U.S. patent application number 11/624165 was filed with the patent office on 2007-05-24 for monitor for injection molding machine.
This patent application is currently assigned to FANUC LTD. Invention is credited to Kenji Araki, Osamu Saito.
Application Number | 20070113691 11/624165 |
Document ID | / |
Family ID | 32709084 |
Filed Date | 2007-05-24 |
United States Patent
Application |
20070113691 |
Kind Code |
A1 |
Saito; Osamu ; et
al. |
May 24, 2007 |
MONITOR FOR INJECTION MOLDING MACHINE
Abstract
Variables such as injection pressure and injection velocity are
detected at a predetermined sampling cycle for each molding cycle
and the variables for a plurality of past molding cycles starting
from the latest molding cycle are stored. Change patterns of the
stored variables of the respective molding cycles are displayed in
the form of graphs in which the first axis represents time (the
number of times of sampling), the second axis represents the
variable values, and the third axis represents the molding
cycle.
Inventors: |
Saito; Osamu; (Yamanashi,
JP) ; Araki; Kenji; (Yamanashi, JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
FANUC LTD
Yamanashi
JP
|
Family ID: |
32709084 |
Appl. No.: |
11/624165 |
Filed: |
January 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11002309 |
Dec 3, 2004 |
|
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|
11624165 |
Jan 17, 2007 |
|
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10749374 |
Jan 2, 2004 |
6904819 |
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11002309 |
Dec 3, 2004 |
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Current U.S.
Class: |
73/865.9 |
Current CPC
Class: |
B29C 2945/76204
20130101; B29C 45/768 20130101; B29C 2945/76688 20130101; B29C
2945/76187 20130101; B29C 2945/7604 20130101; B29C 2045/7606
20130101; B29C 2945/76006 20130101; B29C 2945/7612 20130101; B29C
2945/76381 20130101; B29C 2945/7611 20130101; B29C 2945/7602
20130101; B29C 2945/76083 20130101; B29C 2945/76387 20130101; B29C
2945/76682 20130101; B29C 2945/76394 20130101; B29C 2945/7621
20130101; B29C 2945/76244 20130101; B29C 2945/76073 20130101; G01D
7/10 20130101; B29C 2945/76551 20130101 |
Class at
Publication: |
073/865.9 |
International
Class: |
G01N 19/00 20060101
G01N019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2003 |
JP |
6705/2003 |
Claims
1. A monitor for an injection molding machine, comprising: sampling
means for detecting, at every predetermined cycle, at least the
position of a movable member varying in one molding cycle. in an
injection molding process and one or more other variables and
storing the detected variables; and means for graphically
displaying the variables for a plurality of molding cycles, with a
first axis representing the position of said movable member, a
second axis representing said other variable and a third axis
representing the number of molding cycles.
2. A monitor for an injection molding machine, comprising: sampling
means for detecting, at every predetermined cycle, at least the
position of a movable member varying in one molding cycle in an
injection molding process and one or more other variables and
storing the detected variables; means for storing a time at a
predetermined timing in each the molding cycle; and means for
graphically displaying the variables for a plurality of molding
cycles, with a first axis representing the position of said movable
member, a second axis representing said other variable and a third
axis representing said time.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional Application of application
Ser. No. 11/002,309, filed Dec. 3, 2004, now pending, which is a
Divisional Application of application Ser. No. 10/749,374, filed
Jan. 2, 2004, now Issued as U.S. Pat. No. 6,904,819, and claims the
benefit of Japanese Application No. 2003-006705, filed Jan. 15,
2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a monitor for monitoring a
state of molding in an injection molding machine.
[0004] 2. Description of the Related Art
[0005] States of various variables such as injecting velocity,
injecting pressure, and the like during injection in an injection
molding cycle can be regarded as indicators of good or bad of a
molding state. Therefore, the various variables during molding are
sampled and graphed on a display and molding conditions are
adjusted and evaluated and stability of molding is judged based on
the graphs. Especially in evaluating the stability of the molding,
waveforms are drawn one upon another through a plurality of molding
cycles so that how the waveform fluctuates through the respective
cycles and cycle-to-cycle variation in the waveform can be
grasped.
