CA2115594A1 - System for continuously monitoring curing energy levels within a curing unit - Google Patents
System for continuously monitoring curing energy levels within a curing unitInfo
- Publication number
- CA2115594A1 CA2115594A1 CA002115594A CA2115594A CA2115594A1 CA 2115594 A1 CA2115594 A1 CA 2115594A1 CA 002115594 A CA002115594 A CA 002115594A CA 2115594 A CA2115594 A CA 2115594A CA 2115594 A1 CA2115594 A1 CA 2115594A1
- Authority
- CA
- Canada
- Prior art keywords
- curing
- radiation
- coating material
- reflector
- available
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/0288—Controlling heating or curing of polymers during moulding, e.g. by measuring temperatures or properties of the polymer and regulating the process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J19/12—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electromagnetic waves
- B01J19/122—Incoherent waves
- B01J19/123—Ultra-violet light
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
- B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
- B05D3/065—After-treatment
- B05D3/067—Curing or cross-linking the coating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/10—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation for articles of indefinite length
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
- C03C25/10—Coating
- C03C25/12—General methods of coating; Devices therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
- B29C2035/0827—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using UV radiation
Abstract
System For Continuously Monitoring Curing Energy Levels Within A Curing Unit Abstract The present invention continuously monitors the amount of curing radiation available for curing coating material on a moving optical fiber and includes a curing system having a radiation source capable of providing radiation energy for curing coating material on an optical fiber and a reflector system which redirects non-direct radiation back toward the article. An optical fiber which has been provided with a curable coating material is moved along a path of travel a curing area. The coating material is cured by causing the radiation source to emit energy suitable for curing the curable coating material. The predictable average amount of light energy properly redirected by the reflector system toward the curable article is sensed as the curable coating material is being cured to obtain continuous in-process reading. The average radiation value is obtained by positioning three longitudinally aligned holes adjacent the fiber path and between the fiber and a radiation sensing device. Furthermore, the amount of the light energy available from the reflector system may be sensed at a location which is outside the reflector system to obtain a reference reading.
The in-process readings may then be compared with the reference reading to determine the portion of the radiation available from the radiation source which is actually available for curing the curable coating material.
The in-process readings may then be compared with the reference reading to determine the portion of the radiation available from the radiation source which is actually available for curing the curable coating material.
Description
,,,:.; - 1-System For Continuou~ly Monitoring Curing Energy Level~ Within A Curing Unit .i3 '.' Technical Field - This invention relates to a system for continuously monitoring 5 curing energy levels within a curing unit.
.
-; Background of the Invention ` Radiation curable materials have penetrated several areas of commerce due to their characteristic rapid processing speeds. One class of radiation curable materials are converted from a liquid to a solid upon 10 exposure to ultraviolet portion of the electromagnetic spectrum. Such materials are commonly referred to as W curable materials. Examples of such materials include W curable optical flber coatings, optical fiber ,:l: cabling materials, adhesives, floor coatings, wood coatings, and metal beverage can coatings. Another class of radiation curable materials are 15 converted from a liquid to a solid upon exposure to visible light. Such materials are commonly referred to as visible light curable materials.
Examples of such materials include optical flber coatings, pigmented inks, and adhesives.
. A characteristic of all radiation curable materials is that their 20 extent of cure is dependent upon the amount of exposed curing radiation, referred to as dose. Cure dose is a variable which is sought to be carefully controlled during processing of radiation curable materials in order to ^. ensure complete cure of the material. Some general methods currently used to control radiation curing dose include:
1. Careful control of processing line speed;
.
-; Background of the Invention ` Radiation curable materials have penetrated several areas of commerce due to their characteristic rapid processing speeds. One class of radiation curable materials are converted from a liquid to a solid upon 10 exposure to ultraviolet portion of the electromagnetic spectrum. Such materials are commonly referred to as W curable materials. Examples of such materials include W curable optical flber coatings, optical fiber ,:l: cabling materials, adhesives, floor coatings, wood coatings, and metal beverage can coatings. Another class of radiation curable materials are 15 converted from a liquid to a solid upon exposure to visible light. Such materials are commonly referred to as visible light curable materials.
Examples of such materials include optical flber coatings, pigmented inks, and adhesives.
. A characteristic of all radiation curable materials is that their 20 extent of cure is dependent upon the amount of exposed curing radiation, referred to as dose. Cure dose is a variable which is sought to be carefully controlled during processing of radiation curable materials in order to ^. ensure complete cure of the material. Some general methods currently used to control radiation curing dose include:
1. Careful control of processing line speed;
2. Consistent exposure time for fixed substrates;
3. Output power meters for the curing radiation sources;
4. Preventive maintenance of curing radiation source reflector systems;
'~ 30 5. Routine replacement of curing radiation sources; and 6. Off-line, destructive quality control inspection of cured article to gauge the ultimate degree of cure achieved.
,~
. - - ~ . . ~ - .. , ~ .. . . . . .
- `
~ 2 '':
One growing area of use for curable materials is as coatings for optical fibers. In the manufacture of optical fiber, a preform is suspended vertically and moved into a furnace. Optical fber is drawn from the preform and afterwards is provided with one or more layers of various liquid 5 coating material. In general, the liquid coating material is a curable coatingmaterial and typically it is an ultraviolet (W) light energy curable material.
~- Curing of the coating materials is ascomplished by moving successive lengths of the optical flber having the coating material thereon through a center tube which is disposed within an elliptically shaped 10 housing as depicted in U.S. Patent 5,000,772. At one loci of the elliptical shape is disposed a curing lamp; at the other, the center tube. The elliptical housing has reflective surfaces for reflecting curing energy toward engagement with the optical fiber.
