With the development of the economy, places like hotels, restaurants, restaurants, shopping malls, banks, airports have a growing demand for the bend forming of metal decorative materials in middle and high-grade decoration, such as:
- The bending radius of the workpiece should be small;
- The bending angle of the workpiece bending with stainless steel titanium plate or other colored metal plates cannot have great color changes;
- No obvious color difference;
- The curved section of the workpiece is more complicated;
- It can reflect the unique style of the designer.
Traditional bending methods such as forced bending, free bending and even three-point bending have been unable to meet the above requirements.
In other words, bending the metal sheet with press brake alone can not meet the design requirements of the designer, and can not reach the grade and decorative effect of middle and high-grade decoration.
The following workpiece is not able to be finished just with the press brake machine.
Therefore, a novel bending technique is developed, which is: V-groove bending technology.
What is the fabrication process of V-groove bend forming?
To put it simply, it is:
Adopt V-grooving (or V cut) method on the metal sheet first, then bend the grooved sheet metal into various angles and shapes by press brake with general mold or special mold.
Such a curved workpiece can meet the special needs of high-end decoration in hotels, restaurants, restaurants, shopping malls, bank and airports.
The main equipment of v-groove bending technology is press brake and sheet metal V-groover (also been called V-grooving machine).
The press brake is a traditional plate bending machine, and the thin plate V-grooving machine is a new type of sheet metal processing machinery, which is the key equipment of V-cut bending technology.
To better understand the press brake machine, you can refer to The Ultimate Guide to Press Brake.
So, what is sheet metal V-grooving Machine?
Definition of V-grooving Machine
V-groover, also been called CNC V-Cutting Machine, V-grooving Machine.
It’s mainly used to realize a certain depth V-cutting of stainless steel plate, ordinary steel plate, aluminum plate, copper plate, composite plate under 4mm before bend forming.
The workpiece produced with such technique has small bending radius, not obvious color changes, small bending force requirements etc. Besides, it reduces the straightness error of the round edge of narrow long workpieces, and the common press brake and toolings can be used to bend the workpiece with complicated section shape.
V-grooving machines are widely used in stainless steel decoration, elevator, security doors and cabinet industries.
Before the special V-grooving equipment been designed, the workshop generally uses the planer to make a V-shaped groove for metal sheet material.
Due to the fact that the planer doesn’t have an effective metal sheet pressing device, the V-grooving depth of the metal sheet and the positioning distance of the V groove cannot be precisely controlled.
Besides, the planer has high energy consumption and low efficiency.
At present, the work of v-grooving for metal sheet has been replaced by the metal sheet V-grooving machine
The new type of metal sheet grooving machine is designed and manufactured according to the special needs of the middle and high-end decoration industry and elevator manufacturing industry. It can make V-shaped grooves for materials such as stainless steel sheet, iron plate and copper plate.
If some specially dedicated accessories are installed, the metal sheet V-grooving machine can also be used for grinding, polishing and drawing of metal sheet materials and profiles.
Basic Working Principles of Grooving Process
The basic principles of the metal sheet grooving process are:
The metal plate is fixed, and the metal material on the movement track is cut off by using the mechanical movement of the V groover blade to form a process V groove.
The size of the bending angle is related to the depth of the V-groove. The smaller the bending angle, the larger the value of the V-groove depth that needs to be grooved.
There are several technical parameters that have a greater impact on the grooving process. The following uses the technical parameters of a grooving machine as an example (Figure 2).
Fig.2 Technical parameters of V grooving machine
|Max Grooving Width (mm)||1250|
|Max Grooving Length (mm)||4000|
|Max Grooving Depth (mm)||4|
|Min Grooving Depth (mm)||0.8|
|V-groove minimum distance from side (mm)||10|
|Grooving Speed (m/min)||40|
|Resolution of tool carrier left-to-right movement (mm)||0.001|
|Positioning accuracy (mm)||±0.001|
|Resolution of tool carrier up-and-down movement (mm)||0.001|
|Positioning accuracy (mm)||±0.01|
|Main Power (Kw)||4.4|
(1) Maximum width and length of slotted sheet: This parameter affects the maximum size of the sheet metal that the V grooving equipment can process.
