U.S. patent application number 11/844239 was filed with the patent office on 2008-01-24 for method and apparatus for arc welding with arc control.
This patent application is currently assigned to Illinois Tool Works Inc.. Invention is credited to James L. Uecker.
Application Number | 20080017621 11/844239 |
Document ID | / |
Family ID | 34634624 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080017621 |
Kind Code |
A1 |
Uecker; James L. |
January 24, 2008 |
Method and Apparatus For arc Welding with Arc Control
Abstract
A method and apparatus for providing welding power with an
arc-width control is disclosed. The power supply includes a power
circuit that provides a welding output characterized by a plurality
of welding output parameters, and the power circuit receives at
least one control input. A controller provides control signals to
the power circuit. The controller receives user inputs for arc
width and wire feed speed. The controller has an arc width control
module that provides control signals that adjust one or more
welding output parameters. The adjustment has a gain responsive to
the wire feed speed input, such that there are at least three gains
over a range of possible wire feed speeds, in one embodiment. The
arc width control module provides control signals that adjust at
least five welding output parameters in response to the wire feed
speed input and the arc-width control input, in another
embodiment.
Inventors: |
Uecker; James L.; (Appleton,
WI) |
Correspondence
Address: |
CORRIGAN LAW OFFICE
5 BRIARCLIFF CT
APPLETON
WI
54915
US
|
Assignee: |
Illinois Tool Works Inc.
Glenview
IL
|
Family ID: |
34634624 |
Appl. No.: |
11/844239 |
Filed: |
August 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11531445 |
Sep 13, 2006 |
7262387 |
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11844239 |
Aug 23, 2007 |
|
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10764278 |
Jan 22, 2004 |
7138601 |
|
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11531445 |
Sep 13, 2006 |
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Current U.S.
Class: |
219/130.1 |
Current CPC
Class: |
B23K 9/09 20130101; B23K
9/0953 20130101; B23K 9/093 20130101; B23K 9/0956 20130101; B23K
9/1062 20130101; B23K 9/124 20130101; B23K 9/1006 20130101 |
Class at
Publication: |
219/130.1 |
International
Class: |
B23K 9/10 20060101
B23K009/10 |
Claims
1. A welding power supply having an arc-width control, comprising:
a power circuit having a welding output and at least one control
input, wherein the welding output is characterized by a plurality
of output welding parameters; and a controller, having at least one
control output, connected to the at least one control input, and
having a user adjustable arc-width control input, and a user
adjustable wire feed speed input, wherein the controller includes
an arc width control module having as inputs the wire feed speed
input and the arc width control input, and having at least one
welding parameter adjustment output, and wherein the at least one
welding parameter adjustment output has a gain responsive to the
wire feed speed input, such that there are at least three gains
over a range of possible wire feed speeds.
2. The welding power supply of claim 1, wherein the at least one
welding parameter adjustment output gain varies over the entire
range of possible wire feed speeds.
3. The welding power supply of claim 1, wherein the at least one
welding parameter adjustment output gains have at least three
taught points for a given wire feed speed.
4. The welding power supply of claim 3, wherein the welding
parameter adjustment output gains are interpolated between the at
least three taught points.
5. The welding power supply of claim 1, wherein the plurality of
output welding parameters include peak amps, background amps, pulse
width, frequency, adaptive voltage, ramp up and ramp down, and the
at least one welding parameter adjustment includes adjustments for
at least three of the plurality of output parameters.
6. The welding power supply of claim 5, wherein the at least one
welding parameter adjustment includes adjustments for at least five
of the plurality of output parameters.
7. The welding power supply of claim 6, wherein the at least one
welding parameter adjustment includes adjustments for at least six
of the plurality of output parameters.
8. A welding power supply having an arc-width control, comprising:
a power circuit having a welding output and at least one control
input, wherein the welding output is characterized by at least five
output parameters; and a controller, having at least one control
output, connected to the at least one control input, and having a
user adjustable arc-width control input, and a user adjustable wire
feed speed input, wherein the controller includes an arc width
control module having as inputs the wire feed speed input and the
arc width control input, and having at least five welding parameter
adjustment outputs that are responsive to the wire feed speed input
and the arc-width control input.
