RIF does not just perform the grinding or coating of the roll face, but also cares about the return of cylinder to customer’s mill in the best possible conditions in all its parts, so that it can be immediately installed in the production line.

Each cylinder is systematically subject to a series of checks, from the simple inspection of packaging suitability to the drafting of an inspection report and a complete intervention proposal to the customer.

Amongst the main interventions, please see list below:
• Restoration or replacement of journals
• Refurbishing of bearing seats by metallization and precision grinding
• Check / restore or rebuild internal cooling system
• Regrooving of grooved rolls
• Restoration of bearing housings
• Modification of the sealing system of polymer coated or metal coated rolls
• Non-destructive checks on journals and critical parts subject to high mechanical stress

Paper plants are featured by ever higher operating speeds, which is why it is always more important that cylinders and rotors in general are correctly balanced and free from vibrations.
Vibrations, whatever their origin, beyond a certain intensity can produce malfunctions of the systems, product faults, reduction in production speed, greater wear of components such as bearings and in the most serious cases even the breakage of journals or other components.

RIF offers its experience as well as large capacity balancing machines to solve the problems of unbalance and vibration of the cylinders.
However, a correct dynamic balancing control operation, to be called such, requires that all the parts making up the cylinder or rotor are geometrically in tolerance and perfectly clean. The machining, in particular the precision grinding, which for RIF represents the backbone of its technology, is in fact the first and most important correction phase of dynamic balancing.

The RIF service team is able to perform the following operations:
• Check / possible correction of the heads imbalance
• Check / possible correction of the dynamic runout at face center (this is essential in particular for cylinders with a high length / diameter ratio)
• Check / possible correction of dynamic balance of complete suction rolls

Where necessary, in particular when checking complex cylinders or rotors, equipped with their own supports and bearings, RIF is able to perform the vibration analysis, in order to verify the frequencies and establish which part is at the origin of any vibrations. with different frequencies compared to that of rotation.

In addition to precision grinding, RIF is able to perform complete control and restoration activities for all types of swimming rolls.

Control activity:
• Inspection of individual internal parts, gasket and worn parts
• Functionality check of the mechanical parts
• Inspection of Bearings
• Dimensional and geometric check of the swimming roll shell

Typical reconditioning activities:
• Replacement of internal parts, gaskets, bearings
• Rectification and internal smoothing of the shell and restoration of concentricity between the internal and external surfaces and side faces
• Metallization / regrinding of the internal bearing seats in the shell

Contextually to the activities of grinding and coating of cylinders, whether they are suction roll – couch rolls, wet presses and Yankee press rolls, RIF is able to perform a complete maintenance and reconditioning service of the cylinder in all its components, such as suction box, Bearing housings etc.

Suction cylinders generally have a crucial function in the paper sheet production cycle and are usually used in very severe operating conditions, with high workload and speed, but above all they serve to drain a huge amount of water drained from the sheet. , mixed with various types of chemical products, mineral charges, fibers, etc., materials that cause different effects to the various components of the suction cylinder itself such as corrosion, erosion, clogging of the shell holes and inside the internal suction box.

If not subjected to periodic checks and maintenance in all its parts, the malfunctioning or poorly performing suction cylinder can seriously compromise the productivity of the paper machine.

RIF offers complete control and maintenance cycles, at different levels of detail based on the maintenance program of the individual cylinder; the following are the main phases of activity:

Internal Suction Box:
• High pressure cleaning / overall washing
• Checkout and replacement of the nozzles and sealing strips if necessary
• Checkout and restoration of mechanical parts, manometers, vacuometers and pipings
• Optimization/modernization for improvement of performance and lifetime
• Renewal and application of protective and anti-oxidation treatment

Heads and Journals:
• Measurement check of coupling seats with shell and eventual restoration of suitable interference
• Measurement of bearing seats and renewal by means of grinding and / or metal spraying
• Renewal of surfaces and application of protective and anti-oxidation treatment

Bearing Housings and Bearings:
• Assessment of condition of bearings / replacement if necessary
• Checkout of bearing seats and refurbishing if applicable
• Renewal and application of protective and anti-oxidation treatment

Suction Shell:
• Through holes cleaning by various methods, depending on hardness of deposits
• Measurement of coupling seats, restoration of interference with heads seats
• Assessment of condition of fixing bores and screws/ remachining or replacement
• Repair of damages or indentations on the inside surface
• Inside grinding of shell

Complete Suction Roll:
• Dynamic balancing testing
• Vibration analysis

The dynamic test run of the suction roll is a must to guarantee troublefree performance.