(2) Maximum thickness of the slotted sheet: This parameter affects the maximum thickness of the sheet metal that the equipment can process.
(3) The minimum distance of the V-shaped groove from the edge: This parameter reflects the minimum distance between the edge of the planing groove and the edge of the plate material when processing metal plates.
This distance is mainly used for the grooving machine to grip the slot distance, plus the safety distance set by the manufacturer, the smaller the minimum distance value of the V-shaped slot from the edge, the smaller the minimum distance value of the slot edge from the plate material edge.
(4) Cutting speed: This parameter reflects the speed of the tool’s linear movement when processing metal plates. The larger the value, the higher the equipment processing efficiency.
(5) Left and right, up and down movement resolution and positioning accuracy of the tool holder: Each parameter mainly reflects the processing accuracy of the equipment. At present, the minimum positioning accuracy that domestic technology can achieve is ±0.01mm.
In addition to the above-mentioned equipment parameters affecting the grooving process, another important parameter is the blade.
The quality and number of blades directly affect the machining efficiency and the speed of tool wear.
The traditional slotting equipment uses three blades for simultaneous cutting, and the current technology has using four blades for simultaneous cutting. The structure of the blade is shown in Figure 3.
Figure 3 Schematic diagram of the tool structure
There is a distance of 0.1mm between each knife, and the maximum depth of a single groove with four blades can reach 0.6mm.
In order to ensure the quality of the slotting groove and prolong the life of the blade, the depth of a single slotting groove set by a general enterprise is 0.4 to 0.5 mm.
The latest blades developed in the industry are alloy knives, and the service life of each blade for slotting stainless steel material is 2500 ~ 3000m.
The Classification of Sheet Metal V-groover
Currently, the length of the metal plate for V-grooving is: 2500mm, 3200mm, 4000mm, 5000mm, 6000mm and the processing width of sheet metal mainly is: 1250mm, 1500mm, 2200mm, 2400mm.
The most popular type is 4000×1250 (L*W) V grooving machine.
If classified by the structure style, the sheet metal V-grooving machine can be divided into 4 types:
- Mobile Worktable Type
The structure is fixed for the beam, and the tool holder can be positioned on the crossbeam before the groove.
The processed sheet material is fixed on the worktable by pressing device, and the V-shaped groove is carried out with the worktable moves back and forth along the long rail.
It’s similar to a dedicated planer.
The energy consumption is very high during sheet metal V-grooving because the worktable, which is driven by the motor, is moving back and forth along the long rail.
- Beam Move Along Long Rail Type
The worktable is fixed, and the processed sheet is fixed on the worktable by pressing device.
The tool holder is positioned on the crossbeam by moving left and right.
The V-grooving is realized by the beam moving back and forth along the long rail on the worktable.
During V-grooving process, the worktable is fixed, but the energy consumption is very high due to the reciprocating motion of the beam along the long rail.
- Beam Move Along Short Rail Type
The worktable is fixed, and the processed sheet is fixed on the worktable by pressing device.
The beam conducts the pre-grooving positioning by moving back and forth along the short rail of the worktable.
The tool holder does the left and right reciprocating motion on the beam to conduct V cutting.
The energy consumption is low due to the fixed worktable and beam during V-grooving while the power driving the tool holder do the reciprocating motion along the long rail is much less than the power driving the worktable and beam.
- Fixed Beam & Worktable Type
Fixed beam and worktable, and the processed sheet is conducting pre-grooving positioning by the feeding device moving back and forth.
The tool holder does the left and right reciprocating motion on the beam to conduct V cutting.
During V-cutting, it only drives the tool holder do reciprocating motion along the long rail, and light-duty feeding device is adopted for pre-grooving positioning without the need to drive a multi-ton beam.
Therefore, it has the lowest energy consumption and the most obvious energy saving effect.
If classified by the control method, the thin plate V-groover can be divided into:
- Digital Display V-grooving Machine
- CNC V-grooving Machine
The display resolution is 0.01 mm, enough to meet the actual requirements.
