U.S. patent application number 09/255128 was filed with the patent office on 2001-12-06 for surface treatment.
Invention is credited to SMITH, WALTER W.E. A..
Application Number | 20010049259 09/255128 |
Document ID | / |
Family ID | 10827323 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010049259 |
Kind Code |
A1 |
SMITH, WALTER W.E. A. |
December 6, 2001 |
SURFACE TREATMENT
Abstract
A method of producing an abrasive treatment disc is provided,
whereby the disc is formed from an abrasive material (10)
ultrasonically welded to a mounting member (14). The mounting
member (14) may be used to attach the disc (10) to a tool for
subseguent use. Also provided is an abrasive treatment disc
produced according to an ultrasonic welding method. Woven and
non-woven materials may be used as the abrasive material (10).
Inventors: |
SMITH, WALTER W.E. A.;
(GLASGOW, GB) |
Correspondence
Address: |
JUDITH RILEY
GIFFORD KRASS GROH SPRINKLE
PATMORE ANDERSON & CITKOWAKI
280 NORTH WOODWARD AVENUE SUITE 400
BIRMINGHAM
MI
480095394
|
Family ID: |
10827323 |
Appl. No.: |
09/255128 |
Filed: |
February 19, 1999 |
Current U.S.
Class: |
451/490 |
Current CPC
Class: |
B24B 53/017 20130101;
B29C 66/73921 20130101; B24B 53/12 20130101; B29C 66/71 20130101;
B29C 66/474 20130101; B29K 2077/00 20130101; B29C 66/71 20130101;
B29K 2067/00 20130101; B29C 65/00 20130101; B29C 65/08 20130101;
B29C 66/712 20130101; B29C 66/1122 20130101; B29C 66/472 20130101;
B29C 66/8322 20130101; B24D 7/16 20130101; B29C 66/71 20130101;
B24D 7/02 20130101; B24D 18/009 20130101; B23K 20/10 20130101; B24B
37/245 20130101; B29C 66/30221 20130101; B29C 66/30221 20130101;
B29L 2031/736 20130101 |
Class at
Publication: |
451/490 |
International
Class: |
B24D 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 21, 1998 |
GB |
9803604.9 |
Claims
I claim:
1. A method of producing a surface treatment disc comprising a disc
of material carrying an abrasive and a mounting member fixed to the
rear face thereof to facilitate mounting of the disc on a tool, the
method comprising: providing a disc of material carrying an
abrasives providing a mounting member; locating the mounting member
on a rear face of the disc; and exposing the mounting member and
disc to high frequency energy to weld the member to the disc.
2. The method of claim 1, wherein at least the materials forming
the abutting faces of the adhesive material-carrying disc and the
mounting member are selected to have similar melting
temperatures.
3. The method of claim 1 wherein the mounting member is of nylon
and is welded to a disc of nylon scrim.
4. The method of claim 1 wherein the mounting member is of nylon
and is welded to la disc of polyester backed abrasive cloth.
5. The method of claim 1, wherein ultrasonic welding is utilised to
fix the mounting member to the disc.
6. The method of claim 1, wherein pressure is applied to the
mounting member and disc simultaneously with exposure to the high
frequency energy.
7. The method of claim 6, wherein the exposure to high frequency
energy commences prior to the application of pressure to the
mounting member and disc.
8. The method of claim 6 wherein the application of pressure
continues after the exposure to the high frequency energy has
ceased.
9. The method of claim 7 wherein the application of pressure
continues after the exposure to the high frequency energy has
ceased.
10. The method of claim 1, further comprising providing raised
areas on one or both of the abutting surfaces of the mounting
member and the disc.
11. A surface treatment disc comprising a disc of non-metallic
material carrying an abrasive and a non-metallic mounting member
fixed to a rear face of the disc and comprising means for
facilitating mounting the disc to a tool, the mounting member being
welded to the abrasive material-carrying disc.
12. The disc of claim 11, wherein the disc is a surface
conditioning disc.
