Búsqueda Imágenes Maps Play YouTube Noticias Gmail Drive Más »
Iniciar sesión
Usuarios de lectores de pantalla: deben hacer clic en este enlace para utilizar el modo de accesibilidad. Este modo tiene las mismas funciones esenciales pero funciona mejor con el lector.

Patentes

  1. Búsqueda avanzada de patentes
Número de publicaciónUSRE34559 E
Tipo de publicaciónConcesión
Número de solicitudUS 07/501,741
Fecha de publicación8 Mar 1994
Fecha de presentación29 Mar 1990
Fecha de prioridad12 Ago 1981
También publicado comoUS4734869
Número de publicación07501741, 501741, US RE34559 E, US RE34559E, US-E-RE34559, USRE34559 E, USRE34559E
InventoresJohn Mickowski
Cesionario originalMickowski; John
Exportar citaBiBTeX, EndNote, RefMan
Enlaces externos: USPTO, Cesión de USPTO, Espacenet
Diagnostic method for analyzing and monitoring the process parameters in the operation of reciprocating equipment
US RE34559 E
Resumen
The method of the present invention utilizes a microcomputer in combination with a CRT and a multiplicity of transducers for monitoring process parameters in the operation of a reciprocating device having a linear stroke. A profile of the process parameters including pressure and velocity are generated as a function of stroke length and time and are stored in a non-volatile memory and graphically displayed on the CRT as master traces for comparison with current data profiles. The velocity is calculated by dividing distance transversed with time or by use of a velocity position transducer.
Imágenes(11)
Previous page
Next page
Reclamaciones(13)
What is claimed is:
1. A diagnostic method for analyzing and monitoring the process parameters of reciprocating equipment in which a linear reciprocating injection device is traversed over a fixed stroke length at high speed comprising the steps of:
(a) dividing said stroke length into a predetermined number of incremental positions;
(b) generating analog data corresponding to at least the position of said injection device and the pressure developed by said injection device at each such incremental position;
(c) recording the time transpired in the movement of said injection device along said stroke length;
(d) deriving the velocity of said injection device at each such incremental position;
(e) graphically displaying the data corresponding to pressure and velocity on a display screen of a cathode ray tube as a function of the incremental position of said injection device along said stroke length until said velocity reaches a predetermined minimum level, with said display forming a master profile for said data;
(f) storing the data representing said master profile at a predetermined address location in a nonvolatile memory of a microcomputer;
(g) repeating the sequence of generating, .[.calculating.]. .Iadd.deriving .Iaddend.and storing analog data corresponding to pressure and velocity as a function of stroke position for a second die casting .[.operating.]. .Iadd.operation .Iaddend.to form a current profile of such data for such second operation, and
(h) displaying said current profile on said display screen along with said master profile for diagnostic comparison purposes.
2. A diagnostic method as defined in claim 1 wherein said minimum velocity level is a velocity of approximately zero.
3. A diagnostic method as defined in claim 2 wherein upon reaching said minimum velocity level said analog data is displayed as a function of time by establishing a time frame for the number of incremental positions remaining after said minimum velocity level is reached, dividing said time frame into incremental time increments and recording said analog data at each of said time increments until the increments of time equal the completion of the time frame.
4. A diagnostic method as defined in claim 3 .[.wherein the.]. .Iadd.further including the steps of recording .Iaddend.temperature .[.is recorded.]. .Iadd.in the reciprocating equipment .Iaddend.at each incremental position along the stroke length and .[.is.]. graphically .[.displayed in step (e).]. .Iadd.displaying said temperature .Iaddend.along with said pressure and velocity .[.and stored as master profile data in step (f).]..
5. A diagnostic method as defined in claim 4 further comprising programming the microcomputer .[.in which said master profile data is stored.]. to generate a cursor in the form of a vertical line upon said CRT display at any one of the incremental positions along said stroke length; adjusting the position of said line cursor to a desired position in increments corresponding to distance between said incremental positions; and displaying the data of pressure and velocity on said CRT screen corresponding to the adjusted position of said line cursor.
6. A diagnostic method as defined in claim 1 further comprising detecting when said predetermined minimum velocity level is reached and graphically displaying the analog data of pressure and velocity in step (e) as a function of time upon reaching said minimum velocity level and until said stroke length is completed. .Iadd.7. A diagnostic method for analyzing and monitoring the process parameters of reciprocating equipment in which a linear reciprocating device is traversed over a fixed stroke length at high speed comprising the steps of:
(a) dividing a parameter indicative of movement of the device into a predetermined number of incremental data collection points;
performing, for a first ram cycle, the following steps (b)-(f):
(b) generating data corresponding to said parameter and the pressure developed by said device at each such incremental data collection point;
(c) recording the time transpired in the movement of said device along said stroke length;
(d) determining the velocity of said device at each such incremental data collection point;
(e) generating a graphical representation corresponding to pressure and velocity as a function of the device movement parameter along said stroke length;
(f) storing said data in the form of master profile data at an address location;
(g) repeating the sequence of generating data, determining velocity and storing data corresponding to pressure and velocity as a function of movement of said linear reciprocating device for a second ram cycle to form a current profile of such data for such second ram cycle; and
(h) generating a graphical representation of said current profile along
with said master profile for diagnostic purposes..Iaddend. .Iadd.8. A diagnostic method as defined in claim 7 wherein the step (e) does not generate said graphical representation corresponding to said pressure and velocity as a function of the device movement parameter for a range of device movement parameters that are substantially zero..Iaddend. .Iadd.9. A diagnostic method as defined in claim 8 wherein upon reaching said near zero velocity, said data is graphically represented as a function of time by establishing a time frame for the number of data collection points remaining after said minimum velocity level is reached, dividing said time frame into incremental time increments and recording said data at each of said time increments until the increments of time equal the completion of the time frame..Iaddend. .Iadd.10. A diagnostic method as defined in claim 9 further including measuring temperature in the reciprocating equipment for data collection points along the stroke length and graphically representing said temperature along with said pressure and velocity..Iaddend. .Iadd.11. A diagnostic method as defined in claim 10 further comprising generating a cursor in the form of a vertical line for any one of the data collection points along said stroke length; adjusting the position of said line cursor to a desired point in increments corresponding to distance between said points; and generating an indication of the data of pressure and velocity corresponding to the adjusted position of said line cursor..Iaddend. .Iadd.12. A diagnostic method as defined in claim 8 further comprising detecting when said velocity level is reached, and graphically representing the data of pressure and velocity in step (e) as a function of time upon reaching said velocity level and until said reciprocating device traversal is completed..Iaddend. .Iadd.13. A method for monitoring the process parameters of a linear reciprocating device which traverses a stroke path at high speed to develop pressure, said method comprising the steps of:
