DE3535646A1 - Integrally cast clamping block for multi-piece workpieces as well as method and device for producing it and breaking it open - Google Patents

Abstract

The invention relates to an integrally cast clamping block (6) for clamping and holding double-bladed or multi-bladed turbine vane ring segments (1, 2, 3, 4) or workpieces of similar design for the purpose of machining them on a machine tool, in particular a grinding machine. The integrally cast clamping block (6) is formed by casting around the workpiece in a mould and essentially consists of two or more mould parts (7, 8) which enclose the workpiece from outside and are connected to one another by connecting webs (9, 11) while leaving an intermediate space (12) for inserting a mechanical break-open means, the connecting webs (9, 11) being designed as predetermined breaking points. <IMAGE>

Description

Sprue clamping block for multi-part workpieces as well as

Method and device for its production and breaking and Breaking open The invention relates to a sprue clamping block for clamping and holding of workpieces, in particular turbine blades, which are produced by casting around the workpiece is formed with a fusible material.

The invention also relates to an apparatus for manufacturing this sprue block as well as a method and a device for breaking open of the clamping block in order to be able to detach it from the workpiece again.

The problem occurs particularly with turbine or compressor blades on that they are machined after casting or forging at their ends, for example must be sanded.

To get such a shovel precisely aligned on for this machining To be able to set up the machine, it is known to put them in a block or a Encapsulate metal sheath, so that only the end to be machined remains free. The block is formed by casting around the workpiece, for example the Turbine blade with a fusible material, e.g. a tin-lead-antimony alloy.

The one that encloses the workpiece except for the end to be machined The block can then be used in a machine tool, for example a grinding machine, clamp.

After machining the workpiece on the machine tool is it is now necessary to detach the workpiece from the sprue clamping block.

For this purpose it is already known to melt the block material again. It happens that there is some material from the sprue block on the workpiece surfaces sticks.

This can have serious consequences for a turbine blade Impurities remaining on the shovel destroy the shovel during operation would.

To avoid this, a solution is also known, according to which the workpiece with a curable plastic before being encapsulated with metal is covered.

However, this occurs after the block material has melted required removal of the plastic layer as extremely complicated and expensive.

according to DE-AS 28 22 828, in a further clamping and holding device pursued the removal of the clamping block material from the workpiece by mechanical breaking of the clamping block by means of a tool consisting of two punches, the Punches are provided with prongs that engage in slots in the clamping block. By if the two punches are moved vertically towards one another, the clamping block breaks a predetermined breaking cross-section.

A clamping block and a tool for breaking it open in the above Art are at most suitable for single blades.

In the case of a double-bladed turbine guide vane, for example, in the two airfoils are arranged at a defined distance from one another, would the space between the two blades according to the conventional type of encapsulation also filled with block material, so that a mechanical blasting open of a such a clamping block would hardly be possible. Then again only the possibility would remain of melting out the block material, what but with the above disadvantages described is associated.

For this reason, such workpieces are also available with mechanical ones Clamping means clamped, which, however, requires a high degree of skill on the part of the operator and a sure instinct was required to find out about the workpiece position and to achieve precisely defined clamping of the clamping forces. On the one hand, had to The workpiece is exposed to sufficiently high clamping forces so that the machining operations Able to absorb cutting forces without slipping, but on the other hand high Clamping forces to damage such complicated and sensitive workpieces to lead.

The invention is therefore based on the object of a sprue block to create, in particular for double-bladed turbine guide vanes or the like multi-part workpieces is suitable.

There is also the object of an apparatus for producing a such clamping block as well as a method and a device for breaking it open, i.e. for removing the block material from the workpiece.

According to the invention, there is a clamping block for double-bladed turbine guide vanes or similar multi-part workpieces made up of two or more of the workpiece molded parts encompassing from the outside, which are connected to one another by connecting webs are, wherein the space between the blades or similar workpiece parts as well as undercuts existing on these largely kept free of casting material are.

