Method for determining the surface cleanliness of solid technical bodies using a wipe test

Abstract

Method for determining the surface cleanliness of solid technical bodies by means of a wipe test, whereby a cloth, fleece, pad or similar means for absorbing dirt is passed over the surface of the technical body and adhering particles or substances are subsequently examined and evaluated, where a manually guided or guideable testing device is used for surface scanning, wherein a supply of the contaminant-absorbing means is accommodated within the testing device and this means emerges in sections or pieces from an open side of the testing device, wherein the testing device is further configured such that the contaminant-absorbing means can be moved over the surface of the technical body with an adjustable, substantially constant pressure force, characterized in that Within the test facility, an analysis or evaluation of adhering soiling is carried out by an integrated sensor system, whereby the agent absorbing the soiling is conveyed to the sensor system after the wiping process and remains inside the test facility, protected from interference.

Description

[0001] The invention relates to a method for determining the surface cleanliness of solid technical bodies by means of a light test, wherein a cloth, fleece, pad or similar means for absorbing soiling is passed over the surface of the technical body and subsequently adhering particles or substances are examined and evaluated, according to the preamble of claim 1.

[0002] In industrial processes, surfaces of components or finished parts are mainly wiped with a lint-free, light-colored cloth, dry, damp or using a solvent to check cleanliness.

[0003] The particles adhering to the surface of the respective body as a result of the wiping process, or contamination, are subjectively assessed by visual inspection. If contamination is detected, a subsequent cleaning process with repeated wiping tests is carried out.

[0004] While this assessment is highly subjective, it is virtually impossible to determine the type of contamination simply by examining a wipe. For example, it is impossible to determine whether the contamination is critical dust, oily or greasy, or other contaminants, such as those originating from a previous manufacturing process. Therefore, analyzing such manufacturing processes for the resulting contamination is either impossible or only possible to a very limited extent.

[0005] DE 100 10 839 C2 discloses a device and method for determining the cleanliness or degree of contamination of surfaces to be tested. A transmitter and a receiver for optical radiation are used for this purpose.

[0006] The transmitter is connected to a sine-wave generator via an adjustable amplifier. Both the transmitter and receiver preferably operate in the infrared range. Based on the reflected radiation, the degree of contamination can be determined and, if necessary, cleaning measures can be initiated.

[0007] EP 1 914 538 A1 discloses a method and a device for detecting the cleanliness or contamination of a partial area by measuring the intensity of a background fluorescence of the contamination after prior calibration on reference areas.

[0008] In the method for detecting oil types on technical surfaces prior to cleaning or for determining the amount of residual oil on these surfaces after a cleaning step, according to DE 198 46 775 A1, the oil type in question is identified by the oil's individual fluorescent radiation. A cleaning agent or cleaning solution is then formulated to optimally remove the identified oil type from the surface to be cleaned.

[0009] The cleaning results are tested by adding a tracer substance to the oil on the surface before cleaning. After cleaning, the tracer's fluorescent radiation is excited, and its intensity, after calibration, is used to determine the residual oil remaining on the surface.

[0010] A wipe test device for examining surfaces for radioactive contamination is previously known from DE 77 11 219 U. This device contains so-called wipe test papers in a receiving cylinder, which are detachably connected to one another to form a block. Devices for holding the wipe test paper block are required, consisting of spring elements aligned parallel to a feed direction relative to the block and receiving cylinder. These spring elements act laterally on the surface of the block. Since the spring elements consist of elements aligned parallel to the feed direction relative to the block and receiving cylinder, the entire effect on the surface of the block can only be lateral. In accordance with the previously known teaching, the spring elements are designed from elastic sheets or wires with sections curved towards the surface of the block and are clamped on one side.The spring elements are bent radially at the front of the receiving cylinder, pointing away from the feed direction. This measure ensures that the wipe test paper block does not become jammed in its guide and does not detach from the feed piston on the device.

[0011] The necessary contact pressure is generated by turning a knurled nut with a piston. The contact pressure and its uniformity therefore do not depend on the spring elements. A substantially constant contact force cannot be provided.

