Methods for investigating the expansion behavior of a material that expands during hardening and quality control methods for series production

Abstract

The present invention relates to a method for investigating the expansion behavior of a material (2) that expands during curing, wherein: the material (2) to be investigated is applied in a liquid state to a first test surface (11), a test device (3) with a second test surface (311) is arranged on the first test surface (11) such that the two test surfaces (11, 311) are arranged at a defined distance (A) from each other, the material (2) is located between the two test surfaces (11, 311) after being applied to the first test surface (11) and after the test device (3) has been arranged on the first test surface (11), the test device (3) is removed after a defined curing time has elapsed, and after the test device (3) has been removed, it is checked whether the cured material (2) has an imprint (4) of the second test surface (311) or not.The present invention further relates to a quality inspection method for series production, wherein a series production component (1,31) is regularly taken from the series production and a method according to the invention for investigating the expansion behavior of a material (2) that expands during hardening is carried out with it, wherein the series production component (1,31) forms the first test surface (11) or the second test surface (311).

Description

[0001] The present invention relates to a method for investigating the expansion behavior of a material that expands during hardening and to a quality control method for series production.

[0002] Expanding materials, meaning materials applied in a liquid state that increase in volume as they harden, are particularly well-suited for use as sealants. In this application, the liquid material is applied to a primary sealing surface and, once hardened and expanded, is intended to seal a gap between this surface and an adjacent secondary sealing surface. To ensure reliable sealing of the gap, a thorough understanding of the material's expansion behavior is crucial. Typically, this requires extensive laboratory testing using specialized equipment, which complicates quality control during series production.

[0003] Against this background, the task arises to enable a relatively simple investigation of the expansion behavior of a material that expands during hardening and, in particular, a relatively simple quality control test accompanying series production.

[0004] This problem is solved according to the invention by a method for investigating the expansion behavior of a material that expands during hardening, having the features of claim 1.

[0005] In the method according to the invention, the material to be tested is applied in a liquid state to a first test surface. Preferably, the first test surface extends substantially in a horizontal plane and has a surface directed substantially vertically upwards, onto which the material is applied.

[0006] Preferably, after the material has been applied to the first test surface, a test fixture is arranged on the first test surface. The test fixture comprises a second test surface and is arranged such that the two test surfaces are positioned at a defined distance from each other, and the material applied to the first test surface is located between the two test surfaces. Alternatively, it is also conceivable that the test fixture is arranged on the first test surface before the material is applied, and the liquid material is subsequently applied to the first test surface in such a way that the material is located between the two test surfaces. In either case, after application to the first test surface and after the test fixture has been arranged on the first test surface, the material is located between the two test surfaces.To set the defined distance, the test device can, for example, have spacers protruding from the second test surface, with which the device is placed on the first test surface.

[0007] After a defined curing time, the test fixture is removed from the first test surface, and the now cured and consequently expanded material is then checked to see if it shows an imprint of the second test surface. If the cured material shows an imprint of the second test surface, then during curing, the material has conformed to the second test surface in the area of ​​the imprint, thus filling the gap between the two test surfaces in that area. If, after curing, the material shows an imprint of the second test surface in all relevant areas, preferably along its entire transverse dimension, then the expansion behavior of the material is considered acceptable. Conversely, if the material shows no imprint of the second test surface after curing, or an imprint that is not sufficiently large, then the expansion behavior is considered unacceptable.

[0008] The method according to the invention does not require complex laboratory tests with special laboratory equipment, thus enabling a relatively simple investigation of the expansion behavior of a material that expands during curing. In particular, the method according to the invention can also be carried out relatively easily during series production.

[0009] Preferably, the second test surface is treated with a non-stick coating to prevent the material from adhering to it and thus avoid damaging the cured material when removing the test fixture. The second test surface can, for example, be provided with a non-stick coating or treated with a release agent.

[0010] Since materials that expand during curing are often used as sealing materials, the material is preferably a foam, especially preferably a polyurethane foam or a silicone foam, which have good sealing properties.

[0011] Since, particularly in the automotive sector, expanding materials are frequently applied along component edges during curing, the liquid material is applied to the first test surface in a preferred embodiment of the inventive method in the form of a line, also known as a bead.

[0012] Preferably, the first test surface and / or the second test surface, particularly preferably the first test surface and the second test surface, is formed by a mass-produced component, particularly preferably by a component of a motor vehicle, in order to obtain a particularly good prediction of the expansion behavior of the material under mass production conditions.

[0013] The above-mentioned problem is further solved by a quality control procedure for series production with the features of claim 6.

[0014] In the quality testing method according to the invention for series production, a series production component that comes into contact with the material to be investigated during series production is regularly taken from the series production and a method according to the invention for investigating the expansion behavior of a material that expands during hardening is carried out with it, wherein the series production component forms the first test surface or the second test surface.

[0015] Since the inventive method for investigating the expansion behavior does not require complex laboratory tests with special laboratory equipment, the inventive quality testing method enables relatively simple quality control during series production. Furthermore, because the inventive method for investigating the expansion behavior is carried out with a mass-produced component, the inventive quality testing method allows for particularly good conclusions to be drawn about the expansion behavior of the material under mass production conditions and thus enables reliable quality control.

