Solid State Extrusion and Bonding Tool

Abstract

An extrusion and bonding tool for carrying out a hybrid metal extrusion and bonding process, the tool being for extruding an extrusion material and bonding the extrusion material to a substrate is provided. The tool may comprise a main body and a rotating die through which the extrusion material is extruded, wherein the rotating die moves relative to the main body of the tool, and wherein the extrusion material, in use, is extruded through the rotating die at a position that can vary about a circumferential path about a rotation axis of the tool. The tool may comprise an extrusion chamber; and a plurality of dies through which the extrusion material is extruded associated with the extrusion chamber, wherein the tool is arranged so that, in use, the extrusion material is received in the extrusion chamber and plasticised within the extrusion chamber before being extruded through one of the dies onto the substrate.

Claims

1. An extrusion and bonding tool for carrying out a solid-state hybrid metal extrusion and bonding process, wherein the tool is for extruding a metal extrusion material and bonding the extrusion material to a metal substrate, the tool comprising: a main body; and a rotating die through which the extrusion material is extruded, wherein the rotating die moves relative to the main body of the tool; and wherein the extrusion material, in use, is extruded through the rotating die at a position that can vary about a circumferential path about a rotation axis of the tool

2. A tool according to claim 1, wherein the tool comprises an extrusion chamber and wherein some extrusion material, when in the extrusion chamber, is in contact with the rotating die from the point at which it enters the extrusion chamber and is forced through the moving die once the extrusion material has moved a certain distance around the extrusion chamber and the pressure in the extrusion chamber has increased above a threshold extrusion pressure.

3. A tool according to claim 1 or 2, the tool comprising a rotatable spindle.

4. A tool according to claim 3, wherein the rotatable spindle is arranged to, in use, contact and deform the substrate.

5. A tool according to claim 3 or 4, wherein the rotating spindle comprises the rotating die.

6. A tool according to any preceding claim, wherein the tool comprises a plurality of dies for the extrusion of the extrusion material.

7. A tool according to any preceding claim, wherein the tool comprises a stationary die.

8. A tool according to any preceding claim, wherein the tool is arranged so that when extrusion material is extruded through the moving die it is directed towards a central axis of the tool.

9. A tool according to any preceding claim, comprising a guide, wherein the guide is arranged so that, in use, extrusion material is guided in a direction different to the direction in which it was extruded.

10. A tool according to claim 9, wherein the tool comprises a plurality of guides and wherein at least two of the guides guide extrudate in a different direction to each other.

11. A tool according to any preceding claim, a wherein the tool comprises an extruder housing that surrounds the rotatable spindle, and wherein the extruder housing together with the spindle form an extrusion chamber.

12. A tool according to claim 11, wherein the extruder housing forms a stationary die.

13. A tool according to claim 10, 11 or 12, wherein the extruder housing comprises a slot that permits the removal of extrusion material flash formed when leakage occurs between the rotatable spindle and the housing.

14. A tool according to any of claims 11 to 13, wherein the tool comprises a coating on the surfaces of the rotatable spindle and the extruder housing that contact each other when the tool is in use and/or comprises a coating on the surfaces of the tool that will contact the substrate during use.

15. A tool according to claim 14, wherein the coating is a dual coating with a high wear resistance underlayer and a low friction surface layer

16. A tool according to any preceding claim, wherein the tool is arranged so that cooling of the extruder housing and/or extrudate can be performed during use.

17. A tool according to any preceding claim, wherein the tool is for joining two substrates together, and wherein the tool is arranged so that, in use, the tip of a spindle is received in a gap between the two substrates and deforms at least part of the surface of at least one of the two substrates that face each other.

18. A tool according to any preceding claim, wherein the tool comprises a plurality of interchangeable extruder heads that are each designed for a different application.

19. A tool according to claim 18, wherein the tool comprises one or more of a butt joining extruder head which is for butt joining two substrates, and a fillet joining extruder head which for fillet joining two substrates.