Furthermore, a quartz center tube is sometimes used to maintain 15 an oxygen-free atmosphere (N2 ) for a high degree of cure of the secondary or exterior coating layer.
Disadvantageously, the interior surface of the center tube is often adiabatic. Furthermore, the heat of polymerization of the coating material and the absorption of radiation from the W lamps may heat the 20 flber temperature to about 130 C or higher. Given that many coating materials devolitize at temperatures greater than about ~0 C, deposits of volatiles form on the inner surface of the center tube even during normal usage.
Notwithstanding the rapid flow of nitrogen gas through the ~5 center tube, there normally are sufficient contaminants deposited within about eight hours of operation of the draw line to cause about 3~40% of the ultraviolet (W) radiation incident to the center tube surface to be absorbed instead of being transmitted toward the optical flber as desired.
This attenuation decreases the degree of cure of the optical fber coating ;
30 material, particularly as the rate of reaction increases with the W dose.
Accordingly, the center tubes must be replaced on a regular basis.
Presently, it is typical practice after the fiber has been drawn to measure the degree of cure with an off-line pullout test. In such a pullout test, the force required to pull a 1 cm length of optical fiber out of its ~ -35 coating is measured. This existing off-line technique offers no real-time -feedback as to the overall effectiveness of the cure. Furthermore, the .
:
` existing pull-out test provides no ability to isolate any particular deficieneies , which may exist in various stages or components of the euring system.
One other technique presently known to monitor the degree of cure of a coating material is disclosed in eommonly assigned U.S. Patent No.
5 5,037,763. This patent facilitates the in-line monitoring of the degree of cure by including a probe within the coating material. The probe comprises a material which emits light subsequent to being promoted to an excited electronic state.
What is sought after and what seemingly is not available in the , 10 prior art is an on-line monitoring system which may be used to continuously monitor the overall curing effectiveness of the curing system.
, * Summary ofthe Invention The foregoing problems of the prior art have been solved by the method and apparatus of this invention.
3,.' ` 15 BriefDescriPtion ofthe Drawing '` FIG.lis a schematie view of a manufaeturing line whieh is used to provide one or multiple eoating materials for a drawn optical fiber;
FIG.2is an end view in seetion of an optieal fiber having a eoating provided by portions of the apparatus of FIG.l;
!~ 20 FIG. 3 is a sehematie view of a manufaeturing line whieh is used to provide a matrix material for a plurality of optieal fibers disposed in an array;
FIG.4is a~ end view in seetion of an optical fber array whieh is ' embedded in a matrix material;
FIG. 5 is a top view of a radiation energy euring apparatus whieh is used to eure eoating materials whieh have been applied to optieal fiber drawn from a preform; and FIG.6is an elevational view of the curing apparatus ofFIG.l as taken along FIGS. 5-5 thereof. ~ ~ -30 Detailed Description Referring now to FIG.l, there is shown an apparatus which is designated generally by the numeral 20 and in which is used to draw optical fiber 21 from a specially prepared cylindrical preform 22 and for then `;
~L ~ jiJ~
~ coating the fiber. The optical fiber 21 is formed by locally and - ~ symmetrically heating the preform 22, typically 7 to 25 mm in diameter and 60 cm in length, to a temperature of about 2000 C. As the preform is fed into and through a furnace 23, fiber 21 is drawn from the molten material.
As can be seen in FIG. 1, the elements of the draw system include the furnace 23 wherein the preform is drawn down to the fber size after which the fiber 21 is pulled from the heat zone. The diameter of the fber 21 is measured by a device 24 at a point shortly after the fiber is formed and this measured value becomes an input into a control system.
`10 W~lthin the control system, the measured diameter is compared to the desired value and an output signal is generated to adjust the draw speed such that the fiber diameter approaches the desired value.
~.
After the diameter of the fber 21 is measured, a protective coating 25 (see also FIG. 2) is applied to it by apparatus 27. Preservation of 15 flber strength requires the application of the protective coating, which shields newly drawn fber from the deleterious effects of the atmosphere.
This coating must be applied in a manner that does not damage the surface of the fiber 21 and such that the fiber has a predetermined diameter and is protected from abrasion during subsequent manufacturing operations, ~;20 installation and service. Minimizing attenuation requires the selection of a suitable coating material and a controlled application of it to the fiber.
'Such a coating apparatus may be one such as that described in U.S. Patent : ~: :
4,474,830. Minimizing diameter variation which in turn minimizes the losses due to misalignment at connector and splice points requires careful design 25 of the draw system and the continuous monitoring and control of the fiber ~ ;
diameter during the drawing and the coating steps of the process. Then, the coated fiber 21 is passed through a centering gauge 28.
After the coating material has been applied to the drawn fiber, the coating material must be cured. Accordingly, the optical flber having 30 the coating material thereon is passed through a device 30 for curing the coating and a device 32 for measuring the outer diameter of the coated flber. Afterwards, it is moved through a capstan 34 and is spooled for testing and storage prior to subsequent cable operations.
While one embodiment of the present invention specifcally 35 addresses a manufacturing line which applies coatings to a single drawn fiber, it should be noted that the curing monitoring system of the present :
`~ - s -.
invention is also applicable to manufacturing of bonded ribbons. Such bonded ribbons include a plurality of coated optical fibers disposed in a planar array and held together in that array by a matrix material.
Although reference herein may be made only to the coating material or to 5 the matrix material, it should be understood that the following applies to both.