By Multiple Drilling, in the specific production sector dedicated to the paper industry cylinders, we mean the specific processing dedicated to Suction Rolls and blind drilling of Press Rolls.

For these kinds of processes RIF has expressly built the below listed machines including:

“Gun Drill” CNC Multiple Spindle Drilling Machine, dedicated to the drilling and countersinking of holes of new metal shells, in bronze, stainless steel, carbon steel and cast iron.

“Gun drilling” is the most reliable and precise technology for drilling of new bronze and stainless steel suction shells: in particular it is the only technology able to grant a superior drilling quality for high thickness suction shells, in our case until 120 mm wall thickness. The quality of drilling, especially for suction shells subject to severe operating conditions, does not only translate into a geometrical or visual factor, but is of extreme importance for the stability of the shell and to ensure the absence of faults which might jeopardize the integrity of the shell itself in terms of time.

The main distinctive features of gun-drilling are:
• Internal forced lubrication through the drilling tools
• Use of highly wear-resistant cutters
• Extreme precision of tool guiding and feed
• Controlled working temperature
• Continuous monitoring of every single drilling tool

Traditional Multiple Spindle Machines Type “Twist-Drilling”, custom-built for the following processing:
• Drilling of polymer coverings for suction rolls and blind drilling
• Mechanical clean-drilling of suction rolls, to the purpose of totally removing any foreign matters deposited within the holes of the shells, if not removable with any other means
• Lengthening of the drilled length on used suction shells

Besides the machining, RIF drilling service is implemented by some important accessory operations like:
• Total checkout of drilled face with the aim to single out any defects, anomalies, presence of bits of broken drills originated during previous machining
• Extraction of bits of broken drills in all cases when they were existing on the shell

Most of the mechanical processing is carried out in a department strategically located in a central warehouse of the plant.
This department plays an essential role in the construction of large cylinders and rotors and also has an important auxiliary function for the other specific production departments of RIF SpA being equipped with the main machine tools including:

CNC Boring Machine for Shells, equipped for internal machining such as:
• Internal grinding of pipes and shells when high stock removal is required
• Internal grinding for suction roll shells
• Internal grinding and honing of swimming rolls

CNC Lathes, for various processes:
• Outside turning of shells, heads and journals for cylinders and rotors for various applications
• Machining of threaded bores
• Roll grooving
• Machining /refurbishing of seats

Dynamic Balancing Machine, for checking and correcting the heads unbalance and controlling dynamic deflection at face center on following workpieces:
• Various press rolls – bearing housings and bearing in assembled/disassembled condition
• Yankee Cylinders or Can Dryers
• Rewinding backing rolls or pope drums
• Various guiding rolls
• Reel spools
• Nip rolls for PVC production
• Rolls for Flame treatment and Corona rolls in the PVC sector

For the manufacturing of new rolls and cylinders, RIF suggests the inside mechanical processing (boring) of the tubes / shells constituting the metal core of the cylinders themselves. This process ensures qualitative and functional advantages for the products, including:
• Uniform thickness with consequent significant increase in critical speed, to the advantage of the life of the cylinder and of the mechanical parts connected to it
• Simplification of the dynamic balancing operation
• Better and more uniform heat exchange in the case of cooling or heated cylinders

At RIF we have at our disposal whatever is necessary for the complete design and manufacturing of rolls, in particular:
• A mechanical processing department managed by highly experienced staff
• A highly-skilled technical office perfectly integrated into the Company Quality System, managed by qualified technicians
• A series of dedicated machine tools, with large production capacities and equipped with a CNC control system

We manufacture cylinders and rotors for well-known industrial plants worldwide, based on their specific drawings and / or directly for end-users, taking advantage of our construction and design programs.

