Benefits of Crown Curve for Custom Screen Media

By Serge Raymond, MAJOR Product Specialist

If you’re in the aggregate or mining industry and rely on tensioned screen media for your vibrating screens, you’ve probably heard of the crown curve. But what exactly is it, and why is it important?

What is the Crown Curve?
The crown curve, or camber, is a high point created in the middle of tensioned screen media by the clamp rails that hold the screen media down on either side. This curve is essential because it allows producers to maximize performance and wear life. Let’s break down how it works and why it’s so crucial for your operation.

What does the crown curve do?
The crown curve ensures equal distribution of weight across the screen deck during the screening process and helps set up the correct frequency for the wires. Think of the wires on the screen media like guitar strings — tightening them results in higher vibrations while loosening them does the opposite.


At MAJOR, we help operations achieve the perfect frequency. Our FLEX-MAT screen media, for instance, vibrates at a rate of 6,000 to 10,000 cycles per minute, which is up to 13 times greater than a standard screen box. A proper crown curve helps these wires vibrate at a higher rate, increasing throughput and ensuring you get the maximum efficiency from your screen media.


When do you need the crown curve?
Tensioned screen media requires a crown curve. Clamp rails hold the screening panels down on the east and west or north and south sides of the vibrating screen. The crown curve should be at a high point between the rails. The goal is for the material to hit the crown curve first to help disperse it evenly across the entire deck.

What is the string test?
The string test is a simple way to check the crown curve of a screen deck. Here’s how it works:

  1. Remove the crown bar rubber.
  2. Put a string from corner to corner across the deck.
  3. If any part of the screen doesn’t touch the string, that’s where the crown curve sags.

Often, this test reveals that the clamp rails no longer hold down the screen media, which can happen for several reasons. Maybe the rail pulled away from the first bar, or the deck has been smashed down over time. When this happens, we send a technician to analyze the screen deck and provide a solution.


How can you be sure the crown curve is correct?
Too low of a crown curve results in screen media flapping or breaking prematurely. Too high of a crown curve makes material reach the sides of the screen media too quickly and results in premature wear at those points of the screen.

The string test will show if there are any areas of concern when it comes to the crown curve on your screen deck. A MAJOR technician can come out to a quarry or mine and provide the optimal crown curve for the vibrating screen. We will provide the height of each support bar to redo the deck and create a drawing with suggestions on how to rebuild it to achieve the proper crown curve.

Want to ensure your operation has the most effective crown curve? Contact us today, and let our experts help you maximize your plant’s performance.