(a) collecting data at each of a plurality of data collection points, said data corresponding to a parameter indicative of movement of the device and the pressure developed by said device during a first ram cycle;
(b) graphically representing a first pressure and velocity profile as a function of the movement of said device along said stroke path based on said data collected by said step (a);
(c) repeating said collecting step (a) for a further ram cycle; and
(d) graphically representing a further pressure and velocity profile as a function of the movement of said device along said stroke path based on
said data collected by said repeated step (a)..Iaddend. .Iadd.14. A method as in claim 13 wherein said graphically representing step (d) includes superimposing graphical representations of said first profile and said further profile..Iaddend. .Iadd.15. A method as defined in claim 13 wherein said method further comprises the steps of generating a cursor, permitting a user to move the cursor so as to point to a portion of at least one of said graphically represented first profile and said graphically represented further profile, and providing numerical information indicating pressure and velocity corresponding to said pointed-to portion of said profile..Iaddend. .Iadd.16. A method as defined in claim 13 wherein the graphically representing step (d) includes the step of graphically representing said profiles as a function of positions of said device where said device has a non-zero velocity..Iaddend. .Iadd.17. A method as defined in claim 13 wherein for a range of substantially zero velocities of said linear reciprocating device, said profiles are graphically represented as a function of time..Iaddend. .Iadd.18. A method as defined in claim 13 wherein a temperature is also measured and collected for each data collection point along the stroke length and said collected temperature is graphically represented along with said pressure and velocity..Iaddend. .Iadd.19. A method for monitoring the process parameters of a reciprocating apparatus of a type including a ram which traverses a stroke path at high speed to produce pressure, said method including the following steps:
(a) providing a stored representation of a master velocity profile for said ram as a function of position of said ram along said stroke path;
(b) measuring the movement of said ram;
(c) deriving a velocity signal indicating velocity of said ram at a plurality of positions along said stroke path based on said measured movement; and
(d) generating, based on said stored representation and said velocity signal, a superimposed graphical representation of (i) said ram velocity as a function of said plurality of positions of said ram along said stroke path and (ii) said master velocity profile..Iaddend. .Iadd.20. A method as defined in claim 19 further including the steps of:
providing a stored representation of a master pressure profile for said ram as a function of position of said ram along said stroke path,
deriving a pressure signal indicating the pressure developed by said ram at said plurality of positions along said stroke path, and
generating a superimposed graphical representation of (i) said pressure signal as a function of said plurality of positions of said ram along said stroke path and (ii) said master pressure profile..Iaddend. .Iadd.21. A method as defined in claim 19 wherein the step of measuring includes dividing the stroke length into a number of increments and generating values corresponding to the position of said ram at each such increment based on said measured movement..Iaddend. .Iadd.22. A method for monitoring the process parameters of a high speed reciprocating ram, said ram traversing a stroke path at high speed to produce pressure, said method including the following steps:
(a) storing indicia of electrical signals representing a master pressure profile;
(b) measuring position of said ram along said stroke path;
(c) measuring pressure produced by said ram; and
(d) electrically generating an image including:
a first graphical representation of pressure versus position of said ram along said stroke path based on said measured position and pressure, and
a second graphical representation of pressure versus position of said ram along said stroke path based on said stored master pressure profile indicia,
said first and second graphical representations being at least partially
superimposed in said image..Iaddend. .Iadd.23. A method as in claim 22 wherein said steps (b) and (c) are repeated, and said storing step (a) comprises the step of storing indicia of measurements obtained by a repetition of said steps (b) and (c)..Iaddend. .Iadd.24. A method as in claim 22 wherein said method further includes the steps of:
measuring the passage of time; and
also electrically generating a graphical representation of pressure versus time based on said measured time and said measured position..Iaddend. .Iadd.25. A method for monitoring a reciprocating apparatus including a ram traversing a stroke path at high speed to produce pressure, said method including the following steps:
(a) measuring movement of said ram;
(b) deriving a velocity signal from said measured movement, said velocity signal indicating velocity of said ram at a plurality of positions along said stroke path;
(c) deriving a pressure signal indicating said pressure produced by said ram at a plurality of positions of said ram along said stroke path; and (d) graphically representing said velocity and pressure signals as a function of position of said ram along said stroke path. .Iaddend. .Iadd.26. A method for monitoring a reciprocating apparatus including a ram and for electrically generating a graphical representation of results of said monitoring, said ram traversing a stroke path at high speed during a ram cycle to produce pressure, said method including the following steps:
(a) providing a time base;
(b) measuring position of said ram for a first ram cycle;
(c) measuring pressure produced by said ram for said first ram cycle;
(d) electrically generating a first graphical representation of pressure versus position of said ram for said first ram cycle based on said measured ram position and said measured pressure; and
(e) electrically generating a second graphical representation of pressure versus time for said first ram cycle based on said measured ram pressure and said time base, including the step of facilitating substantially simultaneous viewing of said first and second graphical representations.
