WO2021198971A1

WO2021198971A1 - Assembly and checking process of an electronic board

Info

Publication number: WO2021198971A1
Application number: PCT/IB2021/052725
Authority: WO
Inventors: Luigi Sacchetto; Andrea MANIERO
Original assignee: Carel Industries SpA
Current assignee: Carel Industries SpA
Priority date: 2020-04-03
Filing date: 2021-04-01
Publication date: 2021-10-07
Anticipated expiration: 2022-10-03
Also published as: IT202000007090A1

Abstract

Described is an assembly and checking process of an electronic board which comprises the use of a viewing apparatus, for recognising components prepared on a real RGB, and an assembly station comprising a plurality of seats for electronic components. The process comprising a step A for preparing a virtual model of an electronic board to be assembled, a step B for assisted assembling of the electronic board and a step C for checking the correctness of its assembly.

Description

ASSEMBLY AND CHECKING PROCESS OF AN ELECTRONIC BOARD

TECHNICAL FIELD

This invention relates to a process of assembly and checking of an electronic board, which in particular has a high reliability in the correctness of the assembly whilst requiring limited skills of the assembly worker and high flexibility of application with respect to different electronic board designs to be assembled.

BACKGROUND ART

Currently, it is known that there is a need to check the correct assembly of PTH (Pin-Through-Hole) components on an electronic board.

In order to comply with the checking requirements, the prior art uses test-in- circuit systems, that is, tests aimed at checking the correct assembly of PTH components, which, however, require the soldering of components to the board. This implies that, if one or more components are found to be incorrectly assembled, the board will have to be rejected or repaired, with considerable production disadvantages.

In order to detect the presence of an assembly error before soldering the components onto the board, the prior art uses viewing systems which, once the installation of the components onto the board is complete but before soldering, enables a check of whether the assembly is correct.

If an error is detected, it is, therefore, quicker and easier to correct it.

However, this still requires the interruption of the production in series and the reworking of the board in order to eliminate the error, which is detrimental to the productivity. Moreover, these traditional viewing systems require the preparation of a virtual model of the board to be checked.

When fully operational, the system checks the presence of the real components corresponding to those present in the virtual model. Clearly, this virtual model must be re-programmed if the board in production is changed, that is, each board to be produced requires the preparation of a corresponding virtual model.

This implies preparation times which affect the production activities.

On the other hand, currently, the assembly instructions made available to the operator installing the components on the board are contained on a schedule in paper or electronic form which shows for each part its position and polarity, that is, its orientation in relation to the board.

There are also systems that guide the operator step by step and which, necessarily, require a confirmation of the execution by the operator at each step, to the detriment of fluidity and speed of execution.

SUMMARY OF THE INVENTION

The problem underlying the invention is therefore to improve the productivity of the traditional processes of assembling and checking an electronic board.

As part of this task, one aim of the invention is to propose a process for assembly and checking of an electronic board which allows a reliable checking of the assembly of the PTH components without significantly impacting production times.

Another aim of the invention is to propose a process for assembling and checking an electronic board which will enable any error in the assembly of an electronic board to be detected at an early stage and corrected immediately. Another aim of the invention is to implement a process for the assembly and checking of an electronic board which will drastically reduce the reworking of assembled electronic boards. A further aim of the invention is to propose a process for the assembly and checking of an electronic board which allows the assembly errors to be reduced even in the case of assembly by inexperienced operators or those with reduced ability, without a significant impact on the production times.

This task, as well as these and other aims which will emerge more fully below, are attained by a process of assembling and checking an electronic board according to the appended independent claim.

Detailed features of a process for assembly and checking an electronic board according to the invention are indicated in the dependent claims.

Further features and advantages of the invention will emerge more fully from the description of a preferred but not exclusive embodiment of a process for assembly and checking an electronic board according to the invention, illustrated by way of non-limiting example in the accompanying drawings listed below.

DETAILED DESCRIPTION Disclosed herein is a process for assembly and checking of an electronic board comprising the use of a viewing apparatus configured to recognise components prepared on a real PCB, that is, on a printed circuit board, which is referred to below for sake of brevity as real PCB.

This process also comprises the use of an assembly station comprising a plurality of seats for electronic components.

In particular, such an assembly station comprises a plurality of said seats, each one designed to house electronic components of a single type, so that an operator is provided each time, ordered in each of said seats, with the various electronic components to be assembled on a planned real PCB in order to obtain a specific electronic board.