20. An extrusion and bonding tool for carrying out a hybrid metal extrusion and bonding process, the tool being for extruding a metal extrusion material and bonding the extrusion material to a metal substrate, the tool comprising: an extrusion chamber; and a plurality of dies through which the extrusion material is extruded associated with the extrusion chamber, wherein the tool is arranged so that, in use, the extrusion material is received in the extrusion chamber and plasticised within the extrusion chamber before being extruded through one of the dies onto the substrate.

21. A tool according to claim 20, the tool comprising a rotatable spindle that is arranged to, in use, contact and deform the substrate.

22. A tool according to claim 21, wherein the rotatable spindle comprises a moving die that in use moves relative to a main body of the tool.

23. A tool according to claim 20, 21 or 22, wherein the tool comprises a moving die that in use moves relative to a main body of the tool and wherein the tool is arranged so that when extrusion material is extruded through a moving die it is directed towards a central axis of the tool.

24. A tool according to any of claims 20 to 23, comprising a guide, wherein the guide is arranged so that, in use, extrusion material extruded is guided in a direction different to the direction in which the extrudate was extruded.

25. A tool according to claim 24, wherein the tool comprises a plurality of guides and wherein at least two of the guides guide extrudate in a different direction to each other.

26. A tool according to any of claims 21 to 25, a wherein the tool comprises a rotatable spindle and an extruder housing that surrounds the rotatable spindle, and wherein the extruder housing together with the spindle form an extrusion chamber.

27. A tool according to claim 26, wherein the extruder housing forms a stationary die.

28. A tool according to claim 26 or 27, wherein the extruder housing comprises a slot that permits the removal of extrusion material flash formed when leakage occurs between the rotatable spindle and the housing.

29. A tool according to any of claims 21 to 28, wherein the tool comprises a coating on the surfaces of the rotatable spindle and the extruder housing that contact each other when the tool is in use and/or comprises a coating on the surfaces of the tool that will contact the substrate during use.

30. A tool according to claim 29, wherein the coating is a dual coating with a high wear resistance underlayer and a low friction surface layer

31. A tool according to any of claims 20 to 30, wherein the tool is arranged so that cooling of the tool and/or extrudate can be performed during use.

32. A tool according to any of claims 20 to 31, wherein the tool is for joining two substrates together, and wherein the tool is arranged so that, in use, a tip of a rotatable spindle is received in a gap between the two substrates and contacts and deforms at least part of the surfaces of the two substrates that face each other.

33. A tool according to any of claims 20 to 32, wherein the tool comprises a plurality of interchangeable extruder heads that are each designed for a different application.

34. A tool according to claim 33, wherein the tool comprises one or more of a butt joining extruder head that is for butt joining two substrates, and a fillet joining extruder head which for fillet joining two substrates.

35. A solid-state method of extruding a metal extrusion material and bonding the metal extrusion material to a substrate, the method comprising, using the tool of any preceding claim.

36. A method according to claim 35, the method comprising extruding the extrusion material through a plurality of dies.

37. A method according to claim 35 or 36, the method comprising extruding the extrusion material through a rotating die.

Description

[0248] Certain preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0249] FIG. 1 shows a bonding and extrusion tool;

[0250] FIG. 2a shows the parts of a first extruder head;

[0251] FIG. 2b shows the first extruder head in partial cross-section;

[0252] FIG. 3 shows an extruder head;

[0253] FIG. 4 shows a schematic spindle tip of an extruder head;

[0254] FIG. 5 shows the first extruder head being used;

[0255] FIG. 6 shows a butt joint;

[0256] FIG. 7a shows the parts of a second extruder head;

[0257] FIG. 7b shows the second extruder head in partial cross-section;

[0258] FIG. 8 shows the second extruder head being used;

[0259] FIG. 9 shows a fillet joint;

[0260] FIG. 10a shows the parts of a third extruder head;

[0261] FIG. 10b shows the second extruder head in partial cross-section;

[0262] FIG. 11 shows the third extruder head being used;