.Iaddend. .Iadd.27. A method as in claim 26 wherein:
said step (d) includes the step of representing said pressure as a function of position along a first axis graduated in position increments; and
said step (e) includes the step of representing said pressure as a function of time along a second axis, said second axis being graduated in time increments, said first and second axes being simultaneously viewable. .Iaddend. .Iadd.28. A method as claim 26 wherein:
said stroke path has an end;
said method further includes determining when the ram reaches the ned of said stroke path;
said step (d) comprises representing said pressure versus position of said moving ram; and
said step (e) comprises representing said pressure versus time for pressure existing after said ram has reached the end of said stroke path. .Iaddend. .Iadd.29. Apparatus for monitoring the process parameters of reciprocating equipment, said equipment including a ram which traverses a stroke path at high speed to produce pressure, said apparatus comprising:
measuring means coupled to said ram for measuring the movement of said ram;
velocity means coupled to said measuring means for deriving a first signal indicating velocity of said ram at a plurality of positions along said stroke path based on said measured movement;
a memory storing indicia representing a master velocity profile for said ram as a function of position of said ram along said stroke path; and
imaging means coupled to said velocity means and to said memory for generating a superimposed graphical representation of (i) said velocity as a function of position of said ram along said stroke path and (ii) said
master velocity profile. .Iaddend. .Iadd.30. Apparatus as defined in claim 29 wherein:
said apparatus further includes pressure sensing means for providing a pressure signal indicating the pressure developed by said ram at said plurality of positions along said stroke path;
said memory also stores indicia representing a master pressure profile for said ram as a function of position of said ram along said stroke path; and
said imaging means generating a superimposed graphical representation of said pressure as a function of said plurality of positions of said ram along said stroke path and said master pressure profile. .Iaddend. .Iadd.31. Apparatus as defined in claim 29 wherein the movement measuring means includes means for dividing the stroke length into a number of incremental positions and generating values corresponding to the position of said ram at each such incremental position based on said measured movement. .Iaddend. .Iadd.32. Apparatus for monitoring the process parameters of reciprocating equipment, said equipment including a ram which traverses a stroke path at high speed to produce pressure, said apparatus including:
movement measuring means coupled to said ram for measuring the movement of said ram;
pressure measuring means for measuring the pressure produced by said ram as said ram traverses said stroke path;
means for storing indicia representing a master pressure profile for said ram; and
electrical imaging means, coupled to said storing means, said movement measuring means and said pressure measuring means, for generating an image based on said measured movement and pressure, said image including (i) a first graphical representation of pressure versus position of said ram along said stroke path, and (ii) a further graphical representation of pressure versus ram position along said stroke path based on said stored master pressure profile indicia, said first and second graphical representations being at least partially superimposed in said image.
.Iaddend. .Iadd.33. Apparatus as in claim 32 wherein said first graphical representation corresponds to a first ram stroke; said storing means is coupled to said movement measuring means and said pressure measuring means; and said stored master pressure profile indicia are stored based on said measured movement and pressure for a second ram stroke different from said first ram stroke. .Iaddend. .Iadd.34. Apparatus as in claim 28 wherein:
said apparatus further includes means for measuring the passage of time; and
said imaging means is also for electrically generating a graphical representation of pressure versus time based on said measured time and
said measured position. .Iaddend. .Iadd.35. Apparatus for monitoring the process parameters of reciprocating equipment, said equipment including a ram coupled to a fluid which traverses a stroke path at high speed to produce pressure, said apparatus including:
movement measuring means coupled to said ram for measuring the movement of said ram;
means coupled to said movement measuring means for deriving a first signal indicating velocity of said ram at a plurality of positions along said stroke path based on said measured movement;
pressure sensing means for providing a second signal indicating pressure produced by said ram at a plurality of positions of said ram along said stroke path; and
imaging means coupled to said deriving means and said pressure sensing means for generating a graphical velocity and pressure profile representation of said first and second signals as a function of said plurality of positions of said ram along said stroke path. .Iaddend. .Iadd.36. Apparatus for monitoring the process parameters of reciprocating equipment, said equipment including a ram traversing a stroke path at high speed during a ram stroke cycle to produce pressure, said apparatus comprising:
first measuring means for measuring the movement of said ram for a first ram stroke cycle;
second measuring means for measuring the pressure for said first ram stroke cycle;
third measuring means for measuring the passage of time during which said movement and pressure are measured; and
output means coupled to said first, second and third measuring means, for producing signals representing first and second substantially simultaneously viewable graphical representations based on said measured ram movement, said measured pressure, and said measured time passage, said first graphical representation showing pressure of said fluid versus position of said ram for said first ram stroke cycle, said second graphical representation showing pressure of said fluid versus time for said first ram stroke cycle. .Iaddend. .Iadd.37. Apparatus as in claim 30 wherein said output means provides signals representing an axis, signals representing said pressure as a function of position along an axis graduated in position increments, and signals representing said pressure as a function of time along a second axis being graduated in time increments, said first and second axes being simultaneously viewable. .Iaddend. .Iadd.38. Apparatus as in claim 30 further including an electronic display coupled to said output means, said electronic display displaying said first graphical representation showing pressure versus ram position for a portion of said first ram cycle corresponding to a first time period during which said ram is moving, said electronic display displaying said second graphical representation showing pressure versus time for a portion of said first ram cycle corresponding to a second time period during which said ram has substantially ceased moving. .Iaddend.
Descripción
CROSS-REFERENCE TO RELATED APPLICATIONS