[0006] In order to grasp how the waveform fluctuates and changes
through the molding cycles, order of the drawn waveforms of the
molding cycles needs to be judged. However, if the waveform graphs
are drawn one upon another, the waveforms overlap each other and it
becomes difficult to discriminate the changes in waveforms in the
molding cycles from each other. Therefore, there is a known method
in which the latest waveform graph and preceding waveform graphs
are drawn in different colors to discriminate the changes in the
waveforms in the molding cycles over time from each other (see
Japanese Patent Application Laid-open No. 2-26724, for
example).
[0007] Moreover, there is also known art in which a shot number
(molding cycle number) is designated on a horizontal axis (first
axis), an injection start position or an amount of cushion is
designated on a vertical axis (second axis), a lot is designated on
a third axis, and relative relationships between three kinds of
monitoring data are displayed in three dimensions (see Japanese
Patent Application Laid-open No. 2002-273773, for example).
[0008] In order to judge the stability of the molding state, it is
preferable that how the various variables change and vary over time
in a single molding cycle can be grasped and also that the changes
and variations in the variables in the molding cycles can be
observed and discriminated from each other. In other words, it is
preferable that changing and varying patterns of the respective
variables in the single molding cycle can be grasped and that
variations and changes in the patterns in the plurality of molding
cycles can be discriminated from each other. In the above-described
prior-art method described in the above-mentioned Japanese Patent
Application Laid-open No. 2-26724 in which the molding waveform
patterns are displayed in different colors, the latest waveform
pattern and the past waveform patterns can be discriminated from
each other based on the different colors because they are in
different colors. However, the past waveform patterns are in the
same color and both the past waveform patterns and the latest
waveform pattern are drawn one upon another. Therefore, the
waveform patterns overlap each other and it is difficult to
discriminate variations, changes, and trends in the variations in
the waveform patterns from each other.
[0009] In the method described in the above-mentioned Japanese
Patent Application Laid-Open No. 2002-273773, the waveform patterns
in lots can be compared with each other to grasp differences
between the lots. However, it is impossible to grasp how the
variable varies and how a waveform pattern varies and changes in a
single molding cycle and to judge stability of molding.
SUMMARY OF THE INVENTION
[0010] According to the present invention, a monitor for an
injection molding machine comprises sampling means for detecting,
at every predetermined cycle, a variable varying in one molding
cycle in an injection molding process and storing the detected
variable; and means for displaying the change pattern of the
variable for a plurality of molding cycles in the form of three
dimensional graphs using three axes.
[0011] According to a first aspect of the invention, the displaying
means displays the variable for the plurality of molding cycles in
the form of graphs in which a first axis represents time, a second
axis represents the variable and a third axis represents the number
of molding cycles.
[0012] According to a second aspect of the invention, the sampling
means detects, at every predetermined cycle, at least the position
of a movable member and one or more other variables and stores
these variables and the displaying means displays the variables for
a plurality of molding cycles in the form of graphs in which a
first axis represents the position of the movable member, a second
axis represents the above-mentioned other variables and a third
axis represents the number of molding cycles.
[0013] According to a third aspect of the invention, the monitor
further comprises means for storing a time at a predetermined
timing in each molding cycle. And, the displaying means displays
the variable for a plurality of molding cycles in the form of
graphs in which a first axis represents time, a second axis
represents the variable and a third axis represents the time.
[0014] According to a fourth aspect of the invention, the monitor
further comprises means for storing a time at a predetermined
timing in each molding cycle. The sampling means detects, at every
predetermined cycle, at least the position of a movable member and
one or more other variables and stores these variables. And, the
displaying means displays the variables for a plurality of molding
cycles in the form of graphs in which a first axis represents the
position of the movable member, a second axis represents the
variables and a third axis represents the time.