[0263] FIG. 12 shows in partial cross section the third extruder head being used;

[0264] FIG. 13a shows the parts of a fourth extruder head;

[0265] FIG. 13b shows the fourth extruder head in partial cross-section;

[0266] FIG. 14 shows the fourth extruder head being used;

[0267] FIG. 15 shows another view of the fourth extruder head being used;

[0268] FIG. 16 shows the tool being used for plate deposition;

[0269] FIG. 17a shows the tool being used for the first stage of a multi-pass join;

[0270] FIG. 17b shows the extruder head for the first stage of a multi-pass join in partial cross-section;

[0271] FIG. 18 shows the tool being used for the second stage of a multi-pass join;

[0272] FIG. 19a shows in partial cross section the tool being used for the second stage of a multi-pass join;

[0273] FIG. 19b shows the extruder head for the second stage of a multi-pass join in partial cross-section;

[0274] FIG. 20a shows the tool being used for the third stage of a multi-pass join;

[0275] FIG. 20b shows the extruder head for the third stage of a multi-pass join in partial cross-section;

[0276] FIG. 21 shows a completed multi-pass join; and

[0277] FIG. 22 shows a double sided multi-pass join.

[0278] FIG. 1 shows an extrusion and bonding tool 1 for carrying out a solid-state hybrid metal extrusion and bonding process, the tool being for extruding a metal extrusion material and bonding the extrusion material to a metal substrate. The tool comprises an extrusion head 2 which attaches to and is driven by a drive mechanism 3.

[0279] As shown in FIGS. 2a and 2b, the extruder head 2 comprises a stationary extruder housing 4 which circumferentially surrounds a rotatable spindle 6. The spindle 6 and extrusion housing 4 together form an extrusion chamber 8 which extends around the spindle 6.

[0280] The spindle 6 and housing 4 may both be formed of steel.

[0281] The extrusion chamber 8 has three walls formed by a groove on the rotatable spindle 6 and a stationary wall formed by the extrusion housing 4.

[0282] The groove on the rotatable spindle 6 that forms three walls of the extrusion chamber 8 is formed between a larger diameter die section 10 of the spindle and a spindle ring 12. The spindle ring 12 is mounted on the spindle 6 and is provided to facilitate assembly of the tool 1. The spindle ring 12 has a locking surface 14 which allows the spindle 6 to engage with the aforementioned driving mechanism 3.

[0283] The die section 10 of the spindle has a plurality of moving dies 16 formed thereon. The moving dies 16 are grooves in the surface of the die section 10 of the spindle 6 which connect the extrusion chamber 8 to the environment outside the extrusion head 2.

[0284] The extrusion housing 4 comprises a die 18 which is a stationary die which is also in communication with the extrusion chamber 8.

[0285] Located in the extrusion chamber 8 is an abutment 20. The abutment 20 blocks the extrusion chamber 8. In use, the abutment 20 causes extrusion material in the extrusion chamber 8 to be forced out of the dies 16 and 18.

[0286] The spindle 6 has a deformation portion 22 that in use contacts and plastically deforms the substrate on which the extrudate will be deposited.

[0287] The moving dies 16 and the deformation portion 22 are arranged so that when extrusion material is extruded through the dies 16 the extrudate is guided to towards the rotation axis of the spindle.

[0288] The extruder head 2 also comprises a sealing protrusion 24. In use this sealing protrusion 24 seals against the substrate to prevent leakage of extrudate in front of the tool.

[0289] The rotatable spindle 6 is rotated and extrusion material is fed into the extrusion chamber 8. The extrusion material is pulled through the extrusion chamber 8 by friction from its entrance point towards the abutment 20. When the extrusion material reaches the abutment 20 the pressure in the extrusion chamber 8 rises and extrusion material is forced out of the extrusion chamber 8 through the stationary die 18 in the extruder housing 4 and the moving dies 16 in the spindle 6.