.[.This is a continuation-in-part of U.S. Ser. No. 292,168 filed Aug. 12, 1981, now U.S. Pat. No. 4,504,920 issued Mar. 12, 1985..].

.Iadd.This is a continuation of U.S. Ser. No. 292,168 filed Aug. 12, 1981, now U.S. Pat. No. 4,504,920 issued Mar. 12, 1985. .Iaddend.

BACKGROUND OF INVENTION

Various industrial processes employ reciprocating machinery having a linear stroke to implement the process. In die casting and plastic molding, for example, the linear reciprocating device is an hydraulic cylinder used for loading raw material into the die or mold respectively. In die casting, molten metal is forced into the die from the hydraulic cyliner by a piston type plunger or ram displaced over a linear stroke under controlled operating conditions of pressure and velocity. Research in die casting has achieved a level of sophistication whereby the proper injection speeds, pressure and temperatures required for optimum operation for any given machine can be theoretically calculated. To satisfy the calculated conditions, the operation must be carried out within narrow ranges of settings for each of the critical process parameters. Variation in one or more of the process parameters will affect the performance of the other parameters on the process and will alter the production rate and affect the yield of the product produced. To optimize the production output the process parameter settings are adjusted over a series of production runs until a product with desired characteristics and production yield is obtained. Since the events which affect the production cycle occur much too quickly for human observation it was necessary, heretofore, for operating personnel to make subjective judgements in adjusting process parameters in a production run frequently resulting in high scrap rates. The trial and error technique commonly used heretofore also required more raw material than necessary in getting a given required production output. Moreover, because of the inability to control and adjust the process parameters accurately, the design of the article produced typically had to be made with more material than necessary for functional or strength considerations simply to permit an acceptable yield.

Accordingly, a need exists for a diagnostic instrumentation system which can readily be applied to the process machinery to monitor and record objective measurements of machine performance during an actual production cycle. The objective measurements should represent machine operational data which will provide technical personnel with the means to make appropriate adjustments to maintain optimum process integrity. Prior art instrumentation claiming to satisfy this need are based upon the use of high speed analog graphic plotters which typically used expensive ultraviolet sensitive photographic paper in combination with transducers and signal conditions designed to collect machine data and display it. One of the major disadvantages to the use of a graphic plotter is that its output is a graphical display of the given parameter under observation versus time. A time display is difficult to interpret and requires sophisticated expertise to derive and calculate quantitative values for the critical parameters affecting the process. Not only is the interpretation subject to error but it does not provide readily apparent information from which machine adjustments may be made in the next production cycle. Another significant disadvantage is that the oscillographs must be adjusted to accommodate the transducers used on a specific machine and must be calibrated for each different type of transducer. Also, because of the high speed of the paper travel of the recorder it is necessary for a technical person to be constantly attentive of the oscillograph so as to minimize the waste of the expensive paper.

In a die casting operation the reciprocating device would be representative of the hydraulic cylinder and piston ram for injecting raw material into the die. In accordance with the method of the present invention a profile of the critical operational parameters of the reciprocating device, viz., velocity and pressure, are generated as a function of ram piston along its linear stroke. This permits dramatically reduced set up time and readily provides information for adjustment of the variable parameters within precise limits to assure maximum production quality and performance.

SUMMARY OF INVENTION

The method of the present invention comprises the steps of: dividing the stroke length traversed by the ram into a predetermined number of incremental positions; generating analog data corresponding to the position of the ram and the pressure developed by the ram at each such incremental position; recording the time transpired in the movement of the ram along the stroke length; calculating the velocity of the ram at each incremental position, graphically displaying the data corresponding to pressure and velocity on a display screen of a cathode ray tube as a function of the incremental position of the ram along the stroke length until the velocity reaches a predetermined minimum level, with the display forming a master profile for such data; storing the data representing the master profile at a predetermined address location in a nonvolatile memory of a microcomputer; repeating the sequence of generating, calculating and storing analog data corresponding to pressure and velocity as a function of stroke length for a second die casting operation to form a current profile of such data and displaying said current profile on the display screen along with the master profile for comparison purposes. The best mode for practicing the present invention is described hereafter at length in connection with the system shown in FIGS. 1-7.

OBJECTS OF THE INVENTION

It is the principal object of the present invention to provide a method for generating a profile of at least one process parameter in the control of a reciprocating device having a linear stroke as a function of stroke position.

Another object of the present invention is to provide a method for analyzing the process parameters in the operation of reciprocating equipment in which a profile is recorded of master trace for a given control parameter as a function of stroke position which is then compared against a current profile of such control parameter.

BRIEF DESCRIPTION OF DRAWINGS

Other objects and advantages of the present invention will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings of which:

FIG. 1 is a block diagram of the data analysis and display system of the present invention;

FIG. 1A is a pictorial representation of a typical profile display of velocity versus position generated in accordance with the present invention for a die casting operation;

FIG. 2 shows the pressure interface circuit between the microcomputer of FIG. 1 and the pressure transducer;

FIG. 3 shows the temperature interface circuit between the microcomputer of FIG. 1 and the temperature transducer;

FIG. 4 shows the position transducer interface circuit between the microcomputer of FIG. 1 and the position transducer;

FIG. 5 is a flow diagram for the microprocessor of FIG. 1 corresponding to the start function;

FIG. 5A is a flow diagram identifying the software functions for the program selection "Collect Data" in the flow diagram of FIG. 5;

FIG. 6 is another flow diagram identifying the software functions for the "Graphics" program selection in the flow diagram of FIG. 5;

FIG. 6A is a flow diagram subroutine for performing the "Plot" function in the flow diagram of FIG. 6;

.[.FIG. 6B is a .]. .Iadd.FIGS. 6A-1 and 6B are .Iaddend.flow diagram .[.subroutine.]. .Iadd.subroutines .Iaddend.for performing the "Current", "Master" and "Plot Variable" subroutines of the Plot function of FIG. 6A;

FIG. 6C is a flow diagram subroutine for performing the "Cursor" subroutine for the Cursor function of FIG. 6;

FIG. 6D is a flow diagram subroutine for performing the "Files" function in the flow diagram of FIG. 6;

FIG. 6E is a flow diagram subroutine for performing the "Get Old" and "Make New" subroutines of the Files function of FIG. 6C; and

FIG. 7 is a flow diagram for carrying out the ENTER/EDIT PARAMETER SHEETS function in the flow diagram of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now in particular to FIG. 1 and FIG. 1A inclusive which diagrammatically illustrate the data analysis and display system of the present invention and a typical CRT (cathode ray tube) velocity profile generated by the system of the present invention for a die casting machine.