Referring now to FIG. 3, there is shown a schematic view of such an alternative manufacturing line which is designated generally by the ` numeral 40. The line 40 is capable of manufacturing a bonded ribbon 4210 (see FIG. 4). The ribbon 42 includes a plurality of coated optical fibers 36-36 each of which includes a core, a cladding and one or more layers 25-25 of coating material.
As can be seen in FIG. 4, the optical fibers 36-36 may be disposed in a planar array. The fibers are held bonded together in that 15 array by a matrix material 45. It is common to refer to such a structure as a bonded ribbon. In a preferred embodiment, the matrix material is an ultraviolet (W) curable material.
Along the line 40, a plurality of the optical fibers 36-36 are payed out from supplies 46-46, and an ink from a reservoir is applied thereto by an 20 applicator 48. Afterwards, the ink is dried in an oven 4~. Then the optical fibers are gathered together and embedded in the curable matrix material in an applicator 52. The applicator 52 may be an extruder, for example.
Afterwards, the array in the matrix material is directed past an apparatus 54 which is well known and which is used to cure the curable matrix 25 material and taken up on a spool 56.
As mentioned, after the curable coating material has been applied to the drawn optical fiber or the curable matrix material to the array of optical fibers, the coating or the matrix material must be cured.
The coating material may be cured by thermal, electron beam, microwave, 30 or ultraviolet energy. For the preferred embodiment, the curable material may comprise a silicone-based material, an acrylate-based material or a vinyl-based material.
For rapid application and cure, coatings which cure on exposure to radiation, preferably ultraviolet radiation, are needed. However, 35 radiation-curable coatings for optical glass fiber may be of various types, but it is always necessary to provide the low to moderate tensile modulus -~, . . . .. . ..
,,, ' . . . ' ,. ., . i, . . . ,- ~ . .
35~
'~ 30 5. Routine replacement of curing radiation sources; and 6. Off-line, destructive quality control inspection of cured article to gauge the ultimate degree of cure achieved.
,~
. - - ~ . . ~ - .. , ~ .. . . . . .
- `
~ 2 '':
One growing area of use for curable materials is as coatings for optical fibers. In the manufacture of optical fiber, a preform is suspended vertically and moved into a furnace. Optical fber is drawn from the preform and afterwards is provided with one or more layers of various liquid 5 coating material. In general, the liquid coating material is a curable coatingmaterial and typically it is an ultraviolet (W) light energy curable material.
~- Curing of the coating materials is ascomplished by moving successive lengths of the optical flber having the coating material thereon through a center tube which is disposed within an elliptically shaped 10 housing as depicted in U.S. Patent 5,000,772. At one loci of the elliptical shape is disposed a curing lamp; at the other, the center tube. The elliptical housing has reflective surfaces for reflecting curing energy toward engagement with the optical fiber.
Furthermore, a quartz center tube is sometimes used to maintain 15 an oxygen-free atmosphere (N2 ) for a high degree of cure of the secondary or exterior coating layer.
Disadvantageously, the interior surface of the center tube is often adiabatic. Furthermore, the heat of polymerization of the coating material and the absorption of radiation from the W lamps may heat the 20 flber temperature to about 130 C or higher. Given that many coating materials devolitize at temperatures greater than about ~0 C, deposits of volatiles form on the inner surface of the center tube even during normal usage.
Notwithstanding the rapid flow of nitrogen gas through the ~5 center tube, there normally are sufficient contaminants deposited within about eight hours of operation of the draw line to cause about 3~40% of the ultraviolet (W) radiation incident to the center tube surface to be absorbed instead of being transmitted toward the optical flber as desired.
This attenuation decreases the degree of cure of the optical fber coating ;
30 material, particularly as the rate of reaction increases with the W dose.
Accordingly, the center tubes must be replaced on a regular basis.
Presently, it is typical practice after the fiber has been drawn to measure the degree of cure with an off-line pullout test. In such a pullout test, the force required to pull a 1 cm length of optical fiber out of its ~ -35 coating is measured. This existing off-line technique offers no real-time -feedback as to the overall effectiveness of the cure. Furthermore, the .
:
` existing pull-out test provides no ability to isolate any particular deficieneies , which may exist in various stages or components of the euring system.
One other technique presently known to monitor the degree of cure of a coating material is disclosed in eommonly assigned U.S. Patent No.
5 5,037,763. This patent facilitates the in-line monitoring of the degree of cure by including a probe within the coating material. The probe comprises a material which emits light subsequent to being promoted to an excited electronic state.
What is sought after and what seemingly is not available in the , 10 prior art is an on-line monitoring system which may be used to continuously monitor the overall curing effectiveness of the curing system.
, * Summary ofthe Invention The foregoing problems of the prior art have been solved by the method and apparatus of this invention.
3,.' ` 15 BriefDescriPtion ofthe Drawing '` FIG.lis a schematie view of a manufaeturing line whieh is used to provide one or multiple eoating materials for a drawn optical fiber;
FIG.2is an end view in seetion of an optieal fiber having a eoating provided by portions of the apparatus of FIG.l;
!~ 20 FIG. 3 is a sehematie view of a manufaeturing line whieh is used to provide a matrix material for a plurality of optieal fibers disposed in an array;
FIG.4is a~ end view in seetion of an optical fber array whieh is ' embedded in a matrix material;
FIG. 5 is a top view of a radiation energy euring apparatus whieh is used to eure eoating materials whieh have been applied to optieal fiber drawn from a preform; and FIG.6is an elevational view of the curing apparatus ofFIG.l as taken along FIGS. 5-5 thereof. ~ ~ -30 Detailed Description Referring now to FIG.l, there is shown an apparatus which is designated generally by the numeral 20 and in which is used to draw optical fiber 21 from a specially prepared cylindrical preform 22 and for then `;
~L ~ jiJ~
~ coating the fiber. The optical fiber 21 is formed by locally and - ~ symmetrically heating the preform 22, typically 7 to 25 mm in diameter and 60 cm in length, to a temperature of about 2000 C. As the preform is fed into and through a furnace 23, fiber 21 is drawn from the molten material.
