WO2005063441A1 - Procede et dispositif de rectification de surfaces - Google Patents

Procede et dispositif de rectification de surfaces Download PDF

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Publication number
WO2005063441A1
WO2005063441A1 PCT/EP2004/014649 EP2004014649W WO2005063441A1 WO 2005063441 A1 WO2005063441 A1 WO 2005063441A1 EP 2004014649 W EP2004014649 W EP 2004014649W WO 2005063441 A1 WO2005063441 A1 WO 2005063441A1
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WO
WIPO (PCT)
Prior art keywords
workpiece
process medium
abrasive
machining
medium
Prior art date
Application number
PCT/EP2004/014649
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German (de)
English (en)
Inventor
Ewald Aicher
Henning Ahrens
Gerd Beck
Holger Hilzinger
Original Assignee
C. Hilzinger-Thum
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Filing date
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Application filed by C. Hilzinger-Thum filed Critical C. Hilzinger-Thum
Publication of WO2005063441A1 publication Critical patent/WO2005063441A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B31/00—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor
    • B24B31/10—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor involving other means for tumbling of work
    • B24B31/116—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor involving other means for tumbling of work using plastically deformable grinding compound, moved relatively to the workpiece under the influence of pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C3/00—Abrasive blasting machines or devices; Plants
    • B24C3/08—Abrasive blasting machines or devices; Plants essentially adapted for abrasive blasting of travelling stock or travelling workpieces
    • B24C3/10—Abrasive blasting machines or devices; Plants essentially adapted for abrasive blasting of travelling stock or travelling workpieces for treating external surfaces
    • B24C3/12—Apparatus using nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C9/00—Appurtenances of abrasive blasting machines or devices, e.g. working chambers, arrangements for handling used abrasive material
    • B24C9/006—Treatment of used abrasive material
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

  • the present invention relates to a method and a device for surface revision.
  • Machining of metallic workpieces can create areas on or below the surface with changed physical, chemical and otherwise different material properties. Examples of this in the case of metal surfaces are edge zones with induced internal stresses as a result of the hardening during forming, scaling due to heating and the formation of metallurgical changes such as superficial depletion or enrichment layers or structural changes due to heating or pickling. Tinder is the common technical name for oxide layers, which are created by the action of oxygen, often supported by heat, on the metal surface.
  • boundary layer includes all types of inhomogeneous material composition, in particular according to physically, chemically and metallurgically different states, which are located in, at or near the workpiece surface.
  • oxide layers which are present during processing must be removed: on the one hand, rolling in would deteriorate the strip quality, and on the other hand strips with an oxide layer would not correspond to the surface quality required by the market.
  • a method for removing such scale or oxide layers must also be able to remove depletion and enrichment layers which arise when certain elements disproportionately pass into the scale layer during heat treatment of the workpiece. It is known that such before depletion or enrichment layers deteriorate the usage properties of the workpiece in many ways.
  • Pickling processes can be used to remove oxide layers, but these require a great deal of process engineering effort for plant technology, preparation, regeneration and environmental technology. These pickling processes can be supported by brushing or minimized by reduction under a hydrogen atmosphere, as is described, for example, in EP 1 005 926.
  • US 6273790 describes descaling with a water-ice mixture at a pressure of 700 to 8000 bar.
  • IS-HICLEAN Another method for descaling workpieces is the so-called IS-HICLEAN method, which is described, for example, in the publications US 3984943, US 4251956 and US 4269052. It is a pressurized liquid jet process. This method requires a subsequent pickling step in order to achieve the quality required by the consumer, or is very expensive even with low demands on the surface quality without subsequent pickling. Similar processes are known from the publications US 3427763 and US 4195450.
  • ER 1032486 B1 and WO 9926764 A1 describe a method in which a workpiece is stationary using an abrasive liquid under a pressure of less than 50 bar or less than 20 bar can be shaped, ground and polished.
  • wet blasting processes are known in which a water-abrasive mixture is accelerated with the aid of compressed air and applied through nozzles, so that a three-phase jet is produced.
  • US 3521412 describes a flow grinding method in which a semi-solid medium containing abrasive particles is guided along the workpiece surface. The process is only suitable for batch operation, not for continuously moving workpieces.
  • the US 5700181 describes a device for pressure fluid blasting with abrasive at a pressure of approx. 2000 bar, in which the process medium, which contains abrasive particles with a diameter of 2 to 3 ⁇ m, through an annular gap with a maximum height of 13 ⁇ m at a speed of approx. 120 m / s.
  • High pressure technology the use of the finest abrasives and a very small gap height, which is disadvantageous in terms of control and production technology, of a nozzle which dispenses the abrasive are necessary for this process.
  • US 3524367 describes the effects of adding viscosity-increasing substances to a treatment liquid containing no abrasive in a high-pressure water jet process with pressures between 700 and 7000 bar.
  • a device is also known from publication WO 02074489 in which the workpiece surface and tool form an annular gap through which the process medium flows and thereby grinds or polishes the surface.
  • Methods for recovering the abrasive from the process medium are known from WO 9818598 A1, EP 0968801 A1 and EP 0916463 A1, in which the process medium is first dried in order to subsequently remove abrasion or worn abrasive and to reuse the remaining abrasive.