[0015] The first to fourth aspects of the invention may adopt the
following forms.
[0016] The sampling means is provided in the injection molding
machine (e.g., in a controller) or in an external device (e.g., a
computer) connected to the injection molding machine.
[0017] The graphically displaying means is provided in the
injection molding machine (e.g., in a controller) or in an external
device (e.g., a computer) connected to the injection molding
machine.
[0018] The variable is a difference between a sampled variable and
a reference variable which is a variable in a specific molding
cycle.
[0019] The variables varying in one molding cycle in the injection
molding process include one of injection pressure, injection
velocity, a screw position, screw rotation speed, backpressure,
motor torque, a mold opening/closing position/speed, an ejector
position/speed, and temperatures of a cylinder or a nozzle.
[0020] According to the invention, there is provided the monitor of
the injection molding machine which can judge molding states
including stability of molding.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other objects and features of the present
invention will become apparent from the following description of
the embodiments by reference to the drawings in which:
[0022] FIG. 1 is a block diagram of an essential portion of a
controller of an injection molding machine, which forms a monitor
in each embodiment of the invention, and an essential portion of
the injection molding machine;
[0023] FIG. 2 is a flow chart of monitor data obtaining processing
in a first embodiment of the invention;
[0024] FIG. 3 is an explanatory view of a table in which the
sampling data obtained by the processing in FIG. 2 are stored;
[0025] FIG. 4 is a flow chart of displaying processing of the
sampling data stored in the table in FIG. 3;
[0026] FIG. 5 shows an example of a screen on which monitor data
are displayed by the displaying processing in FIG. 4;
[0027] FIG. 6 is a flow chart of monitor data obtaining processing
in a second embodiment of the invention;
[0028] FIG. 7 is an explanatory view of a table in which the
sampling data obtained by the processing in FIG. 6 are stored;
[0029] FIG. 8 shows an example of a screen on which sampling data
stored in the table in FIG. 7 are displayed;
[0030] FIG. 9 is a flow chart of monitor data obtaining processing
in a third embodiment of the invention;
[0031] FIG. 10 is an explanatory view of a table in which the
sampling data obtained by the processing in FIG. 9 are stored;
[0032] FIG. 11 shows an example of a screen on which sampling data
stored in the table in FIG. 10 are displayed;
[0033] FIG. 12 is a flowchart of monitor data obtaining processing
in a fourth embodiment of the invention;
[0034] FIG. 13 is an explanatory view of a table in which the
sampling data obtained by the processing in FIG. 12 are stored;
[0035] FIG. 14 shows an example of a screen on which sampling data
stored in the table in FIG. 13 are displayed;
[0036] FIG. 15 shows an example in which the monitor for the
injection molding machine according to the invention is provided in
the controller for the injection molding machine;
[0037] FIG. 16 shows an example in which sampling means of the
monitor for the injection molding machine according to the
invention is provided in the controller for the injection molding
machine and sampling data storage means and graph displaying means
of the monitor are provided in a personal computer; and
[0038] FIG. 17 shows an example in which the monitor for the
injection molding machine according to the invention is provided in
a personal computer connected to the injection molding machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] FIG. 1 is a block diagram of an essential portion of a
controller of an injection molding machine, which forms a monitor
in each embodiment of the invention, and an essential portion of
the injection molding machine.
[0040] A reference numeral 1 designates an injection cylinder of
the injection molding machine and 2 designates a screw. The screw 2
is driven in a direction of an injection axis by an injection
servomotor M1 through a driving converter 5 for converting a
rotational motion into a linear motion in the direction of the
injection axis and is rotated for metering by a screw rotating
servomotor M2 through a transmission mechanism 3. A pressure
detector 4 is provided at a base portion of the screw 2 to detect
pressure of resin acting in an axial direction of the screw 2,
i.e., injection pressure in an injection process and screw back
pressure in metering and kneading process. The injection servomotor
M1 is provided with a position/velocity detector P1 such as an
encoder for detecting a position of the screw 2 and an injection
velocity which is a velocity of movement of the screw 2. The screw
rotating servomotor M2 is provided with a speed detector P2 for
detecting a rotation speed of the screw 2.