Key Features of V-groove Bend Forming Technology
Fig.1 V-grooving bend forming process
1. Small bending force requirement for bending the workpiece
It can be seen from the bending force calculation formula that the bending force required for bending of the workpiece is proportional to the thickness of the plate.
The bending force is large for bending thick plate, and the bending force is small for the thin workpiece.
In the V-shaped groove bending technique, the thickness of the plate is reduced by V cutting in the bending position of the plate, and reduced the bending force that is needed.
Since the depth of the V-shaped groove is 1/2 plate thickness, it can save half of the bending force.
2. A small bending radius of the workpiece
For free bending, the bending radius is proportional to the V-opening width of the die. The width of the die opening is generally 8 to 12 times the thickness of the plate.
To obtain a smaller bending radius, you need to select a die with smaller V-opening width.
The thicker the plate, the larger the V-opening width of the die, and the bigger the bending radius.
On the contrary, the thinner the plate, and the smaller the V-opening width of the selected die, and the smaller the bending radius.
The thickness of the plate is reduced at the bend position by V grooving, and the bending radius of the workpiece are naturally proportionally reduced.
In the plate strength range, the thinner the remaining thickness, the smaller the bending radius of the workpiece.
3. Small color changes at the bent round edges of the workpieces
During the V-shape bending process of the plate, the inside of the workpiece’s bending radius is under compress force and generates compression deformation. The outside of the bending radius is under stretch force and generate elongation.
The main factors that influence the color changes of the bent round edge of the workpiece are the elongation deformation caused by the lateral tensile strength.
It can be seen from the V-shape bending process of the sheet that the elongation deformation caused by the lateral tensile force is also related to the thickness of the plate.
By V-grooving the plate, the thickness of the plate at the bending position is reduced and the elongation deformation generated by the lateral tensile force during bending is also decreased, therefore realizing the purpose of small color changes at the bent round edges of the workpiece.
4. Small straightness errors of the bent round edge of the narrow long workpiece
Generally, in the process of bending narrow long workpiece, the inside of the bending radius generates compression deformation under compress force in the direction of width. The deformation materials move at both ends in the length direction. The outside of the bending radius generates elongation under tensile strength in the width direction. The materials move to the center in the length direction. In this way, the bent around edge’s line of the workpiece forms center-concave.
The larger the bending deformation, the more serious the center-concave of the edge line. The smaller the bending deformation, the less serious the center-concave of the edge line.
Since V-grooving reduces the plate thickness at the bending position, the bending deformation also reduced, therefore, V-grooving bend forming technique makes the straightness errors of the edge line of the narrow long workpiece becomes small.
5. Adopt general mold to bend workpiece with a complicated or enclosed cross-section
For press brake, just the general toolings are needed to conduct the V-grooving bend forming technique.
Some workpiece with complicated or enclosed cross-section can be bent without special toolings by correctly control the grooving depth and edge length (as shown in fig.2), which will reduce the expense incurred by the complex toolings with special design and shorten the processing cycle.
Fig.2 Workpiece cross-section shape
The Application Prospect of V-grooving Bend Forming Technology
Due to the obvious advantages of V-shaped groove bending technology, and the traditional bending method and bending equipment are not changed, only the sheet metal V-grooving machine needs to be added, so V-grooving bend forming technology has been widely used in the emerging middle and high-grade decoration industry in the first place.
It was then used in elevator manufacturing.
Next, some experts in medical device manufacturing, electric control cabinet manufacturing industry also show their interest in V-grooving bend forming technology.
It can be seen that with a deep understanding of the V-grooving bend forming technology, the application field of this technology will be broader.
CNC Auto Metal Sheet V-grooving Machine Operating Instruction
PLC Touch Screen Operation Method
Start the V-grooving machine
Open the air switch on the right side of the electricity box and then open the key switch on the front panel. The whole machine is electrified. The touch screen enters the initial screen after a delay of three seconds.
Light touchscreen, the whole machine enters into operation monitoring. The touchscreen has the following contents:
1). The beam position
The position of the beam relative to the initial point. This position is detected by the screw encoder, and the following numbers represent the number of the grooving line.