  • Such discontinuous processes are uneconomical and harmful to the environment (C0 2 emissions) in the case of continuous plant operation and in view of the high energy requirement for drying, and are therefore disadvantageous.
  • JP 2001-232234 and JP 3436304B2 also disclose methods for recovering rubbed-off valuable material from the process medium, which comprises abrasive and cutting oil.
  • the gallium compound ground during the wire sawing of gallium-containing single crystals is recovered from the oily process medium.
  • the aim of the present invention is to provide an environmentally friendly, effective and continuously working method for the machining of workpieces, in particular of strip-shaped rolled products, which is particularly suitable for the removal of metallurgically modified surface layers. Another aim is to provide a device for carrying out such a method.
  • a process medium is stored in a process medium container and passed via a process pump to a processing head in the area of a process container.
  • the process medium is an abrasive liquid that is controlled to move under a pressure of less than 50 bar, preferably less than 20 bar.
  • the workpiece is continuously fed through the process container, which makes the process particularly suitable for processing flat rolled products.
  • At least two essentially parallel machining jets are emitted onto the workpiece by the machining head, the number of machining jets determining the maximum width of the machinable workpiece, or a flow of the process medium running tangentially along the workpiece is generated by the machining head.
  • the impact angle 0 ° corresponds to a flow tangential to the workpiece surface.
  • the method can be applied to long and flat products, in particular rolled products, with less handling effort and enables a more effective method because the product to be processed passes through the process container.
  • the material removal can be kept very low with the inventive method due to the low pressure, if necessary, even if the process parameters so 1 can be chosen such that the material removal rate can be increased considerably. This results in the advantage of less material loss compared to the known methods. Due to the easily controllable material removal 7 rui / crzuu ° *> w 2 «& ⁇ ⁇ . ⁇
  • the method according to the invention enables the use of masks or covers which prevent the processing of covered areas.
  • Such masks wear much more slowly at lower pressures.
  • they can only be applied to the workpiece surface in a sealing manner with respect to the process medium or subsequently removed again under the operating conditions of lower pressure or lower flow speed according to the invention.
  • the extensive surface fidelity of the method is also advantageous, that is to say the shape of the workpiece surface is largely reproduced in a self-similar manner during the shaping or removal.
  • the machining process can be used to achieve a defined roughening or smoothing.
  • the change in the surface shape also changes the reflection and absorption properties of the surface for electromagnetic radiation.
  • the high specific heat capacity of the process medium with the abrasive contained in it results in efficient heat dissipation from the workpiece, which prevents local overheating and thus enables the processing of even heat-sensitive workpiece surfaces (e.g. metal surfaces with a low melting point or applied layers or surface layers such as metals such as tin layers; plastics; workpieces with a low heat capacity due to the material or the geometry, e.g. thin-walled parts or sheet metal strips).
  • even heat-sensitive workpiece surfaces e.g. metal surfaces with a low melting point or applied layers or surface layers such as metals such as tin layers; plastics; workpieces with a low heat capacity due to the material or the geometry, e.g. thin-walled parts or sheet metal strips).
  • the strength of the abrasive attack is often assessed according to the removal rate and the roughness parameters, but can also be assessed using any criteria that describe the change in the workpiece surface due to the machining process depending on the requirements, such as suitability for coating, machining or other subsequent processing or use steps.
  • the strength of the abrasive attack which is to be assessed in the relevant manner, can be influenced by:
  • the choice of the duration of action the choice of the type and geometry of the process medium being brought in and out on the workpiece surface (in the area of impact: eg impact angle a, the angle between the tangent to the workpiece surface at the point of impact and the direction of impact of the flow ; Distance between discharge device and workpiece surface in the tangential flow area, flow velocity, static pressure, cross-section of the flow area, height of the gap, shape of the flow area, friction losses due to eddy formation and viscosity),
  • the combination of two or more steps can significantly improve the machining result or enable higher process speeds.
  • the damping of the abrasive is increased or varied at all according to the invention by changing the viscosity of the process medium. This influences the interaction between the abrasive and the workpiece surface in such a way that smaller machining marks are created with otherwise the same process parameters or the process effect is practically completely suspended. Furthermore, the damping can be varied in that the interaction is considerably intensified by adding gas to the process medium or a particularly low roughness is achieved by dispensing with gas addition and / or increasing the viscosity of the process medium.
  • This interaction between the abrasive and the workpiece surface can be divided into two components, namely the interaction of the abrasive with the workpiece surface in the area in which the flow impinges on the workpiece surface (impact area) and the interaction of the abrasive with the workpiece surface in the area, in which the flow flows essentially tangentially along the workpiece surface (tangential flow area). These two flow areas are often combined in real arrangements.
  • the abrasive particles are brought to the surface at an impact angle a> 0 ° (angle between the tangent to the workpiece surface at the point of impact and the direction of impact of the flow).
  • This interaction therefore has a vertical component that is pronounced depending on the angle of incidence.
  • a pronounced shaping compression, throwing, etc.
  • Tangential flow area out which is particularly pronounced with a small angle of incidence.