[0041] The controller 10 of the injection molding machine includes
a CNC CPU 25 which is a microprocessor for numerical control, a PMC
CPU 18 which is a microprocessor for a programmable controller, a
servo CPU 20 which is a microprocessor for servo control, and a
pressure monitoring CPU 17 of a microprocessor for sampling
injection pressure and screw backpressure through an A/D converter
16. By selecting mutual input and output via a bus 22, information
can be conveyed between the respective microprocessors.
[0042] To the PMC CPU 18, a ROM 13 for storing a sequence program
for controlling a sequence operation of the injection molding
machine, a program for monitor data displaying processing, and the
like and a RAM 14 used for temporarily storing operation data and
the like are connected. On the other hand, to the CNC CPU 25, a ROM
27 for storing a program for controlling the whole injection
molding machine and the like and a RAM 28 used for temporarily
storing operation data and the like are connected.
[0043] To the servo CPU 20 and the pressure monitor CPU 17, a ROM
21 for storing a control program written specifically for servo
control, a RAM 19 for temporarily storing data, a ROM 11 for
storing a control program related to sampling processing for
obtaining pressure data and the like, and a RAM 12 used for
temporarily storing data are connected. Furthermore, to the servo
CPU 20, a servo amplifier 15 for driving servomotors of respective
axes for mold clamping, an ejector (not shown), injection, and
screw rotation based on a command from the CPU 20 is connected.
Respective outputs from the position/velocity detector P1 provided
to the injection servomotor M1 and the speed detector P2 provided
to the screw rotating servomotor M2 are fed back to the servo CPU
20. A current position and the injection velocity (screw moving
velocity) of the screw 2 calculated by the servo CPU 20 based on a
feedback signal from the position/velocity detector P1 and a
rotation speed of the screw 2 detected by the speed detector P2 are
stored in a current position storage register and a current
velocity storage register provided to the RAM 19.
[0044] To an interface 23, an external personal computer and the
like can be connected. A manual data input unit 29 with a display
is connected to the bus 22 via a CRT display circuit 26 to select a
monitor display screen and a function menu item and to carry out
input operation of various data and is provided with numerical keys
for inputting numerical data, various function keys, and the
like.
[0045] A RAM 24 for storing molding data is formed of nonvolatile
memory and stores molding conditions (injection/dwell conditions,
metering conditions, and the like), various set values, parameters,
macro variables, and the like related to injection molding
operation.
[0046] With the above structure, the CNC CPU 25 distributes pulses
to the servomotors of the respective axes based on a control
program of the ROM 27 and the servo CPU 20 carries out servo
controls such as a position loop control, a velocity loop control,
a current loop control, and the like similarly to the prior art to
execute so-called digital servo processing based on movement
commands pulse-distributed to the respective axes and a feedback
signal of a position and a feedback signal of a speed detected by
detectors such as the pulse coder P1 and the speed detector P2.
[0047] In the present embodiment, the pressure monitor CPU 17
repeatedly executes sampling processing in every injection/dwell
process, reads injection pressure acting on the screw 2 through the
pressure detector 4 and the A/D converter 16, and reads an
injection velocity and a screw position stored in the current
velocity storage register and the current position storage register
of the memory 19 to store them in the RAM 12.
[0048] FIG. 2 is a flow chart of monitor data obtaining processing
performed by the pressure monitor CPU 17 in the first embodiment.
In this embodiment, an injection pressure PR and an injection
velocity V are detected as monitor data at every predetermined
sampling cycle.
[0049] If operation starts, a shot counter S for counting the
number of molding cycles (number of shots (injections)) at "0"
(step 100). If the injection starts (step 101), a sampling counter
t for counting the number of sampling is set at "0" (step 102) and
whether dwell process has finished or not is judged (step 103). If
dwell process has not been finished, a current injection pressure
PRa detected from a load cell and a current injection velocity Va
detected from the position/velocity detector are respectively
stored in a table provided in the RAM 12 as PR(S, t) and V(S, t),
respectively, in association with values of the shot counter S and
the sampling counter t (step 104).