9. The welding power supply of claim 8, wherein the at least five
welding parameter adjustment outputs have gains responsive to the
wire feed speed input, wherein the gains vary over the entire range
of possible wire feed speeds.
10. The welding power supply of claim 9, wherein the at least five
welding parameter adjustment output gains has at least three taught
points for a given wire feed speed.
11. The welding power supply of claim 10, wherein the at least five
welding parameter adjustment output gains are interpolated between
the at least three taught points.
12. The welding power supply of claim 9, wherein the at least five
output parameters include peak amps, background amps, pulse width,
frequency, and adaptive voltage, and the at least five welding
parameter adjustment outputs includes adjustments for peak amps,
background amps, pulse width, frequency, and adaptive voltage.
13. The welding power supply of claim 12, wherein the at least five
output parameters further include ramp up and ramp down, and the at
least five welding parameter adjustment outputs further include
adjustments for ramp up and ramp down.
14. A welding power supply comprising: a source of power, having at
least one power source control input; a wire feeder, connected to
the source of power and having at least one wire feeder control
input; and a controller having welding parameter outputs connected
to the power source control input and the wire feeder control
input, and further including an arc width input, wherein at least
five welding parameters are simultaneously controlled in response
to the arc width input such that a desired arc width is obtained,
without changing other arc characteristics.
15. The welding supply of claim 14 wherein the at least five
welding parameters include at least five of peak amps, background
amps, pulse width, pulse frequency, adaptive voltage, ramp up and
ramp down.
16. A welding power supply having an arc-width control, comprising:
power means for providing a welding output in response to at least
one control input, wherein the welding output is characterized by a
plurality of output welding parameters; and control means for
controlling the power means with at least one control output
connected to the at least one control in response to a user
adjustable arc-width control input and a user adjustable wire feed
speed input, wherein the control means includes an arc width
control means for controlling arc width, and having as inputs the
wire feed speed input and the arc-width control input, and having
at least one welding parameter adjustment output, and wherein the
at least one welding parameter adjustment output has a gain
responsive to the wire feed speed input, such that there are at
least three gains over a range of possible wire feed speeds.
17. The welding power supply of claim 16, wherein the at least one
welding parameter adjustment output gain varies over the entire
range of possible wire feed speeds.
18. The welding power supply of claim 17, wherein the at least one
welding parameter adjustment output gains have at least three
taught points for a given wire feed speed.
19. The welding power supply of claim 18, further including means
for interpolating the welding parameter adjustment output gains are
between the at least three taught points.
20. The welding power supply of claim 21, wherein the plurality of
output parameters include peak amps, background amps, pulse width,
frequency, adaptive voltage, ramp up and ramp down, and the at
least one welding parameter adjustment includes adjustments for at
least three of the plurality of output parameters.
21. The welding power supply of claim 21, wherein the at least one
welding parameter adjustment includes adjustments for at least five
of the plurality of output parameters.
22. The welding power supply of claim 21, wherein the at least one
welding parameter adjustment includes adjustments for at least six
of the plurality of output parameters.
23. A welding power supply having an arc-width control, comprising:
power means for providing a welding output in response to at least
one control input, wherein the welding output is characterized by
at least five output parameters; and control means for controlling
the power means with at least one control output connected to the
at least one control input in response to a user adjustable
arc-width control input and a user adjustable wire feed speed
input, and for providing at least five welding parameter adjustment
outputs that are responsive to the wire feed speed input and the
arc-width control input.
24. The welding power supply of claim 23, wherein the at least five
welding parameter adjustment outputs have gains responsive to the
wire feed speed input, wherein the gains vary over the entire range
of possible wire feed speeds.
25. The welding power supply of claim 24, wherein the at least five
welding parameter adjustment output gains has at least three taught
points for a given wire feed speed.
26. The welding power supply of claim 25, wherein the at least five
welding parameter adjustment output gains are interpolated between
the at least three taught points.
