U.S. patent application number 10/035062 was filed with the patent office on 2003-07-03 for method for manufacture of tubular multilayer structure from fiber-resin material.
Invention is credited to Brill, Russell P..
Application Number | 20030121594 10/035062 |
Document ID | / |
Family ID | 21880392 |
Filed Date | 2003-07-03 |
United States Patent
Application |
20030121594 |
Kind Code |
A1 |
Brill, Russell P. |
July 3, 2003 |
Method for manufacture of tubular multilayer structure from
fiber-resin material
Abstract
A method of manufacturing a tubular multilayer structure made
from a continuous fiber pre-impregnated with a thermoplastic resin
includes feeding the material to a shaping station before the
material is wound around the mandrel. The material is heated over a
shaped hot plate while in the shaping station to lightly melt the
material. The material is tensioned to at least 15,000 psi before
the material is wound around the mandrel to ensure good bonding of
the wound layers.
Inventors: |
Brill, Russell P.; (Newark,
DE) |
Correspondence
Address: |
Connolly Bove Lodge & Hutz LLP
P.O. Box 2207
Wilmington
DE
19899-2207
US
|
Family ID: |
21880392 |
Appl. No.: |
10/035062 |
Filed: |
December 28, 2001 |
Current U.S.
Class: |
156/162 ;
156/175 |
Current CPC
Class: |
B65H 49/20 20130101;
B29C 53/74 20130101; B29C 2053/8025 20130101; B65H 81/06 20130101;
B29C 70/46 20130101 |
Class at
Publication: |
156/162 ;
156/175 |
International
Class: |
B65H 081/00 |
Claims
What is claimed is:
1. In a method for manufacturing a tubular multilayer structure
open at both axial ends wherein the tubular structure is made of a
material comprising a continuous fiber pre-impregnated with a
thermoplastic resin and wherein the tubular structure is formed by
winding the material around a rotating heated mandrel, the
improvement being in feeding the material from a supply station to
a shaping station before the material is wound around the mandrel,
heating the material over a shaped hot plate while in the shaping
station to lightly melt the material without heating the entire
wound structure, and tensioning the material to at least 15,000 psi
before the material is wound around the mandrel to ensure good
bonding of the wound layers.
2. The method of claim 1 wherein the material is tensioned in the
range of 15,000-25,000 psi.
3. The method of claim 2 wherein the material is tensioned in the
range of 20,000-25,000 psi.
4. The method of claim 1 wherein the material is tensioned at a
tensioning station located upstream from the shaping station.
5. The method of claim 4 wherein the supply station and the
tensioning station and the shaping station are mounted on a
reciprocating table which moves parallel to the mandrel.
6. The method of claim 5 wherein the material is a continuous
carbon fiber composite.
7. The method of claim 1 wherein the material is tensioned at a
tensioning station located upstream from the shaping station.
8. The method of claim 1 wherein the material is a continuous
carbon fiber composite.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention is directed to techniques for
manufacturing open ended tubular structures of multilayer form such
as seals, bushings and bearings and other wear components from a
fiber-resin material, in particular from
continuous-carbon-fiber-reinforced thermoplastic materials.
[0002] The use of continuous-carbon-fiber-reinforced thermoplastics
for seals, bushings, and bearings is gaining excitement. These
materials have distinct advantages in a wide variety of industries,
including aerospace, oilfield, and chemical/fluid handling. The
benefits include:
[0003] 1) Excellent corrosion and chemical resistance,
[0004] 2) Superior wear properties, due to low coefficient of
friction and self-lubrication,
[0005] 3) High mechanical strength and stability,
[0006] 4) Extreme temperature capabilities,
[0007] 5) high dimensional stability at different temperatures due
to low coefficient of thermal expansion in fiber direction,
[0008] 6) Finished parts are easily machinable.
[0009] It would be desirable if improvements could be made to known
methods for manufacturing tubular structures such as seals and wear
components made from fiber-resin material such as
continuous-carbon-fiber- -reinforced thermoplastic materials. It
would be desirable if such improvements could enhance the end
product while reducing costs.