In other words, once the electronic board to be assembled has been defined, that is, the design of the real PCB and the configuration of each electronic component to be assembled on it, then a real PCB with the appropriate design is placed in an assembly station and each seat is filled with a type of electronic component selected from the types of electronic components required for the assembly of the specific electronic board to be assembled.

Preferably, the assembly station comprises means for selectively indicating to an operator one of the seats, or a group of seats, in which the electronic components are housed which are to be assembled each time on the real PCB in a predefined sequence.

The said indication means may for example comprise a lighting system which selectively illuminates the relevant seat or group of seats.

For example, each seat may comprise a container made of a partially opaque, translucent or transparent material and lighting means, such as LEDs, which are connected to an electronic actuating device that selectively and successively activates the lighting means which illuminate the seat or seats corresponding to the electronic components to be assembled in a predefined sequence. In this case, the seats will be illuminated in succession to indicate the sequence of electronic components housed in them, which are - in the same sequence - to be assembled on the real PCB.

This makes it particularly easy, even for an inexperienced operator, to assembly the electronic components on the real PCB in the correct, best or most efficient sequence.

The assembly station may also comprise illuminators configured to illuminate the assembly station and at least one optical unit facing the assembly station and designed to capture images of the assembly station and especially of an electronic board being assembled there.

The assembly station has a station for the operator.

The illuminators, the at least one optical unit, the assembly station and the station for the operator are positioned in a mutually conventional manner so as to avoid or minimise the possible interference of the body of the operator with light beams emitted by the illuminators or with the field of vision of the at least one optical unit.

The assembly station may also have a display designed to make assembly information available to an assembly operator, for example, a virtual PCB with virtual components, respectively corresponding to the real PCB and to the electronic components to be assembled on it, and representative of them.

According to the invention, said process of assembly and checking an electronic board comprises a step A of preparation of a virtual model of an electronic board to be assembled, a step B of assisted assembly of the electronic board and a step C of checking the correctness of assembly of the electronic board. Step A comprises:

- a step A1 of preparing, in a virtual environment, a virtual PCB and

- a step A2 of preparing, on the virtual PCB, virtual components each imported from a pre-arranged library of virtual components where each of the virtual components has a configuration on the virtual PCB which defines a checking configuration against which to check a correct assembly of said electronic components on the electronic board.

Each virtual component corresponds to a real electronic component to be assembled on a real PCB to obtain an electronic board. In other words, the virtual components are virtual representations of the electronic components to be assembled to form a predefined electronic board. The term "configuration" of a virtual component on the virtual PCB and, correspondingly, of an electronic component on the real PCB, means the combination of the position of that virtual or electronic component on the virtual or real PCB, with its polarity, that is, with its orientation with respect to a reference system integral to the virtual or real PCB, respectively.

Step B comprises:

- a step B1 which comprises making available to an assembly operator, for example by means of said display, the virtual model, selectively highlighting in the latter either one of the virtual components or a group of the virtual components, to be assembled on a real PCB of the electronic board;

- a step B2 comprising highlighting either one of the seats of the assembly station which houses an electronic component corresponding to the virtual component highlighted in step B1, or a group of the seats which house electronic components corresponding to the group of virtual components highlighted in step B1, respectively;

- a step B3 of assembling on the real PCB of the electronic component corresponding to the virtual component or of electronic components corresponding to the group of virtual components, highlighted in step B2.

Step C comprises:

- a step C1 which comprises acquiring, by means of the viewing system, an image of the electronic board being assembled or of the real PCB;

- a step C2 which comprises recognising, for each of the electronic components which is assembled on the electronic board being assembled, an assembly configuration;

- a step C3 for comparing the assembly configuration with the checking configuration and reporting an error in the event of a mismatch between the assembly configuration and the checking configuration. It is therefore understandable how by means of a process of assembly and checking of an electronic board, according to the invention, it is possible to guarantee a high reliability of a correct assembly as an assisted assembly is implemented which allows the operator, even the most inexperienced, to receive in real time precise information on the electronic components to be assembled on the real PCB, on their assembly configuration and on the sequence in which to assemble them.

This process also makes it possible to detect any assembly error in real time, that is, as soon as it is made, and therefore allows the error to be corrected promptly without having to wait for the electronic board to be completed, as is the case with traditional technology.