[0012] DE 103 40 378 B3 shows a device for conducting a wipe test on a moving belt. A sample holder containing an absorbent sample piece impregnated with solvent is mounted on a longitudinal slide of a linear guide gear. The linear guide gear is frictionally connected to the longitudinal movement of the belt via a drive. Therefore, a mechanical coupling must be present between the moving metal belt and the wipe test device so that the wipe test can be conducted across the entire length or width of the metal belt.

[0013] The methods and devices described above for determining the degree of contamination of technical bodies are either too inaccurate due to subjective observation or require considerable technical effort. In many cases, this high level of effort is not communicable to the respective purchaser or customer, given the resulting costs and the necessary coverage amounts for industrial products.

[0014] Based on the above, it is therefore the object of the invention to provide an advanced method for determining the surface cleanliness of solid technical bodies using a wipe test, which, on the one hand, draws on the practical knowledge and experience of conventional manual wipe tests, but, on the other hand, eliminates the disadvantages of previous assessments based on subjective observation. Therefore, a sub-object of the invention is to create a method that provides reproducible assessment results regarding surface cleanliness.

[0015] The object of the invention is achieved by a method according to the combination of features and the sequence according to claim 1, wherein the subclaims represent expedient embodiments and further developments.

[0016] Accordingly, a method for determining the surface cleanliness of solid technical bodies is assumed by means of a wipe test, whereby a cloth, fleece, pad or similar means or material that absorbs dirt is passed over the surface of the technical body and adhering particles or substances are then examined and evaluated.

[0017] A manually operated testing device is used for surface scanning.

[0018] A supply of contaminant absorbing agents is stored within the test facility.

[0019] This agent exits the test device or the test device at an open side.

[0020] Furthermore, the testing device is configured such that the means for receiving the contaminants can be moved over the surface of the technical body with an adjustable, substantially constant pressing force.

[0021] Thus, the respective section of the supply of the means for receiving the contaminants is always guided over the surface of the body to be examined with an exact, reproducible and substantially constant force.

[0022] After a first such wiping process is completed, a fresh means for receiving the contaminants or a correspondingly unused section of this means is transported to the open side of the testing device.

[0023] The section that already has contaminants is located inside the testing device and is thereby protected from further impairments, in particular contaminants or other influences.

[0024] According to the invention, the analysis of the type and / or quantity of contamination per unit area is carried out by sensors arranged within the testing device or by a more complex sensor system.

[0025] In this respect, the testing device also includes a means for transporting the contaminant-absorbing agent, for example, in the form of a textile tape or strip. The transport means can comprise a winding or unwinding reel.

[0026] Alternatively, the contaminant-absorbing device can also be a pin or rod with a head section covered with a puffy material. The pin or rod is then set in a rotating or twisting motion and inserted, for example, into a hole or cavity to be examined to absorb any contaminants that may be adhering there, for subsequent analysis.

[0027] In a further development of the invention, the data acquired by the sensors is recorded, temporarily stored, and transmitted to an external data processing device via an interface. The interface can be wired or wireless, for example, via a Bluetooth interface.

[0028] The test device includes, for example, a winding and unwinding device for a preferred band-shaped and / or a magazine for a rod-shaped dirt-absorbing agent.

[0029] Grease or oil-based contamination is determined by detecting a typical individual fluorescence radiation. Such detection of fluorescent radiation is preferably carried out within the testing facility using appropriately modified sensors.

[0030] The contaminant-absorbing means located within the testing device can be wetted with a liquid. For this purpose, a liquid reservoir can be arranged in the testing device, which, in one embodiment, has a dropper that dispenses a predetermined amount of liquid onto the relevant area of ​​the contaminant-absorbing means.

[0031] The liquid can be a solvent, a cleaning agent, or even distilled water. Wetting with liquid is intended to improve and optimally absorb contaminants from the surface of the technical body, allowing the degree of contamination or cleanliness to be assessed as accurately and comprehensively as possible.

