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.
What are the 3 important parameters of the plate 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.
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.