  • This flow against the workpiece surface can, for. B. can be realized by directing a free jet generated with nozzles onto the workpiece surface. If a process flow is to be realized only with the impingement area without a tangential flow area, then the nozzle direction must be selected so that outflowing process medium flows over the still unprocessed surface or parts of the workpiece surface must be covered in order to minimize the contribution of the tangential flow area formed by the outflowing process medium to the overall effect , The process effect depends, among other things, on the working pressure and the angle of incidence a, as well as on the jet shape (full jet, flat jet with fan angle b, full cone jet, hollow cone jet, atomizer nozzle).
  • the damping effect of the liquid means that the same abrasive produces significantly smaller machining marks than would be the case with sandblasting. It is therefore advantageous to work with coarser grain, which means considerable cost savings. In addition, with the finest available abrasives, less roughness can be achieved with the method according to the invention than is possible with sandblasting.
  • An abrasive attack is first carried out on the surface in the impact area, which is maximum depending on the material, different impact angles.
  • the topography or roughness of the workpiece surface depends on whether the beam direction (or its projection onto the workpiece surface) is selected parallel or anti-parallel to the feed direction of the workpiece. This applies in particular to angles of incidence below approximately 30 ° to 45 °. If the beam direction is parallel, a point on the workpiece surface first experiences the relatively aggressive impact of the currents. tion or the jet and then the weaker, smoothing effect of the tangential flow area. In the case of anti-parallel beam guidance, a point on the workpiece surface is only pre-processed in the tangential flow area, which is followed by the more intensive attack in the impact area.
  • the first variant also leads to success with relatively thin and ductile boundary layers, the second can be advantageous because the incorporation of the layer material into the workpiece surface can be better avoided.
  • FIG. 1 shows a section of a flow field in the case of a liquid flow containing an abrasive and guided tangentially along a workpiece surface.
  • Figure 2 shows a side view in cross section of a machining head.
  • Figure 3 shows schematically an overall view of the inventive device for the machining of workpieces.
  • FIG. 1 shows a section of a flow field 10.
  • the flow adheres to a surface 11 of a workpiece 11 to be machined.
  • the flow runs along the axis 12 perpendicular to the surface in accordance with the vector arrows shown which represent the flow field 10.
  • Each movement on its own and in particular its interaction lead to the abrasive particle 13 exerting a removal effect on the workpiece surface 11 upon contact with it.
  • a tangential flow area and the interaction described for it can be generated by dispensing the process medium into a cavity which is formed by part of or all of the workpiece surface and a suitably shaped shape that is sufficiently sealed off from the workpiece.
  • a gap flow Such a device, which will be explained in more detail below, is referred to below as a gap flow.
  • the kinetic energy of the abrasive particles is not primarily transferred to the workpiece surface in a single interaction, but rather more precisely: Many successive interaction processes take place, which are dampened by the internal friction in the blasting medium. As described below, this damping can be specifically set or optimized via the viscosity of the process medium.
  • the boundary of a space between the gap stream and the workpiece surface is designed in such a way that there is a gap whose height is smaller than its length (defined as the shortest distance between the beginning of the gap on the supply side and its gap outlet); a ratio of height to length of 1: 5 or more is preferred, particularly preferably a ratio of 1:10 or more.
  • the gap height is at least twice the typical abrasive particle diameter, and a maximum of 200 times. A local widening of the gap or a narrowing of the gap that resembles the shape of the workpiece surface weaken or prevent the process effect in the area of the affected parts of the workpiece surface, which can thereby be protected selectively.
  • the volume flow under which the tool is charged with process medium determines the mean flow velocity or the flow conditions for a given geometry and process medium.
  • the number of interactions between abrasive particles and workpiece surface proportional to the volume flow determines the removal rate.
  • the pressure is important for the process insofar as the internal friction of the process medium has to be overcome so that it even passes through the gap with sufficient flow speed.
  • hard metals, sintered metals or ceramic materials are particularly suitable, but preferably polymeric materials such as, for. B. rubber, PTFE, PVDF, synthetic resins or polyurethane.
  • polymeric materials can be fiber-reinforced.
  • the tool surface, in particular in the area of the gap can be coated with these materials or with hard material layers.
  • the machining head is worn out due to the abrasive load and is consequently expanded.
  • the volume flow can be increased to maintain the pressure required for the machining process.
  • the feed of the workpiece is then increased by the same factor. If the feed rate is determined by other specifications (e.g. coupling to previous or subsequent processes in a line production), it is advantageous to provide actuators on the processing head that compensate for the expansion due to wear.
  • the flow field is initially influenced by the shape of the edge of the gap formed between the tool and the workpiece surface. Furthermore, the flow field can be influenced by making its cross-sectional area (ie the imagined perpendicularly flowed area) larger or smaller in the area of the gap than in the inlet, even if this is not fundamentally necessary for the method. From hydrodynamics, however, it is known that the speed of a flow, which is generated by a predetermined static pressure, increases when the cross-section through which flow is narrowed; z. B. for an incompressible liquid without internal friction, the flow rate is inversely proportional to the cross-sectional area. In this respect, the machining result can be influenced by its narrowing beyond the general shape of the cross-section.