27. The welding power supply of claim 26, wherein the at least five
output parameters include peak amps, background amps, pulse width,
frequency, and adaptive voltage, and the at least five welding
parameter adjustment outputs includes adjustments for peak amps,
background amps, pulse width, frequency, and adaptive voltage.
28. The welding power supply of claim 25, wherein the at least five
output parameters further include ramp up and ramp down, and the at
least five welding parameter adjustment outputs includes further
include adjustments for ramp up and ramp down.
29. A welding power supply comprising: power means for providing
welding power in response to at least one power source control
input; wire feeding means, connected to the source of power, for
feeding wire in response to at least one wire feeder control input;
and control means for providing welding parameter outputs,
connected to the power source control input and the wire feeder
control input, and further including an arc width input, and
further for simultaneously controlling at least five welding
parameters are in response to the arc width input such that a
desired arc width is obtained, without changing other arc
characteristics.
30. The welding supply of claim 29 wherein the at least five
welding parameters include at least five of peak amps, background
amps current, pulse width, pulse frequency, adaptive voltage, ramp
up and ramp down.
31. A method of providing welding power, comprising: providing
welding power, wherein the power is characterized by a plurality of
output parameters; and controlling the power, and the plurality of
output parameters, in response to a user adjustable output set
point; and controlling arc width and the user adjustable set point
in response to a user adjustable arc-width control input, by
adjusting the plurality of output parameters with a gain, wherein
the gain has at least three values over a range of possible user
adjustable output set points.
32. The method of claim 31, wherein the user adjustable output set
point is a wire feed speed setting.
33. The method of claim 32, wherein the gain varies over the entire
range of possible user adjustable output set points.
34. The method of claim 31, wherein the gain varies over the entire
range of possible user adjustable output set points.
35. The method of claim 34, wherein the gains have at least three
taught points for a given wire feed speed.
36. The method of claim 35, wherein the gains are interpolated
between the at least three taught points.
37. The method of claim 31, wherein the plurality of output
parameters include peak amps, background amps, pulse width,
frequency, adaptive voltage, ramp up and ramp down, and the
adjusting includes adjusting at least three of the plurality of
output parameters.
38. The method of claim 37, wherein the adjusting includes
adjusting at least five of the plurality of output parameters.
39. The method of claim 37, wherein the adjusting includes
adjusting at least six of the plurality of output parameters.
40. A method of arc welding, comprising: providing welding power in
response to at least one control input, wherein the welding power
is characterized by at least five output parameters; and
controlling the power in response to a user adjustable arc-width
control input and a user adjustable wire feed speed input by
adjusting the at least five parameters in response to the wire feed
speed input and the arc-width control input.
41. The method of claim 40, wherein the at least five welding
parameter adjustments have gains responsive to the wire feed speed
input, wherein the gains vary over the entire range of possible
wire feed speeds.
42. The method of claim 40, wherein the at least five welding
parameter adjustment output gains have at least three taught
points.
43. The method of claim 42, wherein the at least five welding
parameter adjustment output gains are interpolated between the at
least three taught points.
44. The method of claim 40, wherein the at least five welding
parameter adjustment output gains have at least three taught
points.
45. The method of claim 44, wherein the at least five output
parameters further include ramp up and ramp down, and the at least
five welding parameter adjustment outputs includes further include
adjustments for ramp up and ramp down.
46. A method of providing welding power comprising: feeding wire to
a weld; providing power to the weld; and controlling output
parameter of the power and the speed of feeding wire in response to
a user adjustable arc width input, wherein at least five output
parameters are simultaneously controlled in response to the arc
width input such that a desired arc width is obtained, without
changing other arc characteristics.
47. The method of claim 46 wherein the at least five welding
parameters include at least five of peak amps, background amps
current, pulse width, pulse frequency, adaptive voltage, ramp up
and ramp down.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the art of arc
welding. More specifically, it relates to arc welding with control
of arc parameters.
