Crowning: A Guide to Minimal Post-Bending Process through Optimal Crowning in Metal Plate Bending
Updated: Mar 24
The bent workpieces are not always perfectly shaped as required. The deflection of metal plates is a crucial problem, and the solution lies in the crowning of rollers for the plate bending machine. Crowning is a process of applying pressure on the metal plates and providing them with a surface profile so that the diameter difference between the center and end is not too much.
As a manufacturer or a workshop owner, you want to get the most efficient results, and having to work too much post-bending does not help with it. On top of it, metal plates are expensive; slightly misbent plates can be treated and corrected to make them useful, but larger deformation will result in wastage.
Whether you’re a workshop owner or a manufacturer, you would not like such a loss. Thus, it is necessary to understand crowning in detail.
What is Crowning?
The deflection is natural to occur in a metal plate when passed through the multiple rolls of a plate bending machine since the pressure might not be the same every time on the length of the metal plate.
The metal plate gets deflection in the center, which is highly unacceptable. To compensate for this, the operator raises the middle of the roll to create better crowning. But one can never identify how much crowning is required since the metal plates' workload and thickness will not be the same every time and will form either convex or concave shapes when both tails of the metal plate are set to be welded together.
Let’s see the effects of crowning on the metal plates when the machine has a variable workload. The workshop owners have to make compromises with the amount of crowning.
Effects of Too Less or Too Much Crowning on Bent/Rolled Metal Plates
We have already discussed that two types of deflections are formed in the sheets. But, when the crowning sits perfectly for a workpiece, it also provides perfectly rolled metal plates. Although the latter is highly unlikely if a workshop generally gets the same bending job, it s advisable to go with crowning that provides a perfect bending job for that workload.
1) Too Less Crowning
The workload will form a convex structure when the rolls have too little or insufficient crowning. This convex structure is achieved since the pressure is more on the edges and the outer edges are stretched.
A metal plate with too less crowning will have a bending job done, as shown below.
2) Too Much Crowning
When the pressure is applied in the middle, the middle portion of the tails of the metal plates stretches out. This results in the concave structure that we formerly discussed in the article. The metal plate with too much crowning will have a bending job done, as shown below.
3) Ideal Crowning on the Bent or Rolled Metal Plate
Even though it is highly unlikely to have a crowning that will perfectly match since the workload will not be the same, it is possible. For the one-bending job, the workshop mostly has to perform, it can set the specific crowning.
You must doubt why it is necessary to crown while it makes the cases harder to assess post-bending. But, the uniform structure throughout the length of the metal plate being bent is always a priority, and crowning helps achieve that.
Crowning is extremely important to process to get a uniform structure throughout the length of the metal plate. Yet, it is necessary to make sure you don't raise the roll unnecessarily or get the raising of the roll done by miscalculation, as that would be a crucial mistake to make. We hope this article has helped you with your doubts, and we would love to know about your metal plate bending needs. We are leading manufacturers of 3-plate rolling machines, 4-roll plate bending/rolling machines and plate straightening machines for your other metal plate bending needs.