Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
  • B24D11/02—Backings, e.g. foils, webs, mesh fabrics
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials

Definitions

• the invention relates to an abrasive belt with a backing, which comprises threads running in the direction of the sanding belt, providing the greater part of the longitudinal strength of the sanding belt, and a thread binding connecting the threads to one another.
• the invention further relates to a method and devices for producing such an abrasive belt (WO 86/02306).
• Abrasive belts consist of a flexible base which transmits the grinding forces and an abrasive grain layer anchored thereon by means of a binding agent.
• a binding agent As a rule, up to 3000 meters long sheets of the substrate already coated with binder and abrasive grain are wound into rolls.
• the individual sanding belts are made up from these webs by separating strips from a web in accordance with the dimensions of the sanding belt to be produced and joining the ends thereof by means of special connecting techniques to form an endless sanding belt become.
• the connection point forms an undesirable inhomogeneity in the course of the grinding belt, both because of the changed flexibility and the increased or reduced thickness, by which the running behavior of the belt and the engagement behavior of the grain tips can be impaired and errors in the grinding pattern can be caused.
• connection point obliquely or even at an acute angle to the tape running direction (US Pat. No. 4,018,578, EP-A 626238), especially since such an arrangement usually comes into conflict with the requirement to arrange the direction of greatest tensile strength and least elongation of the base in the direction of tape travel.
• connection point obliquely or even at an acute angle to the tape running direction
• EP-A 626238 EP-A 626238
• connection point on the one hand, repeatedly determines the limits of the use of tools and, on the other hand, due to wear (tearing) a premature failure of the grinding belt can cause.
• such a backing appears to have a uniform surface or back structure, as is the case with abrasive belts free of connection points, only when soft, fleece-like fiber materials are used, while the use of firm and low-stretch textile material with threads running in the belt direction in the area the neighboring ends of this textile material must lead to a weak point or to inhomogeneity.
• the invention is therefore based on the object of providing an abrasive belt of the type mentioned at the outset, which is free of joints.
• a production method and a device suitable therefor are also to be made available.
• the solution according to the invention is that the threads are arranged helically running through the bandwidth. This arrangement is achieved in that a thread or a group of threads is wound helically without spacing or at a substantially constant spacing and the turns are connected to one another by means of a thread binding that preferably solidifies from the flowable state and are coated with abrasive grain.
• the grinding belt produced in this way is free of connection points.
• the thread binding can connect the threads directly to one another. If the thread cohesion in the transverse direction is sufficiently firm, it may be possible to dispense with further components of the base or the sanding belt which establish its transverse strength. However, an embodiment is particularly expedient in which an auxiliary underlay is provided and the thread binding is designed to connect the individual threads to the auxiliary underlay.
• the angle between the direction of the grinding belt and the thread direction should not be greater than 3 °. It is better below 1 °, even better below 0.5 °. The thread direction therefore coincides essentially with the running direction of the belt, so that the direction of greatest strength and least elongation of the finished abrasive belt coincides with the belt running direction.
• the auxiliary underlay has the task of simplifying the manufacture of the abrasive belt underlay in the winding process and of facilitating the detachment of this layer from the winding device. It can also take on tasks in the finished abrasive belt, in particular to contribute to the formation of the transverse strength of the abrasive belt or to the thread layer from rear abrasion by the rollers driving the abrasive belt or by a support element that presses the abrasive belt against a workpiece protect. As a rule, the auxiliary underlay is part of the finished sanding belt. However, there may be applications in which it is undesirable or unnecessary in the grinding belt.
• an auxiliary base or the binder connecting it to the thread is selected in such a way that the auxiliary base can be easily removed.
• the transverse strength of the sanding belt can then be ensured, for example, by a fiber-reinforced thread binding.