BACKGROUND OF THE INVENTION
[0002] Electric arc welding is well known, and is performed with a
variety of processes using a variety of types of equipment. One
electric arc welding process is a pulse spray process, which is
typically performed using a wire feeder and a power supply. An
example of a prior art power supply used in pulse spray welding is
a Miller S64M.TM. wire feeder. The Miller S64M.TM. wire feeder may
be used with a Miller XMT304.TM. power supply.
[0003] Typically, in pulse spray processes, power is provided from
the power supply to the wire feeder, and the wire feeder provides
the wire and power to the arc. The wire feeder typically includes a
controller, which may be part of or separate from the wire feeder,
and which controls the wire feed speed based on a user-selected
input. Additionally, the controller provides a command signal to
the power supply which causes the power supply to output a current
and voltage at a desired magnitude. The command is produced at
least in response to a user-selected wire feed speed. The current
amplitude is often controlled as a function of time, switching
between a background current and a peak current, thus creating a
pulsed output.
[0004] The welding process is often controlled by controlling
various welding parameters. For example, the pulse spray process is
typically controlled by controlling such welding parameters as peak
amps, background amps, pulse width, voltage, ramps, and frequency.
The parameters are typically controlled using a controller which
provides control signals to the wire feeder (or power supply). Some
welding power supplies control the ramp up and ramp down
(transition from background to peak, or peak to background). Also
some welding power supplies provide an adaptive output voltage
where the voltage is controlled to provide a desired or constant
arc length. As used herein, welding parameters refer to parameters
of the welding power output, such as peak amps, background amps,
frequency, pulse width, voltage (constant or adaptive) ramp up, and
ramp down. Adaptive voltage, or adaptive arc length, as used herein
includes adjusting (changing or scaling) an output parameter, pulse
frequency modulation for example, to maintain a constant or desired
arc length. Because these welding parameters are used to control
the output it may be said that the output is characterized by a
plurality of output parameters.
[0005] Some wire feeder controllers include factory programs which
preset various welding parameters. The values for these parameters
are stored by the controller (often in digital or other types of
memory). Also, many controllers allow the user to store
user-created programs which store user-selected welding parameters.
In such a case, the user teaches or sets the desired values for
welding parameters, and stores them in the memory.
[0006] When the user wishes to access either the factory preset or
the user-created programs, they are individually selected using
some type of digital interface. Then, the controller commands the
power supply to provide power at the called for current, peak
current, background current, frequency, ramps and pulse width, thus
providing the desired welding parameters.
[0007] Different types of welding require different types of arc
characteristics (such as the plasma cone angle/width and intensity,
hereafter referred to as arc width). For example, flat, horizontal
down, welding typically may be performed using a relatively wide
arc. Conversely, overhead welding, or welding in other difficult or
inconvenient physical positions, often requires a narrow arc.
[0008] The preset factory programs are typically set to provide for
welding with a wide arc, since this is the one most inexperienced
welders will use. To access the narrower arc the welder must adjust
the welding parameters manually and individually until the desired
arc is obtained. It may be necessary to decrease one parameter as
another parameter is increased, without changing other arc
characteristics. Without changing other arc characteristics, as
used herein, refers to not changing an arc characteristic from the
standpoint of the user and/or in such a way the arc is adversely
affected, such as not changing arc length to the extent the weld is
adversely affected or the user notices the change.
[0009] However, many welders lack the experience to know how to
properly adjust the various parameters, and in particular welders
do not understand the interaction between adjusting various
parameters. For example, to decrease arc width, frequency is
increased. However, increasing frequency also increases arc length.
Many welders do not know this, nor do they know how to adjust the
other welding parameters to offset the effect of changing frequency
on arc length.
[0010] Some prior art systems provide for the user to automatically
adjust arc width. As described in U.S. Pat. No. 6,121,575 (owned by
the assignee of the present invention), the system adjusts welding
parameters with a single knob (i.e. a single arc control input)
that controls arc width (or a different arc characteristic) without
adversely affecting some other arc characteristics. Specifically,
the arc width adjustment is made by adjusting three or four welding
parameters simultaneously, such that one or more other
characteristics of the arc are minimally affected. Simultaneous, in
this context, means at the same time from the standpoint of the
user and the welding process. They might occur one after the other,
but so far as the user observes by watching the welding process,
they occur at the same time.
