Electronic circuit board test device design

Abstract

Design of electronic circuit board test device The description relates to the manufacture of a test stand for an electronic circuit board to be tested, the test stand comprising at least: - A shell (11, 12) intended to house the board to be tested and having holes (121) intended to be passed through by conductive needles (3) at one end of which are intended to be in contact with test points of the board to be tested, and - A test housing (14), containing a test circuit (16) having contact points (162) homologous to the test points of the board to be tested and intended to be in contact with each other of said ends of the conductive needles.A process is planned comprising at least the following steps: - Obtaining at least one file of relative position data of the test points of the board to be tested, and a geometry data file of the board to be tested, - Based on at least said data and predefined rules of interaction at least between the board to be tested and said shell, developing a three-dimensional computer model of the shell and the housing, including at least position data of said holes, and - Generating a manufacturing control signal for the shell and the housing, including data from said computer model. (FIG. 1).

Description

Title of the invention: Design of an electronic circuit board testing device technical field

[0001] This description relates to the design of an electronic circuit board (or "PCB" for "Printed Circuit Board") test device. Previous technique

[0002] PCB test points are small, relatively small metallic contacts located on one or both sides of the board. They allow designers to electrically access the board components to ensure they are functioning correctly. Examples of tests that can be performed include: - continuity tests (to verify that the connections between the various components and traces on the PCB are correct and to detect any short circuits, open connections, or other problems), - voltage tests (at different parts of the circuit to ensure they conform to predefined specifications). - resistance tests (to detect faulty or poorly soldered resistors), or capacitance tests (to detect faulty capacitors for example), - etc.

[0003] These test points can also be used for the programming of the board itself. In what follows, the term "test" refers to both test actions of the aforementioned type (of the board components) and programming or calibration actions of the board.

[0004] The test points can be represented by metallized pads, not covered by a protective and electrically insulating layer (known as a "solder mask") on the board to be tested. The test points are then accessible by an external test probe, referred to hereafter as a "needle." Generally, these points are predefined according to a specific test setup.

[0005] Essentially two types of test device are known today: - A device with mobile probes, movable from point to point to test the map: an example of such a device is illustrated for example in document WO2021023744; - A device with fixed probes, generally in the form of metal needles fixed in predefined positions according to the specific test setup, to connect the test points of the board with respective points of a test control circuit, hereinafter referred to as the "intermediate PCB". An example An example of such a device, hereafter referred to as a "test stand", is illustrated in document WO2004017081.

[0006] Such a test foot typically comprises: - in an upper part, a compartment to accommodate the board to be tested, and - in a lower part, a test box in the form of a chassis housing, for example, an intermediate PCB.

[0007] The card and the intermediate PCB are thus separated by at least one wall through which the metal needles pass in order to achieve their interconnection.

[0008] In the example of document WO2004017081, a plate 80 has holes 100 for this purpose (visible in Figures 4 and 6 of the cited document WO2004017081), and thus through which needles 102 pass. A lever activable by an operator and which appears to the left of [Fig.2] of the same document WO2004017081, makes it possible to apply pressure to the board to be tested against the test box, and more precisely to bring the test points of the board to be tested into contact with the corresponding contact points of the intermediate PCB, via the conductive needles 102. These needles are generally cylindrical in shape housing a rod mounted against a spring.

[0009] However, it appears that this type of test stand (as illustrated generally in [Fig.2] of this same document) offers little modularity and flexibility for testing different types of cards, possibly having different dimensions.

[0010] Furthermore, this test stand provides alignment zones for the card under test, consisting of holes in the card allowing the insertion of alignment and holding pins fixed to the test stand. The bulk created by these zones typically prevents the testing of small cards.

[0011] More generally, a test stand (with its intermediate PCB and predefined contact points) is only suitable for testing a single type of board. If the board type is different, another test stand must be designed. Currently, test stands are expensive, and designing one can be time-consuming (several months). If it is ultimately decided to modify the board or the positions of its test points, it is then necessary to design a new test device adapted to these modifications. Summary

[0012] The present description improves the situation.