[0050] The table provided in the RAM 12 is a table for cyclically
storing sampling data of (m+1) times molding cycles as shown in
FIG. 3 and stores the sampling data in accordance with the shot
counter S.
[0051] Next, the sampling counter t is incremented by 1 (step 105)
and the processing returns to step 103. From then on, the
processings from steps 103 to 105 are repeatedly executed at every
predetermined sampling cycle until the dwell process ends and the
sampled injection pressure PR(S, t) and injection velocity V(S, t)
are stored in the table as shown in FIG. 3.
[0052] If the dwell process ends, whether an operation end command
has been input or not is judged (step 106). If the operation is not
ended, the shot counter S is incremented by 1 (step 107) and
whether or not the value of the shot counter S is greater than a
set number m to be stored is judged (step 108). If the value is not
greater than the set number m, the processing returns to step 101.
On the other hand, if the value is greater than the set number m,
the shot counter S is set at "0" (step 109) and the processing
returns to step 101.
[0053] From then on, the above processings from step 101 to 109 is
repeatedly executed until the operation ends. Thus, the injection
pressure PR(S, t) and the injection velocity V(S, t) which are
sampling data for respective shots are cyclically stored for (m+1)
times molding cycles in the table as shown in FIG. 3.
[0054] On the other hand, if a monitor display command is input,
the PMC CPU 18 executes display processing in FIG. 4 at every
predetermined cycle.
[0055] First, whether or not a value of a pointer P agrees with the
shot counter S is judged (step 200). This is for judging whether or
not the pointer P is pointing a molding cycle at which sampling
data is being taken currently. If the value agrees with the shot
counter S, that means the sampling data is being rewritten. In
consequence, the processing of this cycle is finished. If the value
does not agree with the shot counter S, the value of the shot
counter S is stored in the pointer P and an index i is set at the
set number m (step 201).
[0056] Next, 1 is added to the pointer P and the index i is
decremented by 1 (step 202). Whether or not the value of the
pointer P has exceeded the set number m as a result of the
processing at step 202 is judged (step 203). If the value is
greater than the set value m, "0" is set to the pointer P (step
204) and the processing proceeds to step 205. If the value of the
pointer P is not greater than the set value m, the processing
proceeds from step 203 to step 205. By this processing, the oldest
stored sampling data is designated.
[0057] In step 205, as shown in FIG. 5, in a coordinate system in
which time is designated on a first axis, injection pressure and
injection velocity are designated on a second axis, and the molding
cycle number (shot number) is designated on a third axis, sampling
data of the injection pressure and injection velocity pointed by
the pointer P are plotted at a position on the third axis, which
represents cycle number (shot number) indicated by the index i, in
association with the sampling number (time) on the first axis and
are graphically displayed (step 205). In this case, the injection
pressure and the injection velocity are displayed in a solid line
and a broken line or in difference colors as shown in FIG. 5 so
that the graphs of the injection pressure and the injection
velocity can be distinguished from each other.
[0058] Then, whether the value of the index i is "0" or not is
judged (step 206). If it is not "0", the processing returns to step
202. From then on, the processings from step 202 to step 206 are
repeatedly executed until the value of the index i becomes "0".
Then, when the value of the index i becomes "0", sampling data
displaying processing finishes.
[0059] By the above-described processing, sampling data at a
molding cycle which is m cycles before a current shot in which
injection is in progress and sampling data are being obtained are
graphically displayed at a position of (m.sup.-1) on the third axis
and sampling data at a molding cycle (shot) immediately before the
current cycle (shot) are graphically displayed at a position of "0"
(i=0) on the third axis.
