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What is CNC Plate Rolling Machine?
CNC Plate Bending Machine has been around for a while but has become better and better with time and advancement. It is a plate roller that helps roll bend plates of metals into desired geometric. It has several uses which are needed in various industries such as manufacturing, automobile, railway, aircraft, shipbuilding, and so on.
- Consistent leading and trailing edges
- Consistent accuracy
- Consistent shape production
- Simple development of irregular shapes
- Reliability for both low and high volumes
- Automation in varying degrees
How to Programming in the Plate Rolling Machine
Intelligent CNCs today use factory-developed algorithms tailored for the rolling process for plate rollers.
To create programs on the CNC bending machine, operators can choose from a library of shapes, then enter the required data. This can include material length, thickness, material type, yield strength, and other items depending on the shape.
On parts with a blended or changed radius or diameter, for instance, it is critical to know where the blending is to begin and end.
A corrections page on the control allows operators to tweak the program if necessary. In addition, some controls allow for the import of DXF files.
What functions must a CNC plate rolling machine have?
CNC facilitates simple programming and consistency with varying degrees of automation.
On fully automated lines, the plate is loaded automatically onto the feeding table. Motorized alignment ensures that the plate is parallel to roll input, the material is prebent, rolled, and supported. Then it is auto ejected and transferred to the welding station.
On an automated line, plate rolling is not necessarily the only operation. It is part of upstream and downstream processes, such as welding.
The CNC has to be powerful enough to control all the different axes, not only those of the roll bender, but also of all the other accessories such as the feeding table, plate centering, lateral and top supports, and clamping devices. The entire process has to be flexible enough to synchronize with the other operations on the line.
Automated lines can incorporate some manual operations. For example, they can have a manual feed, automated rolling, and manual part removal.
All the parameters can be entered into the CNC, but in reality, material thickness and yield strength can vary, and every difference from the programmed parameters can result in a variation, from design to workpiece.
An operator has to be involved to adjust the parameters as needed. However, this operator does not have to be a rolling expert. Once he has adjusted the program, the plate roll operation can be run in automated mode.
What Plate Rolling Machines Benefit From a CNC?
4-roll plate rolling machines, be they planetary or lineal, are ideal for CNC operation. That is, the 4-roll machine can be programmed and controlled by the CNC.
Two-roll machines can be extremely productive, but they’re usually used for a specific job or job and with an NC. As production systems, two-roll machines with even the most basic controllers can roll part after part at high speeds, often in as little as 10 seconds. They might incorporate sophisticated controllers for associated automation such as material feeding or offloading systems. But the rolling process itself typically wouldn’t gain the full benefits and versatility of a top-of-the-line CNC.
Most people looking for controlled bending rolls are not considering three-roll double-pinch or variable-axis plate rolling machines, though NCs are available for certain applications. They don’t really lend themselves to CNC operation, because the rolls are not constantly pinching the plate for applications requiring pre-bending at both ends. Similarly, single-pinch machines can be used with a CNC, though they’re not ideal for most applications. But four-roll bending machines, be they planetary or lineal, are ideal for CNC operation.
The beneficial use of a CNC has to do with how material must be moved in the machine through the rolling cycle. To prebend, both ends or use a reference point requires a constant reference point. For pre-bending both ends on three-roll double-pinch machines, the plate is usually clamped, released, and clamped again. When the material moves, the control can lose the material’s true position. In a four-roll machine, the middle-bottom roll pinches the material throughout the entire rolling cycle. In this way, the control “knows” the plate position throughout the process.
A Note on Capacity
A machine’s “CNC capacity” is not its “rated capacity” or “pre bending capacity.” It is something less, usually about 40% of its rated capacity.
Consider a machine with a rated capacity to roll up to 1-in.-thick, 36,000-PSI-yield-strength steel in multiple passes. This means the machine can roll this material down to a diameter between three and five times the top-roll diameter, depending on the manufacturer. This same machine rolling the same material would (again, depending on the manufacturer) likely have a prebending capacity of 0.625 in. over multiple passes, down to a minimum rolling diameter between 1.2 and 1.5 times the top-roll diameter, with the flat ends between 1.5 and 2 times the material thickness. Minimum diameters as tight as 1 times the top-roll diameter are achievable on certain material thicknesses.
This same machine would likely have a CNC capacity of about 0.40 in. This is because the control algorithms look for “one-pass rolling,” as none can accurately calculate the influence of the weight and position of the plate during subsequent passes.
Does the CNC on a plate roll really work? Although nothing is perfect, CNC-based systems have had great success. The best chance of success comes when the operator or programmer knows the real properties of the material they are using, such as yield strength and actual thickness. In fact, rolling any shape can be influenced by material grain, the material’s exact thickness and yield strength, the plate temperature, along with how the material was processed before it reached the roll.
Options like top and side supports can help. The top support, for instance, can help support the workpiece and size the part. Say you’re rolling 10-ga. material to a 70-in. inside diameter. Unfortunately, the material bows under its own weight after half the cylinder or more is rolled. This not only creates an inconsistent diameter, but also increases the chance that the plate ends will overlap. In other words, you would be rolling a double material thickness.
In this case, you might set the top support to a lower height (smaller diameter). Once the cylinder’s leading edge is over the top support, you’d move the top support to 70 in. With the cylinder diameter precise and consistent, its edges won’t overlap, preventing you from rolling a double material thickness.
What about material irregularities? For instance, certain materials might have their own peculiarities, even beyond variation in yield strength. To accommodate this, modern controls use artificial intelligence (AI) to “learn” about your materials and their characteristics. The more you roll, the more the controls learn.