[0013] A computer-based method is proposed for this purpose, for manufacturing a test stand for an electronic circuit board to be tested, the test stand comprising at least: - A casing designed to house the board to be tested, comprising holes for conductive needles to pass through, one end of which is intended to make contact with test points on the board to be tested, and - A test enclosure, containing a test circuit (or "intermediate PCB" hereinafter) having contact points corresponding to the test points of the board to be tested and intended to be in contact with each other at the ends of said conductive needles, The process includes at least the following steps: - Obtain at least one file of relative position data for the test points on the map to be tested, and one file of geometry data for the map to be tested. - En fonction au moins desdites données et de règles prédéfinies d'interaction au moins entre la carte à tester et ladite coque, élaborer un modèle informatique en trois dimensions de la coque et du boitier, comportant au moins des données de positions desdits trous, et - Generate a manufacturing control signal for the shell and casing, containing data from said computer model.

[0014] The term "board of an electronic circuit to be tested" refers to the board with its components. Thus, the aforementioned geometry data file of the board to be tested allows, at the very least, the determination of the board's contours with its components in order to develop the three-dimensional computer model of the casing, at least to conform to these contours. However, this terminology is not exhaustive and can also refer to the bare board without components (or with a minimum number of components for initial testing), and even the thickness of the board alone can be considered to adjust the dimensions of the internal housing of the casing, intended to accommodate the board to be tested.

[0015] Thus, the aforementioned casing can form a receptacle for the board to be tested, and the shape of this receptacle can closely follow the 3D contour of the board and its assembled components. It is even possible to use the components as support points for the board to prevent it from tipping over when the needles apply pressure to the board during testing (as will be seen later, for example, in the comments on Figures 6 and 7). Conversely, it is possible to avoid pressure on certain components that may be fragile and therefore potentially provide protective stops made by adding material directly inside the casing (as described later with reference to Figures 6 and 7).

[0016] In one embodiment, the relative position data file of the test points of the map is extracted from a standard file (for example of type “Gerber”), describing layers of the map to be tested, the relative position data being extracted from at least one end layer of the standard file (“top layer” or “bottom layer” for example of a Gerber file).

[0017] In one embodiment, the geometry data file may include three-dimensional coordinates of geometric elements of the map to be tested, the computer model being generated from contour data of said geometric elements.

[0018] This file can be, for example, a ".step" type file giving such a geometric contour (or "outline").

[0019] The aforementioned predefined interaction rules may include at least one constraint on the mechanical stability of the card in the shell, the development of the computer model then taking into account said stability constraint to avoid a tipping of the card in the shell during a testing phase.

[0020] In such an embodiment, the process may include: - determine if a local density of needles intended to be in contact with the card is greater than a threshold, and if the needles of said local density are distant from an axis of possible tipping of the card in the shell during a testing phase, - in case of density greater than the threshold and if the needles of said local density are distant from said tipping axis, provide a means of retaining the card in the shell to prevent said tipping.

[0021] For example, the retention means may include at least one protrusion provided on an internal face of the shell, against which the card is intended to come to rest when the card is subjected to pressure from the needles of said local density greater than the threshold.

[0022] These protrusions can be materialized by blocks added to the surface of the hull to form support areas for the card (or a component of the card) in areas where necessary to prevent tipping.

[0023] Such an example of an embodiment is illustrated in Figures 6 and 7, which are discussed later.

[0024] Alternatively, it is possible to choose needles with higher spring stiffnesses, or greater lengths, in such areas compared to the needles provided in the area of ​​said local density. For example, needles with different Newton-meters of stiffness can be distributed to mitigate these mechanical risks of tipping.

[0025] In one embodiment, said predefined interaction rules may include at least one constraint on inserting the card to be tested into the shell with a permissible displacement clearance of the card to be tested within the shell, less than a threshold. Thus, the computer model of the shell can be determined with dimensions greater than a contour of the card to be tested, but with a difference between the dimensions of the shell model and the contour of the card corresponding to this displacement clearance.

[0026] The tolerance of the play is preferably less than a few tenths of a millimeter, for example, corresponding to a constraint of alignment of the test needles with the test points of the card.

[0027] In addition, the computer model of the test box may include a housing for an electronic circuit board (or "intermediate PCB") containing the test circuit.

[0028] To maintain the alignment of the needles with the test points of the intermediate PCB, the same tolerance mentioned above can be applied for the positioning of the intermediate PCB in the test housing.