• the auxiliary underlay can be formed from different materials, for example from fiber and textile material such as fleece, woven or knitted fabrics. It can be formed from plastic or metal foils. Combinations of several such surface materials are also possible. It can already be grained on the side facing away from the thread layer to be formed. If high uniformity and dimensional stability are important, this is the solution
• REPLACEMENT BLA ⁇ for example polyester or polyimide films. If the structural roughness of textile material is not perceived as disadvantageous, woven fabrics or knitted fabrics in particular are suitable.
• the auxiliary underlay should preferably be such that it guarantees the transverse strength of the grinding belt. However, its strength in the direction of tape travel should influence it as little as possible in relation to the longitudinal strength of the thread layer. It should also influence the flexibility in the belt running direction as little as possible, so that there is no significant discontinuity in the abrasive belt properties at its abutment.
• the thread binding is formed by an adhesive and hardening material, especially since one can rely on proven materials and techniques.
• the threads are welded to the auxiliary support and / or to one another.
• monofilament or ribbon-shaped threads made of thermoplastic material can be connected to a film of the corresponding material forming the auxiliary base by laser welding.
• monofilament threads can also be connected to one another by friction or pressure welding.
• the resin material intended for the formation of the thread binding which has not yet solidified, is applied, for example, over a large area or only to that point on the auxiliary base on which the wound thread is initially laid. Instead, the mass can also be applied to the thread and transported by it to the winding station. Immediate fixation of the thread on the auxiliary pad is possible by a contact adhesive layer on it; in this case, the thread binding serves to achieve sufficient transverse strength.
• the auxiliary underlay is on that of the grain layer
• ERS ⁇ ZBL ⁇ T (RULE 26) opposite side of the threads.
• the underlay then need not be turned over before the grain layer is applied.
• a filler bond to the threads which fills the spaces between the threads on the side facing away from the auxiliary pad and, if appropriate, also completely or partially covers the threads or the spaces between the threads.
• the latter is particularly advantageous if the material of the basic grain bond does not adhere sufficiently to the thread material or if it is necessary, particularly with fine grain, to create a smooth, uniform surface for the application of the grain.
• the filler bond can also be used to form the transverse strength of the abrasive belt, for example by reinforcing it with fibers.
• These can be in the form of a sheet - e.g. a fleece - or in the case of a resin-fiber mixture as an ingredient of the resin. If it is important to ensure greater transverse strength in this area of the sanding belt, further elements can also be inserted between the filler bond and the grain base bond, for example, sheets of thread running in the transverse direction or a film made of plastic or metal or the like .
• the filler bond and the grain base bond need not be separated with regard to the application and the material properties. Rather, the filler bond can also be used as a basic bond for the grain. This also applies in the case of fiber reinforcement of the filler bond.
• the filling binding can also coincide with the thread binding, for example by feeding the thread binding during the winding process in such a way that it also fills the space between the threads on the side facing away from the auxiliary pad. Or it is possible to dispense with the addition of binders during wrapping and instead from the auxiliary pad afterwards facing away from the binder are applied so that it penetrates the interstices sufficiently deep, possibly up to the auxiliary pad. With regard to the terminology of the claims, the filling binding can thus be part of the thread binding or form it (possibly together with the basic binding).
• the base can be turned after the threads have been wound and the thread binding and, if appropriate, the filling binding have hardened sufficiently.
• the auxiliary pad is applied after winding the thread layer.
• the grain layer is then applied to the back of the auxiliary underlay or, after the auxiliary underlay has been removed, to the back of the thread layer.
• it can be advantageous to turn over the underlay consisting of smooth auxiliary underlay, threads, thread binding and / or filler binding and to provide the smooth surface of the auxiliary underlay with binding agents and abrasive grains.
• relatively coarse thread material and larger thread spacings can be selected without this having a direct influence on the surface structure of the tool.
• the threads are expediently arranged in one layer, which does not rule out a multi-layer arrangement in special cases. In the latter case, the threads are then connected to one another by the thread binding and / or the filling binding.
