WO2023111924A1

WO2023111924A1 - A system and method for statistical process management

Info

Publication number: WO2023111924A1
Application number: PCT/IB2022/062270
Authority: WO
Inventors: Amos Shavit
Original assignee: Amos Shavit
Priority date: 2021-12-19
Filing date: 2022-12-15
Publication date: 2023-06-22

Abstract

A system includes at least one module for statistical process management of various characteristics relating to an article. The system is arranged to adjust the values of the various characteristics to a notionally common scale so that the adjusted values can be graphically presented to a user.

Description

A SYSTEM AND METHOD FOR STATISTICAL PROCESS MANAGEMENT

TECHNICAL FIELD

[001] Embodiments of the invention relate to a system and method for statistical process management, for example in injection molding.

BACKGROUND

[002] Statistical process management relates to use of statistical techniques to control a process or production method, which may assist to monitor process behavior, reveal issues in internal systems, and find solutions for production issues.

[003] In quality control procedures that rely on statistical process management techniques, parameters involved in production of an article can be reviewed to ensure that they meet requirements set for example by standards, by a designer of the product (or the like).

[004] A variety of parameters can be monitored in quality control, such as the actual dimensions of a produced article. It is in normally impossible to exactly produce an article according to the predefined dimensions provided by a designer, and hence deviations from the nominal sizes that were designed cannot be avoided. As a result it is necessary to define measurement tolerances that define a range in which a recorded measurement can still be valid.

[005] In injection molding, shrinkage in the size of a molded part can occur due to contraction of the plastic part after it comes out of a mold cavity as it cools down after injection. Different materials have different shrink rates depending on the material type, mold design (and the like). [006] Therefore, when designing a part that is intended to be produced in an injection molded process, aspects such as the expected shrinkage of the part after molding should be taken into account in order to avoid deviating from the designed dimensions of the part and from its tolerances.

SUMMARY

[007] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

[008] In an embodiment there is provided a system and/or method comprising at least one module for statistical process management of various characteristics relating to an article, wherein the system being arranged to adjust the values of the various characteristics to a notionally common scale and to graphically present the adjusted values to a user.

[009] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE FIGURES

[010] Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying figures, in which:

[Oi l] Figs. 1 to 21 schematically show GUI’s of a software program implementing a system and/or method for quality control in accordance with various embodiments of the present invention. [012] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated within the figures to indicate like elements.

DETAILED DESCRIPTION

[013] Throughout the figures of the present disclosure, GUI’s (graphical user interfaces) of various computer software system embodiments may be illustrated that can be used for implementing methods for engineering, quality control and analysis procedures to dimensions, tolerances and measurement results in accordance with the present invention.

[014] The various GUI’s can be used for displaying information to a user, while allowing a user to perform various actions e.g. to data associated with or stored within the software.

[015] The computer software system embodiments disclosed herein may be used by quality engineers, designers, process engineers and quality control personal for a variety of production types, such as injection molding, for example plastic injection molding (and the like).

[016] Attention is drawn to Fig. 1 showing a GUI of an embodiment of a computer software system of the present invention. The GUI as here seen may be arranged to provide access to data within a library 10. The data may be upload into the software, and in any case may be stored within the software or may be associated with the software so that it can be accessed via the library.

[017] The library 10 may be organized to include a project window 101 where various projects may be selected, and each selected project within the project window 101 may include one or more parts that are displayed in a part window 102 that is situated in this example immediately below the project window 101. It is noted that the terms “project” and “part” as used should be broadly understood to possibly refer to other elements, such as “customer” instead or “project”, and the like.

[018] As seen e.g. in Fig. 2, the GUI may include also a module window 12 that is here situated immediately below the part window of the library. Within the module window 12 various modules available in this embodiment of the software may be displayed for selection by the user. The modules here displayed are ‘cavity’, ‘drawing’ and ‘production’, however in various embodiments of the invention other modules may be also available in addition or instead to those mentioned.

[019] By selecting a certain module, a user may gain access to software functionalities for interacting with the data relating to the part previously chosen within library 10. In the example seen in Fig. 2, the part chosen is ‘Part 1’ and the module chosen is ‘drawing’. The selection of the drawing module, in this example, causes the appearance of information associated with ‘Part 1’ within a graph window 14 and a data window 16 of the software’s GUI.

