Crowning helps to keep the sheets straight as they pass through the press brake- MazakPower. This process guarantees better accuracy as it compensates for the deflection that happens when the sheet is placed on the press brake. The deflection, when not compensated for, normally results in a deformed product as observed mostly for machines that are 8 or more feet longer handling more than 80 tons. Crowning is done using a crowning system which may either be installed either in the beam, the table, or in both of them.
The basics…
Many of the newer press brakes use the hydraulic system. When bending is taking place, the pistons have to reach a predetermined position so that correct bending can occur. There is a high likelihood of the machine to deflect when a sheet has been placed underneath. This deflection causes the pistons to not function as intended.
To correct these errors, a crowning system is installed into the press brake to produce a force that opposes the deflection by always ensuring that the table remains parallel to the metal sheet.
Crowning has been in use since the ‘70s and ‘80s as there has been an increasing demand for machines that can bend long high-tensile-strength metals. The process counteracts the deflection which increases proportionally to the length and strength of the metal.
Life before crowning…
In the past, press brake tables used to come predesigned with a curve that was intended to deflect more than half of the machine’s deflection.
There is no programmable software where data about the metal is input. Such data covers the length, thickness, and tensile strength. The software automatically calculates the deflection of the table during bending and the machine works to counteract it. The crowning system aims at achieving accurate bending angles with minimal operator intervention.
Deflecting Forming Challenges
Crowning ensures that there’s a consistent angle all through the bend and, therefore, eliminates the need for constant operator intervention. Ultimately, there’s reduced wastage in the form of scrap and there are minimal setup operations. Without crowning, the challenges associated with deflection have to be dealt with manually which is very tiring and time-consuming.
Manual troubleshooting and alignment are based on “guesswork” and so it does not always give accurate results. A crowning system automatically gives these results minimizing the need for constant intervention from a skilled machine handler. This results in improved accuracy, efficiency, and productivity.
However, it’s worth noting that no amount od crowning can compensate other machine-related issues such as poor punch and die alignment. Such problems can result in non-precision even if a crowning system is in place. Crowning does not solve issues associated with un-uniform angles.
For more accuracy achievement when dealing with bend angles, you need precision-ground tooling throughout the whole length
Conclusion
Crowning ensures that the process goes on efficiently, with accuracy, is repeatable, and produces straight bends in complicated metal sheets. Crowning has become a necessity in today’s processing world as the manufacturing landscape keeps evolving. The systems are critical for accuracy as they result in an overall productive and profitable bending operation.
Crowning systems are especially used in press brakes that are used to bend high-tensile-strength materials as manufacturers these days are interested in producing quality products whose structural integrity hasn’t been compromised.