  • the flow field is influenced by the viscosity of the process medium.
  • the viscosity of the process medium even with a given geometry of the arrangement and concentration of the abrasive, can still be used to control whether a laminar or turbulent flow occurs.
  • the transition to turbulent flow takes place when the viscosity is reduced at a certain threshold value even at a lower flow velocity; then the abrasive particles can be chosen smaller under otherwise identical conditions, since the shear gradient near the workpiece surface is steeper.
  • Increasing the viscosity means that the abrasive attack is less intense. 2 shows an exemplary embodiment of a machining head designed as a gap stream for carrying out the method explained above, in particular for use on flat or almost flat workpiece surfaces.
  • the processing head comprises a first molded part 250, for example made of polyurethane; with a first inlet 251 and a mirror-shaped second molded part 250a with a second inlet. During operation, a process medium is fed to the processing head via these inlets.
  • the two molded parts are assembled in such a way that a gap is created for inserting a workpiece to be machined, or the molded parts are placed on both sides of the workpiece 900.
  • the molded part 250 is laterally so wide that the entire width of the workpiece (which is perpendicular to the drawing plane shown) is covered.
  • the side walls (not shown) of the molded part 250 are closed.
  • a sealing lip 253 which bears against the workpiece 900.
  • a cavity 252 is formed between the workpiece surface and the molded part in the direction of movement of the workpiece following the sealing lip.
  • the molded part 250 is expediently fastened to a positioning unit 210 by means of a support 257, which at the same time stiffens the flexible molded part 250, with a holding device (not shown). If the molded part 250 is supplied with process medium through the inlet 251, the process medium can essentially only escape through a gap-shaped space 254 between the workpiece 900 and the molded part 250, this gap 254 being formed at an end of the machining head opposite the sealing lip.
  • the gap 254 is also formed by the carrier 255, which stiffens the molded part 250.
  • An adjusting device 256 attached to the carrier 257 allows the gap height to be adjusted as described above, so that the desired effect is achieved.
  • the adjusting device 256 can also compensate for the loss of material which arises from the abrasive attack on the molded part 250 and widens the gap, so that the service life of the molded part 250 is increased.
  • the setting device consists of a Pressure plate that can be adjusted manually using pressure screws (spindles) or pressure springs as well as using pneumatic or hydraulic control devices.
  • process-related surface structures may have to be removed or surface properties changed.
  • components of the workpiece surface that have not been completely removed by the machining process can still adhere to the surface. Even if they are pressed into the workpiece surface during subsequent forming processes, they can detach undesirably from the surface.
  • These surface components can be removed from the surface in various ways.
  • a possible implementation is the brushing known per se using rotating rollers with trimmings, past which the workpiece surface is guided.
  • Particles of metal and semimetal borides, carbides, nitrides and oxides are preferably used as the abrasive, and those which occur as a component of natural minerals in nature.
  • the solids content in the process medium is between 0 and 50 volume percent, preferably between 2 and 30 volume percent, particularly preferably between 5 and 20 volume percent.
  • the particle size is between 0.5 and 1000 ⁇ m, preferably between 2 ⁇ m and 500 ⁇ m. However, the practically available size distributions inevitably have a certain spread. With the particle size 25 to 90 ⁇ m and the process parameters described here, for example, a remarkably low roughness of Ra ⁇ 0.1 ⁇ m is obtained.
  • the abrasive particles With increasing volume fraction, the abrasive particles generally increase the viscosity of the suspension, as expressed, for example, by the Einstein-Roscoe formula known from the rheology of inhomogeneous liquids.
  • the flow behavior of suspensions deviates if the particle size is in or above a certain transition range. Accordingly, the viscosity of the process medium is below the transition range and above that the viscosity of the pure carrier liquid is decisive.
  • the viscosity must therefore be adapted to the abrasive particle size and size distribution, whereby the Einstein-Roscoe formula can be used as a starting point.
  • the flow conditions become increasingly laminar. This means that particles carried in the flow have little opportunity to get to the flow boundary (all parts that come into contact with the medium, such as the inner pipe wall, pump parts, inner nozzle wall, workpiece surface, etc.), where they can interact with the flow boundary , This is desirable for the system components because the abrasive load reduces wear. On the other hand, however, the effect of the machining process is reduced or completely prevented with increasing viscosity.
  • the viscosity range is from 0.1 mPas-s to 300 mPa-s, preferably from 0.1 mPas-s to 30 mPa-s. It should be noted that in the case of non-Newtonian (e.g. structurally viscous) process media, the amount of viscosity auxiliary material or auxiliary materials should be selected so that this viscosity value is given for the flow conditions in the impingement area or tangential flow area.
  • a disadvantage of an increase in viscosity is the loss of pressure and volume flow through constrictions (e.g. line system, nozzle or spreading device). tion), which is compensated for in the low viscosity range by the known effect of decreasing flow resistance in these parts of the system.
  • Structurally viscous auxiliaries have a decreasing viscosity with increasing shear rate, the decrease being typical of the substance and varying widely.