[0032] The dirt-receiving means is monochromatic, in particular light-colored, again in particular white-colored, at least on its side that comes into contact with the surface of the technical body. This is to achieve the best possible contrast effect with potential dirt particles in order to improve the detection of the degree of soiling, in particular by optical means.

[0033] In this regard, an optical sensor for detecting the discoloration of the dirt-receiving means is used in the testing device.

[0034] The optical sensor can be connected to an evaluation and display device integrated in the testing device, so that after wiping operations, a first, objective cleanliness evaluation is possible.

[0035] The evaluation and display device can be calibrated in advance in such a way that a previously defined degree of contamination is visualized using an exemplary traffic light display.

[0036] A textile, woven, knitted or nonwoven tape and / or a pin or stick surrounded by a puffy material can be used as the means for absorbing the soiling.

[0037] In this regard, a magazine is provided in the test facility so that unused material can be used very quickly after the corresponding agent has been used up.

[0038] Depending on the surface material of the technical body to be examined, specific soiling absorbent agents can be advantageously used. This takes into account not only the potentially expected soiling, but also the scratch resistance and properties of the body material, particularly to prevent the wiping process from adversely affecting the surface roughness of the body.

[0039] In a further development of the invention, the testing device comprises a CMOS or CCD matrix camera, allowing a current image of the soiling adhering to the cleaning agent to be taken immediately after each wiping process. These images can be transmitted to a monitor via the aforementioned interface or stored within the testing device and read out at a later time. The cleaning agents that absorb soiling are automatically transported further within the testing device after each wiping movement, providing a fresh portion of the corresponding cleaning agent.

[0040] The invention has been defined above by means of essential method features and method steps to be carried out. According to the invention, furthermore, a device, in particular an inspection device, which has the described technical means, and the configuration of a magazine or refill magazine, which contains the relevant means having contaminants, for example the mentioned belts or rods, is provided.

Claims

[1] Method for determining the surface cleanliness of solid technical bodies by means of a wipe test, whereby a cloth, fleece, pad or similar means for absorbing dirt is passed over the surface of the technical body and adhering particles or substances are then examined and evaluated, where a manually guided or guideable testing device is used for surface scanning, wherein a supply of the contaminant-absorbing means is accommodated within the testing device and this means emerges in sections or pieces from an open side of the testing device, wherein the testing device is further configured such that the contaminant-absorbing means can be moved over the surface of the technical body with an adjustable, substantially constant pressure force, characterized by , that Within the test facility, an analysis or evaluation of adhering soiling is carried out by an integrated sensor system, whereby the agent absorbing the soiling is conveyed to the sensor system after the wiping process and remains inside the test facility, protected from interference. [2] Method according to claim 1, characterized by that the data determined by the sensors are recorded, temporarily stored and transmitted via an interface to an external data processing device. [3] Method according to one of the preceding claims, characterized by that the test device has a winding and unwinding device for a band-shaped and / or a magazine for a rod-shaped, soiling-absorbing agent. [4] Method according to one of claims 1 to 3, characterized by that greasy or oily contaminations are determined by detecting a typical individual fluorescence radiation. [5] Method according to one of the preceding claims, characterized by that the soil-absorbing agent is designed in a single colour, light colour or white, at least on the side that comes into contact with the surface of the technical body. [6] Method according to claim 5, characterized by that an optical sensor is used in the test device to detect discoloration of the agent absorbing the contamination. [7] Method according to claim 6, characterized by that the optical sensor is connected to an evaluation and display device integrated in the testing device, so that an initial, objective cleanliness assessment can be carried out after wiping processes have been carried out. [8] Method according to one of the preceding claims, characterized bythat a textile, woven, knitted or nonwoven tape and / or pins or rods surrounded by a puffy material are used as the soil-absorbing agent. [9] Method according to one of the preceding claims, characterized by that the testing device has a CMOS or CCD matrix camera, such that a current image of the dirt adhering to the agent can be taken immediately after each wiping process. [10] Method according to one of the preceding claims, characterized by that the soiling absorbing agents are automatically transported further within the test device after completion of a wiping movement and a fresh section of the agent is provided.