CNC PLATE BENDING MACHINE
What is Plate Bending Machine?
A Plate Bending Machine (also named Plate Roller, Plate Rolling Machine) is a device for the radial forming of flat sheets. The Plate Rolling Machine works similarly to a Profile Bending Machine. However, its design is much simpler.
The Plate Bending Machines are available in a wide range. The smallest devices are table machines with manual operation by a hand crank. The largest Plate Rollers are found in shipyards and can bend sheets several centimeters thick, for example for ship armor.
How does a plate bending machine work?
The sheet metal is pushed between the rollers of the plate rolling machine. If it is moved during the bending process, particularly large radii can be produced.
This is very advantageous for tanks or silos, for example. With the moving bending process, the working range of small plate rollers can be enlarged. The advantage of the bending process is that the sheet cannot buckle during forming. Unwanted hardening or disturbances in the outer geometry are thus prevented. Since a plate bending machine only processes sheet metal but can produce a wide range of bending radii, it is technically very simple.
What is pre-bending in plate rolling?
If the plate ends can be bent prior to rolling, then no extra material is required. This process is called “pre-bending.” Pre-bending can be in a three-roll or four-roll plate roller.
The capacity of a plate bending machine is defined by the maximum thickness and the minimum radius combinations that can be pre-bent for a given plate of maximum width. Pre-bending saves time. You do not have to cut then roll, cut then roll, etc. Pre-bending also eliminates flat spots and material waste.
3 important parameters of the bending machine
Bending Capacity on a plate roll is the capacity at full width the machine is capable of. Rated in mild steel, a ¼” X 10’ plate roll is capable of bending ¼” thick mild steel in a 10’ width to 1.5X the top roll diameter in a single pass but be careful as it may not be able to pre-bend that same material.
Pre-Bend is the initial bend a plate roll operator must make before actually rolling the material. The process involves pinching the material firmly between two of the rolls and then using the side or lateral roll to force the material into an initial bend before rolling commences. This process must be repeated on each end of the plate being rolled to avoid large flattened sections at the mating ends of the cylinder. Pre-Bend capacity is always less than that of the rated bending capacity so it is important to ensure the rolling system you are looking at can properly pre-bend the material you are working with.
The yield strength is the strength of the material you are rolling, or better put, the strength of resistance to bending that the material has. The harder the material the higher the yield strength and the larger/stronger the plate roll must be to roll the material. Yield points vary greatly from Aluminum to Stainless and other materials in between. Make sure you know the Yield strength of your material as plate rolls are all offered on mild steel (30,000 PSI) yield strength rating but can be sized in accordance with your needs.
How to Identify the Right Plate Rolling Machine?
Choosing the right type of plate roller is the first step. As there are various types available and at various prices. When it comes to choosing a plate roller, alongside choosing the correct type it’s imperative that you get the correct size. If the size of the plate bending machine doesn’t match your application you’re going to waste your money unnecessarily. Getting the right type and size for the job should be a priority. To determine what size of plate roll you’re going to need or benefit from the most you’ll need to consider the types of applications, the material you will be rolling mostly, and the operator skill level you have to work with.
Choose the type of plate rolling machine that will perform your work the fastest with the least amount of intervention involved. As 2-Roll bending machines are dedicated to one specific type of application they are not well suited for the job shop. In most job shops and plate production facilities, we see a large variety of initial pinch, pyramid style 3-Roll Bending machines, and 4-Roll Bending Machines. For simple round sections, an initial pinch or 3 Roll Double Pinch Design can be selected, however, for more complex geometry a Variable Translating Geometry or 4-Roll machine with CNC Controls should be used.
5 key points when purchasing a Plate Bending Machine
We covered the general guidelines and uses for the various types of plate bending machines, but when you purchase a new plate rolling machine you will need to have some important information about the plate bending machine, which will help guide you in finding a machine to fit your bending application needs:
What you need to know:
The type of material
The first thing you need to do before you start searching for the best plate roll bender is to determine the type of materials you will be using in your project. Here, you’ll have to consider things such as thickness, width, diameter, strength, and yield. These elements determine the amount of pressure you’ll need and the max and min diameter and width of the plate roller you’ll use.
The minimum diameter of the bending
Taking the thickest material you will be working on and the minimum diameter you will be rolling that material down to will help determine the plate roll size. Plate rolls generally use the 1.5 rule, meaning that a diameter rolled can be no less than 1.5X the top roll diameter. Knowing the minimum diameter you need along with the yield strength of the material is critical in selecting the right plate roll.
How large diameter are you producing?
The larger the diameter rolled the more the need for additional supports around the plate roll. Most manufacturers offer side supports as an option to support the sheet being fed into the rolling process. However, your application may also call for overhead support if a large radius is required and the rolled sheet is being sent high into the air. The combination of side and overhead supports can assist in supporting the sheet during the process and avoid any back bending caused by the unsupported weight of the material itself.
The width of the material
The machine rolling width capacity is very important. The Plate Rolling Machines are available in a range of widths but consider a plate roller with a width capacity that would suit 80% of your production. The wider you go in capacity the larger the top will be. Therefore, increasing the minimum bending diameter.
The overall rolling capacity is determined by the physical length of the rolls. When purchasing a plate roll make sure you are sizing the roll length for the maximum width of the material you will be rolling, understanding that the longer the rolls the larger the roll diameter has to be in order to maintain strength under rolling pressure. The adverse reflection of that is the larger the diameter you will need to be rolling.
What is the thickness of the material you want to bend?
It is important to consider but also remain realistic on the maximum thickness of the plate required. If you are unrealistic in your selection of sheet thickness you may end up with a plate bending machine that is too large for your core production as this would also affect you’re your minimum bending diameter capacity and rolling quality on thinner material.
What is the production quantity you require?
For you to get the best plate roller machine, you need to know the quantity of your output. This will help you determine the type of plate roll machine that will resonate with these needs.
If medium to large production required an electric or hydraulic sheet bending rolls with a digital display for roll positions could help speed up your production.
The CNC three and NC or CNC four roll bending machines are considered to be the best for massive projects, but they boast distinct operational complexity, accuracy levels, and features. You’ll have to choose whether you’ll prefer the three-roll bending machines that are known for their versatility and affordability, or the four-roll bending machines, which are swift, accurate, and precise.
These are the critical factors that have to be taken into consideration when you select a plate bending machine. If you have a plate bending job that requires a new plate roller then contact a BIT representative to help you find the bender that will meet your specifications, production demands, and budget.
Looking for a new plate bending machine? Have the 5 specifications listed above handy and give us an e-mail at [email protected] to find your best plate roller option.