Method for virtually inspecting an actual produced part

Abstract

A method and a computer programme product for virtually inspecting an actual produced part, comprising providing an ideal Finite Element (FE)-mesh corresponding to an ideal produced part, said ideal produced part comprising two or more mounting places, by measuring the actual produced part, generating a numerical representation of the actual produced part, generating an actual FE-mesh by modifying the ideal FE-mesh such that the shape of the ideal FE-mesh adapts to the numerical representation of the actual produced part, and performing an FE-analysis, by forcing the actual FE-mesh into position by constraining the mounting places of the actual FE-mesh, and determining a deformation of the actual FE mesh resulting from its constraint.

Claims

1. A method for virtually inspecting an actual produced part, the method comprising: providing an ideal Finite Element (FE)-mesh corresponding to an ideal produced part, said ideal produced part comprising two or more mounting places; generating a numerical representation of the actual produced part by measuring the actual produced part; generating an actual FE-mesh by modifying the ideal FE-mesh such that the shape of the ideal FE-mesh adapts to the numerical representation of the actual produced part; and performing an FE-analysis by: forcing the actual FE-mesh into position by constraining the mounting places of the actual FE-mesh, and determining a deformation of the actual FE-mesh resulting from its constraint.

2. The method according to claim 1, wherein constraining is provided by a fixture model comprising two or more mounting restraints for constraining the mounting places.

3. The method according to claim 2, wherein the fixture model is: an actual fixture model generated based on an actual produced fixture, or an ideal fixture model generated based on design.

4. The method according to claim 1, wherein the FE analysis further includes: applying a force resulting from at least one of gravity, a seal, and a buffer to the constrained actual produced part, and determining the deformation of the actual FE mesh further resulting from said force.

5. The method according to claim 1, further comprising: generating an inspection result indicating whether the deformation of the constrained actual FE-mesh remains within a given tolerance range.

6. The method according to claim 2, wherein the deformation is characterised by a set of deviation values, wherein each deviation value is assigned to a particular location on the constrained actual FE-mesh, and wherein the deviation values are determined based on a local deviation at each particular location from: a model of the ideal produced part ideally positioned relative to the fixture model, or the ideal FE-mesh forced into position by constraining the mounting places of the ideal FE-mesh.

7. The method according to claim 1, further comprising: placing an adjacent model in a predetermined position relative to the constrained actual FE-mesh such that the adjacent model is adjoining the actual FE-mesh; determining a relative position and orientation between the adjacent model and the actual FE-meshl and deriving at least one of: clearance between the adjacent model and the actual FE-mesh, and flushness of the adjacent model relative to the actual FE-mesh.

8. The method according to claim 2, wherein: the produced part is a body panel, the fixture model is a vehicle body, and the restraints are one or more of a weld spot, a bonding spot, a hemming spot, a hinge, a latch, a lock, a bolting, and a screw connection.

9. A computer program product with program code being stored on a machine readable medium, the program code being configured to execute the method comprising: providing an ideal Finite Element (FE)-mesh corresponding to an ideal produced part, said ideal produced part comprising two or more mounting places; providing a numerical representation of an actual produced part; generating an actual FE-mesh by modifying the ideal FE-mesh such that the shape of the ideal FE-mesh adapts to the numerical representation of the actual produced part; and performing an FE-analysis by: forcing the actual FE-mesh into position by constraining the mounting places of the actual FE-mesh, and determining a deformation of the actual FE-mesh resulting from its constraint.

10. The computer program product according to claim 9, wherein constraining is provided by a fixture model comprising two or more mounting restraints for constraining the mounting places.

11. The computer program product according to claim 9, wherein the fixture model is: an actual fixture model generated based on an actual produced fixture, or an ideal fixture model generated based on design.

12. The computer program product according to claim 9, the FE analysis further comprising: applying a force resulting from at least one of gravity, a seal, and a buffer to the constrained actual produced part, and determining the deformation of the actual FE mesh further resulting from said force.

13. The computer program product according claim 9, further comprising: generating an inspection result indicating whether the deformation of the constrained actual FE-mesh remains within a given tolerance range.