SUMMARY OF THE INVENTION
[0010] An object of this invention is to provide improvements in
the manufacturing techniques for such multilayer tubular
components.
[0011] A further object of this invention is to provide such
manufacturing techniques which result in improved product quality
while reducing costs.
[0012] In accordance with this invention a tubular multilayer
structure open at both axial ends is manufactured by winding a
continuous fiber pre-impregnated with a thermoplastic resin around
a rotating heated mandrel. The manufacturing method is improved by
feeding the material from a supply station to a shaping station
before the material is wound around the mandrel. The material is
then heated over a shaped hot plate while in the shaping station to
lightly melt the material without heating the entire wound
structure. The material is tensioned to at least 15,000 psi before
the material is wound around the mandrel to ensure good bonding of
the wound layers.
[0013] In a preferred practice of this invention the material is a
continuous fiber such as carbon-graphite pre-impregnated with a
thermoplastic resin. The material is tensioned by a tensioning
structure located between the material supply station and the
shaping station. Preferably the material is tensioned from 15,000
to 25,000 psi.
THE DRAWINGS:
[0014] FIG. 1 is a top plan view of an assembly for manufacturing a
tubular multilayer structure in accordance with this invention;
[0015] FIG. 2 is a side elevational view of the assembly shown in
FIG. 1; and
[0016] FIG. 3 is an end elevational view of the formed tubular
structure.
DETAILED DESCRIPTION
[0017] The present invention relates to a process or method for
manufacturing standard tubular shapes such as rings which are open
at both axial ends. Such tubular structures could have various
known uses including seals, bushings, bearings and other wear
components. The invention is directed to improvements in known
processes wherein a thermoplastic winding process uses continuous
fiber such as carbon-graphite that is impregnated with a
thermoplastic resin such as PEEK, PEKK or TPI. Reference is made to
U.S. Pat. No. 5,198,281 and U.S. Pat. No. 5,094,883, all of the
details of which are incorporated herein by reference thereto and
which disclose the types of materials that may be used in the
practice of this invention.
[0018] Although the invention is preferably practiced where
continuous carbon fiber composites are used for forming the
structure, it is to be understood that other materials may be used
within the practice of this invention.
[0019] In order to assure good wet-out of fibers by resin, which is
critical for the applications of this invention, the fiber volume
fraction of the fiber-resin mixture is less than 65%, typically
60%.
[0020] In prior techniques the material is heated before it is laid
down in order to obtain fiber orientation. The tubular structure is
formed by wrapping the material around a hot rotating mandrel until
sufficient layers are created for the intended final structure.
When the mandrel has cooled the tubular structure can then slide
off the mandrel and can then be machined or otherwise finished. In
the conventional practices pressure is applied to the material
through nip rolls. Among the objections to conventional practices
are that residual stresses cause delaminations which impairs the
quality of the tubular structure.
[0021] In accordance with this invention the tubular structure is
formed by winding the fiber-resin material directly onto a mandrel
and then later extracting the thus formed structure from the
mandrel so that the resulting structure can be machined or
otherwise treated particularly with regard to the exposed interior
surface of the tubular structure.
[0022] In accordance with this invention the conventional practices
are modified by managing or controlling the tension and heating in
such a manner as to produce good interlaminate bond strength while
limiting residual stresses, thus reducing the occurrence of
delaminations. This is accomplished without the need for
complicated expensive techniques. The tensioning aspect of
invention involves applying a tension of at least 15,000 psi to the
material before the fiber-resin material is applied to the mandrel.
This ensures good bonding. The range of tension could theoretically
have an upper limit approximating the yield strength of the
material. For practical purposes, however, it would not be
desirable to apply too much tension since this would make it
difficult to extract the structure from the mandrel. In the
preferred practice of the invention the tension could be in a range
of 15,000-100,000 psi. A more preferred range would be
15,000-25,000 psi and the most preferred range would be
20,000-25,000 psi. The tension creates good bonding and
consolidation of the layers in the structure.