  • a highly pseudoplastic material such as cellulose derivative
  • a slightly pseudoplastic material such as polyacrylate derivative
  • the one A decrease in viscosity by a factor of 4 at shear rates between 100 s "1 and 10 4 s " 1 shows that a medium is generated which is relatively viscous at shear rates which are typical for slow movements.
  • the viscosity can be increased by a hydrogel former, for example polysaccharides or polymers or their derivatives such as agar, alginates, carrageenan, guar, gum arabic, tragacanth, and poloxamers.
  • a hydrogel former for example polysaccharides or polymers or their derivatives such as agar, alginates, carrageenan, guar, gum arabic, tragacanth, and poloxamers.
  • one or more substances hereinafter referred to as dispersants, are added to the process medium, which, as an alternative or in addition to the increase in viscosity, advantageously influence the flow behavior of the process medium and thus also the flow form.
  • This increases the process effect and thus the processing speed, the system efficiency through improved pumping action and reduced friction between the process medium and the line element. optimized and the mobility or mobilizability of sedimented or abrasive adhering to surfaces improved, which in particular makes it easier to rinse the workpiece surface and introduce fresh abrasive.
  • Advantageous dispersants are first of all the known amphoteric, anionic, .cationic and nonionic emulsion formers or surface-active substances.
  • Other suitable dispersants are polyacrylates (for example ammonium polyacrylate or sodium polyacrylate), condensation products of sulfonic acids, in particular naphthalenesulfonic acid, preferably naphthalenesulfonic acid / formaldehyde polycondensate as sodium salt, vinyl acetate and vinyl versatate homo- or copolymers, styrene and Butadiene homo or copolymers and polyvinyl alcohol.
  • the above-mentioned substances also have a dispersion-promoting effect to increase the viscosity of the blasting medium.
  • the dispersants used advantageously have the effect that the abrasive is finely distributed instead of forming agglomerates.
  • Agglomerates have a different, usually coarser effect in the machining process, on the other hand they have a shielding effect or reduce the effective abrasive concentration, so that the process effect changes undesirably.
  • gas is generated, for example, by swirling (e.g. by means of Agitator or by flowing) into the process medium or dissolved therein, or a gas stream with sufficient pressure is introduced into the process medium, or a substance which forms a gas by chemical reaction (e.g. propellant, in particular carbonates and bicarbonates, e.g.
  • Sodium hydrogen carbonate is introduced into the process medium.
  • Carbon dioxide dissolves in water in a considerably greater amount than air, so that air is preferred in the lower concentration range of the gas admixture, whereas carbon dioxide is preferred in the middle and upper range.
  • the amount of soluble substance in the relevant area increases approximately proportionally with the pressure. This is exploited by introducing the gas into the process medium under pressure from a pump that pumps the process medium. The gas is released in the area of high flow velocities, where the static pressure of the flow decreases.
  • Examples for 20 ° C, atmospheric pressure and aqueous process medium are: 1 kg process medium can absorb up to 0.001 mol air; 1 kg of process medium can absorb up to 0.02 mol of carbon dioxide; 1 kg of process medium can absorb up to 0.1 mol carbon dioxide if 1 weight percent sodium carbonate is added to the aqueous process medium; Up to 0.1 mol of carbon dioxide is released in 1 kg of process medium if 0.8% by weight of sodium hydrogen carbonate is added to the aqueous process medium.
  • the abrasive used is subject to little wear and can therefore be used for many machining cycles, ie applied repeatedly to the workpiece surface to be machined.
  • the process medium is contaminated by the entry of abrasion from the workpiece surface, which is unavoidable in many applications and reduces the effect of the process medium in the machining process.
  • the worn abrasive and used auxiliary materials must be removed from the process medium. If the process medium were discarded, a large proportion of unused abrasive and auxiliary materials would be lost.
  • the removal itself z. B. as a highly enriched metal oxide a resource.
  • the abrasion and worn abrasive can also have adverse effects on the workpiece, device, tools or effectiveness of the machining process.
  • the machining process according to the invention has the advantageous property that the particles of the abrasion produced have smaller dimensions than the abrasive.
  • the abrasion is also comminuted in the process cycle. Due to the new impact on the workpiece surface as well as the contact with the pipe wall and the mechanisms used to accelerate the solution in the pumps used, even larger pieces of abrasion ultimately become significantly smaller than the abrasive grains.
  • the abrasive itself wears out in such a way that pieces break off the grains, the grains becoming smaller. Therefore, a substance separation process is advantageously used for the solution, which separates according to the particle size. Basically, this is done by known separation processes as well as combinations of two or more such processes.
  • abrasion and worn abrasive are generally distributed homogeneously in the process medium, it must be processed cyclically or continuously overall, which, given the high abrasive content here, only allows most known processes to a limited extent. Therefore, methods using the following devices are preferably used: belt filters, sheet filters, curved sieves (e.g.
  • circular vibrating sieves rotary pressure filters
  • filter centrifuges both discontinuous and continuous
  • flocculation flotation
  • hydrocyclone classifiers
  • lamella separators magnetic separators (only for substances that can be influenced magnetically)
  • press filters cross-flow filters
  • agitation pressure filters disc pressure filters
  • disc filters vibrating sieves
  • sedimentation sieves
  • belt presses drum filters
  • eddy current separators only for substances that can be influenced electrically
  • centrifuge e.g. basket, peeler, cone sieve, pusher centrifuge
  • Dissolved ions are removed by precipitation, electrophoresis, membrane exchange processes or ion exchange. Filtration similar to the known cross-flow principle described below is preferably used as one of the methods.