As can be seen in FIG. 1, the elements of the draw system include the furnace 23 wherein the preform is drawn down to the fber size after which the fiber 21 is pulled from the heat zone. The diameter of the fber 21 is measured by a device 24 at a point shortly after the fiber is formed and this measured value becomes an input into a control system.
`10 W~lthin the control system, the measured diameter is compared to the desired value and an output signal is generated to adjust the draw speed such that the fiber diameter approaches the desired value.
~.
After the diameter of the fber 21 is measured, a protective coating 25 (see also FIG. 2) is applied to it by apparatus 27. Preservation of 15 flber strength requires the application of the protective coating, which shields newly drawn fber from the deleterious effects of the atmosphere.
This coating must be applied in a manner that does not damage the surface of the fiber 21 and such that the fiber has a predetermined diameter and is protected from abrasion during subsequent manufacturing operations, ~;20 installation and service. Minimizing attenuation requires the selection of a suitable coating material and a controlled application of it to the fiber.
'Such a coating apparatus may be one such as that described in U.S. Patent : ~: :
4,474,830. Minimizing diameter variation which in turn minimizes the losses due to misalignment at connector and splice points requires careful design 25 of the draw system and the continuous monitoring and control of the fiber ~ ;
diameter during the drawing and the coating steps of the process. Then, the coated fiber 21 is passed through a centering gauge 28.
After the coating material has been applied to the drawn fiber, the coating material must be cured. Accordingly, the optical flber having 30 the coating material thereon is passed through a device 30 for curing the coating and a device 32 for measuring the outer diameter of the coated flber. Afterwards, it is moved through a capstan 34 and is spooled for testing and storage prior to subsequent cable operations.
While one embodiment of the present invention specifcally 35 addresses a manufacturing line which applies coatings to a single drawn fiber, it should be noted that the curing monitoring system of the present :
`~ - s -.
invention is also applicable to manufacturing of bonded ribbons. Such bonded ribbons include a plurality of coated optical fibers disposed in a planar array and held together in that array by a matrix material.
Although reference herein may be made only to the coating material or to 5 the matrix material, it should be understood that the following applies to both.
Referring now to FIG. 3, there is shown a schematic view of such an alternative manufacturing line which is designated generally by the ` numeral 40. The line 40 is capable of manufacturing a bonded ribbon 4210 (see FIG. 4). The ribbon 42 includes a plurality of coated optical fibers 36-36 each of which includes a core, a cladding and one or more layers 25-25 of coating material.
As can be seen in FIG. 4, the optical fibers 36-36 may be disposed in a planar array. The fibers are held bonded together in that 15 array by a matrix material 45. It is common to refer to such a structure as a bonded ribbon. In a preferred embodiment, the matrix material is an ultraviolet (W) curable material.
Along the line 40, a plurality of the optical fibers 36-36 are payed out from supplies 46-46, and an ink from a reservoir is applied thereto by an 20 applicator 48. Afterwards, the ink is dried in an oven 4~. Then the optical fibers are gathered together and embedded in the curable matrix material in an applicator 52. The applicator 52 may be an extruder, for example.
Afterwards, the array in the matrix material is directed past an apparatus 54 which is well known and which is used to cure the curable matrix 25 material and taken up on a spool 56.
As mentioned, after the curable coating material has been applied to the drawn optical fiber or the curable matrix material to the array of optical fibers, the coating or the matrix material must be cured.
The coating material may be cured by thermal, electron beam, microwave, 30 or ultraviolet energy. For the preferred embodiment, the curable material may comprise a silicone-based material, an acrylate-based material or a vinyl-based material.
For rapid application and cure, coatings which cure on exposure to radiation, preferably ultraviolet radiation, are needed. However, 35 radiation-curable coatings for optical glass fiber may be of various types, but it is always necessary to provide the low to moderate tensile modulus -~, . . . .. . ..
,,, ' . . . ' ,. ., . i, . . . ,- ~ . .
35~
needed in a coating which will contact the glass, to employ a polyethylenic polymeric organic compound. Many appropriate polyethylenic organic compounds are known and are deemed acceptable and within the scope of the present invention.
While the two specific embodiments presented herein are directed to curing coating material on either a single optical fiber or a plurality of fibers arranged as a bonded ribbon, it should also be noted that ~; the curing dose monitoring system of the present invention is also applicable to curing various types of coloring components sometimes applied to '` 10 fiber(s).
The present invention is directed to a method and apparatus for monitoring the overall operational effectiveness of a curing system specifically addressing such systems presently used in drawing optical fiber.
In general, it is accepted that at least three factors affect the amount of ` 15 curing radiation which ultimately reaches the coatings applied to a fiber.
These factors include 1) the output power output level of the radiation source, 2) the cleanliness of the center tube if such device is used, and 3) the efficiency of the reflector system. In order to accurately monitor the overall effectiveness of the curing system, the present invention is capable of 20 continuously gauging substantial changes in any of the three factors identified above which may adversely affect the ultimate cure of the coatings.
