Product provided with security marking for individual identification, and method for preparing the product
The object of the present invention is a product provided with security marking for individual identification, and a method for preparing the product.
Many valuable products are provided with markings such as letters, numbers or Bar code in order to ensure identification. The markings are generally on the surface of the products and, accordingly, can easily be removed and/or replaced by another marking. In most cases the replacement of the marking is not detected at all and can not be proved later on. In case of making valuable equipments. It is elementary interest of the producers and the owner of the product to apply security marking on or in the product, which can not be removed or replaced.
The motor-blocks of cars belong to the most important products to be security marked. These are usually cast from Al-alloy or cast iron. The marking of the blocks contain series of numbers and letters and is important in view of the guarantee, of identification when selling or by police control and finding the stolen cars. It is therefor very important that the marking cannot be amended or replaced.
The security markings used nowadays do not meet these requirements. The mark- series made by casting or punching on the surface of a motor-block can be changed by means of different methods and it is very difficult or impossible to detect this change.
A number of methods have been developed in order to solve the problem. In GB 2331045 a process is described according to which the marking is a ribbon placed on any part of the object and a special welded joint formed on another part of the object. The images of the marking ribbon and then welded joint are commonly fixed on a photo or stored in a computer. The image of welded joints is always so special that
reproduction is practically impossible and, accordingly, it is impossible to change them.
DE 19732306 suggests that the cars shouldn't be marked on the usual place, i.e. on the motor-block, but the marking should be prepared on any of the discs by laser during manufacturing.
Neither the above methods nor other solutions have been applied so far, instead of the traditional method, i.e. the marking of motor-blocks by punching.
The object of the present invention is therefor to provide a security marking and a method for preparing thereof, by means of which the marking can be put into the inside of the object to be marked, where it does not disturb the proper use, at the same time it cannot be removed or replaced without deteriorating the product.
Accordingly, the invention is a product provided with security marking for individual identification wherein the identification mark is formed on a mark-carrier arranged at least partly within the product, between elements which are coupled by permanent joint and/or can be separated only by rendering the product unusable, or inside the cast or pressed material of a single element; and one of the parameters of its material differ from one of the parameters of product-material which can be tested in a nondestructive way.
The invention relates also to a method for preparing products provided with a marking for individual identification, wherein a mark-carrier is made of a material one of the parameters of which differ from one of the parameters of the product- material appropriate for non-destructive testing; an identification mark is formed on the mark-carrier and, during the production of the product, the mark-carrier containing the identification mark or a part of it is placed in the inside of the product between elements joined by permanent joint and/or separable only in case if the
product becomes unusable, or is placed within the cast or pressed material of a single element.
It is very important, that the material serving for marking should not be deteriorated during the production to such an extent, that later the identification becomes impossible. Moreover, the property of this material which will be tested must differ significantly from the same property of the product material to be marked. The material of the product to be marked and the marking product can be metal, plastic, ceramics or composite.
The mark carrier can carry the marking/coding information with its geometry or, in some cases, in its material. It can be formed by means of an optional shaping technology, e.g. by cutting, embossing, steaming, galvanization, etc. It is very important that the used testing method differ the mark-series from the surroundings and that a contrast can develop for the representation. The marking/coding information (mark-series) can also be developed in different ways.
If the product to be marked is transparent, the marking is visible. The test can be made by unaided eye, or - if the size of marking makes it necessary - by means of light microscope. The detector in this case is the human eye. In other cases films sensitive to the visible, infrared or ultraviolet light can be used.
However, the material of the item to be marked absorbs the visible light in most cases, so the marking in its internal part is invisible. So, it can be made visible only by ultrasonic, macro-X-ray, eddy-current or other non-destructive material-testing methods. In case of the ultrasonic test the information appears on the monitor of an equipment, while in case of X-ray or isotope test the information appears either on the monitor (X-ray picture amplifier) or on a film.