  • Filtration similar to the known cross-flow principle described below is preferably used as one of the methods.
  • the material separation is not carried out completely in one step, but is distributed over several steps, even if the same process itself is carried out in the subsequent step, but only with a different separation grain size, for example.
  • Abrasion and worn abrasive are preferably separated from the process medium in a material separation device on the basis of one of the material separation methods mentioned above.
  • the device further comprises an admission device which is adapted to the separation process (e.g. low-pulsation loading with hydrocyclone, loading of a cross-flow filter without pressure or with a pump, loading of a vibrating screen flowing under pressure).
  • the process medium is passed over a mesh or filter fabric with a suitable mesh size, whereby either the solid fraction is retained entirely or up to a limit size determined by the mesh size.
  • the limit grain size is dimensioned so that abrasion or worn abrasive to be separated largely passes through with the liquid.
  • the incoming process medium ensures that thickened parts are washed away.
  • two or more successive grids or filter fabrics can be arranged with successively smaller opening widths, so that both the tendency of the grille or filter fabric to clog becomes less and the abrasive load that wears the mesh or filter fabric becomes lower. This arrangement is referred to below as a cross-flow filter.
  • the strongly thickened abrasion, mixed with the worn abrasive is discharged continuously or periodically from the process medium circuit, preferably collected and, if necessary after processing (removal of dissolved ions, concentration of the abrasion), sent for recycling.
  • parts of the process medium especially abrasive, remain on the workpiece surface. These have to be removed because they are the disturb further processing or impair the quality of the workpiece surface.
  • cleaning for example by rinsing, parts of the process medium are inevitably towed out or rinsing medium is introduced into the process medium.
  • the workpiece surface must be rinsed in such a way that drag-out losses are minimized or replaced quantitatively in order to ensure that the machining result of the machining process corresponds to the specified quality.
  • residues of the process medium must be removed from the workpiece surface, which have an adverse effect on workpiece handling or on subsequent processing steps. This is done using one or more of the following methods.
  • a gas preferably air, that does not influence the concentration ratios in the process medium can be used as the flushing medium.
  • a flushing medium can be applied to the workpiece surface, which does not contain one or more of the process medium portions to be removed, but otherwise corresponds to the process medium and was generated from it before cleaning.
  • the process medium is both diluted and removed from the surface by entrainment effects (effect of pressure, flow, etc.), fed to one of the material separation devices described and separated from the components which interfere with the rinsing processes.
  • the workpiece surface is cleaned with clear water or process liquid obtained from the process medium at a pressure of 0.1 to 100 MPa, the flushing medium preferably being applied by means of one or more nozzles at a pressure of 0.3 to 30 MPa ,
  • a triple-acting piston pump or a centrifugal pump can be used. Both pumps have a low pressure pulsation and thus ensure a sufficiently uniform cleaning result.
  • Nozzles with any spray pattern can be used, the correlation with the geometry of the workpiece surface being decisive in addition to the impact force.
  • a flat jet is preferred for completely or sectionally flat workpiece surfaces, and a hollow or full cone jet for surfaces with undercuts.
  • the cleaning efficiency is influenced by the nozzle-dependent fan angle: the larger the fan angle, the larger the area covered, but the lower the impact force.
  • the overall length of the rinsing section is advantageously reduced to about half by making the line of impingement of the flat jet plow-shaped with a corresponding arrangement of the nozzles, with the plow tip in the middle of the workpiece surface section under consideration. If the cleaning jet acts completely or partially against the feed direction of the workpiece, then an angle between 45 and 180 ° between the projection of the jet axis onto the workpiece surface and the feed direction vector is preferably selected. At 180 °, a barrier barrier is achieved transverse to the feed direction, a preferred drain direction is specified at smaller angles and, in the case of a plow-shaped design of the impact area, the drain path is minimized, as described above.
  • process medium components which have been lost as required are replaced by supplying fresh or temporarily stored material.
  • concentration of the abrasive and the auxiliary substances can advantageously be changed by removing one or more components of the process medium, the total volume either being reduced or kept constant by a compensatory supply of process medium components.
  • the regulation requires the metrological recording described below.
  • the amount of process medium available is measured by level sensors on the storage tank. Measuring methods for the solids concentration are e.g. B. Measurement of turbidity, thermal conductivity, electrical conductivity, vortex shedding, Coriolis force on a moving piece of pipe or the ultrasound propagation.
  • the volume flow can be measured using the same measuring methods and others, such as rotary piston instruments.
  • the amount of process liquid available follows from the level in the process medium container, measured with a level sensor, and the concentration and density of the abrasive.
  • FIG. 3 schematically shows a device for carrying out the machining method according to the invention.
  • several successive processing stages of the type shown can be used to increase the process speed or for graded processing, e.g. B. for the successive reduction of roughness.