According to the invention, the connecting webs are designed as predetermined breaking points educated.

According to the invention, there is an apparatus for producing the sprue block from a at least two-part casting mold provided with a filler neck, the parts of which form the outer boundary of the cast-in clamping block. There are those Mold parts are provided with mold inserts that fill the space between the blades or the like spaced workpiece parts and existing undercuts keep largely free of potting material between the blades and webs. In addition, there are positioning and pressing elements for fixing the workpieces in the correct position Provided in the mold and actuators for opening and closing the Casting mold for actuating the pressure elements and for actuating at least one of the mold inserts.

Another feature of the invention is that the mold inserts Sealing joints along the inner and outer webs of the turbine blades as well as along of the airfoil edges.

According to the invention, these sealing joints can be designed as gap seals be.

But you can also use another feature of the invention Be provided sealing elements made of elastic material.

Another variant according to the invention consists in the sealing joints to be provided with resiliently pressed sealing strips.

The mold inserts present in the casting mold parts are made according to the invention from stationary shaped pieces and / or from actuatable shaped punches.

According to another possibility according to the invention are as mold inserts stationary fittings and / or at least one that can be inflated by means of a pressure medium elastic hollow body provided.

According to the invention, the filler neck for filling the casting mold as a tubular element provided with a heater is formed.

On the one hand, to be able to remove the sprue block from the casting mold, on the other hand, however, being able to fill the casting mold again is according to the invention provided, the filler neck in its mouth zone and in its filling zone to make separately heatable.

The inventive device is also that the Pressure elements as passed through the movable mold part and in one Guide element resiliently supported pressure pins are formed so that they for visual control and correction of the workpiece position with the mold open are actuatable.

According to the invention it is also provided that the mold inserts are designed in such a way that that they also serve as positioning elements for the workpieces.

The invention further includes a method of breaking the sprue block after the workpiece has been processed. This consists in the fact that at the same time Applying tensile and bending forces to the molded parts of the sprue block Connecting webs are separated by mechanical breaking and / or melting, after which the molded parts are removed.

It has been found to be advantageous when doing one at the same time Free melting of undercuts, e.g. B.

Blade edges, made from the pouring material.

The device for performing this method is according to the invention from clamping means holding the sprue block and stressing it in terms of bending and tension and one that can be introduced into the spaces between the connecting webs and breaking means acting on the connecting webs.

According to the invention here are a sprue block on one Molded part holding fixed jaw as well as a sprue block on the opposite molded part gripping, pivotable about an axis of rotation clamping jaw provided, and that by means of an actuating and guide element in two planes movable prying means consists of one or more fingers.

According to the invention, the actuating and guiding element for the pry fingers designed as a cross slide.

Another feature of the invention is that the fingers are provided with heatable edges so that the connecting webs are also melted can be.

In addition, according to the invention, the guide carriage carrying the fingers of the cross slide heated edges on its side facing the sprue block on in order to be able to melt the pouring material surrounding the blade edges.

The jaws of the breaker are according to the invention for Application of the clamping forces and for pivoting movement with appropriate hydraulic actuators connected.

According to the invention, there is another variant of the breaking device in that while retaining the jaws, of which the fixed one Molding holds while the other grips and turns the opposite molding an axis of rotation pivots, the breaking means from a means of a pressure medium Expandable elastic hollow body consists.

The invention makes it possible, in particular, to have two-bladed turbine guide vanes or similar workpieces for further processing precisely positioned on a tool, especially grinding machine. After processing, the inventive Cast-in clamping block again flawlessly by means of the breaking device according to the invention remove from the workpiece, ie. it does not leave any residues of casting material on the workpiece still damage.

The invention is to be described in more detail below using an exemplary embodiment explained.