[0011] A single digital knob (or other input device such as a
digital input panel, keyboard, analog knob, sliding switch, etc) on
the controller allows the user to select between an arc width
adjustment of 0 and 20. An arc width adjustment of 0 is no arc
width adjustment, and an arc width adjustment of 20 is the maximum
arc width adjustment (narrow arc cone) in the preferred embodiment.
No adjustment is having the parameters be as they were in the
original program, which is typically best for flat, horizontal
down, welding (i.e., using a wide arc).
[0012] While the system described in U.S. Pat. No. 6,121,575 is a
considerable advance over the prior art, it only controls three or
four parameters, and does not control adaptive arc length (output
voltage) in response to the arc width setting. Thus, when changing
arc width the arc length other characteristics may remain constant
in some circumstances, but under other circumstances changing the
arc width will also change the arc length. Also, that system
provided two gains, one for over wire feed speeds of more than 225
IPM, and one for less than 225 IPM. This caused a step change from
above and below 225 IPM, which was noticeable at the arc.
[0013] Accordingly, it is desirable that a welding power supply and
wire feeder include a controller that allows the user to adjust the
arc width using a single knob, such that more five or more welding
parameters, preferably including arc voltage, are adjusted to
obtain a desired arc width, while maintaining one or more other
characteristics of the arc, preferably including arc length.
SUMMARY OF THE PRESENT INVENTION
[0014] According to a first aspect of the invention a welding power
supply has an arc-width control. The power supply includes a power
circuit that provides a welding output characterized by a plurality
of welding output parameters, and the power circuit receives at
least one control input. A controller provides control signals to
the power circuit. The controller receives user inputs for arc
width and wire feed speed. The controller has an arc width control
module that provides control signals that adjust one or more
welding output parameters. The adjustment has a gain responsive to
the wire feed speed input, such that there are at least three gains
over a range of possible wire feed speeds.
[0015] According to a second aspect of the invention the welding
power supply with arc-width control includes a power circuit that
provides a welding output characterized by at least five welding
output parameters, and the power circuit receives at least one
control input. A controller provides control signals to the power
circuit. The controller receives user inputs for arc width and wire
feed speed. The controller has an arc width control module that
provides control signals that adjust at least five welding output
parameters in response to the wire feed speed input and the
arc-width control input.
[0016] According to a third aspect of the invention a welding power
supply includes a source of power with at least one power source
control input. A wire feeder is connected to the source of power
and has at least one wire feeder control input. A controller has
welding parameter outputs connected to the power source control
input and the wire feeder control input. The controller also has an
arc width input, and at least five welding parameters are
simultaneously controlled in response to the arc width input such
that a desired arc width is obtained, without changing other arc
characteristics.
[0017] The adjustment gain varies over the entire range of possible
wire feed speeds in accordance with one embodiment of the
invention.
[0018] The adjustment gains have at least three taught points for a
given wire feed speed in other embodiments, and the gains may be
interpolated between the at least three taught points.
[0019] The plurality of welding output parameters include peak
amps, background amps, pulse width, frequency, adaptive voltage,
ramp up and ramp down, and the adjustment includes adjustments for
at least three, five, six or more of the parameters in other
embodiments.
[0020] Other principal features and advantages of the invention
will become apparent to those skilled in the art upon review of the
following drawings, the detailed description and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a waveform of a typical welding output for a
pulsed arc welding process such as that used in the present
invention;
[0022] FIG. 2 is a flow chart of a program or a subroutine used to
implement one embodiment of the present invention; and
[0023] FIG. 3 is a block diagram of the preferred embodiment of the
present invention.