[0029] In one embodiment, the process may further include the execution of software to check whether said computer model complies with the aforementioned predefined rules, and to animate a human-machine interface to warn a user of a non-compliance with these predefined rules.

[0030] For example, the human-machine interface can emit a signal recommending an alternative arrangement of the test points of the board to be tested.

[0031] It can also be checked whether a test point is geometrically close to an edge or component of the board to be tested, so that the human-machine interface is animated if a distance between a test point and an edge or component of the board is below a threshold.

[0032] Typically, such an implementation makes it possible to limit mechanical stresses at the edge of the board, or near a component likely to interact mechanically with a test needle. The positioning tolerance of a needle relative to the board can, again, be taken into account to trigger an alert via the human-machine interface.

[0033] However, these checks are given here as an example, other implementations being possible.

[0034] For example, it can be further checked whether a plurality of test points are mutually close, so that the human-machine interface is animated if a spatial density of test points on the map is above a threshold.

[0035] Such an implementation makes it possible, where appropriate, to limit mechanical constraints (with the risk of the card tipping over, for example), but also local thermal constraints with local heating likely to degrade the card (and / or the intermediate PCB as well).

[0036] In one embodiment, the computer model may provide a recess in the housing, in order to form a slide for inserting a pressure element of the shell against the housing.

[0037] Such a pressure member may be of the type called “grasshopper” and typically illustrated in [Fig.4].

[0038] Alternatively, it may be any other means of compression retention, such as a simple toggle, a slide, or other.

[0039] In one embodiment, the computer model of the test box includes an opening, in order to accommodate a connection element of the test circuit to a test machine.

[0040] Such a connector is illustrated on the same [Fig.4] and is there designated as 161.

[0041] In one embodiment, this opening is defined according to the dimensions of the connection element to be provided, a forecast of the connection element being determined according to a descriptive file of types of tests to be carried out on the card to be tested (file of type "Netlist" for example), this descriptive file of types of tests being obtained in addition before the development of the computer model.

[0042] This Netlist file may be required, for example, in an embodiment where the connector must be harmonized with measuring devices downstream of the test pin, in which case the aforementioned Netlist file is provided by a designer of the board to be tested, for example. The Netlist file then details the assignment of each point of the connector ("pinout") and thus allows the intermediate PCB to be designed to connect each point of the connector to each test pin.

[0043] Alternatively, the connector may not be imposed, in which case an execution of the aforementioned software may establish the Netlist file and propose a connector by describing its complete "pinout".

[0044] Once the computer model has been validated with respect to the aforementioned constraints, it is possible to generate the aforementioned control signal for manufacturing the shell and the casing. For example, this control signal can be transmitted to a 3D printer for additive manufacturing of the shell and the casing from the data of said computer model.

[0045] This description also relates to a test box and a shell of an electronic circuit board to be tested, and a test stand, obtained by implementing the above process.

[0046] Typically, traces of implementation of the above process on these elements can be, for the shell, an adaptation of the dimensions of the inside of the shell to those of the card to be tested (relative to its thickness and possibly to its relief with its components), and, for the test box, an adaptation of the gripping lugs (reference 144 of [Fig.1]) of the shell (11, 12) on the test box.

[0047] Another possible trace of implementation of the process on the hull for example is the presence of a protuberance forming a stop to prevent the card from tipping typically.

[0048] This description also relates to a computer program comprising instructions for implementing the above process, when executed by a processor.

[0049] Typically, this program (corresponding to the aforementioned "software") can be executed by a SER server, with the cooperation of a client IT entity EC, as illustrated in [Fig.5] discussed in detail later. Brief description of the drawings