[0060] For example, if m=5, sampling data of 6 molding cycles from
S=0 to 5 are to be cyclically stored in the table, and the value of
the shot counter S is "2", the sampling data of P=P+1=S+1=2+1=3
stored in the table are the oldest sampling data of a shot which is
m cycles before a current one and these sampling data are first
displayed at a position of i=m-1=5-1=4. Then, because the pointer P
is incremented by 1 and the index i is decremented by 1 in step
202, sampling data of P=4 (=S) are next displayed at a position of
i=3 on the third axis and then sampling data of P=5 (=S) are
displayed at a position of i=2 on the third axis. Next, because P=6
at step 202, P=0 by steps 203 and 204 and sampling data of P=0 (=S)
are displayed at a position of i=1 on the third axis. Lastly,
sampling data of P=1 (=S) are displayed at a position of i=0 on the
third axis.
[0061] In the above manner, from sampling data of S=4 pointed by
the pointer P=4 and which are currently being rewritten, stored
sampling data are displayed in an order from the oldest one to
later ones in positions of i=4, 3, 2, 1, and 0 on the third
axis.
[0062] Thus, when graphic display of the m sampling data stored in
the table, excluding the sampling data which is currently being
written, ends, the processing proceeds from step 206 to step 207
where the pointer P is incremented by 1 to finish the processing at
the present cycle. By incrementing the pointer P by 1, the value of
the pointer P becomes equal to a current value of the shot counter
S indicating a shot in which sampling data are currently being
rewritten.
[0063] Then, if obtaining of the sampling data has finished, the
value of the shot counter S is rewritten by the processings at
steps 107 and 109 in FIG. 2, and the value of the pointer P does
not agree with the value of the shot counter S at step 200, the
processings in step 201 and the following steps are executed again
and sampling data in the latest m shots are graphically displayed
as shown in FIG. 5.
[0064] In FIG. 5, the injection pressure PR and the injection
velocity V, which are variables in the molding cycle, are
graphically displayed of change patterns with respect to time and
it is possible to easily grasp how the variable varies and changes
in each the molding cycle by using single change pattern. Moreover,
because the change patterns of the variable of the respective
molding cycles are drawn in parallel to each other in a direction
of the third axis, it is possible to easily grasp cycle-to-cycle
variation in the change pattern of the variable and to easily judge
stability of molding.
[0065] FIG. 6 is a flowchart of sampling data obtaining processing
in a second embodiment of the invention. The second embodiment is
different from the first embodiment in that a screw position PO is
also sampled as monitor data.
[0066] If comparison is made between the sampling data obtaining
processing shown in FIG. 6 and the sampling data obtaining
processing in the first embodiment shown in FIG. 2, steps 300 to
309 correspond to steps 100 to 109 and processing in FIG. 6 is the
same as that in FIG. 2 except that processing at step 304 and
processing at step 104 are different from each other. In the second
embodiment, the screw position POa stored in the current position
storage register of RAM 19 is also obtained at step 304 where data
is obtained. The injection pressure PRa, the injection velocity Va,
and the screw position POa are obtained at every predetermined
sampling cycle and stored in a table provided to the RAM 12 and
shown in FIG. 7.
[0067] Because the screw position POa is merely added as the
sampling data as compared with the first embodiment, detailed
description of the processing shown in FIG. 6 will be omitted.
[0068] Although monitor data displaying processing in the second
embodiment is mostly similar to the displaying processing in the
first embodiment shown in FIG. 4, the processing at step 205 is
different and the other processings are the same.
[0069] Although the first axis represents time (the number of times
of sampling) in the processing at step 205 in the first embodiment,
the first axis is displayed as an axis representing the screw
position PO in the second embodiment. As shown in FIG. 8, the first
axis represents the screw position PO, the second axis represents
the injection pressure PR and the injection velocity V, and the
third axis represents the molding cycle number, i.e., the shot
number. Then, the injection pressure PR and the injection velocity
V corresponding to the screw position PO in each sampling at every
molding cycle (shot) and stored in the table shown in FIG. 7 are
plotted, and patterns of the injection pressure and the injection
velocity corresponding to the screw position are displayed so that
the later molding cycle (shot) is closer to the front (closer to an
origin point of the coordinate system) as shown in FIG. 8.