2). The target position
Refers to the target position of the current moving beam. If the grooving machine still not start grooving when the beam moved at the right place, press the “beam movement” button, and the machine cannot move.
3). Current distance
Refers to the distance between the current groove and the previous groove.
4). Blade holder position
Refers to the 3D point of the current blade tip relative to the origin point, which is also the initial point. When this position is greater than 29.8mm, the tool holder will not move. The coordinate point is measured by the stepper motor encoder on the screw rod, and the number in the back indicates the number of grooving.
5). Plate width and plate thickness are set working parameters.
6). Press the start button to groove when the position light flashes. When the depth light flashes, press the “Move” button to run to the next position for grooving.
7). Press “manual operation” to control the operation screen by hand.
8). Press the “open groove preparation” button, the beam can be moved to the front of the platform, and the various grooved parameters are initialized to prepare for the grooving of the next metal plate. The beam will not move when the beam position is less than the initial position offset, but the parameter initialization is normal, and the button should not be pressed during the grooving.
9). In order to replace the blade, a grooving pause button is set. When the button is pressed, the grooving machine will stop working, and then press the button to restart the machine.
10). Press “parameter setting” to jump to the parameter setting screen.
The manual operation has the following buttons:
1). “Beam forward” means that the beam moves forward in a manual manner and the moving speed is set in the system parameters.
2). “Beam backward” means to move the beam back in manual mode and set the moving speed in system parameters.
3). “Tool holder to the left” means to move the tool holder to the left in manual mode, and the movement speed is set in system parameters.
4). “Tool holder to the right” means to move the tool holder to the right in manual mode, and the moving speed is set in the system parameters.
5). “Tool holder up” means to move the tool holder up manually.
6). “Tool holder down” means to move the tool holder down manually.
7). “Operation instructions”: press this button to move the screen to the operation instruction screen.
8). “Origin alignment”: press this button to perform the function of returning the original to correct the position of the beam. In general, there is no need to perform the function of returning to the origin (because the computer does not have the function of location memory).
However, if the grooving machine has stopped for more than two days, or if the position is not correctly caused by some other circumstances, the function of returning to the origin should be performed first after electrification to ensure the normal operation of the machine.
1). Press the “parameter setting” button to the parameter setting screen, where the grooving spacing can be set, and 50 grooves can be set totally.
2). The first groove can be set with a minimum value of 8mm and a maximum spacing of 1220mm. The rest grooves have no limits.
3). After pressing the menu you want to set, a digital keyboard appears on the screen。 “ENT” is the input confirmation button, “ES” means the input is canceled, “CR” means the input reset button. All the parameters are positive, if there is a negative number, the machine will report an error.
4). Press the “return” button to return the setting screen.
5). In the parameter setting, press the “system parameters” button to back to the system parameters screen.
6). After setting the parameters, check carefully according to the process sheet to prevent errors.
7). The #1 distance refers to the vertical distance from the 1st groove to the initial point. The #2 distance refers to the vertical distance from the 1st groove to the 2nd groove. And so on, for each of the groove distance.
8). In the parameter setting screen, the current process can be cleared by “parameter full clearance”.
There are several types of buttons in the system parameters:
1). “Deceleration advance” is the position of the beam positioning from high speed to a constant speed. This parameter is important for positioning. If each positioning exceeds the stroke, then increase this parameter, generally set to 8 mm, with a maximum setting of 9.999 mm.
2). “Positioning ahead” is the positioning position of the designated pre-stop. After the stop, the beam moves to the positioning position under the action of inertia. If the grooving machine doesn’t stop at the right position for each stop, it means the parameter setting is too large. Otherwise, the parameter setting is too small. The maximum data of this parameter can be set to 0.8mm.
3). “Allowable error” is the allowable error after the positioning. It is not allowed to groove if not in this range, and manual correction is required.
4). “Initial point error” refers to the distance between the blade tip and the edge after correcting the origin. The minimum setting is 8 mm. Otherwise, the front-positioning proximity switch needs to be adjusted in time.