[0050] Other advantages and features of the embodiment presented above will become apparent upon reading the detailed description of examples of embodiments below and upon examination of the accompanying drawings, in which: - Fig. 1 is an overview of a test setup, of the test stand type, - Fig. 2 illustrates the use of GERBER and 3D volume files for the development of a MOD model, here of a lower half-shell 12B, - Fig. 3 illustrates another example of a board to be tested and the suitable half-shell model 12C for this board, - Fig. 4 is a rear view of the test foot illustrating in particular the pressure member (or "grasshopper" SAU) to be plugged into the test box, as well as the connection member 161 of the test circuit 16 of Fig. 1. - Figure 5 illustrates a computerized system architecture including a SER server, for implementing the process in an example embodiment; - Figure 6 illustrates a first embodiment for adding a stop 122 to the lower half-shell 12, preventing the PCB under test from tilting under the pressure of the pins 13; and - Fig. 7 illustrates a second embodiment for adding a stop 112 here on the upper half-shell 11, also preventing the PCB to be tested from tilting under the pressure of the needles 13. Description of the implementation methods

[0051] With reference to [Fig. 1], the test stand, in the described example, comprises a rigid shell made up of two half-shells 11 and 12 for enclosing the board to be tested (not shown in [Fig. 1]). The test stand further comprises a test housing consisting of a body 14 and a base 15 for enclosing the test board 16, or "intermediate PCB". The test board 16 includes a connection element 161 for connection to a test machine (not shown).

[0052] The test card 16 further includes connection points 162, intended to be in contact with the lower ends of the test needles 13, which are illustrated in [Fig. 1], between the half-shell 12 and the body 14 of the test housing. For this purpose, the body 14 of the housing has through holes 143 so that the lower ends of the needles 13 can come into contact with the points 162 of the test card 16. Similarly, the half-shell 12 has through holes 121 so that the upper ends of the needles 13 can come into contact with the points of Testing the test board. The test board is not shown in [Fig. 1] to avoid cluttering this figure. However, it can easily be understood from [Fig. 1] that the test board is intended to be enclosed between the two half-shells 11 and 12, so that one of the (lower) faces of the test board has test points in contact with the upper ends of the pins 13. This arrangement is also illustrated in Figures 6 and 7 (cross-sectional illustrations) where the test board is labeled "PCB".

[0053] As further illustrated in [Fig. 1], the half-shells 11 and 12 have respective notches 114 and 124 which slide into retaining lugs 144 in the body 14 of the housing. This design allows the board to be enclosed between the two half-shells 11 and 12 and the resulting rigid shell to be slid between the lugs 144 of the lower housing 14. The tolerance clearance between the lugs 144 on the one hand, and the notches 114 and 124 on the other, is less than a few tenths of a millimeter in order to mechanically hold the shell and the board to be tested without movement in practice on the test stand.

[0054] For its part, the test card 16 is enclosed between the body 14 and the base 15 of the test box for example by screwing (via the screw holes 151 of the base in particular).

[0055] The body 14 of the test housing further includes a window 141 to allow the passage, in the example shown, of a light beam from, for example, an optical fiber connected to a laser diode in order to perform tests in the presence of illumination (for example, at desired wavelengths) of the board to be tested. For example, one end of the fiber can be inserted into the window 141 and / or into one of the pinholes 121 to emerge into the housing, and illuminate, for example, a component of the PCB having photovoltaic or optoelectronic properties (such as the PCB illustrated in [Fig. 3] discussed later).It will then be understood that the design of the test stand, and in particular the casing with possibly a needle hole 121 that is possibly larger than the other holes to allow a fiber to pass through, must comply with the aforementioned predefined rules, particularly in terms of the nature of the components to be tested in relation to the tests to be carried out on the board.

[0056] Furthermore, the body 14 of the test housing includes a slide 142, also visible in [Fig. 4], for receiving the foot of a pressure member (or "hopper") SAU, having a pressure head PRE intended to be pressed against a depression 110 formed on the top of the upper half-shell 11. Such an embodiment makes it possible to maintain the mechanical stability of the board to be tested in the shell despite the pressure that the pins 13 may exert on the board to be tested. Typically, as illustrated in Figures 6 and 7, the pins 13 may have points mounted on springs that are under pressure when the board The PCB to be tested is applied against the needles 13 by the action of the SAU pressure organ.

[0057] It is thus understood that efforts must be made to avoid as much as possible any movement of the card to be tested in the casing, particularly during the testing phase, in order to ensure contact of the needles with the corresponding test points of the card to be tested.

[0058] The present description then proposes an implementation aimed at achieving this goal.