13. The disc of claim 12, wherein the disc is of a non-woven
material carrying an abrasive material on at least a front face
thereof.
14. The disc of claim 11, wherein the disc is an abrasive cloth
disc.
15. The disc of claim 14, wherein the disc is of woven material
carrying an abrasive material on at least a front face thereof.
16. The disc of claim 11 wherein the mounting member is circular
with a central mounting profile.
Description
FIELD OF THE INVENTION
[0001] This invention relates to surface treatment, including
surface conditioning and grinding, and in particular but not
exclusively to surface conditioning discs and abrasive cloth
discs.
BACKGROUND OF THE INVENTION
[0002] In a number of industries, high quality metal parts are
still finished by hand, using rotary power tools fitted with discs
of surface conditioning material and abrasive cloth, typically
discs of non-woven and woven material carrying abrasive. The
majority-of such discs comprise an abrasive disc having a "button"
fixed to a rear face, the button including a profile adapted to
releasably engage with an appropriate tool fitting. At present, the
buttons are secured on the discs using an epoxy glue One method of
producing the discs is as follows: a stainless steel sheet having a
series of button-pized holes therein is placed over the rear
surface of a sheet of abrasive-carrying material; epoxy glue is
then applied to the areas of material below the holes; nylon
buttons are then dipped in an agent to soften the nylon; a softened
button is placed in each hole; the stainless steel sheet is
removed; the sheet of material, with the buttons sitting thereon,
is placed in an oven to set the epoxy; the sheets are removed from
the oven, and individual discs cut from the sheet. This process is
time-consuming, results in a large number of rejects and the
machinery traditionally used to cut the discs from the sheet is
considered by many to be unacceptably hazardous to operate and is
indeed illegal in many jurisdictions.
[0003] In addition to this, a number of materials used to make
abrasive discs are unsuitable for direct application of epoxy glue.
Non-woven materials of large pore size, for example, may be porous
enough to allow much of the epoxy to enter the pad, and so be
unavailable for gluing. Other materials are incompatible with
direct fixing of the button to the pad.
[0004] At present this problem is overcome by affixing an abrasive
pad to a backing pad, and then attaching a button to the backing
pad, This process obviously requires more steps than direct fixing
of the button, and so is more time-consuming and expensive.
[0005] An alternative solution presently in use is to mechanically
fix a button to the pad, using for example a nut and bolt
arrangement. This has the disadvantage of compressing the abrasive
pad, which tends to cause a loss of abrasive quality.
[0006] It is among the objectives of the present invention to
provide a method of producing a surface treatment disc which
obviates or mitigates these disadvantages.
[0007] According to the present invention there is provided a
method of producing a surface treatment disc comprising a disc of
material carrying an abrasive and a mounting member fixed to the
rear face thereof to facilitate mounting of the disc on a tool, the
method comprising:
[0008] providing a disc of material carrying an abrasive;
[0009] providing a mounting member;
[0010] locating the mounting member on a rear face of the disc;
and
[0011] exposing the mounting member and disc to high frequency
energy to weld the member to the disc.
[0012] Preferably, the high frequency energy is high frequency
sonic energy, at a frequency in excess of 10 kHz, preferably in
excess of 15 kHz, and most preferably in the region of 20 kHz.
[0013] According to another aspect of the present invention there
is provided a surface treatment disc comprising a disc of material
carrying an abrasive and a mounting member fixed to a rear face of
the disc and comprising means for facilitating mounting the disc to
a tool, the mounting member being welded to the disc.
[0014] It has been found that the present invention allows more
reliable and economical production of surface treatment discs such
as surface conditioning discs and abrasive cloth discs. The
abrasive material-carrying discs and the mounting members may be
readily and efficiently manufactured using automated production
processes, and the task of welding the mounting members on the
discs may be automated or carried out by unskilled personnel.
[0015] The abrasive-carrying discs will typically be circular and
formed of woven or non-woven material carrying an abrasive material
on a front face thereof, although other materials, compositions,
constructions or shapes may be utilised: for example star-shaped or
polygonal discs may be utilised it desired.