• the threads can also be connected to one another in that they are galvanically integrated from the later grain side.
• the threads are arranged free of interstices.
• An even more homogeneous thread layer is achieved if they are arranged to overlap one another (with an elongated cross-section) or to adapt them to one another.
• the latter can be achieved in the case of a loose thread structure, such as is present in particular in the case of rovings (fiber strands which are not or only slightly twisted).
• rovings fiber strands which are not or only slightly twisted
• the thread structures and thread materials most suitable for the respective application can be selected according to known aspects.
• the term "thread” means any windable structural element whose cross-sectional dimensions are very small compared to the sanding belt width. It can be monofilaments that do not necessarily have to have a round cross section. A square or rectangular cross section (ribbon) can be expedient in order to achieve a flat, resilient connection of adjacent thread turns. Their width preferably does not exceed ten times their thickness. Additional stabilization with an auxiliary underlay or a filler layer can therefore be dispensed with. This also applies to thread materials with a large number of individual fibers or thread components oriented transversely to the direction of extension of the thread. But it can also be filament or staple fiber threads. Depending on the application, material suitability includes, for example, cotton, polyester, aramid, glass or carbon fibers as well as metals and the like Materials. Furthermore, it can be mixed materials such as metallic or conductive coated materials.
• a single thread can be provided. To accelerate the winding process, however, several separate threads can also be wound side by side as a group.
• the threads of the thread group can be listed individually or together on the winding support. In the latter case, the thread group can consist of separate threads which are only connected by the thread guides of the winding device. However, the threads can also have previously been combined to form a band, for example by mutual gluing or by connecting the individual threads to a carrier band. This need not have any substantial strength and can therefore consist of paper or nonwoven material or the like. It is not necessary (but also not excluded) that it takes on a function in the sanding belt underlay. If necessary, it can be removed after wrapping.
• a winding drum is suitable for winding the thread layer, the winding circumference of which corresponds to the grinding belt length to be produced. So that the product can be removed, the wrap circumference should be reduced.
• the winding device can also have a plurality of rollers (in particular a pair) rotating around a winding support belt, the length of the winding support belt being equal to the length of the grinding belt to be produced.
• the winding support tape can form the auxiliary pad if necessary. However, an additional support band can also be provided on which the auxiliary support is stretched.
• the winding support tape can also be used to facilitate the removal of the wound product and, if necessary, its transfer for further processing.
• the product can be removed from the winding device in a stabilized manner by the support belt and fed to a further storage or processing station become. It can run through several manufacturing and processing stations on the same support belt.
• a support band also has the advantage that in many cases it is easier to separate from the winding device - be it a pair of rollers or a drum - than a base which is directly wound on the winding device.
• the support band removed from the winding device can easily be separated from the base. This applies regardless of the type of winding device.
• a winding drum it expediently consists of a thin-walled, preferably metallic cylinder, which can be applied to the winding drum by means of only slight changes in the circumference thereof, and tensioned or removed.
• the wound abrasive belt underlay - provided that it has not already been further processed on the winding machine by coating and graining - can be removed from the winding machine in a clamped manner on the auxiliary device and then simply separated from it or fed to other processing devices in this setting.
• the backing of the grinding belt according to the invention becomes particularly demanding just as they apply to the use of high-performance abrasives (eg diamond or cubic drilling nitride) for which a galvanic bond is appropriate.
• high-performance abrasives eg diamond or cubic drilling nitride
• This can be applied to a base with an electrically conductive thread and / or electrically conductive filler bond.
• Used sanding belts can contain individual layers that have to be disposed of as special waste. For this reason, it may be necessary to classify the entire sanding belt as special waste. Furthermore, it may be desirable to use substances in certain Recycle layers of an abrasive belt without being contaminated with certain foreign substances that are found in other layers of the same abrasive belt.
• the invention therefore provides that the sanding belt contains structural or material elements at a suitable point which allow the parts of the sanding belt located on both sides of the separating layer to be separated.
