ROLL GRINDER INSPECTIONS
Often times it is beneficial to perform a complete inspection on a roll grinder, either for diagnostic reasons, or as part of a troubleshooting agenda. One very important justification for such an analysis would be on used equipment to evaluate its condition prior to resale, either by the seller or buyer. The inspection can involve just the mechanical elements, or the complete machine including the electrics and controls. Whatever the case, be assured that the work will be very thorough and complete, and will include a detailed comprehensive report. A typical report outline is as follows:
Background & Scope
List of Enclosures
Vibration Analysis (if applicable - see Vibration section for more detail)
Data Collection Procedures & Techniques
General Observations - Review of Test Data
Inspection Discussion by Topic Headings
Summary & Conclusions
Recommendations to Improve Performance
Some of the inspection points on a typical roll grinder include:
Roll to Headstock Alignment
Headstock Pulleys, Belts, & Bearings
Neckrests (including gibs)
Front Bed Ways
Back Bed Ways
Carriage Traverse Drive Gearbox
Carriage Tracking & Skewing
Carriage Lubrication System
Wheel Spindle Clearance & Lift Checks
Wheel Hub Runout & Fit
Wheelhead Side Guide Roller Setting
Knife Seats and Links
Tilt Infeed System
Spindle Lube Pump & Piping
Vibration Checks - Motors, Bearings, Belts, etc.
On the Farrel two-wheel roll grinder, additional checks include an analysis of the critical swingrest functions and verification of proper operation.
Wherever possible, gaging equipment, electronic indicators, chart recorders, measurement transducers, etc., are used to supplement conventional tools and equipment to evaluate the grinder. This has the advantage of reducing "subjective" opinions with respect to the condition of the equipment, and also provides a convenient baseline to establish quantitative benchmarks for future comparisons. Tests are conducted in both static and dynamic conditions (i.e.: during grinding) to evaluate the overall condition of the machinery. Special attention is paid to chatter and pattern problems, and a section of the report is devoted to presenting the theoretical and practical methods of analysis. One service that is often provided is a static stiffness test and analysis, which compares the grinder's static stiffness response (force/deflection curve) between the wheel and the roll to comparable measurements taken on other grinders. In addition to the overall measurements, comparisons are also made for the various subassemblies and components (i.e.: spindle to wheelhead, wheelhead to subbase, etc.) so that the "weak link" can be determined, if a significant compliance is discovered. This is a good example of the importance of a roll grinder data base on which to draw conclusions. Due to the extensive amount of data collected over the years (since the 1960's), RGB Engineering is one of the few companies able to offer this comprehensive service. Digital photos will be incorporated into the report to help describe the measurement techniques and gaging equipment used.
RGB Engineering has conducted many of these types of inspections on all types of roll grinders. One of the most comprehensive was at an aluminum mill roll shop, where we performed a "capability analysis" on four grinders of different manufacture to establish each machine's capabilities and limitations with respect to shape and finish. The tests were extended to include other roll shop functions as well. References can be provided if required, from steel, aluminum, and paper mill applications.