In case of metals and alloys, the mark carrier, e.g. a thin plate must be placed into the mould-cavity before casting. During casting, the plate carrying the mark-series should not be deteriorated during the time available for the solidification. In case of Al and Cu-alloy the steel or any of the metals having high melting points (e.g. tungsten, molibdene, tantal) or ceramic material can be used, while in case of cast iron or cast steel only this later one can be used.
If the material of the product to be marked is plastic, practically all kinds of metals (alloys) which do not melt at the temperature of the applied technology can be used, as well as ceramics, composite or an other kind of plastic material can also be used. During sintering of the metallic powders and ceramics the requirements are similar. The material of mark carrier should not be deteriorated at the temperature of sintering. In case of ceramics or metallic powders sintered at high temperatures, the material of the carrier can be for example tungsten, molibdene, tantal or ceramic.
The main advantage of the invention is, that the marking is not accessible without deteriorating the product, therefore it cannot be changed, cannot be removed and cannot be replaced. At the same time, the marking can be read quite simply and reliably by means of well-known methods.
Further details of the invention will now be described by way of examples with reference to the accompanying drawings in which:
Fig. 1 :shows a mark-carrier, Fig. 2: is the mark-carrier shown in Fig.l within a mould,
Fig. 3: is the mould containing the mark-carrier and the casting, Fig. 4: is the X-ray photo of the mark-carrier in the casting, Fig. 5 : is the cross-section of a motor-block with mark-carriers, Fig. 6: is a mark-carrier in a mould, Fig. 7: is the location of a mark-carrier in a sand mould,
Fig. 8:shows the identification of mark-carriers arranged in a motor-block by isotope gauge, Fig 9: shows the identification of a mark-carrier placed in the motor-block by ultrasonic gauge, Fig. 10: is the arrangement and testing of a mark-carrier in a cooling rib, Fig. 11 : is the arrangement of a mark-carrier cast in a closed profile, Fig. 12: is the arrangement of a mark-carrier welded (soldered, stuck) in a closed profile Fig. 13:is a mark-carrier rolled between two plates Fig. 14: shows the fixing of the mark-carrier rolled between two plates by spot welding and Fig. 15: is the arrangement of a mark-carrier in ceramic or metallic powder.
The mark-series seen in Fig. 1 (in this case the name ROOSZ ANDRAS) were developed by means of laser cutting in 1 mm thick stainless-steel containing 18% Cr and 8% Ni. One of the mark-carriers 1 was placed into a mould cavity 2 (Fig. 2), then plexiglass has been cast in the mould. The mark-series can well be seen in visible light, but they are inaccessible unless the plexiglass is broken.
An other mark-carrier 1 was placed into a mould cavity 2 made of chamotte, then an Al-alloy was cast into the mould 2. After solidification of the melt, the mark-series surrounded by the metal become invisible (Fig. 3) and could be removed only after the deterioration of the whole casting. However the mark-series can be made visible by means of macro-X-ray technology (Fig. 4).
In the following examples marking a motor-block of a car will be described in details.
Fig. 5 is a cross section of a motor-block with water cooling channels 3 and cylinders 4. Mark-carrier 1 (a thin stainless steel plate in case of Al-alloy casting and a
tungsten-plate in case of iron casting) is placed near the surface of casting 5 at a distance of 5-25 mm from the surface ( "A") or between any of the cylinders 4 and a cooling channel 3 ( "B").
In case of die-casting (Fig 6) the mark-carrier 1 can be inserted into a gap formed in the mould 6 and will be held by the mould parts. Then the mould 6 is filled with Al- alloy or cast iron melt 8. If a sand-mould 9 is used as it can be seen in Fig. 7, the mark-carrier 1 can be connected to a core support 10. Following the solidification of the melt 8, the projecting part of plate has been machined, so it cannot be removed unless deteriorating the casting 5. The plate can have extensions for the safer fixing.
The mark-series consist a combination of numbers and letters and line code on the mark-carrier 1. The marks have been formed by laser cutting on the plates. In the first case the marking was provided by the geometrical shape of numbers and letters, and in the second case by the thickness of gaps (lines) and their distance from each other.