A process of assembling and checking an electronic board according to the invention can therefore significantly improve the productivity of electronic boards, especially by greatly reducing the risk of assembly errors being made and, at the same time, greatly reducing the time for correcting any assembly errors made.

Step A may comprise a step A3 of acquisition, from an assisted design apparatus, or CAD, of an electronic archive or file comprising structural information of the electronic board. This structural information comprises information relative to:

- electronic paths of the real PCB;

- number, type and polarity of the electronic components and position in which each of them is to be placed on the real PCB;

- any information for assembly of the electronic components on the real PCB, such as, for example, information on the optimal or necessary assembly sequence.

In other words, it is possible that following the preparation of a CAD file containing the structural information of the electronic board to be produced, that is, information on how it should look, this information can be directly acquired in the viewing system, which can then operate according to a vision program that incorporates this structural information to check that the assembly of the electronic boards during their production is correct.

This acquisition can, for example, be carried out by means of an interface programme which acquires this structural information, or CAD files, for example in the traditional .dwg or .dxf formats, or in an .xml format and which converts this structural information into an electronic archive with a traditional .svg format necessary for the viewing system to recognise the electronic components being assembled on the electronic board. Preferably, the structural information also comprises information on the assembly sequence of the electronic components on the real PCB, so that a view of the virtual PCB can be made available by means of the assembly station display, where the virtual components appear in succession according to a predefined assembly sequence. The process according to the invention may comprise that the viewing of a virtual component on the virtual PCB is carried out, by means of the display, only after the successful completion of step C in relation to the electronic component corresponding to the previously viewed virtual component.

In other words, according to the invention, a second virtual component to be viewed after a first virtual component, according to the predefined viewing sequence, will only be viewed - to indicate that the corresponding electronic component is to be assembled - after a positive checking by the viewing system of the correct assembly of the electronic component corresponding to the first virtual component. Step A may comprise an automatic execution of the preparation of the virtual PCB, of step A1, and the positioning of the virtual components, of step A2, following an execution of step A3 and in accordance with the structural information.

In other words, the process of assembling and checking an electronic board rn ay comprise that the virtual PBC and the configuration of the virtual components on it, as well as their predefined assembly sequence, are acquired automatically by converting, for example, by means of the above-mentioned interface, an electronic archive containing the structural information, made available by the assisted design apparatus, CAD.

In this way, the process of assembling and checking an electronic board eliminates the times for creation of a program for each board to be produced, which, on the contrary, is traditionally necessary for the use of viewing systems in the checking of the correct production of electronic boards. Steps C1, C2 and C3 can be carried out in sequence, following the assembly carried out in step B3 of each of the electronic components, to report in real time a possible assembly error.

The process of assembling and checking a electronic board may also comprise a step D for correcting an assembly error which comprises: - removing the electronic component or the electronic components corresponding to the group of virtual components and assembled during step B3 on the real PCB for which, in step C3, an assembly error was reported;

- repeating step B with respect to the removed electronic component(s).

The process of assembling and checking an electronic board may also comprise a step E of soldering electronic components assembled on the real PCB.

Step E is carried out following an execution of step C, and a possible step D, following a step C3 of assembly of the last of the electronic components to be assembled on the real PCB to complete the electronic board. For the recognition of electronic components, step B may comprise the use of a vision algorithm based on a neural network structure for deep learning.

This greatly increases the reliability of the recognition of the electronic component in step C. In fact, by means of the use of the vision algorithm based on a neural network structure for deep learning, it is possible to greatly reduce the number of false diagnoses, that is, incorrect or failed recognition of an electronic component or its configuration, which in the traditional systems generally occur as a function of the type and configuration of the assembly stations and/or the lighting conditions of the assembly station and/or the influence of ambient lighting, which are typically dependent on the variability of natural lighting throughout the day and year.

The process of assembling and checking an electronic board may also comprise a step E of integrating into the viewing system a database comprising a plurality of different real images of each of the electronic components, to form a basis for recognising them by the vision algorithm.

In other words, it is possible to set up said database to provide a wealth of experience for the vision algorithm, greatly increasing its reliability in recognising electronic components. For step B it is also possible to set confidence levels and accuracy levels of the recognition of said electronic components.

It is therefore clear how a process of assembling and checking an electronic board according to the invention achieves the set task and aims.

