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This product line was developed in 1987 with the first unit sold to then Reynolds Metals Company in Listerhill, AL for installation on a 44" Farrel grinder.  Since this time, RGB Engineering has built 40 crowner retrofits which are installed on all types of roll grinders (traveling carriage and traveling table), and on many different makes and models - Farrel, Cincinnati, Landis, Mesta, Lobdell, Churchill, and Norton.  Click on the "Customer Reference List" below for a detailed listing of all the crowner retrofit installations.  A complete description of the basic system, including principles of operation, hardware, and software, as well as information on boxing & shipping, bench testing, and instruction manuals, can be accessed by clicking "General Description".  Separate sections are included for specific discussions of "Accuracy Checks", the profile generation techniques ("FFP Profiles"), and the very important "Bed Correction Feature".  Under "Options", information can be accessed on additional enhancements like taper control, precision infeed, load control, the satellite work station, and coarse infeed.  Click on "Installation Examples" for descriptions and photos of some of the representative installations on various types of roll grinders.


Reasons to justify the upgrading to this type of crown control include:



The roll crown and concave shape profiles should be more accurate than those being produced with a mechanical crowning device, which is subject to wear and inaccuracies due to the age of the mechanical components.


Non sinusoidal shapes (like CVC profiles) and empirical curves can be ground, which are not possible with a conventional mechanical crowning system.


In addition to the crowning advantages, the software includes a bed correction feature, which can compensate for wheel path errors.  Corrections can easily be made via the computer at any future time should tweaking of the alignment be required.  This is very expensive to do the conventional techniques (machining and releveling).


An optional precision infeed system is available, which gives the operator the ability to "infeed" as well as crown using the crown tilt axis, which is not subject to the backlash and stick-slip limitations of the existing slideway infeed mechanism common on older roll grinders. 


The system includes an option for "automatic" infeed, which will feed the wheel in continuously across the roll face at a selected rate, with a step infeed at the roll ends.  This will free up the operator so he does not have to be a slave to the grinder during the roughing and semi-finishing cycles.


There is also an optional automatic tripping device, which utilizes the crowner absolute encoder to interface with the carriage (or table)  drive circuit to provide reversing control to the carriage or table. 


The upgrade will greatly enhance the existing machine's capabilities, and can in fact preclude the need for a more extensive and expensive rebuild with the resulting loss of production.  There would only be a few days downtime with the crowner retrofit.


The addition of a computerized crowner will allow the grinding of rolls to tolerance levels consistent with the newer state of the art CNC type roll grinders.  The advantage of this system is that the roll shape accuracy is a function of the computer, feedback transducer, and servo drive, and to a lesser extent, the grinder's mechanical components.


General Description                           


Accuracy Checks


Bed Correction Feature




Installation Examples


Customer Reference List