Systems can use a remote radius-measuring system, wired directly or connected via Wi-Fi, to check the part radius as the sheet or plate emerges from the rolls. The system feeds the information back to the control to make the necessary adjustments and complement the AI library.
Today this represents the state-of-the-art for typical rolling operations. But for certain niche applications, it makes business sense to take real-time measurement to the extreme.
For instance, it is possible to develop a laser-based measurement device on both sides of the machine. The part is rolled completing the pass. The device measures the diameter or radius and feeds this measurement back to the control. The control compares the actual measurement to the measurement the control thinks it should have. Any correction is made for the next pass and continues the process until the final part dimensions are achieved.
For example, if on the first pass the machine sees it’s rolling a 40-in. diameter, and it knows the diameter needs to be 36 in., the machine’s algorithms—using the known material properties such as thickness and yield strength—will make the necessary adjustments for the next pass. Such extreme forms of real-time measurement are rare, simply because of the time and money involved. But it at least shows what pushing the envelope can achieve.
Cones and the CNC
The CNC can perfectly store settings for roll positions, linear travel, and the position at each end of each lower roll, if properly equipped. So if you can place the properly cut plate in the machine in the correct position, it should “theoretically” roll the part with the setting from the property, previously rolled part.
The only problem is that since the cone had two different diameters, the material must slide on the rolls; that is, you must pass the small end close to the cone attachment through at a slower rate than the big diameter. If the plate loses the “0” position, it cannot achieve consistent results cone to cone. Depending on what is being rolled and the quantities that justify the investment, tapered rolls can sometimes help.
Manufacturers have not perfected the needed software and related machine components to consistently roll a cone, especially with the CNC finding the settings. Different factors, and factors in different ways than in the normal cylinder-type rolling, affects the final results. They include plate placement before rolling begins, the tilt of the rolls, the temperature of the plate, dirt on the plate and the location, slag on the material from plasma cutting, and different hardness locations from laser or plasma cutting.
Modern rolling machines now can be part of larger automated systems that can incorporate feed systems, combination cut-to-length and feed systems, part loading, part ejection, special top support devices, and even robotic part handling and part welding. All this offers fabricators ever greater levels of productivity.
And when programming manually, a camera system can help operators locate the plate as close as possible to the center distance between the top and middle-bottom roll. Plate rolling equipment-makers and service providers can even access the control remotely to provide customer support, and safety interlocks can be provided for applications as warranted.
New Opportunities in Rolling
Consider an operation that makes excavator buckets. The operation might bump them on the press brake, but doing so requires careful planning and handling. And no matter how well the brake performs incremental bending, in most conventional applications the brake will probably leave noticeable bend lines.
CNC rolling leaves no bend lines and can produce a better-looking product overall. And the intelligent CNC makes producing those buckets—along with square tanks, ellipses, ovals, and other products that require a truly blended radius—much faster than it used to be. Moreover, CNCs can benefit from training. By working on a CNC roll and observing the process, inexperienced operators learn more about rolling.
As with most machine tools, CNC rolling systems can help you achieve certain goals, but adjustments might have to be made to produce perfect results. Regardless, when you get those adjustments right, the CNC roll can help reduce your cost per part and, in many cases, dramatically shorten your production time.
11 Advantages of CNC Plate Rolling Machine
CNC Plate bending machines are incredibly useful for metal-working companies seeking to optimize their production. If you aren’t convinced already; here are 11 key advantages of using CNC plate rolling machines.
- Accuracy: Using rotary encoders to track the exact position of the plate allows an optional CNC unit to be added to give very precise control of each stage of the rolling process.
- Ease of Operation: Newer operators can perform various functions such as pre-bending and cone rolling with the precision of seasoned plate roll operators.
- Safety: Horizontal material loading is safer than the angle loading required of most three rolls. Not having to remove, rotate and again square the plate to prebend the second edge eliminates many potential hazards from the material handling portion of the operation.
- Versatility: A CNC plate roll can easily bend challenging contours such as rectangles, ovals, or polycentric shapes, a valuable feature for creating non-cylindrical storage tanks.
- Z-Axis Movement: The additional bottom roll of a 4-roll bending machine is able to move up and down in the Z-axis to pinch the material against the top roll, providing incredible control of the plate. This allows for much better pre-bending and tighter part diameters than previously possible with 3-roll plate rolls that lack the Z-axis clamping.
- 16-Segment Speed Control: Facilitating a wide variety of speeds permits these plate bending machines to work with many different metals in different working conditions. And being able to program these into the CNC system, means you can easily create specific programs for dealing with particular metals, thicknesses, shapes, and quantities of material.
- Simple Programmable Logic Controller (PLC): In line with incredible speed control, the simple PLC allows pre-programing of various different tasks.
- Tailored to your needs: With various optional features, the CNC plate bending machine can be tailored to your exact needs. The most common of these optional features are PG vector control, torque control, and V/F control.
- Powerful input and output: With the ability to be programmed for multiple functions, plate roll bending machines offer an incredible range of potential inputs and outputs in one bundle. This can depending on your model, help reduces the necessity for multiple machines which undertake similar tasks.
- Unique Adaptive Control Characteristics: Thanks to the plate rolling machine’s powerful CNC functionality, metal plate roll bending machines offer automatically assigned upper limits of motor torque. This helps to prevent frequent circuit tripping which is most often caused by exceeding torque thresholds.
- Built using Advanced PID Algorithms: Yet another advantage of CNC design is the incredibly advanced PID algorithm. This helps to effectively regulate temperature, flow, pressure, speed, and other variables to ensure the longevity of the machines. The advanced algorithms used in these CNC sheet metal roll bending machine provides fast responses, strong adaptability, and simple debugging if any problems do arise.