[0059] With reference to [Fig.2], another example of the PCB test board has been illustrated in the upper part, and in particular the face of the board having test points to be connected to the pins 13. This PCB board must be inserted in particular into a half-shell 12 (bearing the reference 12B at the bottom of [Fig.2]), limiting as much as possible any play in the movement of the PCB board in the half-shell 12.

[0060] To this end, with reference again to [Fig.2], at least two types of numerical data are obtained to produce the half-hull 12 (and possibly the half-hull 11): - GER#TOP test point data (right-hand side of [Fig.2]), taken from a file containing the entire PCB design without its electronic components, typically a GERBER (or "ODB") format file, and - 3D volume data of the PCB to be tested, from which can be determined in particular the dimensions and positions of the components assembled on the board (left part of [Fig.2]), typically present in a file in STEP or STL format (for example according to the ISO 10303-21 standard).

[0061] The GERBER file contains all the structural data of the PCB, including an end layer (“TOP” or “BOTTOM”) indicating the relative positions of the test points on one side of the board, as illustrated on the right-hand side of [Fig. 2]. Under this first end layer (“TOP,” for example) indicating the relative positions of the test points: - another layer can indicate the 2D outline of the map (reference OUTL in the middle of [Fig.2]), with its precise dimensions, - another layer can indicate the circuit traces on the board (not used here), - another layer can indicate the board components connected by the aforementioned traces (not used here), etc. - and a final end layer (“BOTTOM”) again contains relative positions of test points but on a face of the map, opposite to that of the first layer (not used in the example described here).

[0062] The GERBER file thus allows the positions of the holes in the MOD model of the half-shell 12B to be defined, as well as its contour dimensions.

[0063] As will be seen later with reference to [Fig. 5], in one embodiment, a SER server is configured to extract this OUTL contour and test point position information from the GERBER file and can thus verify that the OUTL contour is indeed closed, even if it has complex shapes, particularly internal holes relative to the external contour. The SER server can also identify a local concentration of test points that requires specific processing for generating the MOD computer model of the lower half-shell (described later with reference to Figures 6 and 7).

[0064] The 3D file of the board (left-hand side of [Fig. 2]) can provide, in particular, three-dimensional data of the board to take into account, among other things, the thickness of the board to be housed in the half-shell 12B, as illustrated at the bottom of [Fig. 2]. This 3D file of the board design makes it possible to create, in particular, support areas for the PCB on the lower half-shell 12 and / or upper half-shell 11 (as detailed later with reference to Figures 6 and 7), so as to obtain a planar contact between the board to be tested and all the test needles 13.

[0065] In addition, the SER server checks for a match between: - a planar X,Y projection (in 2D) of the map as defined by the 3D file, and - the OUTL contour given by the GERBER file, in order to possibly correct the OUTL contour from the GERBER file to only take into account the data actually observed of the map contour and contained in the 3D file.

[0066] Such an embodiment makes it possible to precisely determine the contour of the card that the internal shape of the half-shell 12B, which houses the PCB, must conform to, while limiting any play in the PCB's movement as much as possible. For example, the tolerance of the aforementioned play can be less than one or a few tenths of a millimeter.

[0067] The SER server, depending in particular on these contour constraints, card thickness, and positions of the holes for passing the test needles 13, constructs a 3D model of the lower half-shell (reference MOD of [Fig.2]) and can generate a signal containing display data of this MOD model, so that a user can preview on a computer screen or EC tablet the MOD computer model of the half-shell, including all the holes whose diameter he can select to visualize those used for the insertion of the needles 13.

[0068] Another type of data can also be used by the SER server. This consists of functional data from a "Netlist" type file indicating, in particular, the characteristics of each test signal (integrity, controlled impedance, microwave frequency, power supply, differential pair, etc.) in order to design The test board (or intermediate PCB) correctly connects the lower ends of the needles to the output connector 161 of the test foot. This allows the nature of each signal to be determined at each test tip, enabling optimal routing of the test board 16 and, in particular, the selection of the most appropriate connector type 161 (USB, Ethernet, or others).

[0069] It is thus understood that this type of Netlist file, defining the electrical constraints for carrying out the tests, allows the SER server to optimize the design of the test card 16.