It is generally known and accepted that there is a direct !~, relationship between the energy level of a radiation source and the degree or 25 rate of cure of the curable material. Similarly, it is also known and accepted that there is a direct relationship between the range of emission wavelengths generated by a radiation source and the degree or rate of cure achieved by a particular curable material. Therefore, the specific importance of the radiation source output level and characteristics will not 30 be further discussed below. However, with regard to the effects on curing attributable to either the cleanliness of the center tube or the efficiency of the reflector system, a brief discussion may be warranted and therefore follows below.
Disadvantageously, as a result of high temperatures within the 35 elliptical reflector system, the optical fiber coatings emit chemical vapors during the drawing of optical fiber from a preform. These vapors deposit on ~ -~, ~ ~ , .. .. ~
.. - , . . - ~ . ~. -an inner surface of the center tube and significantly attenuate W light energy which reaches the optical flber coating during a draw. A possible consequence of excessive attenuation of W curing light energy is an unacceptable degree of cure of the coating materials.
Referring now back to element 57 of FIG. 1 and which is . diagrammed in more detail in FIGS. 5 and 6, it can be seen that in thepreferred embodiment, the curing apparatus of the present invention ~ includes an elliptically shaped reflector 60 comprising a primary reflector `' portion 62 and a back reflector 64. A radiation curing source 66, which is 10 preferably an ultraviolet light energy bulb, is disposed at one of the loci of the elliptical geometry. Successive increments of length of the drawn optical fbers are moved through a center tube 68. Preferably the center tube 68 is made of quartz and is disposed at the other loci of the elliptical shape.
A center tube monitor may be positioned directly behind the quartz center tube 68 away from the W light source 66. Additionally, a center tube sensor 70 measures the amount of curing radiation which is transmitted through the center tube 68 to impinge on the optical flber coating material 25. In addition, a reference monitor may be positioned 20 beyond the quartz center tube 68 and is used to measure the amount of light emitted directly from the W bulb 66. However, other calibration techniques may be employed to periodically generate an average radiometry reading along the length of the fiber, thereby alleviating the need to continuously monitor the radiation output of the source. One such 25 alternative calibration method may involve establishing an emission value for a new radiation source and, based on a profile of the projected life deterioration of such sources, generating an ongoing and accurate base or .reference output value of that radiation source throughout its life .
Specifically, as shown in FIGS. 5 and 6, one embodiment of the ~ -30 present invention introduces one hole 72 into the housing of curing assembly and three additional longitudinally arranged holes 74-74 through the reflector surface on the center tube side. Once the radiation is transmitted through the center tube 68, these holes 74-74 provide a path for radiation to pass from the bulb 66 through the reflector surface 64 to the 35 sensor 70. However, the light path described above is indirect since the reflector holes 74-74 are purposefully not aligned with the radiation sensor ~D ~ y ~
While the two specific embodiments presented herein are directed to curing coating material on either a single optical fiber or a plurality of fibers arranged as a bonded ribbon, it should also be noted that ~; the curing dose monitoring system of the present invention is also applicable to curing various types of coloring components sometimes applied to '` 10 fiber(s).
The present invention is directed to a method and apparatus for monitoring the overall operational effectiveness of a curing system specifically addressing such systems presently used in drawing optical fiber.
In general, it is accepted that at least three factors affect the amount of ` 15 curing radiation which ultimately reaches the coatings applied to a fiber.
These factors include 1) the output power output level of the radiation source, 2) the cleanliness of the center tube if such device is used, and 3) the efficiency of the reflector system. In order to accurately monitor the overall effectiveness of the curing system, the present invention is capable of 20 continuously gauging substantial changes in any of the three factors identified above which may adversely affect the ultimate cure of the coatings.
It is generally known and accepted that there is a direct !~, relationship between the energy level of a radiation source and the degree or 25 rate of cure of the curable material. Similarly, it is also known and accepted that there is a direct relationship between the range of emission wavelengths generated by a radiation source and the degree or rate of cure achieved by a particular curable material. Therefore, the specific importance of the radiation source output level and characteristics will not 30 be further discussed below. However, with regard to the effects on curing attributable to either the cleanliness of the center tube or the efficiency of the reflector system, a brief discussion may be warranted and therefore follows below.
Disadvantageously, as a result of high temperatures within the 35 elliptical reflector system, the optical fiber coatings emit chemical vapors during the drawing of optical fiber from a preform. These vapors deposit on ~ -~, ~ ~ , .. .. ~
.. - , . . - ~ . ~. -an inner surface of the center tube and significantly attenuate W light energy which reaches the optical flber coating during a draw. A possible consequence of excessive attenuation of W curing light energy is an unacceptable degree of cure of the coating materials.
Referring now back to element 57 of FIG. 1 and which is . diagrammed in more detail in FIGS. 5 and 6, it can be seen that in thepreferred embodiment, the curing apparatus of the present invention ~ includes an elliptically shaped reflector 60 comprising a primary reflector `' portion 62 and a back reflector 64. A radiation curing source 66, which is 10 preferably an ultraviolet light energy bulb, is disposed at one of the loci of the elliptical geometry. Successive increments of length of the drawn optical fbers are moved through a center tube 68. Preferably the center tube 68 is made of quartz and is disposed at the other loci of the elliptical shape.
A center tube monitor may be positioned directly behind the quartz center tube 68 away from the W light source 66. Additionally, a center tube sensor 70 measures the amount of curing radiation which is transmitted through the center tube 68 to impinge on the optical flber coating material 25. In addition, a reference monitor may be positioned 20 beyond the quartz center tube 68 and is used to measure the amount of light emitted directly from the W bulb 66. However, other calibration techniques may be employed to periodically generate an average radiometry reading along the length of the fiber, thereby alleviating the need to continuously monitor the radiation output of the source. One such 25 alternative calibration method may involve establishing an emission value for a new radiation source and, based on a profile of the projected life deterioration of such sources, generating an ongoing and accurate base or .reference output value of that radiation source throughout its life .
