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Description  |
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FIELD OF THE INVENTION
The present invention relates to a method of presenting the molding data of
an injection molding machine on a display upon detecting the data in an
injection molding cycle.
DESCRIPTION OF THE RELEVENT ART
The conventional injection molding machines were each provided with a CRT
display as disclosed in Japanese Patent Laid-Open Publication No. 4
(1992)-75808, whereby various molding data such as "cycle time",
"injection time", "kneading time", "peak injection pressure", "shifted
pressure", "degree of cushioning", and so forth in the injection molding
cycle were displayed so that the operator might monitor present or past
conditions of injection molding on the display.
The injection molding process for providing one molded product is normally
referred to as comprising an injection molding cycle which ranges from the
start of mold closing to the end of ejecting a molded product from inside
a set of molds (see FIG. 1). So far, the presentation of molding data on a
display used to take place with the whole molding data detected during one
injection molding cycle presented as one molding cycle data in a single
cycle molding data indication frame on the monitor screen of the display.
However, in the injection molding process of an injection molding machine,
normally, the cooling sub-cycle wherein the plastic filled in a space
within the molds is cooled, coincides with the weighing sub-cycle wherein
plastic pellet weighing is carried out in preparation for the next
injection molding cycle. Therefore, with the conventional method of data
presentation in response to each of individual injection molding cycles,
the molding data detected in the current injection molding cycle come to
include separate molding data in the next injection molding cycle. For
example, when "plasticizing time" and "plastic pellet weighing start
position" are selected as respective items of molding data, the data of
these items become the molding data of a product to be molded next,
following the plastic pellet weighing sub-cycle, and these two itemized
data become involved in the molding data of a product molded in the
current injection molding cycle.
Therefore, when the operator takes a look at the value of the plasticizing
time presented currently on a display upon noticing the occurrence of a
product defectively molded from a short shot, etc. for example, he may
sometimes be puzzled whether or not the displayed value corresponds
precisely to the defectively molded product, or may likewise misread said
numeral for those data seemingly concerned with the product molded in the
current injection molding cycle, nevertheless said value is actually
relative of the product to be molded in the subsequent injection molding
cycle. As a result, the operator is thus subject to misconceive the
displayed data and undergoes an interference with his accurate and quick
troubleshooting of the causes behind the occurrence of defectively molded
products.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of presenting the
molding data of an injection molding machine, wherein the misconception of
displayed molding data for separate data in another injection molding
cycle is positively prevented.
Another object of the present invention is to provide a method of
presenting the molding data of an injection molding machine, wherein
accurately and quickly troubleshooting the causes of defectively molding
is allowed.
To achieve each or these objects, the presentation of the molding data in
an injection molding cycle on display D is characterized in that a time
span ranging from the start of a plastic pellet weighing sub-cycle to the
end of an injection sub-cycle is defined as one,data cycle period Td, and
the whole molding data detected during said one data cycle period are
presented in single molding cycle data indication frame Ds on the monitor
screen of display D. In this case, the molding data available in one data
cycle period Td include those data respectively of a plastic pellet
weighing start position, a plasticizing time, an injection start position,
peak plastic pressure, a speed/pressure control shift position, an
injection time, a forward stroke limit position, an injection end position
and an injection stroke. Prior to starting one data cycle period Td, the
currently displayed one injection cycle molding data are loaded into a
memory, followed by totally erasing the whole molding data presented in
all numerical data presentation blocks provided in said frame, and
thereafter, each of the molding data in a succeeding injection molding
cycle is presented in every one of the numerical data presentation blocks,
following the order of being detected and at an optional timing.
As in the foregoing, the time span from the period from the start of the
plastic pellet weighing sub-cycle to the end of the injection sub-cycle is
defined as one data cycle period Td. Accordingly, in single cycle molding
data indication frame Ds on the monitor screen of display D, there are
presented various molding data such as those respectively of "plastic
pellet weighing start position", "plasticizing time", "injection start
position", etc. which are detected from the start of the plastic pellet
weighing sub-cycle--in the order of being detected for example and at an
optional timing. As a consequence, in single cycle molding data indication
frame, there are presented the molding data only of the product molded in
the current injection molding cycle, whereby the trouble on the part of an
operator to misread the displayed data for the molding data of a product
to be molded in the next injection molding cycle, is prevented.