The basic building blocks of the data analysis and display system of the present invention comprise a microcomputer 1 of any conventional design, including a conventional non-volatile memory 7, groups of program selection and function keys, 8, 9 and 12 and a numeric keyboard 10; a plurality of transducers 2, 3, 4 and 5 respectively and a conventional cathode ray tube 6 hereinafter referred to as a CRT.

The transducers 2, 3, 4 and 5 represent pressure, temperature and velocity position transducers respectively. Transducers 4 and 5 represent alternative transducers for providing velocity position data to the microprocessor. Transducer 4 is a conventional digital type transducer connected to the die casting machine to sense the pulses generated during machine production in response to each incremental movement of the reciprocating device (not shown) over its linear stroke. The output is in a binary coded decimal format for direct reading by the microcomputer 1. The transducer 5 is a linear potentiometer having an interface circuit as will be discussed in more detail with reference to FIG. 4. The microcomputer 1 may interface to either the digital velocity position transducer 4 or the linear potentiometer velocity position transducer 5. The temperature transducer 3 is a temperature thermocouple having an interface circuit as will be discussed in more detail with reference to FIG. 3 whereas the pressure transducer 2 is a conventional strain gage type pressure transducer in a bridge configuration with an interface circuit as will be discussed in more detail with reference to FIG. 2.

Each of the transducers 2, 3, 4 and 5 collect data consisting of velocity, temperature and pressure as a function of stroke position during a production cycle. The production cycle for a die casting or plastic molding operation is defined for purposes of the present invention as the stroke and corresponds to the motion of the injection ram (not shown) which injects either metal into the die or plastic into a mold respectively. The stroke length represents the total displaced distance of the injection ram in the hydraulic cylinder for a single production cycle.

The conventional microcomputer is connected to a conventional CRT 6 for displaying a profile representative of the data collected by the transducers 2, 3, 4 or 5 in accordance with programmed instructions corresponding to the flow digrams 5, 6, 6A-6F and 7 respectively as will be discussed in more detail hereafter. Any conventional software program format suitable for use with the microcomputer 1 may be used in the preparation of a program to fulfill the flow diagram requirements. The program itself .[.does not form a part of the present invention and.]. may readily be prepared by any skilled programmer from the flow diagrams.

An illustrated display of a typical profile 14 representative of the velocity of the injection ram for a production cycle as a function of stroke position, i.e., the position of the reciprocating injection ram along the stroke length, is shown on the CRT 6. A further illustrative display showing two velocity traces superimposed for comparison is shown in FIG. 1A. The microcomputer 1 is of any commercially available type which can generate a cursor. The position of the cursor 16 is FIG. 1A is controlled by software following the flow diagram subroutine for the cursor to be discussed hereafter in connection with FIG. 6C and FIG. 7. The cursor 16 is adjustable over the stroke length and provides specific parameter information corresponding to its location on the display thereby permitting the observer to readily compare parameter values between the superimposed traces at any stroke position. One of the superimposed traces may represent a "master" profile defined as an idealized or acceptable profile and may simply represent a previously recorded profile. A master profile is used for comparison purposes with a "current" profile. A current profile is defined as a profile trace formed on the CRT from data received by the microprocessor from one of the transducers in response to a current production cycle. The master profile is stored in the non-volatile memory 7. Any number of master profiles may be recorded and stored in the non-volatile memory 7 so as to constitute a library of master profiles. A master profile is stored at any address in memory 7 identified by the operator through the use of the numeric keyboard 10. By providing this ability to superimpose master profiles over a current profiles, a non-technically trained person can readily distinguish between a master trace identifying a production run classified as acceptable or good and the current production run representing the current profile. It also becomes readily apparent to the operator where and to what extent adjustment may be necessary to conform subsequent production runs to the master trace. This is primarily attributable to the fact that the trace is a function of position and not time. Individual program selection and function control is provided by groups of push buttons 8, 9 and 12. Each individual button in group 9 is assigned a program selection whereas the group of push buttons 8 and 12 are assigned individual function selections corresponding to the function selections in the flow diagrams. The numeric keyboard 10 additionally provides for the numeric entry of upper and lower limits for each important parameter so as to define the acceptable range of such parameter for proper operation of the machine. In addition, the numeric keyboard 10 may be used to enter data corresponding to a machine number, ram plunger diameter and production cycle job number which collectively are used for the file identification for each master trace stored in the non-volatile memory 7.

FIG. 2 shows the pressure interface circuit between the microcomputer 1 and the pressure transducer 2. The pressure transducer 2 is of a conventional bridge type with one leg of the bridge being adjustable and varying in a conventional fashion in response to the amount of resistance to movement of the reciprocating device (not shown). Resistors R1, R2 and R3 form a zero offset adjustment network to cancel out the zero offset of the pressure transducer 2 so as to provide a zero differential input to the operational amplifier U1. Resistors R4, R5, R6, R7 R8 and R9 form an appropriate feedback network to provide an output .[.18.]. .Iadd.19 .Iaddend.of predetermined gain relative to the signal .[.19.]. .Iadd.18.Iaddend.. RC network combination R7 and C1 reduce the noise content from the pressure transducer 2. Integrated circuit 20 is a commercially available analog to digital converter for converting the analog signal to a digital format preferably in BCD form. The resistors R11, R12, R13, R14, R15, R25, R26 and R27 are pull up resistors for providing signals on lines AD, BC and MNL which are connected to provide the microcomputer 1 with continuous data corresponding to the pressure at the instant of time selected to be read by the microcomputer. The microcomputer 1 reads the pressure data in increments of time corresponding to the incremental displacement of the reciprocating device (not shown) over the stroke length to provide a profile of pressure versus stroke position. Resistors R10 and R23 are selected to cancel the zero offset of the analog to digital converter 20. Capacitor C2 is an integrating capacitor used by converter 20 during data conversion. Resistor R22 is used to adjust the gain of the converter 20 to result in a calibrated output.

