Whenever repeatability, productivity and ease of use are of essence, the 4-roll is the technology of choice. In a 4-roll machine, latest development of the rolling technology, the bottom roll clamps the plate guaranteeing a perfect control over its position throughout the whole forming process. The side rolls, actuated by the unique DAVI planetary guides technology, provide the necessary bending force achieving the tightest diameters per capacity on the market (1.1 of the top-roll) obtaining the highest accuracy thanks to the perfect parallelism offered by the patented Servo-Tronic© system. Compared to other technologies, 4-roll machines stand out for allowing fully CNC-automated production processes, significantly decreasing the reliance on operators’ skills and, hence, making it the most suitable tech for mass-production.
SHORTEST FLAT END THANKS TO STURDY AND CLOSED FRAME
The frame constitutes, effectively, the back-bone of the machine. The stress generated during plate forming must be withstood by this critical component and, eventually, transmitted to the foundations. DAVI machines feature the most compact and closed frame on the market, which allows to: improve the rigidity of connection to the ground as well as machine stability; minimize deflections and displacement for the maximum rolls positioning accuracy; construct a much shallower and less expensive pit, due to reinforcement beams installed between frames (intra-frame design) rather than base platform. Based on extensive Finite Element Method (FEM) studies conducted by DAVI R&D, it is observed that the frame is particularly under stress while pre-bending. DAVI exclusive design features a much higher rigidity of the overall structure hence guaranteeing maximum accuracy even in the most demanding pre-bending and re-rolling operations.
TIGHTEST ACHIEVABLE DIAMETERS THANKS TO PLANETARY GUIDES
The bending power of a 4-roll machine is exerted to the plate by two side rolls. Unlike other solutions on the Market, DAVI exclusive design provisions a planetary actuation of the side rolls whereas, rather than being guided up and down, the mechanism rotates around a pivoting point. Thanks to this system: maximum performance thanks to force multiplier effect by leverage arm (distance between pivoting point and cylinder force application point); reduced top-roll deflection due to circular force application; forming the tightest diameters thanks to favorable geometry (with side rolls wrapping around small diameters cans).
BEST ROLLS PARALLELISM THANKS TO PATENTED SERVO-TRONIC© SYSTEM
The rolls movement is actuated by hydraulic cylinders installed at the two ends of the machine. The patented Servo-Tronic© system keeps the machine’s rolls parallel at all times thanks to its dual, independent but integrated, parallelism control system. This system features dedicated pumping groups and circuits guaranteeing that each cylinder receives oil at the very same pressure and mass flow, with electro-valves for fine-tuning only. In this way, even in case of electronics failure, the rolls parallelism is hydraulically and mechanically maintained and the machine can keep operating with excellent results. The Servo-Tronic© allows for: maximum accuracy of the rolls positioning; limited reliance on electronics with reduced downtimes in case of its failure; best geometrical tolerances on the workpiece; automatic compensation for unbalanced loads.
HIGHER TILTING CAPACITY THANKS TO PENDULAR GEARBOXES ARRANGEMENT
Both top and bottom rolls are motorized as a standard. Unlike other solutions available on the Market, exhibiting a bolted-rigid coupling of the gearbox structure to the machine frame, DAVI exclusive pendular arrangement provisions swingable connection between the motor gearboxes and the frame. DAVI pendular shaft-mounted gearboxes configuration allows for stress-free tilting of the rolls up to 100 mm (4”) every 3 meters (10 feet) rolls length. The Pendular Gearboxes arrangement allows for: free deflection of all the rolls under load, with limited stress on shaft-hub connection to the benefit of bearings reliability and durability; much higher tilting capacity for cones-forming
MACHINE READY FOR ACCESSORIES THANKS TO THE HIGHEST LEVEL OF CUSTOMIZATION ON THE MARKET
With more than 50 years of experience designing and supplying first class plate rolling machines, DAVI understands that every customer need is different. DAVI R&D Department will process your requirements and help you selecting the optimum technical and commercial solution to maximize as much as possible the return on your investment. For this reason, even the small and medium capacity machines solutions can be fully customized to better support the most diverse production requirements and industrial sectors. DAVI MCB machines are equipped with state-of-the-art control systems, specifically designed by DAVI R&D Department to help you getting the most out of your 4-roll plate rolling machine. Thanks to DAVI Industry 4.0 CNC, all your operators, even the most inexperienced ones, will finally have the capacity to comply with the required tolerances with maximum repeatability: a real boost to your competitiveness. Moreover, all DAVI CNC systems are expandable to allow retrofitting of auxiliary equipment (such as vertical and side supports, gantry loaders, etc.) at any time you may need it.
BEST OPERABILITY AND MAINTAINABILITY THANKS TO THE NEW DESIGN OF THE MACHINE
The improved designof the machine allows for increased operability during the whole process, provisioning: forged reinforced yoke (no welding) with large pivoting points for reducing the top-roll deflections; compact frames to easily eject the formed workpiece and to make extreme cones with no interference. Moreover, the planetary guides technology significantly reduces the required machine maintenance, thanks to: no need for regular lubrication with friction free movements (permanently lubricated bearings); maximum energy efficiency and durability with eliminated risk of guides wearing on accumulated mill-scale.