[020] Attention is additionally drawn to Fig. 2A that provides an enlarged view of the graph window 14 and the data window 16 seen in Fig. 2. Part 1 can be seen including several part dimensions here named 1 to 7. It is noted that in other embodiments, such ‘naming’ may take other form, such a “letters” (e.g. “a”, “b” etc.), words (e.g. “height”, “diameter” etc.) or any combination thereof. These part dimensions may be of any kind, such as: width, length, thickness, diameter (and the like).

[021] Data window 16 includes a lower section 161 where raw data of each part dimension may be exhibited and an upper section 162 where analysis functions associated with each part dimension, and which are executed on raw data of each part dimension, may be exhibited.

[022] Part dimension #7 for example as seen in lower section 161 has a drawing dimension (DD) of 28.3 millimeters with an upper tolerance (UT) (indicated: ‘Tol +’) of +0.1 millimeter and a lower tolerance (LT) (indicated: ‘Tol - ‘) of -0.1 millimeter. The ‘upper specification limit’ (USL) and the Tower specification limit’ (LSL) of part dimension #7 in this example may thus be 28.4 mm (i.e. DD+UT=28.3+0.1) and 28.2 mm (i.e. DD-LT=28.3-01), respectively. The computations executed on the raw data of part dimension #7 can be seen including the following values in upper section 162.

[023] Total tolerance (TT) is computed as the overall distance between the upper and lower tolerance limits (i.e. USL-LSL, in this example 0.2 millimeter). A value of central dimension (CD) is defined according to the median of the computation (USL+LSL)/2.

[024] In the example of part dimension #7, this median value of CD is 28.3 millimeters since the upper and lower tolerances are identical and therefore symmetrically distributed about DD. In part dimension #2 where the upper and lower tolerances are different, the CD median value is 11.24 millimeter (i.e. the median between the lower limit 10.6 and the upper limit 11.24) and therefore not identical to DD.

[025] Percentage of Tolerance (POT%) is computed as the percentage of the total tolerance (TT) from the drawing dimension (DD) of part dimension #7, i.e. 0.2 millimeter / 28.3 millimeter * 100 ~ 0.71%.

[026] Total Percent of Range (POR) expected (also termed expPOR in the figures) - is representative of the percentage of change that a produced part having a certain drawing dimension (DD) (here of part dimension #7) is expected to exhibit during production.

[027] In the case of production that involves injection molding, the expPOR value may be defined according to the expected difference of shrinkage of substantially all dimensions of produced parts, which may be affected by various parameters, such as the material of the part, mold temperature, melt temperature (and the like). In the example seen in Fig. 2A, a default value of 0.2% is assigned as the expPOR of all the part dimensions 1 to 7. It is noted that a user of the software may assign and/or change the expPOR of all part dimensions together and/or each one of the part dimensions independently.

[028] Deviation Expected (here termed Dev. Exp.) may be defined according to the following equation: Dev. Exp. = (1 - (TT - (expPOR * CD)) / TT) * 100. In dimension part #7, Dev. Exp. = (1 - (0.2mm - (0.2%*28.3mm)) / 0.2mm) * 100 = 28.3%. In dimension part #2, Dev. Exp. = (1 - (0.1mm - (0.2%* 11.2mm)) / 0.1mm) * 100 = 22.38%. It is noted that entering the numbers presented in data window 16 into the equations provided here above may derive slightly different results e.g. the Dev. Exp. of dimension part #2 will result in 22.4% (and not 22.38%) since not all digits of the numbers may be presented in data window 16.

[029] Graph window 14 includes graphical data that is based on the information presented in data window 16. The Y-axis is in percentage % and along the X-axis the various part dimensions, in this example 1 to 7, are exhibited.

[030] The graphical data provided in graph window 14 includes an upper line 14U and a lower line 14L that extend respectively along the +50% and -50% marks of the Y-axis. These upper and lower lines 14U, 14L therefore define the maximal range percentage wise (i.e. 100%) that a certain part dimension (and hence all part dimension here seen) may vary according to its (their) defined tolerances.

[031] The upper line 14U represents the maximal value that a given part dimension can vary according to its tolerance and the lower line 14L represents the minimal value that a given part dimension can vary according to its tolerance.

[032] In part dimension #7 this maximal value in millimeters is USL i.e. 28.4 (i.e. 28.3 + 0.1), and this minimal value in millimeters is LSL, i.e. 28.2 (i.e. 28.3 - 0.1), while e.g. in part dimension #2 this maximal value (i.e. USL) in millimeters is 11.24 (i.e. 11.2 + 0.04), and the minimal value (i.e. LSL) in millimeters is 11.14 (i.e. 11.2 - 0.06).