FIG. 3 shows the temperature interface circuit between the temperature transducer 3 and the microcomputer 1. Thermocouple 41 is adapted to be coupled to the reciprocating device to provide a temperature signal corresponding to the temperature in the reciprocating device as a function of stroke position. The thermocouple 41 is connected through lead lines 25 and 26 to a conventional operational amplifier U2. Resistors R28 and R29 provide the .Iadd.input and .Iaddend.feedback resistors for setting the gain of the first stage of amplification. A second stage of amplification is provided by a conventional operational amplifier U3 in conjunction with its feedback .Iadd.and .Iaddend.resistor network R30, R31, R32, R35 and R34. The output 30 from the second stage of amplification is fed relative to the potential on line 33 to a conventional analog to digital converter 32 in a manner similar to that in the interface circuit for the pressure transducer 2. The output from the analog to digital converter 32 is provided on the same lines LM N, AB, CD as for the pressure transducer circuit in FIG. 2.

FIG. 4 shows the linear potentiometer interface circuit between the linear potentiometer 5 and the microcomputer 1. The linear potentiometer 5 may be readily mounted to the die casting .[.maching.]. .Iadd.machine .Iaddend.with its variable wiper arm 35 connected to move with the reciprocating device. Accordingly, the position of the wiper arm 35 is directly proportional to the position of the reciprocating device along the stroke length. Since the velocity of the reciprocating device is equal to distance divided by time; the velocity is readily determined relative to each incremental stroke position. The stroke length may be divided into any number of increments with the velocity representing the differential of each reading with respective to time.

Linear potentiometer 5 is connected to the interface circuit operational .[.amplifier.]. .Iadd.amplifiers .Iaddend.U4, U5 and U6 respectively. Operational amplifiers U4 and U5 serve to apply positive and negative reference voltage levels across the opposite ends 36, 37 of the potentiometer 5. The operational amplifier U6 amplifies the signal output 38 from the wiper arm 35. Operational amplifiers U4 and U6 are connected in a conventional unity gain configuration. Resistors R54 and R55 form a unity gain feedback circuit which generates a positive reference voltage on end 36 of potentiometer 5 equal in magnitude to the negative reference voltage developed by zener diode D1 from a negative power supply voltage -V through resistor R56. Accordingly, the output 40 of the operational amplifier U6 is automatically adjusted against drift in power supply voltage. The output 40 is connected to a conventional analog to digital converter 65 such as Beckman AD7556. The data presented on the data bus lines D0 through D7 are connected to the microcomputer 1. The A to D converter 42 generates a twelve bit digital signal corresponding to the analog signal 40. Nor gates 71, 72 and 73 control the conversion of data and the interrogation of the twelve bit output D0 through D11.

Each time the microcomputer takes a reading the enable conversion line 74 goes to the zero logic state. At the same time, address lines 75 and 76 are set to a logical zero. When all three of the signals are logical zero's the output of Or gate 72 is a logical one thereby enabling the low byte labeled LBI in the A to D converter 42. This causes the lower significant bits D0 through D7 to be impressed upon the data bus lines .[.B0 to B7.]. .Iadd.D0 to D7.Iaddend.. After reading the lower eight bits, the microcomputer 1 then interrogates the upper four bits D8 to D11 by setting the enable conversion line to a zero logic state while setting address lines 77 and 76 to logical zero. This combination causes the output of Or gate 73 to go to a logical one which, in turn, enables the end of Conversion Signal EcoI and the high byte HBI causing the upper significant bits D8 to D11 to be impressed upon the data bus lines .[.B0 to B3.]. .Iadd.D0 to D3.Iaddend.. The conversion of data is initiated when the microcomputer sets the enable conversion line 74 to a zero logic state and sets the address lines 78 and 76 to logical zero. This causes the output of Or gate 71 to go to a high state thereby impressing a start signal to the start input of the A to D converter 42 for starting another conversion cycle. By continuously repeating the start conversion and reading sequence in predetermined intervals corresponding to incremental distances the microcomputer 1 knows at all times what the position of the ram is along the machine stroke. Upon collecting the position data as a function of time it need only perform an algorithm representing a simple mathamatical quotient of distance and time to convert the position data to velocity data. Accordingly, a profile can be generated corresponding to velocity versus position as well as velocity versus time or a combination of both. The latter is significant in that certain periods may exist when a momentary time display would be beneficial. In die casting this is true at approximately the end of the stroke where the velocity of the ram approaches zero. Accordingly, a combination display is particularly useful for the pressure profile in a die casting operation over the final stroke length known to those skilled in the art as the "biscuit" length.

FIG. 5 illustrated the flow diagram for start up of the microcomputer 1. Upon depressing the start function key three program selections identified as Collect Data, Graphics and Entry/Edit Parameter sheets become selectable. A program is selected by depressing one of the dedicated function keys corresponding to the program selection. Any one of the keys in the function key groups 8, 9, and 12 may be assigned the appropriate functions.

FIG. 5A shows the flow diagram for the program selection "Collect Data". The letter (N) designates each incremental position at which data is to be collected over the stroke length. The stroke length may be divided into any fixed number of incremental data collection points preferably corresponding to the screen increments for the particular microcomputer being used. At each data collection point a time reading is taken with the number of the data points designated IT. The start position is labeled Sφ at time IT φ whereas the current position of the injection ram along the stroke length is designated SI. The algorithmic statement SI∝Sφ+E is met only when the ram has advanced from the start position a fixed distance E representing the desired incremental spacing between the incremental positions. Once this is met the incremental position N is advanced by one and a reading is taken from the transducers 2, 3, 4 or 5 of current velocity, current temperature, and current pressure. The microcomputer, clock is used for generating a time frame.