Further scope of applicability of the present invention will become
apparent from the detailed description given hereinafter. However, it
should be understood that the detailed description and specific examples,
while indicating preferred embodiments of the invention, are given by way
of illustration only, since various changes and modifications within the
spirit and scope of the invention will become apparent to those skilled in
the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed
description given hereinbelow and the accompanying drawings which are
given by way of illustration only, and thus are not limitative of the
present invention, and wherein:
FIG. 1 is a diagram illustrating the principle of the method of data
presentation to which the present invention relates.
FIG. 2 is a front view showing the single molding cycle data indication
frame on the monitor screen of a display on which the molding data are
presented according to the present invention.
FIG. 3 is a flowchart illustrating the method of data presentation to which
the present invention relates.
FIG. 4 is a sketch showing the rough structural constitution of an
injection molding machine for which the method of data presentation of the
present is applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Next, one of the preferred embodiments of the present invention quoted
herein is described with reference to the accompanying drawings.
To help understand the method of data presentation concerned with one
preferred embodiment of the present invention, the rough structural
constitution of an injection molding machine is described with reference
to FIGS. 2 and 4.
An injection unit 10 of the injection molding machine is provided which
includes a barrel cylinder 11 which is provided with an injection nozzle
12 and material feed hopper 13, respectively, at the fore and rear end.
Barrel cylinder 11 incorporates screw 15 which is turned by an oil motor
17 while being driven forth and back with an injection cylinder 16.
Injection cylinder 16 is coupled via changeover valve 18 to a hydraulic
circuit 19 to which oil motor 17 is also joined.
Meanwhile, a central controller 21 is provided with computer functions,
wherein there are provided not only RAM 21m and timer 21t but also various
functional units such as a CPU, a ROM, etc. necessary for computer
functioning and to which an input unit such as a keyboard or the like
(omitted from being illustrated) is connected. Central controller 21 is
provided with an injection molding machine operation sequence control
function, and the ROM thereof stores a control program to work the method
of data presentation to which the present invention relates.
Injection unit 10 is mounted with position sensor 22 to detect the position
of the screw 15, which position sensor 22 is coupled to a central
controller 21. In this case, screw speeds are obtained through
differentiating the outcome of screw position detection within the central
controller 21. Further, the injection cylinder 16 is installed with a
pressure sensor 23 which is also coupled to the central controller 21.
Meanwhile, a CRT display or display D using a plasma cathode-ray tube, etc.
is coupled to a central controller 21. Display D has a function to present
various molding data available in the injection molding cycle of an
injection molding machine. As shown in FIG. 2, the monitor screen of the
display is provided with at least a single cycle molding data indication
frame Ds. Single cycle molding data indication frame Ds comprises a series
of blocks Dc in which are entered the respective items specifying each of
categorized molding data such as "injection time", "injection start
position", "V-P (speed/pressure) control shift position", "forward stroke
limit position" of a screw, "injection end position", "injection stroke",
"peak plastic pressure", "plasticizing time", "plastic pellet weighing
start position" and their corresponding blocks Dd provided aside the data
item-specifying said blocks and in which are filled Dc with the numerals
quantitatively particularizing the respective itemized molding data.
The method of data presentation to which the present invention relates is
described in detail hereunder with reference to FIGS. 1 and 3.
First, referring to FIG. 1, the principle of the method of data
presentation to which the present invention relates is illustrated. As
referred to above, a series of in-process sub-cycles serving to provide
one molded product are collectively called an injection molding cycle. As
specified in FIG. 1, the injection molding cycle includes mold clamping
sub-cycle 1, injection nozzle advancing sub-cycle 2, injection sub-cycle
3, plastic pellet weighing (cooling) sub-cycle 4, injection nozzle
retreating sub-cycle 5, mold opening sub-cycle 6, ejection sub-cycle 7,
and inter-cycle standby sub-cycle 8 extending over a given period from the
preceding injection molding cycle to the succeeding injection molding to
cycle. This injection molding cycle has its starting and ending point
generally prescribed respectively at the start of the mold clamping
sub-cycle and the end of the ejection sub-cycle. In the present invention,
a new concept of a data cycle to collect the one injection molding cycle
data is introduced in addition to the traditional, wherein a time span
from the start of the plastic pellet weighing sub-cycle to the end of the
injection sub-cycle is defined as one data cycle period Td which is used
as a unit of time length during which one injection molding cycle data are
detected, stored and displayed.
