One of the main requirement of rotary drums proper operating is an assurance of adequate forces' distribution in their support systems.
Unfortunately, this aim is not always possible to achieve. One of the obstacle is shape errors of roller raceway such as conicity, saddleback distortion or characteristic edges, which take place even with correct rollers' position parameters. They make that the assurance of rotary drum's mechanical stability is impossible, being a boundary of its free axial motion.
In the past, and at present, the error roller's replacement with the new one with cylindrical shape is the antidote to this state.
But this is the economic groundless activity (dis- and assembly expenses, transport and machining expenses), and besides, it forces the plant to stop.
The need of the new solution of this important problem appeared.

Going to satisfy this demand, our firm took on the activity leading to study and create device to large dimensions and weights rotary parts' resurfacing during their normal operation.

The attempts of rotary parts regeneration during their operation were performed for many years, but the imperfection of past control and power transmission systems and the gap in metrology assortment's field, manifesting as the lack of precision positioning systems and the lack of the big diameter measuring devices in the operation conditions, destined this method to fail.

But taking advantages of the processing way into consideration, the temptation to improve was significant. So, in the first quarter of 1995, after one year of experiments, we managed to outline final machine tool concept.
Simultaneously we made the project of precision device to large diameter's measurement during rotation, with 0.1 mm accuracy.
This device, operating on circumference measurement principle, arised in 1996 and has been tested during many of rotary drum inspections.

Soon, we could offer, with a big satisfaction, to our clients usage of full numerical moveable machine tool.

For the first time, the machine was used during complex rollers of lime kiln no 1 regeneration in KUJAWY S.A. (LAFARGE) in October 1996.

Work on this plant (3 piers) has lasted for 16 days (24 hours per day). No disruption appeared and new cylindrical rollers' raceways restored the proper operation's conditions of support system's rotary elements.

Since that moment, roller regeneration has been the constant position of our company's services proposal.

ADVANTAGES

• no necessity of expensive and laborious dis- and mantling. Avoiding of these actions lets us in simply way save time and people's effort. Besides, this makes, that no heavy equipment such as cranes, jacks etc. are needed,
• elimination of expensive transportation to and from regeneration place. Parts, to which the method is destined, are generally large and heavyweight. Regeneration of them requires massive stationary machine tools, but they are only in few machine-shops,
• possibility of process continuity assurance. More than once, especially in seasonal lines, there are priorities, which force to uninterrupted plant's operating. It is difficult to reconcile these non drum stoppage's requirements with replacement of its parts. In the case mentioned above this method seems to be irreplaceable, making possible combination of regeneration with full plant operating,
• basing on real rotary axis during regeneration. Such machining datum assures the more proper part's work during its normal usage. Wrong established rotary axis on stationary device is often the cause of work's disruptions after part mantling on spot.

APPLICATION

Technology of resurfacing by turning has been replaced by the technology of grinding.

See also:

• Regeneration of rings and rollers raceways by grinding.