A process of assembling and checking an electronic board according to the invention in particular improves the productivity of traditional processes of assembling and checking an electronic board.

Moreover, an assembly and checking process for an electronic board according to the invention allows a reliable checking of the assembly of PTH components without significantly impacting production times.

An assembly and checking process of an electronic board, according to the invention, also allows an error in the assembly of an electronic board to be identified at an early stage and corrected immediately.

Moreover, a process of assembling and checking an electronic board, according to the invention, can drastically reduce the reworking of assembled electronic boards.

The process of assembling and checking an electronic board in accordance with the invention also reduces assembly errors, even in the case of assembly by inexperienced or low-skilled operators, without a significant impact on production times.

The invention as it is conceived is susceptible to numerous modifications and variants, all falling within the scope of protection of the appended claims.

Further, all the details can be replaced by other technically-equivalent elements.

Claims

1. An assembly and checking process of an electronic board which comprises the use of a viewing apparatus, for recognising components provided on a real PCB, and an assembly station comprising a plurality of seats for electronic components; said process comprising a step A of preparing a virtual model of an electronic board to be assembled, a step B of assisted assembling of an electronic board and a step C of checking the correctness of assembly of said electronic board; where said step A comprises: - a step A1 of providing, in a virtual environment, a virtual PCB and

- a step A2 of providing, on said virtual PCB, virtual components each imported from a pre-arranged library of virtual components where each of said virtual components has a configuration on said virtual PCB which defines a checking configuration against which to check a correct assembly of said electronic components on said electronic board; wherein said step B comprises:

- a step B1 which comprises making available to an assembly operator said virtual model, selectively highlighting in the latter either one of said virtual components or a group of said virtual components, to be assembled on a real PCB of said electronic board;

- a step B2 comprising highlighting either one of the seats of said assembly station which houses an electronic component corresponding to said virtual component highlighted in said step B1 , or a group of said seats which house electronic components corresponding to said group of virtual components highlighted in said step B1, respectively;

- a step B3 of assembling on said real PCB of said electronic component corresponding to said virtual component or of said electronic components corresponding to said group of virtual components, highlighted in said step B2; wherein said step C comprises:

- a step C1 which comprises acquiring by means of said viewing system an image of said electronic board being assembled;

- a step C2 which comprises recognising, for each of said electronic components which is assembled on said electronic board being assembled, an assembly configuration;

- a step C3 for comparing said assembly configuration with said checking configuration and reporting an error in the event of a mismatch between said assembly configuration and said checking configuration.

2. The process according to claim 1 wherein said step A comprises a step A3 of acquiring from an assisted design apparatus an electronic file comprising structural information of said electronic file; said structural information comprising information relating to:

- electronic paths of said real PCB;

- number, type and polarity of said electronic components and position of each of the latter on said real PCB;

- any assembly information of said electronic components on said real PCB.

3. The process according to claim 2 wherein said step A comprises an automatic execution of the preparing of said virtual PCB, of said step A1 , and the positioning of said virtual components, of said step A2, following an execution of said step A3 and in accordance with said structural information.

4. The process according to any one of the preceding claims, wherein said steps C1 , C2 and C3 are carried out in sequence following the assembly carried out in said step B3 of each of said electronic components, to report in real time a possible assembly error.

5. The process according to any of the preceding claims comprising a step D of correcting an assembly error comprising:

- removing said electronic component or said electronic components corresponding to said group of virtual components and assembled during said step B3 on said real PCB for which, at said step C3, an assembly error was reported;

- repeating said step B with respect to said removed electronic component(s).

6. The process according to any one of the preceding claims comprising a step E of soldering said electronic components assembled on said real PCB which is performed subsequent to an execution of said step C, and a possible step D, subsequent to a step C3 of assembling a last of said electronic components to be assembled on said real PCB to complete said electronic board.

7. The process according to any one of the preceding claims wherein said step B comprises the use of a vision algorithm, for recognition of said electronic components, which is based on a neural network structure for deep learning.

8. The process according to claim 7 comprising a step E of integrating into said viewing system a database comprising a plurality of different real images of each of said electronic components to form a basis for recognition of the latter by said vision algorithm.

9. The process according to any one of the preceding claims wherein, for said step B, confidence levels and accuracy levels of the recognition of said electronic components can be set.