The experience in serving the paper industry for the refurbishment, repair, grinding and coating of used cylinders allows us to fully understand the purpose of use and needs of the various types of cylinders, therefore giving the utmost care in design, in choosing semi-finished products and in the realization of finished products.

Our Cylinder Construction Program includes:
• All type of guide rolls, smooth or profiled
• Drilled rolls in the Drying Section
• Breast rolls and wire drive rolls
• Rewinder backing rolls, Pope rolls and Reel spools
• Wet press rolls and Yankee pressure rolls
• Size-Press rolls, Film-Press rolls and Coating cylinders
• Suction roll shells or complete suction rolls
• Bearing housings for all rolls
• Cooling cylinders for the Plastic Industry
• Cylinders, rotors, shafts for various industrial sectors

Design Program:
• Optimization of the construction project in order to reduce the weight of the cylinders and increase their operating speed
• Verification of the bending curves of the cylinder for the calculation of the crowns
• Computerized simulation of operating conditions
• Calculation of mechanical stresses
• Selection of suitable materials for rough pieces
• Calculation and design of the internal cooling system
• Check of the deflection curves of the roll for crown calculation
• Study of drilling patterns for the suction shells at the purpose to avoid compromising the mechanical resistance of the shell, eliminate the risk of “shadow marking”, improve dewatering and reduce the noise level

Production sector with a long tradition for RIF, currently one of the few manufacturers in Europe of Elastic Coatings made with fibrous materials, for:

• Supercalander cylinders
• Counter-Cylinders of Embossing Machine
• Rolls for calendering of fabrics

The Supercalander treatment still plays a fundamental role today in obtaining some important surface properties of many types of natural and coated graphic papers, for label papers, support for silicon base paper and some special papers. These properties are conferred by the particular friction glazing effect generated by the elastic refilling in the contact “nip” with the metal cylinders of the supercalender, an effect not obtainable with other types of coatings. Thanks to this peculiarity, the Elastic Coatings are indispensable at least for a part of the cylinders of the existing Supercalanders.

Our range of Elastic Coatings is based on a series of different materials to meet the different application needs in terms of applied load, temperature and surface effect towards calendered paper.

An “inimitable effect” is conferred by the elastic refilling also for the counter rolls of the embossing machines for the treatment of some papers for niche sectors.

The production capacity of our Elastic Coatings Department:
• Outside diameter range of the coatings: from 240 to 900 mm
• Maximum length coated table: 9000 mm
• Maximum weight of the roll: 28 tons

The activity relating to packaging of polymeric coatings for cylinders dates back to 1982 with the acquisition by RIF of the know-how and systems from a multinational company leader in the sector of polymeric compounds and finished rubber products, with decades of experience also in the sector of rubber coating for cylinders. Contextually to the beginning of activity in this sector, RIF provides a service of research and development in order to constantly update the technological characteristics of coatings with the growing application requirements of various industries, including:

• Paper Industry
• Plastic Industry
• Metallurgical Industry
• Textile Industry

In 1998 the company “RIF Roll Cover” was established, consisting in a joint venture between RIF and the Voith group for the business branch relating to polymeric coatings.

Currently, the RIF Roll Cover range of products allows to cover most of the applications of rollers and cylinders for the various manufacturing lines.
The integration with the other departments and above all with the great experience of RIF in the grinding and mechanical reconditioning of cylinders, allows us to provide a complete service, not limited to pure rubber coating.

Production Capacity:
• External diameter: 1800 mm
• Total length (including pins): 13,500 mm
• Maximum weight: 40 tons

Research and continuous improvement of the technological properties of coatings and the expansion of the range of applications represent our constant dynamic goal.