  • the device comprises a process medium container 101 in which a process medium of a desired composition, in particular with a desired viscosity and a desired abrasive content, is held.
  • a suction line 103 leads from this container 101 to a process pump 106 which conducts the process medium via a valve 109 to a processing head 220 which is arranged in a processing chamber 200.
  • the process medium is conveyed to the processing head when valve 109 is open and a further valve 565, via which the line is connected to a first rinsing liquid container 501, is closed.
  • the machining head 220 is mounted on a positioning unit 210, which serves to position the machining head 220 relative to a flat workpiece 900 to be machined, which is continuously guided through the machining chamber 200 during the process.
  • the processing chamber 200 is followed by rinsing units 313 and 323, which are used for rough and final rinsing of the workpiece 900 after the abrasive processing.
  • One 313 of the rinsing units is arranged in the treatment chamber 200, the other is in a separate rinsing chamber 350 downstream of the treatment chamber 200.
  • the rinsing units are supplied with rinsing liquid, for example water, via pumps 310 and 320.
  • the workpieces 900 to be machined are guided through the machining chamber 200 and the rinsing chamber 350 by a feed unit (not shown in more detail).
  • This feed unit comprises, for example, two pairs of rollers, one of which can be arranged in the direction of movement of the workpiece 900 in front of the processing chamber 200 and one after the processing chamber or rinsing chamber 350.
  • the workpiece is in each case picked up between the spaced-apart rollers of a pair of rollers which rotate during operation and are guided through them through the chambers 200, 350.
  • a pair of squeeze rollers 324 is arranged, by means of which rinsing liquid still remaining on the surface of the workpiece 900, which remains in the chamber, is removed.
  • This pair of squeeze rollers can take over the function of a pair of rollers of the feed unit.
  • the pressure and the volume flow of the process medium supplied to the processing head are recorded by measuring devices 112 and 114 in the feeds of the processing head. These pressures and volume flows at the machining head can be changed via the regulating devices 111 and 113 in the feeds.
  • the entire process is controlled by a 590 system controller, which ensures that the specified concentrations, pressures and volume flows in the relevant parts of the system are adjusted after prompt recording.
  • sensors 112, 114, 312, 322, 281, 560, 570 and 563 are on different Positions of the line system of the device arranged.
  • the control system controls 590 regulating and adjusting units 118, 113, 116, 421, 118, 281, 320, 310, 560, 570, 561 and 106 with the aim of regulating the to achieve explained parameters.
  • An abrasive fluid mixture to be discharged from the process container 200 is returned via a pipeline 280 to the process medium container 101, where it is kept for the continuously configured machining process.
  • the process medium is depleted of abrasive as a percentage by the introduction of rinsing water via rinsing nozzles of the rinsing unit 313.
  • part of the medium discharged from the process container is discharged via a line 410 to a filter unit 440, in which liquid, for example water, is withdrawn from the abrasive-fluid mixture, in order to produce an abrasive-enriched process medium, which a line 458 is fed back into the process media container 101.
  • the separated liquid is temporarily stored in the first rinsing liquid container 501 and held by the first rinsing unit 313 for rinsing processes.
  • part of this liquid from the container 501 is fed to a second filtration unit 470 as required, finely filtered by this and temporarily stored in a second rinsing liquid container 598.
  • the filtrate from the container 598 is used in the second rinsing stage 323 and is used for the final cleaning of the treated workpieces. Flushing liquid from the flushing chamber 350 is drained off and fed to the filtration unit 440.
  • the particles separated by the filter unit 470 which can contain both abrasive and contaminants, are temporarily stored in a container 488 and removed from the process.
  • the composition of the process medium in the container 101 is controlled by the system controller 590.
  • An excess of process liquid is separated in the material separation device 440, the proportion of the device derived process medium can be regulated via a valve arranged in the feed line to the process medium container 101.
  • a sensor 563 for density or solids content measures the composition of the process medium discharged from the container 101 immediately before the machining process.
  • the fill level in the process medium container 101 is measured with a fill level sensor 560, the fill level being increased by means of a pump 561 using a pump 561, the fill level via line 562 with flushing liquid from the first flushing liquid container 501. If the sensor 563 detects a decrease in the density or the solids content, then abrasive is supplied from an abrasive container 550.
  • Flushing liquid is supplied to the system from the outside via a feed line 510 opening into the first flushing liquid tank.
  • a supply container 520 for an agent that adjusts the viscosity of the process medium is connected to this feed line, from which the agent is fed, controlled by the system controller 590, to the process fluid for adjusting the viscosity of the process medium.
  • the device shown has a closed circuit in which both the abrasive and the necessary rinsing liquids are circulated, spent abrasive and impurities being removed from the circuit and fresh abrasive and fresh rinsing liquid being supplied to compensate for losses.
  • FIG. 4a and 4b show a further exemplary embodiment of a processing head or processing unit 22 which can be used in connection with the device according to FIG. 3 for processing a flat rolled product.
  • the unit has two nozzle bars 1221a, 1221b, which are arranged at a distance from one another in order to be able to carry out the rolled product in an intermediate space 1222 between the nozzle bars.