[0070] FIG. 9 is a flowchart of sampling data obtaining processing
in the third embodiment of the invention. In the third embodiment,
data to be obtained as sampling data are injection pressure PR and
injection velocity V at every shot and are similar to those in the
first embodiment. However, the third embodiment is different from
the first embodiment in that a time of a predetermined timing (for
example, time when dwell process ends) in the molding cycle is
stored. In other words, if comparison is made between the flow
chart of the sampling data obtaining processing shown in FIG. 9 and
the flow chart of the first embodiment and shown in FIG. 2, it is
apparent that the third embodiment is different from the first
embodiment only in that a time Ta is stored in a reading table at
step 406 after dwell process has finished. The other processings
are the same.
[0071] Then, in the third embodiment, the injection pressure PR,
the injection velocity V and the time T at every predetermined
sampling cycle are stored at every shot in the table as shown in
FIG. 10.
[0072] Although the monitor data displaying processing in the third
embodiment is mostly similar to the displaying processing in the
first embodiment shown in FIG. 4, the processing at step 205 is
different and the other processings are the same. In the third
embodiment, as shown in FIG. 11, a first axis represents the
sampling time, a second axis represents the injection pressure PR
and the injection velocity V, a third axis represents a dwell end
time T in each the molding cycle, and patterns of the injection
pressure PR and the injection velocity V with respect to time are
drawn at a position on the third axis corresponding to the dwell
end time T stored in the table.
[0073] In a case of the third embodiment, in the processing at step
205, a position corresponding to a value obtained by subtracting a
time of the present molding cycle stored in the table from a
current time is the position on the third axis (position of i at
step 205) where the sampling data in the molding cycle are
drawn.
[0074] FIG. 12 is a flow chart of sampling data obtaining
processing in the fourth embodiment of the invention. The fourth
embodiment is different from the third embodiment only in that the
screw position PO is also obtained as sampling data. In other
words, only processing at step 504 is different from the processing
at step 404. Because the other processings are the same,
description of the processing shown in FIG. 10 will be omitted.
[0075] In a case of the fourth embodiment, the injection pressure
PR, the injection velocity V, the screw position PO, and the dwell
end time T at every sampling time are stored at every molding cycle
(every shot) in the table provided to the RAM 12 as shown in FIG.
13.
[0076] In the monitor data displaying processing in the fourth
embodiment, the first axis represents the screw position, the
second axis represents the injection pressure PR and the injection
velocity V, the third axis represents the dwell end time T in each
molding cycle as shown in FIG. 14, and the injection pressure PR
and the injection velocity V are plotted at a position on the third
axis corresponding to the dwell end time T stored in the table, in
association with the screw position PO, so that the patterns of the
injection pressure PR and the injection velocity V with respect to
the screw position PO are drawn.
[0077] Although the variables (such as injection pressure,
injection velocity, screw position) are detected at each molding
cycle and graphically displayed in the above-described respective
embodiments, it is also possible to store the sampling data of the
variables of one molding cycle in the table at every predetermined
number of molding cycles and at intervals of the predetermined
number of molding cycles and to display the graphs based on the
stored data and at intervals of the predetermined number of molding
cycles. If the data are displayed for every process such as
injection, dwell, metering, and the like, timings of storing times
are preferably start time or end time of each the process and it is
possible to automate selection of the timing. Moreover, it is
possible that the monitor data obtaining processing is started and
finished by operation by an operator.
[0078] Although data to be sampled as monitor data are injection
pressure, injection velocity, screw position and dwell end time in
the above-described embodiment, it is also possible that other
variables such as screw rotation speed, backpressure, motor torque,
mold opening/closing position/speed, ejector position/speed, and
temperatures of a cylinder and a nozzle are sampled as monitor data
and displayed in three dimensions as described above. The timings
of storing times may be when the injection starts, the cycle
starts, or closing of the mold starts. Furthermore, as a time to be
stored, not only a time obtained from a clock but also a time which
has elapsed from a specific time such as a time of turning on of
the power may be used.