[0070] Another type of data that the SER server can also use is that contained in a file usually named "pick and place". Such a file can be transmitted by the client entity EC to the SER server. This data concerns the nature of the components on the board to be tested. From this data, the SER server can determine, in particular, the risk of overheating of one of these components during the board tests and thus, for example, plan for an opening in the casing for improved air circulation (see ventilation in the casing). More specifically, the SER server can determine a free volume left in the casing near (below or above) this component to allow for its ventilation. Such an implementation also implies placing a stop 112 or 122 (as illustrated in Figures 6 and 7) at a distance from this type of component.Thus, taking into account the aforementioned predefined rules implies, in particular, the possibility of heat being released from a component during testing.

[0071] The SER server can then run an online test foot command service according to this method. Referring now to [Fig. 5], a client entity EC (represented by a computer, tablet, smartphone, or other connected device equipped with a screen for previewing the 3D model) can send the aforementioned GERBER file to the SER server via a RES network in a first step (arrow S1). In a subsequent step, the SER server can extract the test point layer and the 2D outline of the board to be tested. The server can also receive the 3D file of the three-dimensional dimensions of the board to be tested (arrow S2) in order to design the MOD computer model of at least one of the half-shells 12. The SER server can then transmit the screen display data to the entity EC for previewing the MOD model (arrow S3).Upon validation by the EC client entity, the latter can send a manufacturing order for the complete test foot, for example in the form of an STL file for an IMP 3D printer in order to manufacture all the components of the test foot 11, 12, 14, 15 by additive synthesis (arrow S4).

[0072] Alternatively, the SER server can receive (following step S3) a validation message for the MOD model, originating from the client entity EC, and transmit such an STL file to a 3D printer (arrow S4') to manufacture the complete test stand and organize then the delivery of this test stand with the intermediate PCB to an address of a user of the EC client entity.

[0073] Figure 5 illustrates a possible embodiment of the SER server. The latter comprises a processing circuit typically including: - a COM communication interface to communicate with the EC client entity via the RES network, - a MEM memory storing, at least temporarily, the data from the received files, as well as the instructions for a computer program to implement the above process, and - a PROC processor capable of cooperating on the one hand with the MEM memory to read and execute the instructions of the computer program and thus implement the aforementioned process, and on the other hand with the COM communication interface to receive the aforementioned files and send the MOD model data and possibly the 3D printing order to the IMP printer.

[0074] The SER server can also receive the aforementioned Netlist file for manufacturing the test board 16. This manufacturing process is relatively quick (a few days). Since 3D printing takes only a few hours, the complete test device can be manufactured in a few days, whereas manufacturing test devices in conventional testing machines can generally take several months.

[0075] Another advantage of the embodiment in the sense of this description is the consideration of constraints (in particular mechanical, but also possibly thermal) related to the position of the contact points, their density, their possible local concentration.

[0076] Reference is made to [Fig. 3] to illustrate such an embodiment. Here, the board to be tested consists of two circuits P1 and P2 connected by an NC ribbon cable (left side of [Fig. 3]). It is a "flex-rigid" type board comprising two rigid parts connected by the flexible NC ribbon cable. Based on its GERBER file and its three-dimensional data, it is possible to generate at least the model of the lower half-shell 12C (right side of [Fig. 3]). Although the half-shell model 12C perfectly matches the shape of the two circuits P1-P2, it appears in particular here that the holes 121 of the model are arranged above a median axis XX passing through the CONT connector of the P2 circuit, while no test holes are provided below this median axis.Thus, the pressure exerted by the needles 13 arranged in these holes 121 against the circuit P2 can cause the circuit P2 to tilt so that the other test points of the circuit P2 lose their contact with the other needles.

[0077] This situation is illustrated in [Fig. 6] where a density of needles 13 is located locally to the left of a possible tilting X axis of the PCB under test. the pressure of the needles 13 (tilting by an angle alpha). To compensate for this risk of tilting, the SER server determines an optimal location (not already obstructed by holes or protruding components of the board to be tested) for an addition of material 122 to be provided on the inner face of the half-shell 12C, as illustrated in [Fig.3], and forming a stop against a possible tilting of the PCB board, as illustrated in [Fig.6].