  • Each of the nozzle bars has a plurality of outlet nozzles 1223a, 1223b which are arranged at a distance from one another and are designed to pressurize the workpiece with the process medium.
  • the elongated nozzle bars 1221a, 1221b are preferably arranged rotatably, as indicated by arrows in FIG. 4a, in order to be able to set an angle of incidence of a medium jet emerging from the nozzles.
  • the reference numeral 1224 denotes a medium jet emerging from one of the nozzles 1223 in FIG. 4a.
  • the angle a is designated by the beam 1224 with the flat workpiece surface.
  • an angle of incidence less than 90 ° means that a beam 1224 is applied to the workpiece surface, its tangential component against a direction of movement v of the workpiece 900 is directed.
  • the nozzle bars 1221a, 1221b have connections (not shown) for connecting supply lines carrying process medium. To distribute the medium within the nozzle bars 1221a, 1221b, these are hollow on the inside.
  • One of the two nozzle bars shown in FIG. 4 is sufficient for machining only one side of the workpiece surface.
  • both nozzle bars are present in order to enable effective machining of both workpiece surfaces at the same time and thus to avoid "turning over" the workpiece after a machining cycle has been carried out.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

Abstract

Procédé et dispositif de traitement par enlèvement de matière de pièces plates. Selon ledit procédé, un milieu de travail est dirigé sur la pièce (900) via une tête de traitement (220) située dans une cuve de traitement (200). Selon la présente invention, le milieu de traitement est un liquide contenant un abrasif, qui se déplace de manière commandée à une pression inférieure à 50 bars, la pièce est guidée en continu à travers la cuve de traitement (200), au moins deux jets de traitement essentiellement parallèles sont envoyés par la tête de traitement (220) sur la pièce (900) et le milieu de traitement de la pièce (900) est guidé dans un circuit.
PCT/EP2004/014649 2003-12-23 2004-12-22 Procede et dispositif de rectification de surfaces WO2005063441A1 (fr)

Applications Claiming Priority (2)

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DE10361483 2003-12-23
DE10361483.4 2003-12-23

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WO2005063441A1 true WO2005063441A1 (fr) 2005-07-14

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1037571C2 (nl) * 2009-12-18 2011-06-21 Lasbedrijf Vink B V Systeem voor het stralen van objecten met een mengsel van vloeistof en abrasief.
DE102011051790A1 (de) * 2011-07-12 2013-01-17 Haver & Boecker Ohg Vorrichtung und Verfahren zur Bestimmung einer Verschleißfestigkeit von Gewebe

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB866948A (en) * 1958-07-30 1961-05-03 Boulton Aircraft Ltd Improvements relating to the polishing of the surfaces of articles
US3984943A (en) * 1974-10-17 1976-10-12 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Apparatus for treating surfaces of sheet steel or the like
GB1558030A (en) * 1978-04-13 1979-12-19 Secretary Industry Brit Abrasive treatment of elongate members
US4269052A (en) * 1978-06-09 1981-05-26 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Mechanical descaling device
US5276998A (en) * 1992-06-08 1994-01-11 Joen Anton P Method and apparatus for washing and cleaning a workpiece
US5783497A (en) * 1994-08-02 1998-07-21 Sematech, Inc. Forced-flow wafer polisher
US5827114A (en) * 1996-09-25 1998-10-27 Church & Dwight Co., Inc. Slurry blasting process
WO2002074489A1 (fr) * 2001-03-20 2002-09-26 Fisba Optik Ag Dispositif pour l'usinage par abrasion de surfaces d'elements et notamment d'elements ou de pieces optiques

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB866948A (en) * 1958-07-30 1961-05-03 Boulton Aircraft Ltd Improvements relating to the polishing of the surfaces of articles
US3984943A (en) * 1974-10-17 1976-10-12 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Apparatus for treating surfaces of sheet steel or the like
GB1558030A (en) * 1978-04-13 1979-12-19 Secretary Industry Brit Abrasive treatment of elongate members
US4269052A (en) * 1978-06-09 1981-05-26 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Mechanical descaling device
US5276998A (en) * 1992-06-08 1994-01-11 Joen Anton P Method and apparatus for washing and cleaning a workpiece
US5783497A (en) * 1994-08-02 1998-07-21 Sematech, Inc. Forced-flow wafer polisher
US5827114A (en) * 1996-09-25 1998-10-27 Church & Dwight Co., Inc. Slurry blasting process
WO2002074489A1 (fr) * 2001-03-20 2002-09-26 Fisba Optik Ag Dispositif pour l'usinage par abrasion de surfaces d'elements et notamment d'elements ou de pieces optiques

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1037571C2 (nl) * 2009-12-18 2011-06-21 Lasbedrijf Vink B V Systeem voor het stralen van objecten met een mengsel van vloeistof en abrasief.
WO2011074944A1 (fr) 2009-12-18 2011-06-23 Lasbedrijf Vink B.V. Système et procédé pour sabler des objets avec un mélange de liquide et d'abrasif
DE102011051790A1 (de) * 2011-07-12 2013-01-17 Haver & Boecker Ohg Vorrichtung und Verfahren zur Bestimmung einer Verschleißfestigkeit von Gewebe

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