[0024] Before explaining at least one embodiment of the invention
in detail it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments or of being practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting. Like reference numerals are
used to indicate like components.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] While the present invention will be illustrated with
reference to a particular implementation and a particular flow
chart for use with a particular power supply and wire feeder, it
should be understood at the outset that the invention may also be
employed with other flow charts, routines, values, limits,
parameters, and equipment.
[0026] The invention generally includes adjusting welding
parameters with a single input (i.e. a single arc width control
input) that controls arc width without adversely affecting other
arc characteristics, such as arc length, i.e., arc width control.
(Power and/or deposition rate do not change in alternative
embodiments.) For example, in the preferred embodiment a single
digital input (such as a digital input panel, digital knob,
keyboard, analog knob, sliding switch, etc) on the controller
allows the user to select between an arc width adjustment of 0 and
50. An arc width setting of 25 is no arc width adjustment, an arc
width setting of 0 provides the maximum arc width, and an arc width
adjustment of 50 is the minimum arc width in the preferred
embodiment. No adjustment is having the parameters be as they were
in the original program, which is typically best for flat,
horizontal, welding.
[0027] The preferred embodiment uses a wire feeder design similar
to the Miller S64M.TM. wire feeder, and a power supply design
similar to the Miller XMT304.TM. power supply, but packaged in a
single housing, or the MM251.TM. or a system such as that described
in U.S. Pat. No. 6,107,602. The preferred wire feeder includes a
digital controller, which includes a microprocessor and an memory.
The controller, as described above, sets welding parameters
according to factory set, or in an alternative embodiment,
user-set, programs. Alternative embodiments provide that the
controller is part of the power supply, or in a separate housing.
The controller also receives as a user set input the arc width
adjustment knob (or other input device) setting in the preferred
embodiment. A user set input can be from an individual or an
automated system. This input is used to scale (i.e. change from the
previous setting) the program welding parameter settings, as
detailed below, to adjust the arc width from a minimum to a
maximum. The knob setting is stored with the other weld parameter
settings in any user-created programs.
[0028] The arc width adjustment is made by adjusting five or more
welding parameters simultaneously, such that other characteristics
of the arc, such as arc length, are minimally affected. The
inventor has determined various percentage adjustments of these
parameters which is believed to adequately satisfy these objectives
given the equipment used in the preferred embodiment, but other
adjustments may be made, and the invention is not limited to the
specific adjustments detailed below.
[0029] Referring now to FIG. 1 a typical wave form of a pulse spray
welding process is shown. The wave form includes a background
amperage level B.sub.A and peak amperage level of P.sub.A, pulse
width P.sub.W and period (1/f or 1/frequency). Also shown is the
ramp up from background to peak and ramp down from peak to
background. Output voltage is not shown, and is generally held
constant for a constant arc length, or is adaptively controlled
(such as by known adaptive voltage control, which can use peak
voltage). Adaptive control, in at least one known scheme, works by
modulating the pulse frequency to produce a desired arc voltage,
and thus a desired arc length.
[0030] Five welding parameters: peak amps, background amps, pulse
width, frequency and adaptive voltage (arc length) are adjusted
according to the preferred embodiment of the present invention (or
six, seven or more are adjusted according to one alternative) such
that when the user adjusts the arc width one or more other arc
characteristics are not changed or adversely affected.
[0031] For example, a decrease in arc width is obtained by
increasing frequency. If only the frequency is changed, the arc
length will increase. The present invention also adjusts background
amps and pulse width, peak amps, and adaptive voltage/arc length.
The magnitudes of the changes are selected to offset the increase
in arc length caused by the frequency increase, resulting in a no,
or little, net change in arc length. Adjusting adaptive arc
voltage/length control in the present invention can be implemented
by adjusting both the nominal frequency (the frequency without
adaptive voltage control), and adjusting the frequency modulation
(i.e., adaptive voltage) of the adjusted nominal frequency.
[0032] Each of the parameters are set by a program (a factory
program or user-defined program) implemented by the wire feeder
microprocessor (or analog control circuitry in an alternative
embodiment). The preferred embodiment adjusts those parameters as
set forth below. The specific adjustments of the preferred
embodiment were determined using empirical data, and may be
different in different alternatives. Thus, a decreased background
amps, and a decreased pulse width. Proper adjustment of these
parameters will also result in a relatively unchanged arc length.