In the drawings, FIG. 1 shows a two-bladed turbine guide vane in the sprue clamping block in plan view, FIG. 2, section A-A according to FIG. 1, FIG 3 shows the section B-B according to FIG. 1, FIG. 4 shows the section C-C according to FIG. 1, FIG. 5 the Section D-D according to FIG. 1, FIG. 6 a side view according to FIG. 1, FIG. 7 the device for the production of the sprue clamping block with the mold open in section, FIG. 8 a Section through the device according to FIG. 7 with the mold closed, FIG. 9 a Section through the device according to Figure 7 with visible heated filler neck, FIG. 10 shows a section through the closed form with at the same time as positioning elements formed mold inserts, Figures 11 and 12 two sealing variants as a detail X according to Figure 10, 13 shows the detail Y according to FIG. 10, FIG 14 the detail Z according to FIG. 10, FIG. 15 the device according to FIG. 7 with a A mold insert consisting of an expandable elastic hollow body, FIG. 16 the device for breaking open the sprue clamping block in section, FIG. 17 the section E-E according to Figure 16, Figure 18 shows a section of the breaking device with a expandable elastic hollow body as breaking means.

A two-winged part of a guide vane ring (Fig. 1), consisting of from the two blades 1,2, which through the inner rim segment 3 and through the outer rim segment 4 are connected, is for clamping on a machine tool cast in a clamping block 6.

In this case, the cast-in clamping block 6 consists of two molded parts 7, 8, which are connected to one another by connecting webs 9, 11 and the blades 1, 2 embrace from the outside. The molded part 7 thus surrounds the convex side of the airfoil 1 and the molded part 8, the concave side of the other airfoil 2. Except for the Connecting webs 9, 11 remain the space 12 between the blades 1, 2 free of casting material. Also largely kept free of casting material, d. H. Except for the area of the connecting webs 9, 11, the blade edges are 13, 14, 16, 17 (Figures 1 to 6). The connecting webs 9, 11 are intended as predetermined breaking points formed, the breaking of the cast-in clamping block 6 and its removal from Workpiece, here from the two-winged part of a guide vane ring, after machining allow its free ends on a machine tool. As a result of the cast-in material Blade edges 13, 14, 16, 17 which are largely kept free will damage them avoided when breaking the casting clamping block 6.

For the production of such a cast-in clamping block 6 is a device provided in accordance with FIGS. 7 to 15.

This consists of a two-part mold 18, 19, which is shown in Fig. 7 is shown in the open state. The one mold part 19 is by means of in the drawing only indicated connecting elements 21, 22 fixed to a base plate 23 connected, while the other mold part 18 to open and close the mold relative to fixed mold part 19 is movable. For this the movable mold part 18 is guided on a guide rod 24, which is attached to her one end with the fixed mold part 19 and at its other end with a Holding plate 26 is firmly connected to the base plate 23 by means of connecting elements 27 is attached.

The casting mold part 18 is moved by means of a hydraulic one or pneumatic drive 28, which is attached to the holding plate 26 by means of connecting elements 29, 31 and its piston rod 32 with the movable mold part 18 connected is.

The mold parts 18, 19 are provided with mold inserts, which as stationary molding 33 and as an actuatable molding die 34 are formed.

The shaped piece 33 and the die 34 are formed so that they the space 12 between the blades 1, 2 and the Undercuts and shovel edges 13, 14, 16, 17 (Fig. 2) largely from the pouring material keep clear. The forming die 34 has a pneumatic or hydraulic drive 36 is provided, which is attached to a holder 37 fixedly connected to the base plate 23 by means of Connecting elements 38, 39 is attached and the piston rod 41 with the forming die 34 is connected.

To hold the two-winged guide vane ring part to be cast in the mold, d. H. in the fixed mold part 19, two are each on a blade 1, 2 acting pressure pins 42, 43 provided by the movable mold part 18 are passed through.