[0016] The mounting members may take any suitable form, and will
typically be circular with 4 central mounting profile such as a
threaded post, a threaded recess or mounting fingers, that is a
"roll-on", "turn-on" or "snap-on" fitting. The mounting profile of
the mounting members may conveniently be designed to fix to
standard hand tools, so enabling the user to rapidly and easily
interchange treatment discs so as to use the disc most suitable for
the work,
[0017] Preferably, at least the abutting faces of the
abrasive-carrying discs and the mounting material are of compatible
material, it having been found that bonding is facilitated by using
materials which behave in a similar manner an heating, and in
particular materials having similar softening or melting
temperatures, for example a mounting member of nylon 66 may be
welded to a disc of nylon scrim with melting occurring both in the
mounting member and disc. Nylon 66 mounting members may also be
welded to discs of other polyamides or polyesters. If necessary, a
disc of material or mounting member which does not lend itself to
bonding may be provided with an appropriate coating or layer of a
more suitable material, for example a polyester backed cloth disc
may be welded to a nylon mounting member. Preferably, the melting
temperatures of the materials are within a 100.degree. C.
range.
[0018] The compatibility of certain pairs of materials may be
optimised by a variation in the conditions of the process used to
produce the surface treatment disc. For example, variations may be
made in the duration of the exposure of the mounting member and
disc to high frequency energy; the frequency of the energy applied;
the power of the energy applied; the point of the process at which
onset of the application of the energy occurs; or in any pressure
which may be applied to the disc and the mounting member during the
manufacturing process; among other conditions. The precise
conditions under which two materials will optimally bond may be
determined by simple experimental trials, and is not a matter of
undue burden to the experimenter.
[0019] Preferably also, pressure is applied to the mounting member
and abrasive material-carrying disc simultaneously with exposure to
the high frequency energy. The pressure facilitates formation of a
secure bond and minimises the effects of high spots on one or both
faces, which may otherwise lead to an undesirable concentration of
energy and damage to one or both of the disc and mounting member,
typically in the form of "burn-through" of the mounting member.
[0020] The effects of high spots may further be mitigated by
providing raised areas on one or both of the abutting surfaces,
most preferably on the surface of the mounting member. The raised
areas may take the form of lines or ribs, and most preferably one
or more raised circular ribs. It has been found that, when using a
mounting member provided with such circular ribs, bonding tends to
occur at a number of circumferentially spaced locations on the
ribs. The raised areas may be formed by pressing or moulding.
[0021] Alternatively, in a preferred embodiment, such ribs are
omitted, as their provision increases the cost of production of the
mounting member. It has been found that where there is a problem
with high spots, the occurrence of burn through may be reduced by
slightly increasing the thickness of the mounting member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] These and other aspects of the present invention will now be
described, by way of example, with reference to the accompanying
drawings, in which:
[0023] FIG. 1 is a perspective view of a disc of material carrying
an abrasive and a mounting member of a surface treatment disc in
accordance with a preferred embodiment of the present
invention;
[0024] FIG. 2 is a view of the underside of the mounting member of
FIG. 1;
[0025] FIG. 3 is a view of the underside of a mounting member in
accordance with an alternative embodiment of the present invention;
and
[0026] FIG. 4 is a diagrammatic view of a step in the operation of
welding the mounting member to the abrasive material-carrying disc
of FIG. 1.
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] Reference is first made to FIG. 1 of the drawings, which
illustrates the elements of a surface treatment disc in the form of
a surface conditioning disc in accordance with a preferred
embodiment of the present invention, that is a disc of material 10
carrying an abrasive 12 on a front face thereof, and a mounting
member in the form of a button 14 for fixing to a rear face of the
disc 10. In this example the disc 10 is formed of nylon scrim and
the button 14 is formed of nylon 66, the button having a "roll-on"
post 16 extending from its rear face for releasably engaging with a
suitable rotary power tool.
[0028] The front face of the button 14 is illustrated in FIG. 2 of
the drawings, and it will be noted that the button face is flat. An
alternative button 14 is shown in FIG. 3, where the button face can
be seen to define two raised circumferential ribs 18, 19.