In case of version "A" (see Fig.5) the test was made by using isotope and ultrasonic sound, while in case of version "B" only isotope was used for testing. In the course of the isotope-testing (Fig. 8) the spark plug was removed from a cylinder 4 behind the mark-carrier 1 and an isotope 11 was introduced into the cylinder 4 in a flexible shielding metal tube. Then the isotope 11 was pushed out of the tube and the mark- series on the mark-carrier 1 were read by holding a film 12 or a sensing detector 2 on the wall of the casting.
In case if the mark-series consist of numbers and letters, the identification can take place immediately but if the mark-series are line-codes, it has to be transformed into numbers by means of a line-code reading device.
If cooling ribs or the like are on the motor-block, the mark can be arranged in a cooling rib 14 as it is shown in Fig 10. The information on the mark-carrier 1 can
than be read not only by isotope and ultrasonic methods but by X-ray as well. If an X- ray tube 15 emitting X-ray is on the one side of the cooling rib 14 and a detector 16 (film or X-ray picture amplifier) on its other side, the mark-series appear on the film or on the monitor connected to an X-ray picture amplifier.
This invention can also be used in the same form for the secret marking of the gear box or other cast parts of the car.
Moreover, the invention can be used for marking the chassis and body of cars as well. If the chassis is completely or partly made of Al-casting, the method described for the marking of motor-block can be used in the same way as described above. However, the chassis (bottom plate) of modern cars usually is not made of casting. In such cases, the closed profiles in the bottom plate and the body can be used for housing the markings. The door-column is especially suitable for this purpose.
The plate carrying the marking can be arranged in a closed section in many different ways. In case of a shape shown in Fig. 11 the mark-carrier 1 was first cast into an Al- alloy melt by casting process, and the casting 5 was fixed in the closed profile 17. The mark-series can be read by ultrasonic method. The casting 5 containing the mark-series can be produced directly in the closed profile 17 as well.
Fig. 12 shows the version, where the mark-carrier 1 is fixed on the inner surface of a closed section 17 by spot welding, soldering or sticking. In this case the mark-series can be read by ultrasonic method.
The mark-carrier 1 can also be locked between two plates by rolling (Fig. 13). It is then placed between two parts of object 18 to be provided by marking and the "sandwich" formed such a way is passed between two rolls 19. The plastic properties of the object to be marked and that of the mark-carrier should be chosen in a way that the mark-carrier 1 does not change its shape significantly during the plastic
deformation, while the object to be marked 18 covers it by significant deformation (Fig. 14). The locking action can be increased by welding 20.
By using the method according to the invention, the marking of an object can be changed only by deteriorating the whole product, i.e. by damaging the motor-block, gear-box, the cast part of chassis or the closed profiles of body. At the same time the marking according to the invention does not disturb the operation of the product (motor, gear-box, chassis).
Nowadays a number of products are made by sintering of ceramic- and metallic powders. Similar to the products described above, these products can also be marked. During production, the mark-carrier 1 is placed into a gap 22 formed between the two halves of tool 21. (Fig. 15). When closing the two halves of tool, the mark carrier is fixed and when the tool-cavity is filled with ceramic (metallic) powder 23 and the powder is pressed with a pressing tool 24, the mark-carrier becomes inseparable part of the product. Then the pressed material is sintered to the desired product provided with security marking. In this case the material and sizes of the mark-carrier must be chosen such a way that it should not be deteriorated during the technological steps. The mark-series can be read by ultrasonic, X-ray and isotope methods.
It is to be noted, that the above examples serve merely for the illustration of the invention, and both the product and the method can be carried out in many other different ways. The mark-carrier can be made inaccessible not only by casting or sintering or fixing it in the inside of the closed profile. The mark-carrier can be placed between any two parts which are joined by permanent joint, e.g. by welding during their production. The mark-carriers can also have different shapes or they can be objects which can be identified with their material or material-combination in a special way.