Title: Ultrasound welding of plastics components
Abstract: A process for the bonding of a plastics pipe to another plastics part by ultrasound welding using sound waves which act longitudinally with respect to the pipe axis, while the arrangement of the areas to be welded is substantially parallel to the pipe axis. The welding procedure is combined with the forced insertion of the other plastics part into the plastics pipe in such a way that there is at least some overlap between the exposure to sound and the forced insertion.
Patent Number: 7,025,842 Issued on 04/11/2006 to Monsheimer, et al.
| Inventors:
|
Monsheimer; Sylvia (Haltem am See, DE);
Göring; Rainer (Borken, DE);
Ries; Hans (Marl, DE);
Brudny; Günter (Marl, DE)
|
| Assignee:
|
Degussa AG (Duesseldorf, DE)
|
| Appl. No.:
|
826334 |
| Filed:
|
April 19, 2004 |
Foreign Application Priority Data
| Apr 19, 2003[DE] | 103 18 321 |
| Current U.S. Class: |
156/73.1; 156/294; 264/445 |
| Current Intern'l Class: |
B32B 37/00 (20060101) |
| Field of Search: |
156/731,293,294,308.2,580.1,580.2
264/442,443,445
|
References Cited [Referenced By]
U.S. Patent Documents
| 3929958 | Dec., 1975 | Parmann.
| |
| 4655486 | Apr., 1987 | Tarnay et al.
| |
| 5090745 | Feb., 1992 | Kluger.
| |
| 5622394 | Apr., 1997 | Soles et al.
| |
| 5879115 | Mar., 1999 | Medal.
| |
| 5957163 | Sep., 1999 | Ito et al.
| |
| 6231085 | May., 2001 | Olson.
| |
| 6454891 | Sep., 2002 | Goss.
| |
| 6555243 | Apr., 2003 | Flepp et al.
| |
| 6609729 | Aug., 2003 | Nishiyama et al.
| |
| Foreign Patent Documents |
| 41 27 039 | Feb., 1992 | DE.
| |
| 0 242 480 | Oct., 1987 | EP.
| |
| 58-122822 | Jul., 1983 | JP.
| |
Other References
W. Land, Kunstsloffe, vol. 68, No. 4, pp. 233-237, "Untersuchungen Zum Ablauf
Des Ultraschallschweissens", 1978.
|
Primary Examiner: Sells; James
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Claims
What is claimed is:
1. A process for the bonding of a plastics pipe to a coupling end portion of
another plastics part by means of ultrasound welding, which comprises the steps of:
performing ultrasound welding with sound waves which act longitudinally with
respect to a plastics pipe axis while maintaining an arrangement of areas to be
welded substantially parallel to the plastics pipe axis, and
forcing insertion of the coupling end portion into the plastics pipe so that
the coupling end portion is inserted inside of and widens the plastics pipe during
at least part of the time that the sound waves are being provided during the ultrasonic
welding step.
2. The process according to claim 1, wherein the exposure to the sound waves
is substantially simultaneous with the forced insertion.
3. The process according to claim 1, wherein the plastics pipe is a multilayer
pipe comprising a barrier layer and/or comprising an internal layer which has been
rendered antistatic.
4. The process according to claim 1, wherein the plastics pipe is a fuel line,
a coolant line, a brake fluid line, a hydraulic fluid line, or a windshield washer
system line.
5. The process according to claim 1, wherein the other plastics part is a quick
connector, a branch, a valve, or a cap for the plastics pipe.
6. The process according to claim 1, wherein the other plastics part is composed
of an electrically conductive material, or has been internally and/or externally
covered with an electrically conductive layer.
7. The process according to claim 2, wherein the plastics pipe is a multilayer
pipe comprising a barrier layer and/or comprising an internal layer which has been
rendered antistatic.
8. The process according to claim 2, wherein the plastics pipe is a fuel line,
a coolant line, a brake fluid line, a hydraulic fluid line, or a windshield washer
system line.
9. The process according to claim 2, wherein the other plastics part is a quick
connector, a branch, a valve, or a cap for the plastics pipe.
10. The process according to claim 2, wherein the other plastics part is composed
of an electrically conductive material, or has been internally and/or externally
covered with an electrically conductive layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This patent document claims priority to German Patent Publication 103 18 3213.3
filed Apr. 19, 2003, the entire contents of which are hereby incorporated herein
by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for the bonding of a single- or multilayer
pipeline to another plastics part, e.g. to a quick connector.