1). Grooves must meet the following conditions
- The emergency stop switch is not pressed;
- Positioning (indicator light flashing);
- The pressing foot at the side pressed the sheet metal;
- There is no limit on the right or left of the tool holder;
- The beam is not out of stroke range;
- The tool holder stop button is not pressed;
- The longitudinal position of the blade tip ≥ 8mm;
2). Moving beam
When confirmed finished grooving, press the “Moving Beam” button, the grooving machine will read out the position for next grooving and automatically add to the target position. The beam begins to move and positioning. After automatic positioning, a grooving process must be carried out before the beam can move again. It will keep going back and forth until finish all the grooving line.
3). Conditions for moving beams
- Beam stroke not greater than 1220mm;
- Position positioning does not flash OK;
- The position of the beam is not greater than the target position;
- The follow up pressing device lifting up;
- The emergency stop switch is not pressed down;
- The beam front limit switch is connected;
- The grooved motor contactor is not pull in.
4). Press the “Grooving ready” button to move the beam to the front of the platform.
The Grooving Machine Accessories
- Programmable controller
- Step motor
- Step driver
- Proximity switch
- Switch power
The Operation Method for Mechanical Grooving
- Lay the metal sheet flat on the workbench. If the metal sheet has a protective film, then the side with the protective film facing down. One side of the sheet metal clings to the benchmark block in front of the worktable.
- Press the sheet metal pressing button to tighten the edge of the sheet material and complete the positioning of the sheet material.
- Adjust the position of the proximity switch limit block at the left and right side of the tool holder slide block properly according to the length of the plate.
- Determine the spacing of the grooves and the forward and backward adjustment of the beam. Jog the “origin alignment” in the PLC touch screen to realize accurate positioning. That is, the beam displacement to the first groove position, press the follow-up press button to press the plate material tightly.
- The blade block with a thickness of 35mm is used to set the initial point of the blade, lock the pressing screw, and check the blade block to ensure the height of the blade. This is an important preparatory work to ensure the precise depth of the grooves and the production of safe grooves.
- Check whether the blade is in good condition and if the blade is badly worn, loosen the blade. Press the screw and rotate the blade 90 degrees, that is, change it to a new blade edge. Or flip the blade and change another blade surface.
- Press the work-in button on the operation panel of the electrical box to perform the first grooving. Generally, the first grooving depth is 0.3mm, followed by the thickness of the processed plate.
- After the groove depth meets the requirement, let the grooving blade exit the plate surface. The sliding frame automatically moves to the pre-set right limit position. The PLC controls the beam displacement to the next groove, and then the second grooving is processed. Until the whole grooving process is finished, press the “release button” of the follow-up material’s pressing on the mobile operating station and loosen the follow-up press device. The PLC performs the next groove positioning instruction. The beam immediately moves back to the next groove and repeats until all grooves are finished.
- After the completion of the grooving work, loosen all the pressing devices, back the beam to the appropriate position, take out the plate materials, and clean the working table.
- When spray cooling is needed, the switch in the electric cabinet will be opened first, and the cooling system will be automatically lubricated during the cutting process.
Safe Operation Procedure for CNC V-grooving Machine
- CNC Grooving machine should be maintained and operated by the specially-assigned person;
- The operator of CNC V-groover must pass the training of the professional department. After passing the examination and obtaining the qualification certificate, the operator can operate independently;
- Before the operation, wear long-sleeve work clothes (to prevent burning by the grooved debris from splashing), and gloves must be worn when loading and unloading the sheet metal;
- Before starting the V-grooving machine, check whether the machine table is clean, especially between clamps and table;
- Reset the origin after starting up. When working, check whether the workpiece conforms to the process requirements and correctly input the size and grooving depth;
- When the operator is put on the small sheet, remember to handle lightly. Before loading, clean the machine surface and the feeding table, and can not residual grooved wire and other sundries;
- When running the grooving machine, check if the plate is pushing to the origin. The staff shall not extend the head and any part of the body into the machine motor area (to prevent hurt by the machine). The air gun and hand should not be placed under the fixed clamp;
- When the grooving machine is in moving, the operation must be stopped in case of a machine collision or a collision of the materials. First, reset the origin to prevent the moving of the origin at the time of the collision;
- After grooving, gently place the sheet in the designated position to prevent the workpiece from being scratched;
- After the operation, conduct the daily maintenance of the grooving machine, cut off the power supply and clean the workplace.