[0023] In accordance with the heating aspect of this invention
before the fiber-resin material is applied to the mandrel the
material is heated over a shaped hot plate such that the incoming
material is lightly melted without heating the entire wound part.
If desired, supplemental heat from an external source can be added
to the wound part at specific locations such as wear surfaces and
highly machined areas. The supplemental heat may come from any
suitable external source such as a torch which could be manually
operated or automated. The heating would take place for a short
period of time at a location away from the mandrel where the part
or structure is actually made.
[0024] FIGS. 1-2 illustrate an assembly 10 which may be used in the
practice of this invention. As shown therein, the assembly 10
includes a supply station 12 which may take any suitable form such
as being a supply roll or creel from which the fiber-resin material
28 is removed. Various components of the assembly as later
described including the supply station 12 are mounted on a
transversing table or carriage 14 which moves back and forth in the
direction of the arrow shown in FIG. 2 parallel to mandrel 38. From
the supply station 12 the material 28 passes through a tensioning
station 16 which may take any suitable form. For example, the
tensioning station 16 may include a support 18 having a pivotable
arm 20 at the end of which is a tensiometer 22 which operates in
conjunction with brake 24 and roller 26 to control the tension of
the material 28. The material 28 then passes through guide rollers
30,32 and then into shaping station 34. Shaping station 34 includes
a shaped hot plate arrangement 36 which may be of the type
disclosed in U.S. Pat. No. 5,160,561, all of the details of which
are incorporated herein by reference thereto. The material 28 is
heated over the shaped hot plate 36 so that the incoming material
is only lightly melted at a location upstream from the mandrel 38
so that the heating can be done without heating the entire wound
part.
[0025] In the shaping station 34 the material 28 is shaped into a
generally ribbon form which facilitates the application of the
material 28 to the mandrel 38. The plate 36 in the shaping station
34 gives intimate contact with the melted resin to create the
desired shape for application of the material 28 to the mandrel
38.
[0026] When the fiber-resin material passes through the shaping
station the material is heated to a temperature slightly above the
resin melting point and remains in the station over its path of
travel for a sufficient residence time to accomplish the light
melting. For example, with a plate 36 which is about 6 to 8 inches
long, the material would be fed at a rate of about 20 feet per
minute. The material entering the station 34 cold would then
gradually heat as it passes over the plate 36 until it leaves
station 34 slightly melted.
[0027] From the shaping station 34 the material 28 is wound
directly on the mandrel 38. Except for mandrel 38 and its
associated structure all of the components of the system 10 are
mounted on the table 14 in such a manner that the table 14
reciprocates back and forth parallel to the mandrel thereby
permitting the material to be wound around the mandrel and create a
plurality of layers. Any suitable drive mechanism may be used for
moving table 14 back and forth. FIG. 2 schematically illustrates a
reversable motor 42 rotating a lead screw 44 on which a drive nut
46 is mounted. The drive mechanism includes a guide rod 48 at the
opposite end of table 14. In this manner, depending on the
direction of rotation of lead screw 44 the table 14 would move
toward or away from the motor 42 in accordance with the back and
forth movement of nut 46.
[0028] Mandrel 38 may take any suitable construction such as being
driven by motor 50 with the mandrel 38 supported by bearing
supports 52. Mandrel 38 would be heated and rotated as is known in
the art. Thus, during the rotation of mandrel 38 the material 28 is
applied or wound on the mandrel 38 to create the desired number of
layers in accordance with the intended end product.
[0029] FIG. 3 illustrates a tubular structure 54 which is open at
both axial ends and is formed from a plurality of layers. Tubular
structure 54 could then be used in any conventional manner such as
seals, bushings and bearings, wear rings, driveshafts, collars, and
sleeves that match desired properties and anti-extrusion rings,
drilling tool components, bearings, drill collars, logging sleeves,
supports, subsea bearings, drive shafts, pump wear rings and
bushings, non-conductive collars, valve seats, tractor systems,
single trip perforators, tool bodies, abrasion resistant cylinders,
drillable seals and cementing drillable plugs.
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