2. Discussion of the Background
There are known bonds between a pipe and a plastics part where the plastics
part acts as a mandrel broaching the pipe. In this process, the pipe is widened
in order to receive the nipple of the plastics part. The pipe then replicates any
profile present on the nipple. This bond is required to have maximum resistance
to permeation and leakage, to withstand high separation forces, and to resist distortion.
In the case of bonding of a fuel line and a quick connector, the use of a "wedding
band" is also known (e.g., see DE 41 27 039 A1). The "wedding band" is forced onto
the pipe prior to the process of broaching by a "mandrel," and during the process
of broaching by the "mandrel" it is likewise widened, the separation forces thus
being increased by virtue of the additional material.
However, the capabilities of a bond resulting from broaching by the above-noted
"mandrel" do not meet all requirements, particularly not at high temperatures like
those likely to occur in the engine compartment of a motor vehicle. Under such
high temperatures, there is a marked reduction in resistance to separation and
in resistance to distortion, the result sometimes being that the bond loses its coherence.
Other applications, such as medical technology applications, demand that the
bond has coherence and stiffness.
One way of eliminating this problem consists of welding the two components to
be bonded, for example, by high-speed hot gas welding, infrared welding, or electrical
sleeve welding, or by means of a high-frequency field. The process most frequently
used in plastics technology is ultrasound welding. Ultrasound is a term used relative
to sound in a frequency range beyond the range perceptible to the human ear, e.g.,
from 20 kHz extending to frequencies of 1 GHz. In industrial ultrasound welding,
an electrical method is used to excite the oscillations, by producing electrical
oscillations in a generator. The piezoelectric converter principle, which underlies
ultrasound welding, permits the electrical power of the generator to be converted
into mechanical energy at very high efficiency. Electrical oscillations thus produce
mechanical oscillations of identical frequency. Conventional ultrasound frequencies
for plastics welding are from 15 to 40 kHz, but it is also possible to operate
at substantially higher frequencies (e.g., up to 1010 kHz).
These ultrasound converters always oscillate longitudinally, which means that
the direction of propagation and the direction of oscillation are coincident. An
amplitude transformer unit, known as a sonotrode, couples the ultrasound converter
to the energy-conducting welding tool. With the aid of the sonotrode, the longitudinal
wave is substantially all conducted into the work piece to be welded. In the zone
where welding occurs, the sound waves are converted into heat, initially via interfacial
friction and then via both interfacial friction and friction at the molecular level.
The material in the zone where welding occurs melts and melt flow occurs due to
sonotrode pressure.
Examples of these processes are shown in W. Land, Kunststoffe 68 (1978)
4, pp. 233-237. However, the only arrangements known hitherto are those where the
movement of the sonotrode takes place perpendicularly with respect to the area
to be welded. If the area to be welded has a profile design, for example, a conical
profile or olive profile on the stem of a quick connector, it is not the surfaces
of the profile that are referred to here, but rather the outer surface of a cylinder
represented by the stem. The profile then acts as an energy flow director which
gives an energy concentration with a defined start (trigger) zone and welding zone.
If a pipe is then welded to a quick connector, the parts to be welded have to be
rotated once around their own axis so that an annular weld can be produced. This
can cause problems if the individual components are bulky. In addition, the areas
to be welded have to be mutually superposed prior to the welding process. For the
bonding of a pipe and a quick connector, this means that a process of broaching
using a "mandrel" still has to be carried out first. In the case of the abovementioned
bond, therefore, the use of conventional ultrasound welding does not represent
any simplification of the process, but rather an additional operation.
SUMMARY OF THE INVENTION
An object of the invention is to simplify the known process of ultrasound welding
of components to be bonded, with no resultant impairment of the durability of the weld.
Surprisingly, this object is achieved by using a process for the bonding
of a plastics pipe to another plastics part, which comprises performing ultrasound
welding with sound waves which act longitudinally with respect to the pipe axis
while maintaining the arrangement of the areas to be welded substantially parallel
to the pipe axis, and forcing insertion of the other plastics part into the plastics
pipe in such a way that there is at least some overlap between the exposure to
the sound waves and the forced insertion during the ultrasound welding step.