The actuation of these pressure pins 42, 43 takes place by means of a hydraulic one or pneumatic drive 44, which by means of connecting elements 46, 47 on the Holding plate 26 is attached. The piston rod 48 of the drive 44 is with connected to a guide element 49 which is guided on the guide rod 24. In a recess 51 of the guide element 49, the pressure pins 42, 43 are on one end is resiliently supported by means of compression springs 52, 53.

Such an arrangement of the pressure pins 42, 43 makes it possible to to carry out a control of the workpiece position with the mold 18, 19 open. The pressure pins 42, 43 can be used to correct the workpiece position if necessary against the force of the compression springs 52, 53 also by hand by means of a not shown Retract the tool.

In Fig. 8 the mold 18, 19 is shown in the closed state, The course of the section through the workpiece corresponds to that of the line A-A in Fig. 1, and FIG. 9 shows a sectional illustration of the closed casting mold 18, 19 with a filler neck 54, in which the cutting path through the workpiece of Line B-B of Fig. 1 corresponds.

Through this filler neck 54, the casting mold 18, 19 is filled with the liquid Potting material, for example a tin-lead-antimony alloy, filled. The filler neck 54 is equipped with a heating device 56, the filler neck 54 in two separate zones 57, 58 heated.

To remove the finished sprue clamping block 6 from the casting mold 18, 19 it is necessary to remove the solidified metal in the filler neck, which is still in communication with the sprue block 6, in the mouth zone 57 of the To melt the filler neck 54 again, which happens with the heating device 56.

To after removing the cast-in clamping block 6 a new filling In order to be able to make the casting mold 18, 19, the filling zone 58 must also be used of the filler neck 54 be heated to include what is inside to melt solidified casting material and thus the filler neck 54 for a to open a new filling process.

The sectional illustration shown in FIG. 10 corresponds to a sectional profile through the workpiece according to the line C-C of Fig. 1, the designated therein Details X, Y and Z in Figures 11 to 14 are shown enlarged.

The already mentioned mold inserts, which are designed as stationary moldings 33 and / or are designed as actuatable forming punches 34, form along the rim segments 3, 4 (Fig. 1) and along the blade edges 13, 14, 16, 17 (Fig. 2) sealing joints, the penetration of potting material in the intended free spaces, z. Tie Space 12, prevent.

These sealing joints can, for example, be designed as gap seals be.

But you can also according to FIG. 11 by elastic material 59 or 12 are formed by strips 61 which are pressed on by a spring.

The mold inserts can also be used to position the workpieces, here of the double-bladed blade ring segment, serve, as in Figures 13 and 14 (details Y and Z of Fig. 10) is shown.

A safe position is ensured by the three contact points 62, 63, 64 of the two blades 1, 2 given on the mold inserts.

As mold inserts are in addition to the aforementioned stationary moldings 33 and movable die 34, other designs are also conceivable.

In FIG. 15, for example, an elastic hollow body that can be expanded is shown 66 formed mold insert shown. This elastic hollow body 66 is over a channel 67 filled with a gaseous or liquid pressure medium, so that he rests against the blades 1, 2.

It thus simultaneously fulfills the sealing function, so that separate Sealing elements as described above are not necessary here.

In the example shown, the elastic hollow body 66 also acts still another mold insert, the molding punch 34.

The forming die 34 can also be omitted and its function from elastic hollow body 66 are taken over with.

The hollow body 66 would then have to be designed so that it up to the Blade edges 14, 17 are sufficient.

Such an expandable elastic hollow body must of course consist of a heat-resistant rubber or plastic, which at least the melting temperature of the casting material, the z. B. in a tin-lead-antimony alloy is 1350 C, withstands.

After the workpiece on a machine tool, e.g. B.

The sprue block has been finished on a grinding machine so has fulfilled its clamping and holding function, it is important to remove it from the workpiece to replace.

For this purpose, a device is shown in section in Fig. 16, which it enables the casting clamping block 6 described to be broken open.