Gantry (Horizontal) V Grooving Machine vs. Vertical V Grooving Machine
When you decide to purchase one V grooving machine, you will definitely face such confusion – which one should I choose between the gantry (horizontal) V grooving machine and the vertical V grooving machine.
Here let me tell you the difference between them.
Currently there are two types of V grooving machines on the market: vertical and horizontal.
The structure of the vertical V groover is similar to that of the door frame type. The fixture is used to pull the plate to the corresponding processing position. After the clamp is pressed, the V groove is processed by the cutter movement.
It can be understood that through the movement of the plate to cooperate with the tool processing, the tool only performs linear movement of the processing.
The principle of the horizontal V groover is opposite to that of the vertical V groover.
It is provided with a large working table, the plate is fixed on the table by pressure clamps, and the cutter is a gantry automatic mechanical structure.
The tool moving device on the gantry first locates the machining route on the Y-axis, and then the gantry drives the tool to perform the V groove machining on the X-axis.
It can be understood as a fixed plate, which is processed by the movement of the cutter.
Each type of groover has advantages and disadvantages (Table 1).
Table 1 Comparison of vertical and horizontal V groover technology
|Item||Vertical V Groover||Gantry V Groover|
|Processing range||When processing workpieces that need to be grooved around, if the workpiece is long, you need to add a table to carry the workpiece when processing the short side, which is inconvenient to operate.||Three-axis CNC machining with a large processing range, suitable for a variety of large-sized shapes.|
|Worktable processing technology||The worktable surface is made of high-quality mold steel after overall heat treatment, and is finely ground by a grinder. The surface fineness reaches a mirror effect.||The worktable surface is welded by ordinary iron plates. The hardness of the workpiece is higher than it. The grooving steel wire, damaged blades, etc. will make the worktable surface pitted (requires the self-planing function to restore the worktable surface regularly).|
|Processing efficiency||The minimum distance between the V-shaped groove and the edge is 10mm, and the cutting speed is 40m/min.||The minimum distance between the V-shaped groove and the edge is 8mm, and the cutting speed is 50m/min or higher. No need for reciprocating feeding, so is more efficient.|
|Power loss||The tool carrier moves back and forth with less loss (main motor power 4.4kW).||The gantry and the tool carrier are moving back and forth together, and the loss is large (the main motor power is 5.5kW).|
|Safety||The vertical grooving machine automatically clamps the workpiece by hydraulic pressure, automatically positions and works automatically. The operator is away from the moving parts of the machine.||The workpiece is clamped within the movement range of the machine. The gantry moves at high speed, and the control part runs with the gantry. The operator needs to pay attention to safe use.|
|Overall effect||Due to the need for automatic feeding after gripping the workpiece, the iron scraps generated by the grooving often scratch the decorative surface, and frequent alignment and movement are required when processing large-sized workpieces, which is more likely to damage the surface.||The workpiece does not need to be moved during processing. It can be operated by one person during the whole process, and the decorative surface of the workpiece will not be scratched, ensuring the surface processing quality (an important reason for use in the elevator industry).|
The application characteristics of the two can be seen from the comparison items. The specific choice of equipment for processing needs to be determined according to industry requirements and workpiece characteristics.
Generally, the gantry V grooving machine has high working efficiency, however, the accuracy of grooving (slotting) is not as good as vertical V grooving machine.
Besides that, if the sheet metal is in non-specific shape (cut by laser cutting), more grooving line will be needed, then we suggest you choose vertical V grooving machine.
If it is a whole piece of sheet metal or more symmetrical piece (square or rectangular), we recommend choosing the gantry type or horizontal type V grooving machine.
Furthermore, the current price of the gantry type V grooving machine is a little cheaper than the vertical V grooving machine and the gantry type is still the relatively popular type and selected by most of the customers.
As customers have higher and higher requirements for the aesthetics of their products, the application of the grooving process is becoming more and more widespread. It is believed that the grooving process will definitely bring more benefits and contributions to the manufacturing industry in the future.
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