[0029] To fix the button 14 to the disc 10, the button 14 is placed
centrally on the rear face of the disc 10 and the button 14 then
ultrasonically welded to the rear face of the disc 10.
[0030] FIG. 4 of the drawings is a diagrammatic illustration of
apparatus 20 suitable for use in welding the button 14 to the disc
10. In particular, the apparatus 20 comprises a rotating table 10
carrying a number of circumferentially spaced plates 24 (only one
shown), each plate defining a circular recess 26. A disc 10 is
placed in a recess 26 at an operator accessible location and a
button 14 then placed centrally on the rear face of the disc 10.
The table 22 indexed to a button centring station (not shown), and
then indexes to a welding station, where an ultrasonic welding head
28, including a sonic emitter 30, or sonotrode, spaced from the
head end face 32, is lowered to engage the rear of the button 14,
and ultrasonic energy is emitted from the head 28 to melt one or
both of the abutting surfaces of the button 14 and disc 10, to
secure the button 14 on the disc 10.
[0031] In an alternative embodiment of the apparatus 20 illustrated
in FIG. 4, the disc 10 is placed in the recess 26 as before, while
a button 14 is placed on a guide rail. A mechanical arm draws the
button 14 toward the ultrasonic welding head 28, which head further
comprises an air suction device which lifts the button 14 to the
head 28, while automatically ensuring the button 14 is aligned
correctly with respect to the disc 10. The head 28 then lowers to
engage the button 14 with the disc 10, and the ultrasonic welding
process is carried out as before.
[0032] Using a button 14 as described in FIG. 3 above, it has been
found that welding tends to occur at circumferentially spaced
locations around the button ribs 18, 19.
[0033] The process described above may be used on a wide range of
materials and types of disc. The optimal conditions necessary to
produce a fir weld vary according to the materials used, and may
best be determined by a matter of experiment. Indeed, it has been
found that the optimal welding parameters vary even between
different batches of the same materials.
[0034] By way of example, certain of the materials successfully
welded, and the conditions used in the process are set out
below.
[0035] Typical conditions suitable for ultrasonically welding a
nylon 56 button to a disc made from non woven nylon scrim
impregnated with abrasive grain are as follows.
[0036] A 3000 watts output ultrasonic welder emitting sonic energy
at a frequency of 20 kHz was used. The distance between the
sonotrode and the welding head end face was 33.66 mm. Ultrasonic
energy was initially applied 6 mm before contact was made between
the herd and the button to be welded. A pressure of 1.1 bar was
applied to the button and disc, while ultrasonic energy was applied
for 0.8 seconds after contact. The pressure was maintained for a
further 0.5 seconds after the ultrasonic energy application
ceased.
[0037] This produced a secure weld, and subsequent testing
demonstrated that the bond between the button and disc was at least
as secure as a bond formed by conventional means.
[0038] Each of these parameters may be varied to find the most
suitable conditions for welding other materials.
[0039] It will be clear to those of skill in the art that the
above-described method of producing a surface treatment disc is
straightforward and may be carried out far more easily and
efficiently than the conventional method of fixing the button to
the disc of abrasive carrying material using an epoxy glue. As the
abrasive-carrying material may be cut before the buttons are
applied, the discs of material may be cut more accurately, reducing
waste by approximately 20%. Also, the button is fixed without the
use of solvents and the like, thus simplifying health and safety
requirements and providing a safer environment for production
personnel. The absence of a layer of solidified epoxy between the
button and the abrasive-carrying material also provides surface
treatment discs in accordance with embodiments of the invention
which are more flexible than conventional discs.
[0040] It will be further apparent to those of skill in the art
that the above-described embodiments are merely exemplary of the
present invention, and that various modifications and improvements
may be made thereto without departing from the scope of the
invention: in another embodiment, a nylon button has been
ultrasonically welded to the rear face of a polyester-backed
abrasive cloth disc.
* * * * *