[0290] In use the deformation portion 22 of the spindle is in contact with the substrate (not shown in FIG. 1 or 2a, b). This plastically deforms the substrate immediately before the extruded extrusion material is deposited on the substrate.

[0291] In use the tool is moved in direction x to create a strip of extrusion material which bonds to the underlying deformed substrate.

[0292] FIG. 2a shows the separate component parts of the extruder head 2 (including the housing 4 being shown twice from different perspectives). The view of the housing 4 at the top of the figure shows the underside of the housing 4 and in particular shows a sealing surface 34 (which is shaded grey for clarity). In use this sealing surface 34 is in contact with the top surface of the substrate (or substrates in the case that two substrates are being joined together) and seals thereto. The extrusion material is extruded out of the stationary die 18 through the seal surface 34.

[0293] The extruder head 2 shown in FIGS. 1 and 2a, b is specially designed for butt joining two plates together.

[0294] FIG. 4 shows a schematic of the tip of the spindle 6. The arrow at the top of the figure shows the rotation direction of the spindle 6. This schematic shows the direction in which extrusion material enters the extrusion chamber by arrow 26. The extrusion material is pulled around the spindle 6 and is forced out of the extrusion chamber either at the stationary die 18 in the housing 4 and guided in a direction illustrated by arrow 28 or at one of the moving dies 16 in the spindle 6 and guided in a direction illustrated by arrow 30.

[0295] As shown in FIG. 3, the housing 4 may have a slot 32 therethrough. Whilst the extruder housing 4 and spindle 6 may mate together to form the extrusion chamber 8, due to the high forces involved there may be leakage of extrusion material through the seal between the stationary housing 4 and the rotating spindle 6. In view of this, the housing 4 may be provided with a slot 32 therethrough. The slot 32 permits the removal of extrusion material flash formed when such leakage occurs. The slot 32 is shaped to permit a machining tool to be inserted which can remove the extrusion material flash. Such a slot 32 allows the extrusion material leakage problem to be solved without significantly affecting the mechanical integrity of the extruder housing 4.

[0296] The tool 1 is specially designed to minimise forces on the spindle.

[0297] Shear fracture in a rotating spindle will occur when the maximum shear force r during operation exceeds the shear strength T.sub.0 of the material of the spindle:

[00001]$>{}_0=\frac{2}{}.Math.\frac{M_t}{r^3}$

[0298] from which the maximum allowable torque M.sub.t can be calculated:

[00002]$M_{}<{}_0.Math.\frac{}{2}.Math.r^3$

[0299] Thus, if the spindle is made of steel with a shear strength of 850 MPa and has a radius of 5 mm the maximum allowable torque will be 167 Nm.

[0300] To minimise the forces the tool may comprise low friction coatings on the surfaces of the spindle 6 and the extruder housing 4 which contact each other when the tool is assembled and in use. These coatings may be for the purpose of reducing friction between these two parts 4 and 6 which move relative to each other.

[0301] The tool 1 may also comprise a coating on the surfaces of the tool that contact the substrate during use. This may comprise parts of the tool, such as the extrusion housing 4 and sealing protrusion 24, which seal against the substrate when the extrusion and bonding is occurring.

[0302] The abutment 20 which guides extrusion material out of the extrusion chamber 8 may comprise a coating on the surface which in use contacts the extrusion material.

[0303] The coating may be a dual coating with a high wear resistance underlayer, and a low friction coating surface layer.

[0304] The high wear resistance layer may be an AlTiN type coating. The low friction coating may be a diamond-like carbon coating, e.g. a W-DLC type coating.

[0305] The extrusion chamber 8, or at least the moving walls of the extrusion chamber 8 may be uncoated, or at least not comprise a low friction coating. This is to ensure that there is sufficient sticking friction between the extrusion material and the extrusion chamber 8 to obtain a high enough drag force on the incoming extrusion material to allow the extrusion to occur.

[0306] FIG. 5 shows the extruder head 2 for butt joining two plates together in use joining two plates 36 and 38.