[0016] In order to enable a particularly reliable quality test, the material is preferably applied to the first test surface under series production conditions when carrying out the inventive method for investigating the expansion behavior.

[0017] Preferably, two different mass-produced components, between which the material to be investigated is positioned during mass production, are taken from the production line. In carrying out the inventive method for investigating the expansion behavior, one of the two mass-produced components forms the first test surface and the other the second test surface. It is particularly preferred that the two mass-produced components are positioned relative to each other under mass production conditions when carrying out the inventive method for investigating the expansion behavior. This enables a particularly reliable quality test.

[0018] An embodiment of the present invention is described below with reference to the accompanying figures. These show: Fig. 1 schematically a first test surface onto which a material to be investigated by means of a method according to the invention for investigating the expansion behavior was applied in liquid form and on which a test device with a second test surface was arranged, Fig. 2 the first test surface and the material made of Fig. 1. after the test device has been removed following a defined curing period, in the event that the cured material shows an imprint of the second test surface, and Fig. 3 the first test surface and the material made of Fig. 1 after removal of the test device, however, in the event that the hardened material does not show an imprint of the second test surface.

[0019] Fig. Figure 1 schematically shows a first test surface 11, which in the present embodiment is formed by a first series production component 1 taken from a series production. The first series production component 1 can, for example, be a battery frame of a traction battery of a motor vehicle.

[0020] A material 2, which expands during curing, was applied to the first test surface 11 in a liquid, i.e., uncured, state. In the present embodiment, the material is a foam and was applied to the first test surface 11 in the form of a line under series production conditions.

[0021] A test device 3, comprising a second test surface 311, was arranged on the first test surface 1. In the present embodiment, the test device 3 comprises a second series production component 31, also taken from series production, which forms the second test surface 311, and several spacers 32 arranged on the second test surface 311 of the second series production component 31. The second series production component 31 can, for example, be an underride guard of the motor vehicle.

[0022] In the present embodiment, the second test surface 311 of the series production component 31 was treated to be non-sticky by applying a release agent after the series production component 31 had been removed.

[0023] The test device 3 was arranged on the first test surface 11 such that the material 2 is located between the first test surface 11 and the second test surface 311.

[0024] The spacers 32 are designed such that the first series production component 1 and the second series production component 31 are positioned relative to each other under series production conditions when the spacers 32 are placed on the first test surface 11. In particular, the first test surface 11 and the second test surface 311 are arranged at a defined distance A from each other.

[0025] During hardening, material 2 expands as shown by the arrows. Fig. 1 indicated.

[0026] To investigate the expansion behavior of material 2, the test device 3 is lifted from the first test surface 11 after a defined curing time, i.e., after material 2 has cured, and then it is checked whether the cured material 2 behaves as described in Fig. 2 shows an imprint 4 from the second test surface 311 or as shown in Fig.Figure 3 shows no imprint 4 from the second test surface 311.

[0027] In the quality testing method according to the invention, the first series production component 1 and the second series production component 31 are taken from series production at regular intervals and the expansion behavior of the material 2 is examined with these as described above. Reference symbol list 1 first mass-produced component 11 first test area 2 Material 3 Test device 31 second series production component 311 second test area 32 spacers 4 Print A distance

Claims

[1] Method for investigating the expansion behaviour of a material (2) which expands during curing, wherein: the material (2) to be examined is applied in a liquid state to a first test surface (11), a test device (3) with a second test surface (311) is arranged on the first test surface (11) in such a way that the two test surfaces (11,311) are arranged at a defined distance (A) from each other, the material (2) is located between the two test surfaces (11,311) after being applied to the first test surface (11) and after the test device (3) has been arranged on the first test surface (11), after a defined curing time, the test device (3) is removed, and after removing the test device (3), it is checked whether the cured material (2) has an impression (4) of the second test surface (311) or not. [2] The method according to claim 1, wherein the second test surface (311) is treated to be anti-adherent. [3] Method according to one of the preceding claims, wherein the material (2) is a foam. [4] Method according to one of the preceding claims, wherein the material (2) is applied in the form of a line. [5] Method according to one of the preceding claims, wherein the first test surface (11) and / or the second test surface (311) is formed by a series production component (1,31). [6] Quality control method for series production, wherein a series production component (1, 31) is regularly removed from the series production and a method according to one of the preceding claims is carried out with this, wherein the series production component (1, 31) forms the first test surface (11) or the second test surface (311). [7] Quality control method according to claim 6, wherein the material (2) is applied to the first test surface (11) under series production conditions. [8] Quality control method according to claim 6 or 7, wherein two different series production components (1, 31) are taken from the series production, and wherein one series production component (1) forms the first test surface (11) and the other series production component (31) forms the second test surface (311). [9] Quality control method according to claim 8, wherein the two series production components (1,31) are positioned relative to each other under series production conditions.

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