This device consists of a frame 68, which is a fixed Clamping jaw 69 and a pivoting clamping jaw 71 carries. The sprue block 6 is of the fixed jaw 69 and held by the pivotable Clamping jaw 71 loaded on bending and train. To apply the clamping forces are both clamping jaws 69, 71 each with a hydraulic actuating element 72 and 73, respectively fitted. To achieve the pivoting movement of the clamping jaw 71 this is from a part 76 which is pivotable about an axis 74 and to which the piston rod 77 of a hydraulic cylinder 78 is articulated. The hydraulic cylinder 78 is on the other hand pivotally connected to the frame 68.

The cast-in clamping block 6 is clamped in such a way that the fixed clamping jaw 69 its one molded part 7 and the pivotable clamping jaw 71 its other molded part 8 detected.

A compound slide 79 is arranged above the clamping jaws 69, 71, the fingers 81, 82 for breaking the connecting webs 9, 11 of the sprue clamping block 6 carries (Figures 16 and 17).

By lowering the slide 83 of the cross slide 79, the Fingers 81, 82 in the space 12 between the connecting webs 9, 11 and in the space between the one connecting web 11 and the inner rim segment 3 is introduced.

In the slide 83, another slide 84 is guided, which the fingers 81, 82 moved in the direction of the connecting webs 9, 11, so that these of the fingers 81, 82 are broken. The fingers 81, 82 can also have heated edges 86, 87 (Fig. 17) be provided, the connecting webs 9, 11 wholly or partially melt.

In the same way, the end face of the carriage 84 can also be heated Edges 88, 89 be provided during the lowering movement of the carriage 83 in the direction on the vorblatt whose Schaufe3kanten 13, 16 are delivered and this by them Remove any encapsulating casting material.

After the connecting webs 9, 11 have been severed and the blade Sn 13, 16 have been exposed, the Moldings 7, 8 through Pivoting the part 76 finally removed from the workpiece. They then fall behind Loosen the two clamping jaws 69, 71 in a collecting container (not shown).

The workpiece remains on the fingers 81, 82 and can with the Cross slide 79 are transported out of the clamping zone.

In the opposite way, it is also possible to use the clamping block 6 with Workpiece to be broken open by means of these fingers 81, 82 and the compound slide 79 to be introduced into the restraint.

Instead of the fingers 81, 82 it is also possible as a break-open means to use a expandable elastic hollow body 91 (Fig. 18), as it is similar 15 was already shown as a mold insert. This is on the entrance side firmly and tightly connected to a nozzle 92, through which the expansion of the Hollow body 91 required pressure medium is supplied.

Although the invention is based on two or more-bladed turbine guide vanes or similar multi-part workpieces was aligned because it was specially So far there has not been a practicable solution for this, but it is quite conceivable that it can also be used for single blades or similar single workpieces.

Claims (22)