Specifically, as shown in FIGS. 5 and 6, one embodiment of the ~ -30 present invention introduces one hole 72 into the housing of curing assembly and three additional longitudinally arranged holes 74-74 through the reflector surface on the center tube side. Once the radiation is transmitted through the center tube 68, these holes 74-74 provide a path for radiation to pass from the bulb 66 through the reflector surface 64 to the 35 sensor 70. However, the light path described above is indirect since the reflector holes 74-74 are purposefully not aligned with the radiation sensor ~D ~ y ~
~, .
, hole 72.
The plurality of misaligned holes 74-74 establishes the monitor reading as an accurate representation of the average clouding of the center tube, unbiased by an isolated high-intensity signal passing through a single - 5 section of the center tube. Additionally, the particular hole alignment of the present invention reduces the effects of alignment error that often occurs during installation of center tube 68.
Even though the preferred embodiment provides for the introduction of three misaligned holes as described above, it should be 10 noted that an equally suitable alternative within the scope of the present ~ invention may involve a longitudinally extending slot which allows for direct illumination of the sensor instead of the indirect illumination as provided in the embodiment shown. ~ ~
- Since the present invention may be directed at serving and 15 measuring various forms of radiation, it should be noted that any well -known type of radiometry may be used in accordance with the present invention.
Preferably, the radiation sensor 70 includes a plurality of photodiodes with a sensitivity value in the range of 320-390 nm and are 20 mounted in a heat-insulating phenolic block 76. Such devices are presently available from Electronic Instrumentation and Technologies Corp. of Sterling, Vlrginia. The block 76 should be thick enough to act as a sufficient thermal insulator for the cured dose monitoring system. In general, the mounting block 76 is about one inch (1") thick.
For operation, the W monitors are calibrated to read 100% with a new center tube in place. As a test, the accuracy of the sensors was tested by measuring the clouding of two center tubes, both in the lamps with the sensors and in a lab with a spectrophotometer. A tube with a 12% W
monitor reading measured 10% transmittance on the spectrophotometer at 30 350 nm, while one with a monitor reading at 60~ measured 50%
transmittance. A clean tube measured 35% transmittance at the same wavelength. Thereby with this correction, the spectrophotometer and W
sensor readings agreed verywell.
The amount of light impinging the fiber coating is equal to the ~ -35 combination of light which passed through the reflective housing, plus the light reflected by the reflector system plus the amount of light emitted from . . ~ - ~ . .
~ 9 , the light source.
The advantages of the methods and apparatus of this invention are many. First, continuous feedback of the optical fber coating cure process quality is achieved. Secondly, costly, time-consuming off-line 5 quality control testing is no longer needed.
.;
.s~
s~
~, '
, hole 72.
The plurality of misaligned holes 74-74 establishes the monitor reading as an accurate representation of the average clouding of the center tube, unbiased by an isolated high-intensity signal passing through a single - 5 section of the center tube. Additionally, the particular hole alignment of the present invention reduces the effects of alignment error that often occurs during installation of center tube 68.
Even though the preferred embodiment provides for the introduction of three misaligned holes as described above, it should be 10 noted that an equally suitable alternative within the scope of the present ~ invention may involve a longitudinally extending slot which allows for direct illumination of the sensor instead of the indirect illumination as provided in the embodiment shown. ~ ~
- Since the present invention may be directed at serving and 15 measuring various forms of radiation, it should be noted that any well -known type of radiometry may be used in accordance with the present invention.
Preferably, the radiation sensor 70 includes a plurality of photodiodes with a sensitivity value in the range of 320-390 nm and are 20 mounted in a heat-insulating phenolic block 76. Such devices are presently available from Electronic Instrumentation and Technologies Corp. of Sterling, Vlrginia. The block 76 should be thick enough to act as a sufficient thermal insulator for the cured dose monitoring system. In general, the mounting block 76 is about one inch (1") thick.
For operation, the W monitors are calibrated to read 100% with a new center tube in place. As a test, the accuracy of the sensors was tested by measuring the clouding of two center tubes, both in the lamps with the sensors and in a lab with a spectrophotometer. A tube with a 12% W
monitor reading measured 10% transmittance on the spectrophotometer at 30 350 nm, while one with a monitor reading at 60~ measured 50%
transmittance. A clean tube measured 35% transmittance at the same wavelength. Thereby with this correction, the spectrophotometer and W
sensor readings agreed verywell.
The amount of light impinging the fiber coating is equal to the ~ -35 combination of light which passed through the reflective housing, plus the light reflected by the reflector system plus the amount of light emitted from . . ~ - ~ . .
~ 9 , the light source.
The advantages of the methods and apparatus of this invention are many. First, continuous feedback of the optical fber coating cure process quality is achieved. Secondly, costly, time-consuming off-line 5 quality control testing is no longer needed.
.;
.s~
s~
~, '
Claims (10)
1. A method of continuously monitoring the amount of radiation energy available for curing a material on an article, said method including the steps of:
providing an article coated with a curable material into a curing system which includes a radiation source capable of providing energy for curing the material and a reflector system which redirects non-direct radiation back toward the article;
curing the coating material by causing the radiation source to emit energy suitable for curing the curable coating material; and sensing the amount of radiation available from the curing system and directed to impinge the article as the article is being cured to obtain in-process readings.
providing an article coated with a curable material into a curing system which includes a radiation source capable of providing energy for curing the material and a reflector system which redirects non-direct radiation back toward the article;
curing the coating material by causing the radiation source to emit energy suitable for curing the curable coating material; and sensing the amount of radiation available from the curing system and directed to impinge the article as the article is being cured to obtain in-process readings.