[0307] As shown most clearly in FIG. 6, the tool is used to join two parallel plates 36 and 38. The plates 36 and 38 are placed in a set up with a gap 40 between the two plates. The deformation portion 22 of the spindle 6 is received in the gap 40 between the two plates 36 and 38 (see FIG. 5). The width of the gap 40 may be smaller than the diameter of the deformation portion 22 of the spindle 6. This is so that when the spindle 6 rotates the deformation portion 22 plastically deforms the two plates 36 and 38.

[0308] The seal surface 34 of the extruder housing 4 may contact the upper surface of each of the plates 36 and 38 and seal thereto.

[0309] The sealing protrusion 24 may be received in the gap 40 and seal on each side against the two substrates.

[0310] To join the two plates 36 and 38 the deformation portion 22 and sealing protrusion 24 are lowered into the gap 40 until the sealing surface 34 contacts and seals against the top surfaces of the two plates 36, 38. The spindle 6 is rotated so as to plastically deform the substrates 36, 38 and extrusion material is fed into the extrusion chamber 8 and forced out through one or more of the dies 16, 18 into the gap 40 which has just been deformed by the spindle 6. The tool 1 is moved in direction x to form a continuous bond 42 along the joint between the two plates 36, 38.

[0311] The tool 1 may also, in addition to the aforementioned butt joining, be used for fillet joining (see FIGS. 7 to 9), bead-on plate deformation (see FIGS. 10 to 12), additive layer manufacturing (see FIGS. 13 to 15), surface plating (see FIG. 16) and/or multi-pass joining (see FIGS. 17 to 22).

[0312] The tool 1 may have different, interchangeable extruder heads 2, 102, 202 and 302 respectively for butt joining (see FIGS. 1 and 4), fillet joining (see FIGS. 7a and b), bead-on-plate deformation (see FIGS. 10a and b) and additive layer manufacturing (see FIGS. 13a and b). These heads may be used and in certain cases together in sequence to achieve a plurality of different applications.

[0313] For each of the extruder heads the like features and components to the butt joining extruder head will generally not be described but rather the description will focus on the main differences and features specially adapted for the particular application the extruder head is designed for.

[0314] The fillet joining extruder head 102 is used for joining two plates 136 and 138 which extend at an angle to each other about a join 140. The spindle 6 of the fillet joining extruder head 102 comprises a tapered/conical deformation portion 122 which is designed to contact and deform both the plates 136, 138 near the join 140.

[0315] The bottom of the extruder housing 4 has a first sealing surface 134a which in use seals against one of the plates 138 and a second sealing surface 134b which in use seals against the other of the plates 136. The angle between the surfaces of the first and second sealing surfaces 134a and 134b may be substantially the same as the angle between the two plates 136 and 138.

[0316] Instead of a sealing protrusion 24 the extruder head 102 comprises a nose 124 which is designed to seal against the two plates 136 and 138 in front of the deformation portion 122 of the spindle 6.

[0317] To join the two plates 136 and 138 the deformation portion 122 and sealing nose 124 are inserted in the crevice/gap 140 between the two plates 136 and 138 until the sealing surfaces 134a and 134b contact and seal against the surfaces of the two plates 136, 138 about the crevice 140. The spindle 6 is rotated so as to plastically deform the substrates 136, 138 about the join 140 and extrusion material is fed into the extrusion chamber 8 and forced out through one or more of the dies 16, 18 into the crevice 140 which has just been deformed by the spindle 6. The tool 1 is moved in direction x to form a continuous fillet bond 142 along the join 140 between the two plates 136, 138.

[0318] The bead-on-plate extruder head 202 is used for joining an extruded bead of material onto the surface of a plate 236. The spindle 6 of the bead-on-plate extruder head 202 comprises a flat deformation portion 222 which is designed to contact and deform the surface of the plates 23 on which the extrudate will be deposited.

[0319] The bottom of the extruder housing 4 has a sealing surface 234 which in use seals against the surface of the plate 236. The sealing surface 234 extends around the front of the spindle 6.