• This separating layer can, for example, be distinguished from neighboring layers by a lower separating resistance, which may also only be achieved by suitable chemical or physical treatment before or during the separation. For example, it can be a thermoplastic layer which allows the abrasive belt layers on both sides to be separated at elevated temperature.
• a particular advantage of the invention is that the entire production of an abrasive belt can be carried out in one go, while the base is kept on one and the same supporting structure, if possible in one and the same machine.
• the manufacturing technology according to the invention makes it possible to manufacture abrasive belts of different sizes and properties without having to resort to specific semi-finished products in the form of sheets of already grained base, as is the case with conventional manufacturing consisting of basic manufacturing and further processing. Accordingly, not only does the requirement for the availability of an extensive range of semi-finished products become obsolete, but moreover a higher degree of manufacturing flexibility and variety of products is achieved in that virtually all design and structural elements that determine the specific properties of the tool are specified at the start of production become can. The products obtained in this way are quickly available and could also be manufactured decentrally in comparatively small production facilities.
• the conventional sequence of document production, basic production and assembly is overcome in favor of a flexibly controllable, modularly structured complete production.
• FIG. 3 shows the schematic structure of an abrasive belt according to the invention opened in layers in perspective
• FIG. 4 shows a cross-sectional illustration of the grinding belt according to FIG. 3,
• Fig. 8 is a plan view of a double layer of threads with crossing threads and
• 9 to 14 are cross-sectional representations of different exemplary embodiments.
• a winding device consisting of two rollers 1 with a variable spacing is first one Auxiliary pad 2 applied, which has a thinly formed auxiliary connection point 3.
• auxiliary connection point 3 For example, it consists of a polyester film. Their length corresponds to the length of the sanding belt to be produced.
• the rollers 1 are set so that the auxiliary support 2 is sufficiently tensioned for the winding process but is stretched as little as possible.
• the corresponding thread stretch is set by means of the thread brake 8.
• a thread 4 is wound on the winding device, which is rotated in the direction of the arrow, one turn coming next to the turn and the distance between the individual turns being set in such a way that such a large number of thread turns per unit width of the grinding belt is omitted that this has the desired longitudinal strength, longitudinal elongation and surface structure provided by the threads.
• the thread 4 is unwound from a roll 5 and guided by a thread guide 6 so that the desired thread spacing is achieved.
• only one winding drum 7 is provided, which consists of a plurality of drum segments which are adjustable in relation to one another in such a way that the circumferential length of the drum is changed and can be adjusted to the respectively desired belt length.
• an auxiliary support 2 is stretched onto the winding device, onto which the thread 4 is then wound from the roll 5 via the thread guide 6.
• the surfaces of the rollers 1 or the drum 7 can be provided with a strongly adhesive surface.
• the thread binding is provided, which is expediently applied to the auxiliary base or to the thread before winding is and glued to the auxiliary base and / or with the thread winding previously applied or connected in another way.
• the thread binding is applied before or during the winding process, it can be restricted in such a way that it merely fixes the thread on the auxiliary support or the thread on adjacent threads sufficient for handling the elements during the production process brought about.
• the final mutual connection of the elements then takes place through a subsequently applied filler layer.
• the thread binding supplemented by the filling binding has the task of firmly integrating the threads into the arrangement. If necessary, it can form the only binding for the threads, for example if a previously applied thread binding is missing or if it is also detached from the grinding belt when the auxiliary underlay is detached. It connects the threads with each other and, in special cases, also with an auxiliary pad. With fine grain, which requires a smooth surface of the abrasive belt base, it also contributes to the formation of such a uniform surface by filling the spaces between the threads. Finally, the filling layer can also contribute to the formation of the transverse strength of the band, in particular when it Is fiber reinforced (Fig.12). The grain layer is applied thereon in a conventional manner, the filling layer also being able to form the basic bond for the grain at the same time.