2. The method of claim 1, wherein the reflector system includes an elliptically shaped reflector comprising a primary reflector portion and a back reflector portion.
3. The method of claim 1, wherein the radiation source is disposed at one of the loci of the elliptically shaped reflector.
4. The method of claim 1, wherein the article to be used is disposed at one of the loci of the elliptically shaped reflector.
5. The method of claim 1, wherein said method further includes the steps of:
sensing the amount of the light energy available from the radiation source at a location which is outside the reflector system to obtain a reference reading; and comparing the in-process readings with the reference reading to determine the portion of the light available from the curing lamp which is available for curing the curable coating material.
sensing the amount of the light energy available from the radiation source at a location which is outside the reflector system to obtain a reference reading; and comparing the in-process readings with the reference reading to determine the portion of the light available from the curing lamp which is available for curing the curable coating material.
6. An apparatus for continuously monitoring the amount of radiation energy available for curing a coating material on a moving optical fiber, said monitoring apparatus comprising a tubular member which is disposed within a reflector system which includes a radiation source capable of providing energy for curing the coating material on an optical fiber; and a sensor which measures the amount of radiation energy available from the reflector system and directed to impinge the fiber æ a curable coating material being cured to obtain in-process readings.
7. The apparatus of claim 6, wherein the reflector system includes an elliptically shaped reflector comprising a primary reflector portion and a back reflector portion.
8. The apparatus of claim 6, wherein the curing lamp is disposed at one of the loci of the elliptically shaped reflector.
9. The apparatus of claim 6, wherein the coating material is cured at one of the loci of the elliptically shaped reflector.
10. The apparatus of claim 6, wherein a reference sensor which measures the amount of the energy available from the radiation source at a location which is outside the reflector system to obtain a reference reading; and means for comparing the in-process readings with the reference reading to determine the portion of the light available from the curing lamp which is available for curing the curable coating material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/030,501 US5418369A (en) | 1993-03-12 | 1993-03-12 | System for continuously monitoring curing energy levels within a curing unit |
| US030,501 | 1993-03-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2115594A1 true CA2115594A1 (en) | 1994-09-13 |
Family
ID=21854486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002115594A Abandoned CA2115594A1 (en) | 1993-03-12 | 1994-02-14 | System for continuously monitoring curing energy levels within a curing unit |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5418369A (en) |
| EP (1) | EP0616843A3 (en) |
| JP (1) | JPH0727900A (en) |
| CA (1) | CA2115594A1 (en) |
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| US5521392A (en) * | 1994-04-29 | 1996-05-28 | Efos Canada Inc. | Light cure system with closed loop control and work piece recording |
| FR2729152A1 (en) * | 1995-01-06 | 1996-07-12 | Alcatel Cable | UV CROSSLINKING DEVICE |
| US5726815A (en) * | 1996-04-12 | 1998-03-10 | Fusion Uv Systems, Inc. | Apparatus for aligning the object focus in filament irradiating units |
| EP0854022A1 (en) * | 1997-01-15 | 1998-07-22 | Lucent Technologies Inc. | Two stage curing for optical fiber |
| US7322122B2 (en) | 1997-01-15 | 2008-01-29 | Draka Comteq B.V. | Method and apparatus for curing a fiber having at least two fiber coating curing stages |
| WO1999010717A1 (en) * | 1997-08-22 | 1999-03-04 | Morlock Richard C | Sensor housing for uv curing chamber |
| DE19834184A1 (en) * | 1998-07-29 | 2000-02-03 | Basf Ag | Process and device for optimizing paints |
| US6456895B1 (en) * | 1999-09-13 | 2002-09-24 | Fitel Usa Corp. | Method and apparatus for detecting conditions in a UV curing lamp system |
| JP2001089199A (en) * | 1999-09-28 | 2001-04-03 | Shin Etsu Chem Co Ltd | Electron beam irradiation equipment and hardening method |
| JP3505470B2 (en) | 2000-04-06 | 2004-03-08 | 古河電気工業株式会社 | Optical fiber coating forming equipment |
| JP2004510675A (en) * | 2000-10-06 | 2004-04-08 | スリーエム イノベイティブ プロパティズ カンパニー | Ceramic agglomerated particles |
| US6521004B1 (en) | 2000-10-16 | 2003-02-18 | 3M Innovative Properties Company | Method of making an abrasive agglomerate particle |
| CA2423597A1 (en) | 2000-10-16 | 2002-04-25 | 3M Innovative Properties Company | Method of making ceramic aggregate particles |
| MXPA03003290A (en) * | 2000-10-16 | 2004-05-04 | 3M Innovative Properties Co | Method of making an agglomerate particles. |