Claims 1. Sprue clamping block for clamping and holding Workpieces, in particular turbine blades, made by casting around the workpiece is formed with a fusible material, characterized in that it for clamping and holding two or more winged turbine guide vanes (1, 2, 3, 4) or similar multi-part workpieces made up of two or more the workpiece from the outside comprehensive molded parts (7, 8) consists of connecting webs (9, 11) are connected to one another, and that the space (12) between the blades (1, 2) or similar workpiece parts as well as undercuts existing on these are largely kept free of casting material. 2. casting clamping block according to claim 1, characterized in that the Connecting webs (9, 11) are designed as predetermined breaking points. Apparatus for producing the sprue block according to claim 1 or 2, characterized in that it consists of an at least two-part, with one Filler neck (54) provided casting mold, the parts (18, 19) of which the outer Limitation of the cast-in clamping block (6) shape that the mold parts (18, 19) with Mold inserts are provided, which the gap (12) between the blades (1, 2) or the like spaced workpiece parts and existing undercuts between the blades (1, 2) and webs largely free of casting material hold that positioning and pressure elements for correct positioning of the workpieces are provided in the mold and that actuating elements (28, 44, 36) for opening and closing the casting mold, for the actuation of the pressure elements as well as for the actuation at least one of the mold inserts are present. 4. Apparatus according to claim 3, characterized in that the mold inserts Sealing joints along the inner and outer rim segments (3, 4) of the turbine blades as well as along the airfoil edges (13; 14; 16; 17). 5. Apparatus according to claim 4, characterized in that the s Sealing joints are designed as a gap seal. 6. Apparatus according to claim 4, characterized in that the sealing joints are provided with sealing elements made of elastic material (59). 7. Apparatus according to claim 4, characterized in that the sealing joints are provided with resiliently pressed sealing strips (61). 8. The device according to one or more of claims 3 to 7, thereby characterized in that the mold inserts present in the mold parts (18, 19) consist of stationary shaped pieces (33) and / or of actuatable shaped punches (34). 9. Device according to one or more of claims 3 to 7, characterized characterized in that the mold inserts present in the mold parts (18, 19) from stationary shaped pieces (33) and / or from at least one by means of a pressure medium expandable elastic hollow body (66) exist. 10. Device according to one or more of claims 3 to 9, characterized characterized in that the filler neck (54) for filling the casting mold as a with a heating device (56) provided tubular element is formed. 11. The device according to claim 10, characterized in that the Filler neck (54) separated in its filling zone (58) and in its mouth zone (57) is heatable. 12. The device according to one or more of claims 3 to 11, characterized characterized in that the pressure elements as through the movable mold part (18) durchge led and pressure pins resiliently supported in a guide element (49) (42, 43) are designed so that they can be used for visual control and correction of the Workpiece position can be actuated when the mold (18, 19) is open. 13. The device according to one or more of claims 3 to 12, characterized characterized in that the mold inserts also serve as positioning elements for the Workpieces are formed. 14. A method for breaking open the sprue block according to claim 1 and / or 2, characterized in that with simultaneous application of tensile and bending forces on the molded parts (7, 8) of the sprue clamping block (6) the connecting webs (9, 11) are separated by mechanical breaking and / or melting, after which the molded parts (7, 8) are removed. 15. The method according to claim 14, characterized in that at the same time a melting of undercuts, z. B. blade edges, from the pouring material he follows. 16. Apparatus for performing the method according to claim 14 or 15, characterized in that these from the sprue clamping block (6) holding as well Tensioning devices that put stress on him on bending and tension and from one into the gaps (12) between the connecting webs (9, 11) collectable and on the connecting webs (9, 11) consists of breaking means acting. 17. The device according to claim 16, characterized in that it a fixed clamping jaw holding the sprue clamping block (6) on a molded part (7) (69) as well as a sprue block (6) on the opposite molded part (8) has sensing jaws (71) pivotable about an axis of rotation (74) and that the break-open means which can be moved in two planes by means of an actuating and guide element consists of one or more fingers (81, 82). 18. The device according to claim 17, characterized in that the Actuating and guiding element for the opening fingers (81, 82) as a compound slide (79) is formed. 19. Apparatus according to claim 17 or 18, characterized in that that the fingers (81, 82) are provided with heated edges (86, 87). 20. The device according to claim 18, characterized in that the guide carriages (84) of the compound carriage (79) carrying the fingers (81, 82) its side facing the sprue block (6) heated edges (88, 89) for melting of the pouring material surrounding the blade edges. 2 1. Apparatus according to claim 17, characterized in that the Clamping jaws (69, 71) for applying the clamping forces and for pivoting movement corresponding hydraulic actuators (72, 73, 78) are connected. 22. The device according to claim 16, characterized in that it a fixed clamping jaw holding the sprue clamping block (6) on a molded part (7) (69) as well as a sprue block (6) on the opposite molded part (8) capturing, has a clamping jaw (71) pivotable about an axis of rotation (74) and that the breaking means consists of an elastic hollow body (91) which can be inflated by means of a pressure medium.