Why Does Deformation Happen in Plate Rolling Machines? How to Reduce it?
Plate-rolling machines are used in all parts of the world and yield a multi-million dollar market cap from the $206 billion metal forming industry. For such a ginormous industry, it is very crucial to get output that doesn’t settle for subpar quality. For example, the deformities in plate bending can be put away to get better final results by performing various experiments before, during and after the rolling process while operating a plate rolling machine.
Deformation in the metal plates is common because the metal plates either lose their elasticity, get cracked or get rolled with an improper diameter. As stated, meeting the quality standards is essential for the workshops working with plate roller machines. The work is time-bound and requires the least number of deformities possible. Thus, the workshops put immense effort into doing everything in their control to deliver final results with the least number of deformities possible.
The deformity is caused due to the size of the metal plates and the top rolls of the plate bending rolled not being suitable for each other. We will discuss later in this article how to deal with deformities. First, let’s understand what deformity is and how it is formed.
What is Deformity?
A misshapen metal plate is as useful as a spoon with a hole. Deformity in simple terms, means that the two ends of the metal plate will not be parallel in the final results upon being rolled. You may already know what we are talking about if you are an engineer working in the metal forming industry. But it is our duty to help you understand this thoroughly.
To help you with what a deformity in the metal plate rolling process looks like, we have shared a few examples below. In the first image, you can observe that the ends of the metal plate are not meeting properly. This means that when the plate is to be set for forming a cylinder, it will be a difficult task.
There are various types of defects, too, when it comes to metal plate rolling. There are edge cracks, alligators cracks, zipper cracks, wavy edges, zipper cracks, center buckling, and several others, but deformities are one of the few which can be treated before putting the metal plate through the set of rollers.
We will be discussing the solution for deformities in further parts of the article, but first, let’s understand how deformities are formed during the metal plate rolling process in a plate rolling machine.
How Does Deformity Form in a Plate Rolling Process?
The metal plate passed through the plate roll machine gets thinner when it is rolled through the bottom and top rolls rotating in opposite directions. The gap between the rollers is lesser than the thickness of the metal plate in order to create enough friction for final bending results.
While the above-explained situation is not the only cause, metal plates of various lengths and thicknesses will affect the plate roll, and the roll will deform too. Let’s discuss what makes the top roll free from deformation and also makes the ends of the metal plate meet parallel to each other. Moving on to the solution for reducing the deformation.
Crowning: Reducing the Deformity in Plate Rolling
Crowning the top roll will result in getting the top roll in a barrel shape. This barrel shape has to be set according to the width, length and thickness of the metal plates the workshop handles on a regular basis or most times.
To achieve a barrel shape of the top roll, the workshop will grind or cut the top roll using a modern CNC lathe machine. Upon achieving the crowning, the top-roll will look as shown below.
Although, it is necessary, and we would like to shed light on the point that a workshop should crown the top roller with respect to the most used metal plate size and material. If a workshop uses a metal plate that is half-inch thick and 6 feet wide would make a 72-inch diameter cylinder, it must crown the top roll in a convex structure to meet these specifications.
While a workshop that uses different steel plates / grade metal plates and shapes will have to use another crowning on top-roll, which is the barrel shape, roll bending machines used by workshops mostly have the top rolls crowned.
We hope we have helped you with all the doubts that you have regarding the deformity in plate rolling machines. If you want to make sure that the final results are near to what you want and the top roll of your roll bending machine doesn’t get deformed, it is advised to get the top roll crowned. We at Himalaya Machinery have 40+ years of experience in serving the metal-forming industry with plate rolling machine needs, and we would like to hear from you.