14. The computer program product according to claim 10, wherein the deformation is characterised by a set of deviation values, wherein each deviation value is assigned to a particular location on the constrained actual FE-mesh, and wherein the deviation values are determined based on a local deviation at each particular location from: a model of the ideal produced part ideally positioned relative to the fixture model, or the ideal FE-mesh forced into position by constraining the mounting places of the ideal FE-mesh.

15. The computer program product according to claim 9, further comprising: placing an adjacent model in a predetermined position relative to the constrained actual FE-mesh such that the adjacent model is adjoining the actual FE-mesh; determining a relative position and orientation between the adjacent model and the actual FE-mesh; and deriving at least one of: clearance between the adjacent model and the actual FE-mesh, and flushness of the adjacent model relative to the actual FE-mesh.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention will be described in detail by referring to exemplary embodiments that are accompanied by figures, in which:

(2) FIG. 1-3: show the generation of an actual FE-mesh corresponding to an actual produced part;

(3) FIG. 4,5: show different embodiments of constraining the mounting places of the actual FE-mesh;

(4) FIG. 6: shows an embodiment of the method wherein an adjacent model is brought into the analysis;

(5) FIG. 7,8: show different evaluations based on the method or computer programme product according to the invention;

(6) FIGS. 1, 2 and 3 show the generation of an actual FE-mesh 10 corresponding to an actual produced part. Each part mentioned herein may be a single part, a sub-assembly, or an assembly. FIGS. 1, 2 and 3 exemplarily refer to a vehicle door which usually is a sub-assembly or an assembly of at least two parts (e.g. formed sheets made of metal or composite). The method steps, in particular the steps that FIGS. 1, 2 and 3 refer to, may however also be applied to any other produced part, whether that be a vehicle part (e.g. fender, roof, trunk), an airplane part (e.g. wing, tail fin, body panel) or a part of any other product, the assemblage of whose components needs to be checked (e.g. computer body, phone or tablet casing).

(7) A three-dimensional point cloud 12 being a numerical representation of the actual produced part is recorded by three-dimensionally measuring the actual produced part. An ideal FE-mesh 11 corresponding to an ideal produced part then is fitted toor in other words: matched withthe point cloud 12, such that the shape of the ideal FE-mesh adapts to the shape of the point cloud. The shape of the mesh is set in a way to conform with the numerical representation of the actual part as it was produced. As seen in FIG. 2, each of the nodes 13 of the mesh, thereby, may be shifted if necessary to come as close as possible to the actual shape of the produced part. This approximation process results in the actual FE-mesh, see FIG. 3.

(8) While FIGS. 4, 5 and 6 may as well refer to a real-world situation, where an actual produced door is mounted to the body fixture, here, said figures are supposed to show a part of a graphical user interface of Finite Element software run on a computer, as a user of the method or computer programme product according to the invention would utilise it.

(9) FIG. 4 shows one exemplary utilisation according to the invention. An actual FE-mesh 10 generated as described above, comprises mounting places 11 and 12 which may be forced into position by being constrained. The constraints may be achieved by a fixture 13, said fixture comprising according mounting restraints 14, 15 at defined locations and orientations. Exemplarily, hinges are used as a medium of constraint between the body 13 and the door 10. As shown, the mounting restraints 14, 15 are barrels of said hinges, and the mounting places 11, 12 are the pins of the hinges. Although the pins of the hinges are shown on side of the door, the pins and barrels may be arranged the other way round. Also, the door mounting may be realised by means entirely other than hinges, which are known in the art.

(10) With the actual FE-mesh having the at least two constraints shown in FIG. 4, an FE-analysis is determining deformations resulting from said constraints. The application of gravity force may be regarded or disregarded in the FE-analysis.

(11) The mounting restraints on the fixture's side and the according mounting places on the door's side may each be more than just two, as FIG. 5 shows. Further constraints may for example be enforced by elements of a latch 18/17, and a further force may be induced by a door seal 19. The mounting place on the door corresponding to the latch 18 is a hook 17 and the place of force application on the door corresponding to the seal 19 is a surface on the inner circumference of the door (not numbered in the figure). The seal 19 may as well be arranged on the door's side.