Next, following the flowchart in FIGS. 2 and 3, the method of data
presentation to which the present invention relates is further described
in detail.
In step with the start of one data cycle period, the data thus far
presented in respective numerical data presentation blocks Dd are already
through with total erasure, and the molding data (numerical data) in the
subsequent injection molding cycle are presented therein in the order of
being detected and at an optional timing.
When the plastic pellet weighing sub-cycle first starts, position sensor 22
serving to detect "plastic pellet weighing start position" sets about
functioning, subsequently outputting one molding data related thereto and
the data (25.65 mm in the present embodiment) output from the position
sensor is then loaded into RAM 21m housed within central controller 21
while at the same time said data is presented (steps 51, 52, 53) in one
numerical data presentation block Dd within a single cycle molding data
indication frame Ds. Next, when the plastic pellet weighing sub-cycle is
over, the molding data (0.16 sec. in the present embodiment) relative of
"plasticizing time" which timer 21t incorporated in central controller 21
has counted is detected, followed by being stored in RAM 21m and
simultaneously presented (steps 54, 55, 56) in another numerical data
presentation block Dd. Thereafter, the machine has its operation sequence
advanced to the injection sub-cycle when the inter-cycle standby sub-cycle
of a given period (step 57) is over.
When the injection sub-step starts, position sensor 22 begins functioning,
whereby the molding data (119.39 mm in the present embodiment) concerned
with "injection start position," is detected and is loaded into RAM 21m,
while simultaneously presented in a further numerical data presentation
block Dd (steps 58, 59, 60). Though omitted from being illustrated in the
flowchart in FIG. 3, the injection sub-cycle, the plastic pressure is
monitored with reference to the detected value of pressure output from
pressure sensor 23, whereby "peak plastic pressure" is detected, with
position sensor 22 functioning to detect the position ("V/P
(speed/pressure) control shift position") of shifting from speed control
to pressure control, timer 21t counting up thereby to detect "injection
time", position sensor 22 also working to detect "forward stroke limit
position" of the screw, and with the respective data therefrom getting
stored in the memory and presented on the display as in the foregoing.
On the other hand, as the injection sub-cycle expires, position sensor 22
starts functioning, whereby the molding data concerned with "injection end
position" is detected and loaded into RAM 21m, getting simultaneously
presented in one numerical data presentation block Dd steps 61, 62, 63).
Further, the molding data relative of "injection stroke" is calculated
according to the screw position detected by position sensor 22, followed
by being loaded into RAM 21m and presented in one numerical data
presentation block Dd (steps 64, 65, 66).
With these series of i steps completed, the collection of a set of molding
data is over, and the whole molding data are presented in all numerical
data presentation blocks Ds within single cycle molding data indication
frame Ds. The numerals presented in these blocks are the data which have
been gathered in one data cycle period Td, namely, the whole data are
concerned with only one product molded in the current injection molding
cycle. Therefore, when the operator reads the data "plasticizing time and
"plastic pellet weighing start position" on the display, he will not be
puzzled which of molded products is concerned with said data nor will
misread said data respectively of "plasticizing time" and "plastic pellet
weighing start position" for those of a separate molded product by
accident.
Further, when gathering the molding data in one data cycle period Td is
over, one injection molding cycle data thus far stored in RAM 21m are
transferred to another memory, with RAM 21m getting thereby ready for
loading another set of molding data due to be gathered in the subsequent
one data cycle period, and also with said one injection molding cycle data
so far presented in numeric data presentation blocks Dd getting erased. In
this case, it is permissible that the molding data presented in said
blocks Dd are maintained on the display. Namely, as a mode of data
presentation, the whole molding data thus far presented in numeric data
presentation blocks may be erased as in the present embodiment, with the
presentation of another set of molding data detected in one succeeding
data cycle period to follow at an optional timing or else even after the
data collection in one subsequent data cycle, the whole molding data so
far presented in the numeric data presentation blocks may be maintained
therein but subject to replacement with new data at an optional timing,
depending on whether or not there is a difference between each two former
and new data.
In the foregoing, one preferred embodiment of the present invention has
been described. However, it should be understood that the present
invention is by no means limited only to this embodiment, and also that
the data presentation methodic constitutional particularities, processes,
and so forth may be altered optionally within the spirits and scope of the
present invention.
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