The program of FIG. 5A provides for consecutive reading at each incremental position until the assigned number of incremental positions reaches maximum. In die casting near the end of the operation when the ram approaches the end of the stroke the velocity will drop to a plateau level of slightly above zero at which time it is preferred to continue readings as a function of time. Accordingly, as shown in FIG. 5A, a time frame is established for the remaining number of incremental positions with tφ representing the starting time for further consecutive readings as a function of time. As soon as the current time t(N) plus a predetermined time increment "δ" is reached representing a time data increment IT within the established time frame, from tφ to IT maximum, the next reading is taken. At such instant the time data increment IT is advanced by one and further readings are taken until the increments of time IT equal the completion of the established time frame.

FIG. 6 shows the flow diagram for the program selection Graphics. With this program selection the operator is given a further choice of the subordinate functions Plot, Cursor, Frame, Files and Quit. Any one of these functions become available upon depression of one of the assigned function keys 8. The Erase function .Iadd.clears the screen and .[.return.]. .Iadd..Iaddend.returns the program selection. The program selection is also returned upon depressing the quit function key.

The Plot function is shown in FIG. 6A providing further selection of the subroutines Master or Current. FIG. 6B shows the flow diagram for both the master and current subroutine for the function selection Plot. The subroutine is the same whether current data or master data is plotted with the data of each of the variables loaded and plotted corresponding to each incremental position. The Cursor function flow diagram is shown in FIG. 6C. A vertical line is plotted at the existing incremental position on the CRT screen upon selection of the cursor with corresponding variables for the cursor position printed on the display for either a master or current profile. The cursor position is adjustable by the operator to either the left or right of the displayed cursor position by depression of the assigned dedicated function keys for cursor left or right control. The cursor will move in increments N preferably corresponding to the assigned incremental positions N for the stroke. Accordingly, the cursor position for one trace will automatically correspond to the same incremental position for a superimposed trace. As the flow diagram indicates the cursor may only be moved to the left or right to an incremental position which satisfies the statement defining the number of N positions.

In FIG. 6D the flow diagram for the function selection Files is shown. The operator is provided with a further choice of subroutine selections "Get Old", "Make New", or "Quit". The subroutines Get Old and Make New .[.is.]. .Iadd.are .Iaddend.illustrated in FIG. 6E. The files selection "Get Old" corresponds to the selection of a master trace whereas the files selection "Make New" corresponds to the storing of current data in forming a master trace in the non-volatile memory 7. The address number for the old or new master trace in the non-volatile memory is designated by use of the numeric keypad.

The Enter/Edit Parameter Sheet program selection identified in the flow diagram for start up of the microcomputer 1 is shown in FIG. 7. The microcomputer 1 is instructed to go to the numeric keypad and wait for the operator to read in the numbers corresponding to the machine in use, the part in use and the machine type. The microcomputer assigns and constructs characters used for the file name. The parameters may then be printed out on the CRT screen. The screen prompt is adjustable to the left, right or up and down. The screen prompt refers to the flashing inverse video enhancement of the location on the CRT screen which the computer is currently monitoring. The user may at any time depress Fields complete to save the File name. The parameter sheet program may also be used to print out acceptable high and low limit settings. .[.The velocity of the injection device may be calculated as indicated heretobefore by dividing the traversed distance between incremental positions of stroke length with the differential in time transpired between such positions or alternatively by using a velocity position transducer consisting of the analog output variety including but not limited to potentiometers or LVTD's connected to a conventional analog to digital (A/D) converter. The A/D converter will generate an absolute position input for processing by the microcomputer. Another alternative means of measuring velocity is to use any conventional velocity position transducer such as the analog output variety mentioned above in combination with an analog differential circuit as shown in FIG. 4 enclosed within dotted lines. The analog differentiator circuit 80 is connected to the position signal output 40 of the operational amplifier U6 which in turn is connected to the potentiometer transducer 5. The differentiator circuit 80 will generate a signal 82 proportional to velocity which, in turn, is connected to an analog to digital converter 84 which corresponds to the conventional A/D converter 68 with output data bus lines equivalent to the data bus lines D0-D7 for connection to the microcomputer.

Although the foregoing invention has been described specifically in connection with a die casting machine the invention is equally applicable for use with other machine types including, but not limited to, extrusion presses, low pressure die casting machines, permanent hold casting machines, forging presses, powder metal presses and trim presses. In addition, it should be understood that the present invention is not limited to graphic display and embraces numerical analysis and tabular display. It should further be understood that although multiple process parameters may be displayed the invention is not limited to the display of a plurality of parameters. A single profile of any parameter including velocity, position, pressure, temperature, etc. may be displayed. In addition, the profiles may be analyzed and reduced to discreet results for display which results may be compared against preprogrammed constants stored in the microcomputer such as low limits and alarm conditions.

A predominant feature discussed throughout the specification is the ability to store profiles in memory as master traces to be compared against current data profiles. It is obvious, however, that the method of the present invention encompasses a display of only the current data profiles without necessarily superimposing a master trace..].