(12) In case all of the four different constraints shown in FIG. 5 being present, the door is exposed to various applications of force when it snapped shut. The latch elements 17, 18 and the hinges elements 11, 12/14, 15 provide the door being pressed against the sealing 19 such that forces apply in all of said mounting places on the door, which results in deformations of the door. These deformations are determined with the simulation of the Finite Element Analysis according to the invention.

(13) In the FE-analysis, the stiffness of the fixture model 13 may be considered significantly higher than the stiffness of the actual FE-mesh. In particular, the deformability of the fixture model may be considered negligible.

(14) FIG. 6 shows an adjacent model 20 (fender) adjoining the actual FE-mesh 10 (door). The adjacent model 20 in this case is also an FE-mesh, however, it may also be a mere 3D CAD model of the part. Said adjacent FE-mesh may be an ideal FE-mesh (i.e. corresponding to a designed part) or an actual FE-mesh (i.e. corresponding to a produced part). In the shown embodiment, the adjacent FE-mesh 20 also has mounting places by which it may be constrained by according mounting restraints on the fixture. As a result from the three constraints shown in the figure, the adjacent FE-mesh may also experience deformations. Generally, the simulated constraints may represent e.g. magnetising or physical clamping, welding, screwing, coupling, riveting, etc.

(15) FIG. 7 shows the evaluation of the arrangement as set in FIG. 6: two adjacent parts may be analysed relative to each other regarding flushness. The scale 30 indicates a deviation from the ideal part form/position. The shades or colours of the scale 30 are applied to at least one of the models or meshes to identify the problematic regions. The shown evaluation may as well be made for only one part, e.g. according to the arrangement of FIG. 4 or 5.

(16) With the evaluation according to FIG. 7, the flushness between part 10 and part 20 may be checked ergonomically. Where the neighbouring parts have high contrast regarding the shade/colour, the gap perpendicular to the part surface is larger.

(17) In particular, a marking 40 may be provided, signalising that in the marked region a given tolerance range has been exceeded regarding deviation from an ideally positioned/formed part.

(18) In particular, a marking 41 may be provided, signalising that in the marked region a given tolerance range regarding flushness has been exceeded.

(19) As an exemplary embodiment, FIG. 8 shows a further evaluation of the arrangement as set in FIG. 6: two adjacent parts may be analysed relative to each other regarding clearance. The scale 30 indicates a deviation from an ideal gap width. The shades or colours of the scale 30 are applied to at least one of the models or meshes to identify the problematic regions.

(20) With the evaluation according to FIG. 8, the clearance between part 10 and part 20 may be checked ergonomically. A stripe may be shown along the gap between the two parts. Said stripe may be shown in the gap, towards one of the neighbouring parts, or two stripes towards both neighbouring parts (as shown in the figure). Where the stripes have high contrast regarding the shade/colour, the gap along the part surface is larger.

(21) In particular, a marking 42 may be provided, signalising that in the marked region a given tolerance range has been exceeded regarding deviation from an ideal gap. Also further criteria may be considered, when evaluating two parts relative to each other, such as a check if reflections of light are coherent or smooth when looked at the gap between the parts. Many other criteria known in the art of quality management may be considered just like the aforementioned.

(22) Following the principle as shown in the figures and as described above, it is a particular purpose of the present invention to examine the effect of a combined mounting of a plurality of parts together. According to known strategies in Quality Management, it is not desired to manufacture every part in the highest possible preciseness, but rather to achieve a total accuracy of the symphony of several assembled/mounted parts which is just acceptable. Therefore, the FE-meshes of every part participating in the simulation according to the invention, but also the fixture itself, may correspond to an actual produced part.

(23) Although the invention is described above with exemplary reference to the construction of vehicles, where the assemblage of parts is checked in a virtual way, the invention as well relates to aerospace (spaceships, aircrafts), the electronics industries (laptops, Smartphones, stereo equipments) or any other industry facing challenges in constructing multi-component products, especially products having thin-walled body panels.

(24) Although the invention is illustrated above, partly with reference to some embodiments, it must be understood that numerous modifications and combinations of different features of the embodiments may be made. All of these modifications lie within the scope of the appended claims.