer than that of direct processing on the original slider. The cost is relatively higher CNC Press Brake Slider Deformation

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  1. Avatar di Bruce Bruce ha detto:

    It is helpful for me to solve my problem of my press brake.

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