| US6555823B2 (en) * | 2000-12-22 | 2003-04-29 | 3M Innovative Properties Company | Energy collection instrument and method of use |
| CA2456673A1 (en) | 2001-10-16 | 2003-04-24 | Valspar Sourcing, Inc. | Method of monitoring extent of cure of a coating |
| US7267546B2 (en) * | 2004-08-09 | 2007-09-11 | Ultradent Products, Inc. | Light meter for detecting and measuring intensity of two or more wavelengths of light |
| US8314408B2 (en) | 2008-12-31 | 2012-11-20 | Draka Comteq, B.V. | UVLED apparatus for curing glass-fiber coatings |
| US8637115B2 (en) * | 2009-12-24 | 2014-01-28 | Ofs Fitel, Llc | Systems and methods for purging UV curing tubes |
| EP2388239B1 (en) | 2010-05-20 | 2017-02-15 | Draka Comteq B.V. | Curing apparatus employing angled UV-LEDs |
| US8871311B2 (en) | 2010-06-03 | 2014-10-28 | Draka Comteq, B.V. | Curing method employing UV sources that emit differing ranges of UV radiation |
| EP2418183B1 (en) | 2010-08-10 | 2018-07-25 | Draka Comteq B.V. | Method for curing coated glass fibres providing increased UVLED intensitiy |
| FR2965746B1 (en) * | 2010-10-11 | 2013-09-27 | Sidel Participations | METHOD OF SLEEPING A THERMAL CONDITIONING OVEN OF PREFORMS |
| US9277623B2 (en) | 2012-03-29 | 2016-03-01 | Phoseon Technology, Inc. | Load current control circuit |
| DE202013101500U1 (en) * | 2013-03-06 | 2013-06-18 | Verfahrenstechnik Hübers GmbH | Device for the production of plastic moldings from a mixture of several components |
| US9442007B2 (en) * | 2013-05-06 | 2016-09-13 | Phoseon Technology, Inc. | Method and system for monitoring ultraviolet light for a fiber cure system |
| US9442008B2 (en) * | 2013-05-06 | 2016-09-13 | Phoseon Technology, Inc. | Method and system for determining curing tube clarity |
| US9370046B2 (en) * | 2013-07-23 | 2016-06-14 | Phoseon Technology, Inc. | Compound elliptical reflector for curing optical fibers |
| CN115190872B (en) * | 2020-02-26 | 2024-03-15 | 住友电气工业株式会社 | Optical fiber manufacturing method and optical fiber manufacturing apparatus |
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| US4165463A (en) * | 1977-09-27 | 1979-08-21 | American Can Company | Radiation monitors and method for positioning |
| US4474830A (en) * | 1982-12-29 | 1984-10-02 | At&T Bell Laboratories | Multiple coating of fibers |
| GB2136112B (en) * | 1983-02-23 | 1988-01-13 | Hanovia Ltd | Apparatus for monitoring the intensity of a uv source |
| JPS60191038A (en) * | 1984-03-07 | 1985-09-28 | Oak Seisakusho:Kk | Ultraviolet irradiating device |
| NL8402124A (en) * | 1984-07-04 | 1986-02-03 | Philips Nv | DEVICE FOR EXPOSING A UV-CURING LAYER ON A WIRE-BODY. |
| JPS61130011A (en) * | 1984-11-29 | 1986-06-17 | Sumitomo Electric Ind Ltd | Ultraviolet resin curing apparatus |
| JPS61270628A (en) * | 1985-05-24 | 1986-11-29 | Furukawa Electric Co Ltd:The | Instrument for measuring ultraviolet rays for curing coating resin of device for curing resin for coating optical fiber |
| US4665627A (en) * | 1985-11-01 | 1987-05-19 | Research, Incorporated | Dry film curing machine with ultraviolet lamp controls |
| JPS62158143A (en) * | 1986-01-07 | 1987-07-14 | Sumitomo Electric Ind Ltd | Process and device for coating glass fiber for transmitting light |
| JPS62262807A (en) * | 1986-05-09 | 1987-11-14 | Sumitomo Electric Ind Ltd | Ultraviolet-ray emitting device for wire rod |
| JPS62292657A (en) * | 1986-06-13 | 1987-12-19 | Furukawa Electric Co Ltd:The | Ultraviolet ray radiating device |
| JPH0788241B2 (en) * | 1986-07-03 | 1995-09-27 | 住友電気工業株式会社 | Optical fiber coating method and coating apparatus |
| JPS63277538A (en) * | 1987-05-08 | 1988-11-15 | Sumitomo Electric Ind Ltd | Ultraviolet light irradiating device |
| US4913859A (en) * | 1987-10-30 | 1990-04-03 | At&T Bell Laboratories | Methods of curing optical fiber coatings |
| CA1337056C (en) * | 1987-10-30 | 1995-09-19 | Bob J. Overton | Methods of and apparatus for curing optical fiber coatings |
| JPH0676230B2 (en) * | 1988-11-28 | 1994-09-28 | セントラル硝子株式会社 | Manufacturing method of crystalline glass |
| JPH02145460A (en) * | 1988-11-24 | 1990-06-04 | Furukawa Electric Co Ltd:The | Optical fiber coating method |
| CA2012263C (en) * | 1989-03-30 | 1996-07-16 | James R. Petisce | Article coated with cured material and methods of making |
| US5000772A (en) * | 1990-03-09 | 1991-03-19 | At&T Bell Laboratories | Methods of and apparatus for making coated optical fiber |
-
1993
- 1993-03-12 US US08/030,501 patent/US5418369A/en not_active Expired - Lifetime
-
1994
- 1994-02-14 CA CA002115594A patent/CA2115594A1/en not_active Abandoned
- 1994-03-02 EP EP19940301497 patent/EP0616843A3/en not_active Ceased
- 1994-03-14 JP JP6068155A patent/JPH0727900A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0616843A2 (en) | 1994-09-28 |
| JPH0727900A (en) | 1995-01-31 |
| US5418369A (en) | 1995-05-23 |
| EP0616843A3 (en) | 1994-10-12 |
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