[0079] In displaying, it is possible that the displayed
three-dimensional coordinate system can be rotated.
[0080] Moreover, a variable in a specific cycle may be employed as
a reference variable and the variable displayed as a graph may be a
difference between a sampled variable and the reference variable.
For example, if the reference specific cycle is the oldest cycle in
the stored cycles and a variable in this cycle is employed as a
reference variable, a reference pointer for pointing the reference
cycle is provided and "S+1" is stored in the pointer to set the
oldest cycle in the stored cycles at step 201 in FIG. 4 ("0" is
stored in the reference pointer when S+1 is greater than the set
number m). Then, at step 205, a difference is obtained by
subtracting a variable of corresponding sampling data in a cycle
stored in the reference pointer from sampling data in the cycle
pointed by the pointer P and this difference may be displayed.
[0081] It is also possible that a variable of sampling data at a
specific cycle employed as a reference cycle is set as reference
data and stored in advance and that a difference between a variable
at each sampling and a corresponding variable at the reference
sampling is obtained and displayed, at step 205.
[0082] In the above-described embodiment, the monitor is formed of
a controller 10 itself of the injection molding machine and all of
means A for sampling respective variables x, means B for displaying
graphs, and means C for storing variable data sampled at each
molding cycle (shot) are provided in the controller for controlling
an injection molding machine. Schematic illustration of this form
is as shown in FIG. 15.
[0083] On the other hand, it is also possible that the means A for
sampling the various variables x is provided in the controller 10
of the injection molding machine and that the means C for storing
the sampling data and the means B for displaying the graphs are
provided in a personal computer 50 so as to perform processings
such as summarization and editing of the sampled data. FIG. 16 is a
schematic diagram of this form.
[0084] In a case of this form, the personal computer 50 is
connected through the interface 23 provided to the controller 10 of
the injection molding machine. The pressure monitor CPU 17 forming
the sampling means A samples the variables (such as injection
pressure and injection velocity) at each molding cycle (shot),
stores them in the RAM 12, and transfers them every time the
molding cycle (shot) ends or transfers data for the predetermined
number of shots at a time at every predetermined number of shots to
the personal computer 50 through the interface 23. On the other
hand, the personal computer 50 is provided with the table as shown
in FIGS. 3, 7, 10, and 13 and stores the received sampling data of
the various variables x for each the molding cycle. Then, the
personal computer 50 displays the stored sampling data in three
dimensions. By employing the form shown in FIG. 16, sampling data
of various variables x in a plurality of injection molding machines
maybe stored in a concentrated manner in storage means provided to
a computer of a central controller and the sampling data of the
respective injection molding machines may be graphically displayed
so that molding states of a plurality of injection molding machines
can be monitored in a concentrated manner.
[0085] Furthermore, as shown in FIG. 17, it is also possible that
the sampling means A, the graph displaying means B, and the storage
means C for storing the sampling data are provided to the personal
computer. In this case, means for detecting variables of the
injection molding machine and the personal computer 50 need be
connected to each other. For example, if injection pressure PR,
injection velocity V and screw position PO are to be sampled as
variables x, a pressure detector 4 and a position/velocity detector
P1 are connected to a personal computer 50 and the injection
pressure PR, the injection velocity V and the screw position PO,
detected by these pressure detector 4 and the position/velocity
detector P1, are detected by the personal computer 50 at every
predetermined cycle, stored in the storage means as in the
above-described first to fourth embodiments, and graphically
displayed.
[0086] As described above, according to the present invention,
various variables indicating molding states at respective molding
cycles are graphically displayed as waveforms with respect to time
and screw position, along an axis representing the molding cycle,
in three dimensions. As a result, it is possible to easily and
visually grasp how the change patterns of variables (change
waveforms of variables) vary through the molding cycles. Therefore,
it is easy to judge the stability of the molding
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