The plastics pipe usually serves to convey fuels, solvents, oils, crop-protection
agents, or the like. In one preferred embodiment, the plastics pipe is a motor
vehicle pipeline, in particular a fuel line, a coolant line, a brake fluid line,
a hydraulic fluid line, or a windshield washer system line. The pipe may have one
or more layers, and up to seven layers are currently feasible industrially. This
multilayer structure may include a barrier layer which inhibits the permeation
of fuel components. Whereas the functional layers are generally composed of a molding
composition based on polyamide or polyolefin, the barrier layer is composed of
a molding composition based on materials such as polyester, fluoropolymer, or ethylene-vinyl
alcohol copolymer. Any antistatic internal layer which may be present is composed
of a molding composition which has been rendered antistatic by adding an electrically
conductive component, such as conductivity black or graphite fibrils. These layers
are conventional and are described in many publications. They may be produced by
conventional extrusion or coextrusion, using a pipe calibrator or a plate calibrator,
or they can be produced by using shaping tools (corrugated pipe take-off). Another
known production process for these single- or multilayer pipes is blow molding,
for example, suction blow molding or blow molding with parison manipulation.
The other plastics part to be bonded to the pipe can be an attachment, for example
a quick connector, a branch, a valve, or a cap for the pipe. The other plastics
part has at least one nipple intended for bonding to the pipe. This nipple may
be of smooth design, or else may have an external profile, e.g., a conical profile
or an olive profile in the case of quick connectors. The other plastics part can
be mostly composed of a single material, but may also be composed of two or more
different materials produced by multicomponent injection molding, for example.
The material may also have reinforcement, for example by means of glass fibers
or by carbon fibers, or it may have been rendered antistatic, for which purpose
carbon fibers may likewise be used, but use may also be made of conductivity black,
graphite fibrils, or any other suitable additive. To this end, the material may
be composed entirely of material which has been rendered electrically conductive,
or may have been covered internally and/or externally with a layer rendered electrically conductive.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and many of the attendant
advantages thereof will be readily obtained as the same becomes better understood
by reference to the following detailed description when considered in connection
with the accompanying drawings, wherein:
FIG. 1 shows the starting position of the plastics pipe and the other plastics
part prior to welding.
FIG. 2 shows the start of the insertion of the other plastics part into the
plastics pipe.
FIG. 3 shows the full insertion of the other plastics part into the plastics pipe.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate
identical or corresponding parts throughout the several views, and more particularly
to FIG. 1 thereof, this figure shows the starting position of the ultrasound welding
machine sonotrode (
3), the pipe (
2) held in fixing system (
4)
and the other plastics part (
1), a quick connector, for example. As further
illustrated by FIG. 1, the sonotrode (
3), the pipe (
2), and the quick
connector (
1) are initially separated elements.
FIG. 2 illustrates the quick connector (
1) beginning to be forced to
some extent into the pipe (
2) with the aid of the ultrasound welding machine
sonotrode (
3). This is when exposure to ultrasound from the ultrasound sonotrode
(
3) begins for the quick connector (
1).
Simultaneously with this exposure to ultrasound, the quick connector
(
1) is pressed further into the pipe (
2) by the welding machine sonotrode
(
3) as illustrated by FIG. 3. After the welding procedure, the sonotrode
(
3) is moved upward and the fixing system (
4) for the pipe can be
released. If angle connectors have an area for contact with the sonotrode, this
process can also be used to produce angle quick connector/pipe bonds.
In one modified arrangement, the sonotrode (
3) may also protrude into
the
quick connector. In another embodiment, the fixing system or block (
4) can
be provided with elastic walls on the side facing toward the sonotrode (
3)
so that the widened section of the pipe can be supported by the elastic walls.
The process of the invention may also be used when the pipe area to be welded
to the other plastics part is not internal, as described above, but external. This
may be necessary if the internal area of a multilayer pipe is unsuitable for welding—for
example because of the nature of its material. The pipe to be welded is then advantageously
stiffened. The stiffening may, for example, be composed of a flange, or else of
an increased wall thickness, of ribbing, of a corrugated structure at the end of
the pipe, of a support sleeve forced onto the pipe or fixed thereto, or of a support ring.
An advantage of the process of the invention is the fact that it carries out
two
steps simultaneously, specifically the forced insertion of the other plastics part
and the production of the weld. The weld is produced simultaneously around the
periphery, and this means that the parts to be bonded do not have to be rotated
around their axis. The implementation of the process requires no new geometric
arrangements, and, moreover, can use conventional ultrasound welding equipment
at the usual frequencies, e.g., in the range from 15 kHz to 1010 kHz, preferably
in the range from 18 kHz to 40 kHz.
*