This is especially useful when welding in physically inconvenient
positions.
[0033] FIG. 2 is a flow chart showing a routine which implements
one embodiment of the present invention. The flow chart is
implemented with a routine in the controller for the wire feeder.
The routine may be accessed on an ongoing basis, or when the
welding process is initiated. The user-selected arc control is
determined in a box 201. This is the input used to scale the
welding parameters to change the arc width, without adversely
affecting one or more other arc characteristics. The preferred
embodiment uses a scalar value of between 0 and 50 for the arc
width setting, for the adjustments that provide the widest and
narrowest arc width. A setting of 25 provides no adjustment to the
arc width.
[0034] The controller has a number of taught points. Preferably,
separate taught points are provided for a number of different
common materials, wire size and gas type. Pulse welding systems
have various programs for common materials. According to the
preferred embodiment taught points are provided for some or all of
these programs, such as for 0.035 steel, 0.045 steel, 0.035 Al
4043, 0.047 Al 4043, 0.035 Al 5356, 0.047 Al 5356, 0.035 stainless
and 0.045 stainless.
[0035] Taught points for a given material are provided for a number
of wire feed speeds, and for at least 3 arc width settings in the
preferred embodiment. (Taught point refers to setting parameters
for one arc width setting at one wire feed speed). For example, in
the preferred embodiment there are 8 wire feed speeds having three
arc width taught points each, for a total of 24 taught points, for
0.035 steel. The arc width settings for which taught points are
provided are 0, 25 and 50. It should be noted that the taught point
of 25 corresponds to no adjustment for arc width. Therefore 8 of
the 24 taught points are no adjustment. Each taught point has a
gain for each parameter being adjusted. Thus, in the preferred
embodiment each taught point has 5 gains stored in memory. Each
gain is used to change, by a percentage, the nominal settings for
its respective parameter. Gains are interpolated between arc width
settings and between wire feed speed settings. The tables below
show taught points for 0.045 stainless steel at an arc width
setting of 0 and 50. The data is percentage change of various
parameters, and since an arc width setting of 25 corresponds to no
arc width adjustment, all gains are zero for the taught points for
an arc width setting of 25. Gain, as used herein in conjunction
with arc width control, refers to changing the nominal setting of
an output parameter in response to an arc width setting.
TABLE-US-00001 ARC WIDTH SETTING = 0 wfs Adapt V Peak Amp Back Amp
Freq Pw 50 0.0 -11.3 20.0 -21.9 35.0 100 -1.8 -12.7 22.2 -10.3 23.5
125 -6.2 -9.1 20.0 -19.0 35.3 175 1.0 -8.1 18.5 -22.6 37.5 225 3.3
-4.4 20.0 -23.1 38.1 325 3.3 -8.6 17.8 -22.7 36.4 425 0.0 -6.9 45.5
-24.5 40.4 500 0.9 -6.7 16.7 -22.1 36.0
[0036] TABLE-US-00002 ARC WIDTH SETTING = 50 wfs Adapt V Peak A
Back A Freq Pw 50 -9.1 21.0 -20.0 12.5 -27.5 100 -8.9 19.7 -16.7
11.8 -30.0 125 -4.1 21.2 -32.0 22.8 -23.7 175 -9.5 22.4 -47.7 24.5
-27.5 225 -11.6 32.9 -62.7 34.6 -34.3 325 -12.9 30.0 -66.7 36.9
-36.4 425 -12.5 30.6 -68.2 17.0 -36.2 500 -12.3 26.7 -70.0 26.8
-38.0
[0037] The number of taught points is chosen to provide a smooth
change over both arc widths and wire feed speeds. The gain, or
data, for each taught point was empirically determined by observing
the arc. Other taught points are obtained in a similar manner. The
specific gains shown above are subjective and other gains may be
adequate as well. Implementation of this invention is properly done
by empirically determining gains for the particular system used to
implement this invention.