[033] By adjusting the values of the various part dimensions to a notionally common scale here defined by percentage, the distributions of various part dimensions, in this example of a certain selected project, can be viewed more easily. [034] As a result, a user of the software can view all the dimension parts one aside the other in the same graphical view and by that obtain valuable comparable insights between quality parameters associated to the various part dimensions.

[035] For example, a user can more easily identify which part dimension may be closer to its allowed tolerances and by that may choose to perform certain actions (such as modifying certain tolerances) or may choose to more closely monitor such a part dimension during quality assurance procedure as will be described herein below.

[036] In graph window 14 in addition, a line marked 14M extends along the 0% value of the Y-axis and each one of the vertical lines extending above the X-axis location of each one of the part dimensions 1 to 7 is indicated, respectively, as 14Vi (where i assumes the same digit of the part dimension it extends above).

[037] In the notionally common scale provided in graph window 14, line 14M passes through and represents the central dimensions (CD) of all the dimension parts 1 to 7 and each vertical line 14Vi represents the computed Dev. Exp. of its dimension part.

[038] Finally, adjacent each one of the vertical lines 14Vi, a process capability index of expected Cp (also termed Exp. Cp in the figures) may be indicated for each one of the part dimensions (1 to 7). A process capability index, is commonly used in statistical process management to define the ability of a process to produce a product that meets requirements. In this example, the value of Exp. Cp of each part dimensions is computed according to the equation: Exp. Cp = 100 / Dev. Exp.

[039] That is to say that Exp. Cp is computed by dividing the full range of 100% that a part dimension can vary between lines 14U and 14L by Dev. Exp. Generally, the higher the Exp. Cp is - the easier it may be to produce the part while not breaching its tolerances, and conversely the lower the Exp. Cp is - the harder it may be to produce the part while not breaching its tolerances. In other words, the longer the vertical line (which represent the Dev. Exp) the more difficult to meet the drawing requirements and vise versa. The vertical lines are arranged from left (the longer ones) to right (the shorter ones).

[040] With attention drawn back to Fig. 2, it is seen that the software’s GUI may include also a parameter window 18 where a user can choose the part dimension to be displayed and accessed in graph and data windows 14, 16; and an uploading window 20 for uploading and/or allowing access to data relating to various modules of the software.

[041] Attention is drawn to Figs. 3 and 4 to further review additional functionalities that may be accessed in at least certain computer software system embodiments. In this example, the software’s GUI can be seen including a ‘steel safe’ toggle 22 that when activated may prompt the software to present additional data within lower section 161 of data window 16, which are marked within the ‘dotted’ rectangle 163.

[042] The ‘steel safe’ functionality in at least certain embodiments of the invention, is aimed at assisting a designer/user in increasing the likelihood that changes made to the design of a part being produced by injection molding, will preferably require only removal of metal in the part’s mold in order to produce the desired geometry. Such changes are typically important to monitor when e.g. a dimension of a part is changed after the mold has been manufactured, since then the mold can be modified rather than requiring adding steel or mold part replacement, which are more complex and expensive processes for such modifications.

[043] In Fig. 4, part dimension 7 can be seen being marked with the letter ‘E’ indicating it as an external dimension, while part dimension 5 can be seen being marked with the letter T indicating it as an internal dimension. The designation of part dimension 7 as an external dimension can be seen in this example prompting a minus 25% steel safe value being assigned to part dimension 7, while the designation of part dimension 5 as an internal dimension can be seen in this example prompting a plus 25% steel safe value being assigned to part dimension 5. [044] These modifications in rectangle 163 to data related to part dimensions 7 and 5, can be seen in graph window 14 as resulting, respectively, in the downwards and upwards shifts that are performed to the vertical lines 14V? and MV5 that accordingly represent the expected deviation (Dev. Exp.) of these dimension parts.

[045] By indicating respective part dimensions as ‘Internal’ or ‘External’, a user of the software system can be presented with visual feedback in graph window 14 that may assist in performing possible changes to data of such dimension parts prior to the production of the mold, which are aimed at increasing excess material within the mold for possible removal if corrections to the mold will later be necessary.