[0078] Alternatively, the addition of material can be provided on the inner face of the upper half-shell 11 (reference 112 of [Fig.7]), preferably with regard to the needles 13 (or the test points of the map) whose local density is greater than a threshold on the map.

[0079] The SER server can then: - Identify a local density of test points that exceeds a threshold compared to other areas of the map. - Identify a risk of the card tipping over, due to pressure that can be expected from the needles at these test points. - Identify a possible area for adding a stop 122 or 112 to an inner face of a half-shell 12 or 11, and - Construct a MOD model of the half-hull with this stop to be presented to the EC entity before validation.

[0080] The SER server can then execute a computer program of the aforementioned type to verify compliance with the aforementioned predefined rules (mechanical strength of the card, possible heat dissipation at the edge of the card or near a component, etc.).

[0081] Advantageously, the shell 11,12 offered by the SER server in its MOD model has dimensions adapted to the contour of the card to be tested, but also adapted to the components that the card can carry (dimensions, positions, risk of overheating by allowing possible ventilation, mechanical fragility by avoiding having the stops 112, 122 opposite these components).

[0082] Based on the test specifications requested by the client entity EC, the SER server is also able to propose the design of the test card 16 (intermediate PCB).

[0083] From the shape of the shell and the dimensions that the intermediate PCB and possibly its connector must have, the SER server is then able to determine an optimal shape of the body 14 of the test foot, in particular to minimize the material to be used by 3D printing.

[0084] In addition to the aforementioned test card 16, the SER server can also offer the design of a so-called "short-circuit board". This is a card of the same dimensions as the card to be tested and equipped with a conductive surface allowing connection between All the probes are used to test the conductivity and continuity from each test point to the connector, and are typically used for self-diagnostics to verify that no short circuits are likely to occur during board testing. Such a short-circuit board can be designed by the SER server and provided by a SER server user, in addition to the test stand and intermediate PCB.

[0085] Indeed, the Gerber file can also be used by the SER server to create this short-circuit board.

[0086] In addition, the SER server can store in memory subsequent physical test results, carried out to confirm the continuity of each test point, by a full copper printed circuit board replacing the circuit to be tested, as well as impedance measurements at each test point to confirm the absence of a short circuit.

[0087] The SER server can record the result of the complete test sequence from the needles to the output connector in a computer report (bearing the name of the operator, the date of the physical test, the reference of the device tested, the results of the continuity test, the impedance value measured between each signal of the interface connector, etc.).

[0088] Thus, it is understood that the 3D representation of the board (STEP file) makes it possible to anticipate the position of any components on the board and to determine an optimal position for the aforementioned stop. The SER server can follow Boolean logic to take these parameters into account. For example, if the search for a local pin density greater than a threshold is positive, the server calculates a risk of the board tipping relative to its possible tipping axes, and if necessary calculates the size of a stop to be added, taking into account, in particular, the presence or absence of a nearby board component, or other factors. Similarly, if this local density risks causing the board to overheat, the SER server can transmit an alert signal to the EC entity, suggesting, for example, an optimized test sequence or other types of tests.

[0089] Typically, the SER server can select or suggest needles adapted to different test planes on the board, and thus predict variable needle heights, typically thanks to the three-dimensional computer model, for example, needles of possibly different lengths to test a "stepped" board. The shell itself can be stepped and easily obtained by 3D printing.

[0090] Of course, this description is not limited to the embodiments presented above by way of example. It extends to other variants.

[0091] Typically, for the manufacture of the half-shells and the test case, the signal containing the data of the half-shells and the test case to be manufactured (step S4 or S4') can be transmitted to a machine tool machining for example a material such as bakelite or other, as an alternative to manufacturing by 3D printing.

[0092] Of course, the types and formats of the files previously presented may evolve over time and already have variants (OBD, GERBER, or others, for example).

[0093] Furthermore, the computer instructions of the aforementioned program can be distributed between the SER server (for the design of the MOD model) and the EC client entity (for previewing the model before placing the order).

[0094] More generally, an advantageous embodiment of a SER server for implementing the method has been presented above. However, this method can be implemented by any type of computing device, for example a computer, a tablet, or other, as an alternative.

