Fluid metering roll and method of making the same

Details Fluid metering roll and method of making the same Fluid metering roll and method of making the same

1997-03-26

2001-06-05

Rosenbaum, I Cuda (Department: 3726)

Metal working

Method of mechanical manufacture

Roller making

C029S895300, C492S030000, C492S053000, C492S056000

Reexamination Certificate

active

06240639

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention is directed to a fluid metering roll and to a novel method of manufacturing same. More particularly the invention is directed to an anilox roll characterized in that the roll is comprised of a carbon fiber composite core having an exterior ceramic surface formed with outward opening metering cells.
It is the objective of anilox rolls to pick up liquid, typically ink, from an ink source and to deposit on a subsequent printing roller or the like, discrete increments of ink, the quantity deposited by each cell being controlled within precise tolerances across the entire surface of the printing roller, this result being effected by the anilox roller having a multiplicity of closely-spaced, i.e., up to 1,000 or more, cells per lineal inch, the cells having virtually identical volumetric capacities.
PRIOR ART
Conventional anilox rolls are manufactured from either steel or aluminum cores. The external surfaces of the cores are typically mechanically engraved with the desired cell pattern and thereafter electroplated with one or more metallic layers.
Premium anilox rolls are formed by overcoating a smooth metallic core with a metal layer or layers and thereafter depositing, by plasma spray techniques, a ceramic coating over the layers, the coating being subsequently engraved via laser technology to form the desired cell pattern in the ceramic. The ceramic is then sealed to render the same resistant to the passage of corrosive liquids through the ceramic. Representative examples of ceramic coated fluid metering rolls are described and illustrated in U.S. Pat. Nos. 4,009,658 and 4,301,730 assigned to the assignee of the instant application.
Anilox rolls as heretofore known incorporate many characteristics which are undesirable. As will be set out more fully hereinafter, drawbacks of conventional anilox rolls include high weight and inertia, characteristics which result in roll deflection, premature bearing wear, difficulty of dynamic balance, and mandated high driving forces. By way of example, a typical light weight metal core anilox roll for corrugated printing may weigh approximately 1500 pounds, whereas a comparably sized roll in accordance with the instant invention will weigh less than 100 pounds.
A further drawback of conventional anilox rolls, which typically may require use in caustic environments, resides in their low resistance to corrosion. Despite the various sealants employed in ceramic, conventional anilox rolls, and notwithstanding the nature of the electroplated layers used in fabricating metallic anilox rolls, exposure to corrosive reagents, and necessity for frequent cleaning of the anilox roll surfaces, rapidly compromises the roll, resulting in the necessity of reprocessing. In general, roll reprocessing of a steel core anilox roll may be accomplished about three times following which the roll is useless and must be discarded. When it is considered that a roll of ten-inch diameter and one hundred ten inch face length may cost up to about $14,000.00, it will be readily recognized that the ability to provide higher corrosion resistance in a roll which also permits additional reprocessing cycles will result in significant economic advantages.
High inertia conventional steel core anilox rolls must be carefully balanced to assure that the mass distribution is such that vibration is minimized. In fact, slight imbalances are governing factors in the speeds at which the roll may be employed, and hence, the speed of the printing or other process.
To summarize, it would be highly desirable to provide an anilox roll which is light in weight, stronger than steel, having low inertia, virtually perfect dynamic balance, freedom from roll deflection, high resistance to corrosion and subject to multiple cycles of reprocessing. Characteristics such as those noted will minimize down time required for roll change, ability to operate at lower power consumption, simplicity of handling, operation at higher press speeds, and decrease in waste deriving from lower initial costs and more frequent cycles of reprocessing.
PRIOR ART CITATIONS
In addition to the U.S. patents cited above, the following additional patents were located in the course of a search of the prior art effected in respect of the incident invention.
U.S. Pat. No. 2,129,125 H. D. Geyer
U.S. Pat. No. 4,835,022 Huhne
U.S. Pat. No. 4,963,404 Jenkins
U.S. Pat. No. 4,991,501 Yokoyama
U.S. Pat. No. 5,094,877 Bieringer
U.S. Pat. No. 5,153,021 Litchfield
U.S. Pat. No. 5,191,703 John
U.S. Pat. No. 5,262,206 Rangaswamy
U.S. Pat. No. 5,409,782 Murayama
U.S. Pat. No. 5,411,463 Brookstein
Of the collected references, U.S. Pat. No. 4,835,022 is relevant in its disclosure of flame spray application of a composition comprised of polymer and an additive such as carbide or metal powder.
U.S. Pat. No. 4,991,501 discloses a dampening water feed roll comprised of a metal roller flame sprayed with ceramic, the pores of the ceramic being occluded with SiO2.
U.S. Pat. No. 5,094,877 discloses a mixture of metal and high temperature resistant polyimide used as a flame spray material for coating a substrate.
U.S. Pat. No. 5,191,703 discloses a method forming an anilox roll by coating a core with soft material, forming grooves in the material, filling the grooves with hard wear-resistant material and thereafter forming cells in the remaining islands of soft material.
U.S. Pat. No. 5,262,206 teaches forming an abradable metal coating by injecting polymeric material into the stream of combustion gases used to atomize metal wire.
U.S. Pat. No. 5,411,463 relates to a lightweight roll useful in the paper manufacture trade the roll having an outer casing and elongate fiber-filled chambers.
U.S. Pat. No. 4,963,404 is directed to an anilox roll formed by plasma-flame applying a metal adhesion layer to a thin walled metal cylinder, thereafter applying a coating comprised of ceramic and fluorocarbon polymer to the adhesion layer. Thereafter a surface pattern of cavities is formed using a laser beam treatment. The patent mentions that the core could be a plastic based material such as glass fiber reinforced polyester but does not teach or suggest how such material could be employed as a receiver for the coatings.
In addition to the above references, reference is made to the following articles dealing generally with thermal spray coatings “Let's Talk Thermal Spray” (Products Finishing, March 1993, pages 41 through 47) and “Functionally Effective Coatings Using Plasma Spraying” (
Sulzer Technical Review
3-1986 pages 1 and following).
SUMMARY OF THE INVENTION
The present invention relates to a method of forming anilox rolls utilizing a carbon fiber composite core rather than a metal core, the core being coated via flame spray techniques with a ceramic outer layer. The invention further relates to a fluid metering roll such as an anilox roll fabricated by the novel method.
Briefly stated, while it is well known that carbon fiber composite material possesses many characteristics which would render the material ideal for use as the core of an anilox roll, and while it is conventional to form metal core anilox rolls utilizing flame spray techniques (as hereinafter defined), no one, prior to the applicant, has been able to satisfactorily apply a coating to a carbon fiber composite core which coating is suitable for use as an anilox roll.
In summary, applicant has made the surprising discovery that as a result of departure from conventional flame spray techniques and by the use of selected layering and manufacturing steps, it is possible to form over the surface of a carbon fiber composite core, an external ceramic surface suitable for engraving by known laser techniques to define the cellular configurations required for use as an anilox roll.
In evaluating the method, it must be recognized that anilox rolls, particularly those employed in the printing industry for fine printing, are precision instruments which are subjected to grueling operating conditions in use. While various flame spray techniques have been sugge

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