[046] Fig. 5 exemplifies a possible change in the steel safe value of dimension part 7 in this example to minus 40% while notably any other number may also be possible (instead of minus 25% as in Fig. 4). This results in computation of a new recommended Steel Safe defined value e.g. for dimension part 7, in this example being 28.22 millimeter (i.e. computed according to: CD (here 28.3mm) minus 40%)). Vertical line 14V? of this dimension part 7 can thus be seen being shifted further downwards towards lower line 14L according to this new recommended value for dimension part 7.

[047] Such change in the steel safe value may be performed by the designer e.g. because a certain dimension (e.g. #7) may have been identified as critical according to his/her experience, and in an attempt to ensure that sufficient material is available in the mold in case possible changes to the mold cavity may be deemed necessary later on during initial trials of the mold.

[048] In Fig. 6 a state of the software system can be seen after the user chose ‘cavity’ module from within module window 12 and pressed in this example the ‘production’ and ‘production data’ buttons (see marked in ‘double lined dashed’ rectangles). By choosing/pressing these buttons in this optional example, a production phase of the software is reached where measurements in this example of part dimensions 1 to 7 performed on parts produced by a mold can be accessed. This mold may be the same mold designed in the previous phase described with respect to Figs. 3 to 5 (but not necessarily).

[049] The software as seen in Fig. 6 can be prompt to present additional data points within the lower section 161 of data window 16, which are marked within the ‘dotted’ rectangle 164. These data points are of measurements of part dimensions 1- 7 that were performed on identical parts that originated in this example from four different cavities of the mold. The numbers of these cavities in this example are 9, 10, 11 and 12 as seen in the left hand side column of ‘dotted’ rectangle 164.

[050] As seen, for each part dimension now a batch (BA) in this example of four measurements are provided, each originating accordingly from a different cavity of the mold. For the measurement batch (BA) associated with part dimension 7 these measurements are: 28.27 mm (cavity 9), 28.25mm (cavity 10), 28.26mm (cavity 11) and 28.3 mm (cavity 12). As seen, color coding’s may be provided indicating the lowest and highest results.

[051] In graph window 14, such batches (BA’s) of production results obtained for each given part dimension are indicated on the right hand side of the respective vertical line 14Vi associated with the given part dimension. The horizontal line provided for each batch indicates the average value of the batch.

[052] As seen in this example with respect e.g. to part dimensions 6, 2 and 1 - the difference between the batch (BA) of the four measurements performed on these part dimensions (accordingly from four different cavities), exceeds the theoretical expected deviation (Dev. Exp.) previously computed for these part dimensions in the previous drawing module phase of the software. The maximal difference between such measurements will be defined herein as Max. Diff.

[053] As seen in Fig. 6, an added POR% value is assigned to each part dimension 1 to 7 in this example within lower section 161 of data window 16. The added POR% is computed from the batch (BA) data of each part dimension, according to the following equation. Added POR% = ((max value of a BA - min value of a BA) / (average of a BA)) * 100. In the example of dimension 2, added POR% = ((11.22-11.18)/(11.2))*100 = 0.357% (and rounded in Fig. 6 to 0.36%).

[054] As seen, in the cavity mode of the software, the parameter POR Act% in upper section 162 of data window 16 is assigned with the same value of the added POR%.

[055] Fig. 7 illustrates that by pressing the ‘Calc Added POR%’ toggle (seen in the lower right hand side of the GUI) - changes can be performed to extend all the vertical lines 14Vi (accordingly previously representative of the respective Dev. Exp. values) of these dimension parts according the batches (BA’s) of real measurements that were performed on parts produced by the different cavities.

[056] These changes to the vertical lines 14Vi are performed by adding for each part dimension, the previously computed added POR% value to the default value (here of 0.2%) of the expPOR parameter - in order to derive a Tot. POR Exp% value (see indicated in upper section 162 of data window 16) according to which the vertical line 14 Vi of each part dimension is drawn. As illustrated in the enlarged section provided in the upper left hand side of Fig. 7 - in the cavity mode of the software, the Tot. POR Exp% value is in this example takes into account the POR Act% values in its creation.

[057] Pressing the ‘Save Data’ toggle as seen in Fig. 8, can re-arrange the data points in graph window 14, so that the data points will be sorted from left to right according to a descending value of Tot. POR Exp%.

[058] As seen in Fig. 9, activating the ‘Prod Norm’ toggle (see marked by dotted arrow), can shift the averages of the batches (BA’s) of measurement results of each one of the part dimensions to a position where they are each centrally placed along line 14M that extends along the 0% value of the Y-axis.

