There is a lot of technology wrapped up in creating today’s modern plate rollers. If one is unfamiliar with the process of rolling plate or sheet, then they will have a lot of homework to do before being able to make an informed decision on which type and size of plate rolling machinery will best suit their needs. Some of the major areas that one will need to investigate are:
The type of material(s) that they expect to bend, the yield strength of the material(s), the lengths, material thicknesses, and the diameters of the finished part(s) that they wish to produce
The type of plate roller needed to produce a finished part of acceptable quality and capable of inducing the forces necessary to bend the longest, thickest, or strongest sheet or plate efficiently and effectively
Examine the machines “static” and “dynamic” load ratings.
The portion of the bend that can acceptably remain as an “unbent flat”
Simply put, plate rolling machinery that cannot generate enough force to overcome the materials yield strength will not be capable of making the bend. Therefore one must perform an analysis of the plate rollers capacity against the different materials expected to be processed in the machine based on length, material width, and yield strength.
The type of plate rolling machinery that you select makes a difference as well. Knowing the capabilities of the following type of equipment is important
3 Roll Initial Pinch 3 Roll Double Pinch 4 Roll Double Pinch 3 Roll Variable with Translating Geometry 3 Roll Pyramid 2 Roll Vertical Rolls
By way of introduction, 3 Roll Initial Pinch plate rollers are designed for lighter duty than their 4 Roll Double Pinch counterparts. A brief synopsis of the operational process is the plate rolling machinery will “pinch” the flat sheet between two rollers while the third roller or “bending roll” moves upwards to contact the then bent sheet. The rollers are then rotated and the sheet leaves formed to a given radius.
4 Roll Double Pinch plate rollers employ an extra roller that constantly “pinches” the sheet or plate material during the process of rolling the material. One significant advantage of 4 Roll machines over 3 Roll machines is that the 4 Roll machines often do not require that the material be pre-bent before processing. 4 Roll machines also have a slight advantage in shorter overall material processing cycle times.
The static pressures that occur when the material is pinched to form the leading edge of the bend is a critical factor as plate rolling machinery will always bend thicker material in the dynamic mode than it will it the static mode.
An unavoidable part of the “pinching” step is that it will unfortunately leave a section of the sheet or plate material as an “unbent flat.” Determining how much of an “unbent flat” is acceptable is an important consideration as well. The following considerations are paramount to making an informed decision
The thickness of the sheet or plate being rolled The width of the sheet or plate The cylinder diameter required in the finished rolled size Machine geometry The size of the top roll
Sheet or plate widths The finished rolled cylinder diameter required Machine geometry The size of the top roll The experience and skill levels of the machine operator
All of the information above just begins to scratch the surface of what one needs to consider before making a major investment in capital equipment such as plate rolling machinery. Most distributors will have highly capable salespeople and technicians available to assist you, but first you need to know some of the important questions to ask and a few of the details that they are going to need to know as well.
Roberto Leoni is the Owner of Heli Engineering, a Press Brake Manufacturer situated in Boksburg, South Africa. For more information in relation to Plate Bending Machinery please visit our website or alternatively contact us on +27 11 397 3650/7