[0095] Furthermore, the SAU "grasshopper" has been described as an example of a means for applying pressure to the board under test within the housing. Alternatively, the housing can be closed by clipping. In this case, the number of clips and their respective arrangements can again depend on predetermined rules, particularly the distribution of the pins in contact with the board to prevent the board from tipping within the housing under the (possibly local) pressure of the pins. In addition, lateral slides can be provided as an alternative to screws / nuts (passages 151 of [Fig. 1]) to close the body of the test stand housing the intermediate PCB 16.

Claims

Demands

1. A method implemented by computer means for manufacturing a test stand for an electronic circuit board to be tested, the test stand comprising at least: - A housing (11, 12) for holding the board to be tested and having holes (121) for passing through conductive needles (3), one end of which is intended to be in contact with test points of the board to be tested, and - A test enclosure (14) containing a test circuit (16) having contact points (162) corresponding to the test points of the board to be tested and intended to be in contact with each other of said ends of the conductive needles. The method comprising at least the steps: - Obtaining (S1, S2) at least one file of relative position data of the test points of the board to be tested, and a file of geometry data of the board to be tested.- Based on at least the aforementioned data and predefined interaction rules between the board to be tested and the said casing, develop (S3) a three-dimensional computer model of the casing and the housing, including at least position data for the said holes, and - Generate (S4; S4') a manufacturing control signal for the casing and the housing, including data from the said computer model.

2. A method according to claim 1, wherein the relative position data file of the map test points is extracted from a standard layer description file of the map to be tested, the relative position data being extracted from at least one end layer of the standard file (GER#TOP, OUTL).

3. A method according to any one of the preceding claims, wherein the geometry file includes three-dimensional coordinates of geometric elements of the map to be tested (3D), the computer model (MOD) being generated from contour data of said geometric elements.

4. A method according to any one of the preceding claims, wherein said predefined interaction rules include at least one constraint for the mechanical stability of the card within the shell, the development of the computer model (MOD) taking into account said stability constraint to avoid a tipping of the card in the shell during a testing phase.

5. Method according to claim 4, comprising: - determining whether a local density of needles intended to be in contact with the card is greater than a threshold, and whether the needles of said local density are distant from an axis (XX) of possible tilting of the card in the shell during a test phase, - in case of density greater than the threshold and if the needles of said local density are distant from said tilting axis, providing a means of retaining (122) the card in the shell to prevent said tilting.

6. Method according to claim 5, wherein the retaining means comprises at least one protrusion (122) provided on an inner face of the shell, against which the card is intended to come to rest when the card is subjected to pressure from the needles of said local density greater than the threshold.

7. A method according to any one of the preceding claims, wherein said predefined interaction rules include at least one constraint for inserting the card to be tested into the shell with a tolerated displacement clearance of the card to be tested in the shell, less than a threshold, and wherein the geometric model of the shell is determined with dimensions greater than a contour of the card to be tested, a difference between the dimensions of the shell model and the contour of the card corresponding to said displacement clearance.

8. A method according to any one of the preceding claims, further comprising the execution of software to check whether said computer model complies with said predefined rules, and to animate a human-machine interface to warn a user of a non-compliance with said predefined rules.

9. A method according to claim 8, wherein the human-machine interface emits a signal recommending an alternative arrangement of the test points of the board to be tested.

10. A method according to any one of claims 8 and 9, wherein it is verified whether a test point is geometrically close to an edge or component of the board under test, and the human-machine interface is animated if a distance between a test point and an edge or component of the board is below a threshold.

11. A method according to any one of the preceding claims, wherein the computer model provides a recess in the housing, in order to form a slide (142) for inserting a pressure member (SAU) of the shell (11,12) against the housing (14).

12. A method according to any one of the preceding claims, wherein the computer model of the test box has an opening, for the purpose of accommodating a connection element (161) of the test circuit to a test machine.

13. Method according to claim 12, wherein said opening is defined according to the dimensions of the connection element to be provided, a prediction of the connection element being determined according to a descriptive file of types of tests to be carried out on the card to be tested, said descriptive file of types of tests being further obtained before the development of the computer model.

14. Test box and shell of an electronic circuit board to be tested, of a test stand, obtained by implementing the method according to one of the preceding claims.

15. Computer program comprising instructions for carrying out the method according to any one of claims 1 to 13, when executed by a processor.

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