[059] As seen, this action may also bring the averages of the corresponding NDE’s associated with each such batches to also lie on line 14M. This action of shifting the averages of the BA measurement results is performed according to a Corr, to Central parameter (CTC) that can be seen in Fig. 9 in line 5 of the analysis information presented in upper section 162.

[060] The CTC parameter is computed by deducting the value of an average of batch (BA) from its central dimension (CD). In the example of part dimension #7 CTC is equal 0.03 mm according to 28.27 mm (the average of this part dimension’s batch (BA)) minus CD i.e. 28.30 mm.

[061] The value presented on the right hand side of each one of the Tot. POR Exp% values, represents the CTC change needed in the mold in order to bring the averages of BA measurements to center line 14M. This CTC change can alternatively instead of being applied to the BA measurements (i.e. to the mold) may be applied instead to the drawing dimensions (DD’s) of the part dimensions. It is noted that such corrections according to the CTC parameter can be performed if such change does not affect functionality of the part being produced.

[062] In the discussion herein below, methods for quality assurance not necessarily relating to physical part dimensions may be addressed. For example, reference herein below to ‘part dimension’ may be understood in certain embodiments to relate to a certain objective (e.g. measured) specific characteristics of a produced article, such as hardness (e.g. according to the Brinell scale or the like), surface quality (e.g. roughness) (such as those defined in the BS EN ISO 4287:2000 British standard, identical with the ISO 4287: 1997 standard, or the like), PH values (e.g. in the food and chemistry industries, or the like), etc.

[063] Thus, in certain software embodiments, the ‘production’ module of the software may be used by its own for analyzing real obtained data not necessarily arriving from the previous ‘modules’ described herein above.

[064] Attention is drawn to Fig. 10 where ‘production’ module has been selected in module window 12, and Production data toggle is pressed. This figure can be seen in graph window 14 showing an example where each part dimension (or possibly any other objective characteristic) is provided in this example with a batch (BA) of physical measurements of seven part dimensions in this example numbered 1, 2, 3, 5, 6, 7 and 8. Pressing the ‘Save Data’ toggle as seen in Fig. 11, can rearrange the data points in graph window 14, so that the data points will be sorted from left to right according to a descending value of the Tot. POR Exp%.

[065] In certain embodiments, data relating to measurements may be uploaded into the software, and in any case may be stored within the software or may be associated with the software so that it can be accessed via the library. In certain other embodiments, data relating to measurements may be entered in real time by a user into the software.

[066] With respect to part dimension 3 in this example, a concern may arise that measurement mistakes may have caused an actual POR% distribution of 2.19% that is substantially larger than the expected POR% of 0.64% (see these values indicated in the dashed rectangle provided in Fig. 11).

[067] A user of the software system may explore by changing the default expected POR% value to 0.6% (as seen in the dashed rectangle marked in Fig. 12) - which part dimensions may have a small likelihood of breaching their tolerances. As seen in graph window 14 of Fig. 12, part dimensions 1, 3, and 8 (see indicated in the dotted rectangle), have a small likelihood of extending outside of their respective tolerances - and thus such user may decide upon such experimentation that fewer or no measurements are needed for these part dimensions in future produced parts.

[068] Actual POR% results may be exhibited within graph window 14 as seen in Fig. 13 by assigning a ‘V’ to the POR% option as seen in the dashed rectangle provided in this figure. By assigning a ‘V’ to the Cpk option as seen in the dashed rectangle provided in Fig. 14 - such Cpk data may also be indicated within graph window 14. SPC data can also be indicated in graph window 14 by pressing the SPC button as indicated in the dashed rectangle provided in Fig. 15.

[069] In an aspect of the present invention, comparisons between various criteria may be performed by at least certain software system embodiments. For example, the pop-up window provided in Fig. 16 exhibits several possible comparisons that may be performed, while a chosen comparison in this example is the name of person performing measurements on the part dimensions.

[070] Such a comparison can be seen in Fig. 17 where data related to the name of person performing the measurements is exhibited in graph window 14. The comparison can be made by pressing the ‘comparison’ toggle as seen in the lower right dashed rectangle provided in Fig. 18.

[071] As seen in Fig. 19, a user operating the software can be provided with a pop up window for selecting names and/or production series to compare between - where in Fig. 20 such comparison can be seen being provided.