[0038] Referring again to FIG. 2, after determining the arc width
setting, the peak amps are adjusted 202 and the background amps are
adjusted at 205. The frequency is adjusted at 206 and the pulse
width is adjusted at 208. The adaptive voltage (frequency
modulation in the preferred embodiment) is adjusted at 210, and in
various embodiments the ramp up and ramp down are adjusted at 212.
The ramp up and ramp down are not adjusted in the preferred
embodiment. The adjustments are made for the given wire feed speed,
and the gain or new weld parameters are interpolated from both arc
width setting and wire feed speed.
[0039] The actual code used to implement the invention need not be
described, since any number of routines can accomplish the
interpolations. It is a linear interpolation in the preferred
embodiment, but other interpolations are also contemplated. By
interpolating over wire feed speeds the gains vary over the entire
range (between the max and min wire feed speeds) of possible wire
feed speeds.
[0040] While there are many ways of determining output parameters
in accordance with this invention, the following examples show one
manner of doing so. Using the tables above for 0.045 stainless
steel, and looking at background amps, if the set points are a WFS
(wire feed speed) of 425 inches per minute (IPM) and an arc width
setting of 12, the percentage may be interpolated to be
(12)/25)*45.5=21.8. Thus, background amps are adjusted upward by
21.8 percent for an arc width setting of 12 at a WFS of 425.
[0041] When the WFS is between taught wire feed speed points, then
another interpolation is performed. For example, given a WFS of 400
IPM and an arc width setting of 12, in addition to the calculation
above, the adjustment may be calculated at a WFS of 325 and an arc
width of 12, or (12/25)*17.8=8.5 percentage adjustment. Then, the
adjustment is interpolated between the two speeds,
(400-325/(425-325)*(21.8-8.5)+8.5=18.5% upward adjustment.
[0042] Another way of preforming the interpolation, is to first
interpolate between wire feed speeds, and then between arc width
settings. For the settings above (WFS of 400, arc width of 12), the
interpolation between WFS=425 and WFS=325 for an arc width of 0
gives (400-325)/(425-325)*(45.5-17.8)+17.8=38.6. Then interpolating
to an arc width setting of 12, the result is (12/25)*38.6=18.5.
[0043] It may be seen that either manner yields the same result.
Other types of interpolation will provide different results, and
many routines may be used to perform the calculations.
[0044] Referring now to FIG. 3, a block diagram of a welding system
300 made in accordance with the preferred embodiment includes a
controller 302, a wire feeder 303 and a power source 304 that
cooperate to provide an arc 306. Controller 302 receives two user
inputs, one for wire feed speed and one for arc width. These inputs
are provided to an arc width control module 307 which adjusts
output parameters using a welding parameter adjustment output, as
set forth above to control the arc width in response to the arc
width setting. Controller, as used herein, includes digital and
analog circuitry, discrete or integrated circuitry,
microprocessors, DSPs, etc., and software, hardware and firmware,
located on one or more boards, used to control a device such as a
power supply or power source. Module, as used herein, includes
software and/or hardware that cooperates to perform one or more
tasks, and can include digital commands, power circuitry,
networking hardware, etc.
[0045] Controller 302 provides control outputs which are a control
inputs to power source 304 in response to the program therein, as
adjusted by the arc control module. Power source, or source of
power, as used herein, includes the power circuitry such as
rectifiers, switches, transformers, SCRs, etc. that process and
provide the output power. Control input, as used herein, includes
an input used to control a power supply, such as a set point, gate
signals, phase control signals, etc. Control output, as used
herein, includes an output used to control a circuit, such as a
setpoint, switch signals, gate signals, phase control signals,
etc.
[0046] Numerous modifications may be made to the present invention
which still fall within the intended scope hereof. Thus, it should
be apparent that there has been provided in accordance with the
present invention a method and apparatus for controlling a welding
process that fully satisfies the objectives and advantages set
forth above. Although the invention has been described in
conjunction with specific embodiments thereof, it is evident that
many alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims.
* * * * *