• FIGS. 3 to 5 The normal structure of the abrasive belt with base 2, thread binding 10, threads 4, filling layer 11, basic binding 12, grain 13 and finally cover layer or post-glue 14 is illustrated in FIGS. 3 to 5.
• FIG 5 shows the angle ⁇ (shown enlarged for illustration), which the threads form with the tape running direction, as well as the thread diameter d ⁇ and the thread spacing a .., on the underside of the thread binding 10 and on the top of the filling bond 11 is filled.
• a particularly high stability of the tape in the diagonal and transverse directions is obtained when the neighboring threads are very intimately connected. This is achieved, for example, by an overlapping arrangement according to FIG. 6 using threads which have an elongated cross-sectional shape.
• a high longitudinal tensile strength per unit of width is obtained by multilayer thread arrangement as shown in FIG. 7.
• the threads 4 of the lower thread layer can run parallel to the threads 4 'of the upper thread layer by being wound in the same direction, or the threads 4' of the upper thread layer run antiparallel to the threads 4 of the lower thread layer according to FIG for example at the opposite angle to the direction of tape travel.
• thermosetting resins are also at the sanding belt according to the invention normally used. If, however, one wishes to dispose of the grain separately from the rest of the layer material in an abrasive belt of the type shown in FIG. 4, a layer which is variable under the influence of energy, for example heat, is switched on, for example from the filling layer 11 or the base ⁇ bond 12 can be formed and it z. B. after heating the abrasive belt to be disposed of, to separate the grain layer from the wound backing component.
• the auxiliary underlay is selected from a thermoplastic material and the grain layer is applied to the free side of the auxiliary underlay, so that this enables the separation of the grain layer and the wound components during disposal.
• Fig. 9 shows a structure in which the filling bond and the base bond of the grain layer form a uniform layer.
• this uniform layer is equipped with a reinforcement by glass fibers and carbon fibers or the like to increase the transverse strength of the belt.
• Belts of this type are particularly suitable for use with high transverse loads, such as occur with pronounced geometric complexity of the workpieces.
• the threads 4 are each connected to the auxiliary underlay by a laser-welded seam 15. This forms or replaces the thread binding.
• the filling bond 11 also forms the basic bond 12 for the abrasive grain.
• the aforementioned constructions provide for fixing the abrasive grain - preferably consisting of corundum or silicon carbide - by means of a synthetic resin bond
• the Using high-performance abrasives e.g. diamond or cubic boron nitride
• a galvanic bond may be advisable.
• 12 to 14 show constructions which are suitable for this.
• the surface of the filling layer 11 is made electrically conductive by an electrically conductive fiber filling, so that the abrasive grain 13 can be bound thereon by means of a galvanic layer 12.
• an electrically conductive thread is used in addition to the filler layer 11 filled with electrically conductive fibers.
• the top of the belt is sanded.
• the galvanic grain binding layer 12 is applied directly to the seamlessly wound, ground, electrically conductive thread 4.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Decoration Of Textiles (AREA)

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Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (5)

• 1995
  • 1995-08-29 DE DE19531774A patent/DE19531774A1/de not_active Withdrawn
• 1996
  • 1996-08-29 ZA ZA967330A patent/ZA967330B/xx unknown
  • 1996-08-29 AU AU69299/96A patent/AU6929996A/en not_active Abandoned
  • 1996-08-29 ES ES96930131T patent/ES2153977T3/es not_active Expired - Lifetime
  • 1996-08-29 AT AT96930131T patent/ATE197924T1/de active
  • 1996-08-29 DE DE59606193T patent/DE59606193D1/de not_active Expired - Lifetime
  • 1996-08-29 WO PCT/EP1996/003804 patent/WO1997007936A1/de active IP Right Grant
  • 1996-08-29 EP EP96930131A patent/EP0847323B1/de not_active Expired - Lifetime

Patent Citations (5)

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