[072] In this example two dimensions (7)x and (7)y are selected, which are measured by 5 different people, in the same production series (19734750). This information can be used to help a quality control manager teach the staff to measure the dimension properly.

[073] As seen in Fig. 21 further details here regarding the measurement tools being used can be also provided via the software. Provision of such details may assist e.g. in detecting a possible measurement tool that may be the cause for certain measurements that e.g. fall outside of tolerances - possibly hinting for possible problems with the tool and not the actual dimensions that is examined.

[074] In certain embodiments of the present invention, the software may be configured to alarm that a certain measured objective characteristic has been breached e.g. by exceeding its expected tolerances. Such breach may also be due to errors in measurements performed by quality assurance personal as discussed above. Such errors may be due to various causes, such as a malfunctioning measurement tool, human error, miss typing, measurement of a wrong objective characteristic. Also, an error in production may obviously be the cause.

[075] In certain cases, an alarm may be set by a user of the software according to criteria he/she defines. For example, such criteria may be defined as following: if in a certain batch (BA) of measured characteristics, only one of the measurements is located at a distance of about above 2 sigma from the average value of the batch (BA).

[076] In certain embodiments, such alarm by the software may be in real time (e.g. as close as possible to the occurrence) - e.g. in order to warn the quality assurance personal of the detected problem, so that he/she may react in real time, by e.g. re-measuring the objective characteristic (or the like), stop the production, etc.

[077] In certain embodiments of the present invention, the software may be configured to communicate with a manufacturing execution system (MES) in order to present within the MES system relevant quality data, besides e.g. production data presented in the MES system.

[078] In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.

[079] Further more, while the present application or technology has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and non- restrictive; the technology is thus not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed technology, from a study of the drawings, the technology, and the appended claims.

[080] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures can not be used to advantage.

[081] The present technology is also understood to encompass the exact terms, features, numerical values or ranges etc., if in here such terms, features, numerical values or ranges etc. are referred to in connection with terms such as “about, ca., substantially, generally, at least” etc. In other words, “about 3” shall also comprise “3” or “substantially perpendicular” shall also comprise “perpendicular”. Any reference signs in the claims should not be considered as limiting the scope. [082] Although the present embodiments have been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.

Claims

CLAIMS:

1. A system comprising at least one module for statistical process management of various characteristics relating to an article, wherein the system being arranged to adjust the values of the various characteristics to a notionally common scale and to graphically present the adjusted values to a user.

2. The system of claim 1, wherein the at least one module comprises a drawing module and the various characteristics are various part dimensions of a designed article.

3. The system of claim 2 and being arranged to present to the user data relating to the various part dimensions, wherein the data comprises raw data associated with each part dimension and results of analysis functions that are applied on at least some of the raw data.

4. The system of claim 3, wherein the raw data associated with each part dimension comprises a drawing dimension (DD), an upper tolerance (UT) and a lower tolerance (LT).

5. The system of claim 4, wherein analysis functions applied on raw data of at least some of the part dimensions comprises deriving an upper specification limit (USL) that is equal to DD+UT, a lower specification limit (LSL) that is equal to DD-LT, a total tolerance (TT) that is equal to USL-LSL, and a central dimension (CD) that is equal (USL+LSL)/2.

6. The system of claim 5, wherein a Percentage of Tolerance (POT%) value is equal to TT / DD * 100.

7. The system of claim 6, and being arranged to receive for at least certain part dimensions a Total Percent of Range expected (expPOR) value that is the percentage of change that a drawing dimension (DD) of a part dimension is expected to exhibit during production.

8. The system of claim 7, wherein in production that involves injection molding, the expPOR value is the expected difference due to shrinkage of the produced article.

9. The system of claim 8, wherein the received expPOR value is initially set in the system as a default value for all part dimensions of a certain similar article.

10. The system of claim 9 and being arranged to allow manual changes to the default expPOR value.

11. The system of claim 7, and being arranged to compute a Deviation Expected (Dev. Exp.) value according to the equation: Dev. Exp. = (1 - (TT - (expPOR * CD)) / TT) * 100.

12. The system of claim 11, wherein values graphically presented to the user in the notionally common scale are based on raw data and/or results of analysis functions applied on raw data, and the graphical presentation is generally in form of a bar chart comprising a Y-axis in percentage % and an X-axis along which data relating to various part dimensions is exhibited.