Citas de patentes
Patente citada Fecha de presentación Fecha de publicación Solicitante Título
US3818201 *16 Nov 197218 Jun 1974IbmMethod and system arrangement for monitoring and indicating pulse timing functions with measurable time reference
US3860801 *19 Jun 197314 Ene 1975Hunkar Denes BInjection molding control
US3911419 *23 Nov 19737 Oct 1975Xerox CorpController for cursor positioning on a display medium
US3945255 *4 Mar 197423 Mar 1976H. Maihak AgMethod of and apparatus for monitoring a process involving a plurality of parameters
US3977255 *18 Ago 197531 Ago 1976Control Process, IncorporatedEvaluating pressure profile of material flowing to mold cavity
US3982440 *13 Ago 197528 Sep 1976Control Process, IncorporatedMethod of determining molded part profile
US3990046 *12 Jun 19742 Nov 1976Interactive Systems, Inc.Multiple terminal computer system with mixed terminal data reception rates
US4094940 *22 Abr 197413 Jun 1978Usm CorporationInjection molding machine controls
US4249186 *18 Ago 19783 Feb 1981Leeds & Northrup LimitedProcessor system for display and/or recording of information
US4335778 *27 May 198022 Jun 1982Toshiba Kikai Kabushiki KaishaApparatus for measuring injection speeds of die casting machines
US4344142 *6 Ago 197510 Ago 1982Federal-Mogul CorporationDirect digital control of rubber molding presses
US4471348 *15 Ene 198211 Sep 1984The Boeing CompanyMethod and apparatus for simultaneously displaying data indicative of activity levels at multiple digital test points in pseudo real time and historical digital format, and display produced thereby
US4504920 *12 Ago 198112 Mar 1985John MickowskiData analysis and display method for reciprocating equipment in industrial processes
US4534003 *24 Ago 19816 Ago 1985At&T Bell LaboratoriesOptimized reaction injection molding
DE2615445A1 *9 Abr 197627 Oct 1977Westfaelische Metall IndustrieVerfahren zum steuern einer spritzgiessmaschine
DE3142811A1 *28 Oct 19815 May 1983Idra Pressen GmbhMethod and apparatus for controlling the movement of a casting piston during the injection process on a die-casting machine
EP0018551A1 *17 Abr 198012 Nov 1980Siemens AktiengesellschaftSet point input for injection moulding machine
EP0126174A1 *20 May 198328 Nov 1984John MickowskiProcess for monitoring and controlling intermittently working molding and casting devices and apparatus for performing said process
Otras citas
Referencia
1"A Building Block Approach to Shot End Monitoring and Control," Die Casting Engineer, pp.1 6-26, 1981.
2"Assessing the Performance of Metal Feed Systems," 9th SDCE International Die Casting Exposition and Congress, Paper No. G-T77-071 (1977).
3"Australian Research for the Die Casting Industry," Die Casting Engineer, pp. 14-24, 1980.
4"Here's A Profitable Alternative to Trail-and-Error Die Casting", Honeywell, Test Instruments Division, Advertisement, (1979).
5"Predicting Shot Speed Using A Programmable Calculator," Die Casting Engineer, pp. 42-44.
6"Shot Monitoring Instrument," Die Casting Engineering, pp. 35-36, 1981.
7 *A Building Block Approach to Shot End Monitoring and Control, Die Casting Engineer, pp.1 6 26, 1981.
8 *Assessing the Performance of Metal Feed Systems, 9th SDCE International Die Casting Exposition and Congress, Paper No. G T77 071 (1977).
9 *Australian Research for the Die Casting Industry, Die Casting Engineer, pp. 14 24, 1980.
10 *Here s A Profitable Alternative to Trail and Error Die Casting , Honeywell, Test Instruments Division, Advertisement, (1979).
11 *Listing of Papers & Authors from 11th DCE International Die Casting Congress in 1981 (pp. 42, 91 77 of May/Jun. 1981 issue of Die Casting Engineer).
12Listing of Papers & Authors from 11th DCE International Die Casting Congress in 1981 (pp. 42, 91-77 of May/Jun. 1981 issue of Die Casting Engineer).
13Lousanne, "Process Control: Now It's an Aid in Everylay Injection Molding", 9 Modern Plastics In., No. 3, pp. 13-15, (Mar. 1979).
14 *Lousanne, Process Control: Now It s an Aid in Everylay Injection Molding , 9 Modern Plastics In., No. 3, pp. 13 15, (Mar. 1979).
15 *Predicting Shot Speed Using A Programmable Calculator, Die Casting Engineer, pp. 42 44.
16 *Shot Monitoring Instrument, Die Casting Engineering, pp. 35 36, 1981.
Citada por
Patente citante Fecha de presentación Fecha de publicación Solicitante Título
US5868020 *29 Abr 19979 Feb 1999Allen-Bradly Company, LlcBrake time monitor and brake control system for a press having a programmable controller
US626000431 Dic 199710 Jul 2001Innovation Management Group, Inc.Method and apparatus for diagnosing a pump system
US63305252 Ago 200011 Dic 2001Innovation Management Group, Inc.Method and apparatus for diagnosing a pump system
US65233844 Oct 200025 Feb 2003The Minster Machine CompanyCarry through monitor
US6868351 *2 Oct 200015 Mar 2005The Minster Machine CompanyDisplacement based dynamic load monitor
US700422319 Dic 200328 Feb 2006Spx CorporationMethod and apparatus for vacuum measurement during die casting
US703185016 Abr 200418 Abr 2006Festo Ag & Co. KgMethod and apparatus for diagnosing leakage in a fluid power system
US712405719 Ago 200317 Oct 2006Festo CorporationMethod and apparatus for diagnosing a cyclic system
US717353930 Sep 20046 Feb 2007Florida Power And Light CompanyCondition assessment system and method
US740591716 Jun 200629 Jul 2008Festo Ag & Co.Method and apparatus for monitoring and determining the functional status of an electromagnetic valve
US74363126 Feb 200714 Oct 2008Florida Power & Light CompanyCondition assessment system and method
US796615017 Nov 200521 Jun 2011Florida Power & Light CompanyData analysis applications
US81708354 Feb 20111 May 2012Florida Power & Light CompanyData analysis applications
Clasificaciones
Clasificación de EE.UU.702/183, 700/206, 345/16, 345/672, 425/169, 264/40.7
Clasificación internacionalG06F17/40, G07C3/00, G01D3/08, G01P3/54, G01D21/02, G01L1/22, G01L5/00, G05B19/4063, G01P3/52
Clasificación cooperativaY10S482/902, G01L1/2256, G06F17/40, G01P3/52, G01D3/08, G01P3/54, G07C3/00, G01D21/02, G01L5/0076, G05B19/4063
Clasificación europeaG06F17/40, G01D3/08, G07C3/00, G01L5/00M8, G01P3/52, G01D21/02, G01L1/22C2, G01P3/54, G05B19/4063