13. The system of claim 12, wherein values graphically presented to the user comprise an upper line (14U) and a lower line (14L) that extend respectively along the +50% and -50% marks of the Y-axis, wherein the upper and lower lines 14U, 14L define the maximal range percentage wise (i.e. 100%) that a certain part dimension may vary according to its defined tolerances.

14. The system of claim 13 and comprising a middle line (14M) that extends along the 0% value of the Y-axis and a plurality of vertical lines (14Vi), wherein each vertical line extends above a respective one of the part dimensions and is representative of the part dimension.

15. The system of claim 14, wherein middle line 14M passes through and represents the central dimensions (CD) of all the dimension parts, and each vertical line 14Vi represents the computed Dev. Exp. of the dimension part it extends above.

16. The system of claim 15 and being arranged to indicate adjacent each vertical live 14 Vi of a certain part dimension, an expected Cp (Exp. Cp) value of the part dimension that is computed according to the equation: Exp. Cp = 100 / Dev. Exp.

17. The system of claim 16 and being arranged to sort appearance of the part dimensions along the X-axis according to descending or ascending order of the Dev. 19

Exp. values associated with each part dimension and represented by to the vertical line 14 Vi of the part dimension.

18. The system of claim 14, wherein the at least one module comprises a cavity module and the cavity module comprising a steel safe (SAFE) functionality for assisting in guiding and/or monitoring changes made to data relating to part dimensions of an article being produced by injection molding, wherein activation of the SAFE functionality prompts a user of the system to indicate for each part dimension if it is an external (E) dimension or an internal (I) dimension.

19. The system of claim 18, wherein indicating a given part dimension as external (E) or internal (I) is adapted to shift the vertical line 14 Vi of the given part dimension downwards or upwards, respectively.

20. The system of claim 18, wherein the at least one module comprises also a production module and the various characteristics are various part dimensions of a produced article.

21. The system of claim 20, wherein each given part dimension being associated with a batch (BA) of several measurements of the same given part dimension but on different produced articles.

22. The system of claim 21, wherein the different produced articles originate from different cavities of a similar mold.

23. The system of claim 22 and being arranged to indicate to the user a lowest and highest measurement within a certain batch (BA).

24. The system of claim 21 and being arranged to indicate a batch (BA) of results of a given part dimension adjacent the vertical line 14 Vi of the given part dimension.

25. The system of claim 24 and being arranged to indicate also an average value of each batch (BA) adjacent the vertical line 14 Vi of the given part dimension.

26. The system of claim 25 and being arranged to compute an added POR% value from each batch (BA) of measurements of a given part dimension according to the 20 equations: added POR% = ((max value of a BA - min value of a BA) / (average of a BA)) * 100.

27. The system of claim 26 and being arranged to extend the vertical line 14Vi of each given part dimension according to a Tot. POR Exp% value that is derived for a given part dimension by adding the added POR% value of the given part dimension to the expPOR parameter of the given part dimension.

28. The system of claim 27 and being arranged to sort appearance of the part dimensions along the X-axis according to descending or ascending order of the Tot. POR Exp% values associated with each part dimension and represented by to the extended vertical line 14Vi of the part dimension.

29. A system comprising a production module for statistical process management of various measured characteristics relating to a produced article, wherein the system being arranged to adjust the values of the various characteristics to a notionally common scale and to graphically present the adjusted values to a user, wherein the characteristics are any one of hardness, surface quality, PH values, part dimension (or the like).

30. The system of claim 29, wherein the measured characteristics are uploaded and/or stored within the software and/or associated with the software so that they can be accessed via the library and/or inputted possibly in real time by a user into the software.

31. The system of claim 30 and comprising at least one criteria type that is associated with each measured characteristic, wherein the system being configured to compare between similar criteria types of different characteristics of a produced article.

32. The system of claim 31, wherein the at least one criteria type is the name of the person that measured a characteristic of a produced article.

33. The system of claim 32, wherein the comparison is between articles that are produced in the same production series. 21

34. The system of claim 31, wherein the at least one criteria type is the measurement tool used to measure a characteristic of a produced article.

35. The system of claim 34 and being arranged to alarm that a measured characteristic has been breached, for example by exceeding its expected tolerances.

36. The system of claim 35, wherein criteria defining an alarm may be set by a user of the software.

37. The system of claim 26, wherein an alarm is configured to be activated in real time, e.g. as close as possible to detection of a breach.

38. The system of claim 29 and being configured to communicate with a manufacturing execution system (MES) in order to present within the MES system data of relating to measured characteristics of produced articles.