[0320] The spindle 6 does not comprise any moving dies and the bottom wall of the extrusion chamber 8 is formed instead by a top surface of the deformation portion 222 of the spindle 6.

[0321] The stationary die 18 in the extrusion housing 4 opens into a channel 219 which directs the extrudate in a rearward direction away from the spindle 6 and in a direction parallel to the surface of the plate 236 to form a bead 242 on the plate.

[0322] The bottom surface of the housing 4 comprises a recess 235 which allows beads 242 to be deposited close together as shown in FIG. 11.

[0323] To deposit and bond the bead 242 on the plate 236 the deformation portion 222 and sealing surface 234 are put in contact with the surface of the plate 236. The spindle 6 is rotated so as to plastically deform the plate 236 underneath the deformation portion 222 in location where a bead of extrudate is about to be deposited. Extrusion material is fed into the extrusion chamber 8 and forced out through the die 18 and guided onto the deformed surface in a continuous bead by the channel 219 such that the extrudate bonds to the plate 236 in a bead 242. The tool 1 is moved in direction x to form a continuous bead 242 on the surface of the plate 236. This process may be repeated a number of times to form a plurality of beads 242 on the surface of the plate 236. The recess 235 can be used to form the beads a set distance apart. This can be achieved by accommodating a bead 242 which has already been formed on the plate 236 in the recess 235. As a result, each bead 242 will be separated by a distance equal to the distance between the recess 235 and channel 219 on the extruder head 202.

[0324] As shown for example in FIG. 16, the tool 1 can be used to form a layer on a plate 236. This can be achieved by forming a plurality of beads 242 on the plate 236 as shown in FIG. 12 using the bead-on-plate extruder head 202 and then forming a butt joint 42 between two adjacent beads 242 using a butt joining extruder head 2.

[0325] The additive layer manufacturing extruder head 302 is used for joining an extruded bead of material onto an already deposited bead of material (a substrate bead) 343. The spindle 6 of the additive layer manufacturing extruder head 302 comprises a flat deformation portion 322 which is designed to contact and deform the surface of the already deposited bead 343 on which the extrudate will be deposited.

[0326] The bottom of the extruder housing 4 has a sealing surface 334 which in use seals against the top surface of the already deposited bead 343. The sealing surface 334 extends around the front of the spindle 6.

[0327] The spindle 6 does not comprise any moving dies and the bottom wall of the extrusion chamber 8 is formed instead by a top surface of the deformation portion 322 of the spindle 6.

[0328] The stationary die 18 in the extrusion housing 4 opens into a channel 319 which directs the extrudate in a rearward direction away from the spindle 6 and in a direction parallel to the surface of the already deposited bead 343 to form a bead 342 on the already deposited bead 343.

[0329] The bottom surface of the housing 4 comprises a sealing rim 337 which when the sealing surface 334 is in contact with the surface of the already deposited bead 343 extends down the sides of the bead 343. This is used to guide the tool 1 and ensure that the bead 342 is deposited on top of the previously deposited bead 343.

[0330] To deposit and bond the bead 342 on the substrate bead 343 the deformation portion 322 and sealing surface 334 are put in contact with the surface of the substrate bead 343. The spindle 6 is rotated so as to plastically deform the bead 343 underneath the deformation portion 322 where a bead of extrudate is about to be deposited. Extrusion material is fed into the extrusion chamber 8 and forced out through the die 18 and guided onto the deformed bead surface in a continuous bead by the channel 319 such that the extrudate bonds to the substrate bead 343 in a newly deposited bead 342.

[0331] The tool 1 is moved to form a continuous bead 342 on the substrate bead 343 which creates a taller bead of material on a component. This process may be repeated a number of times to form a plurality of beads 342 on top of each other.

[0332] The tool 1 can be used to form a multi-pass joint 400 between two plates 436 and 438 which have an angled gap 440 therebetween. This may be achieved by (see for example FIGS. 17a and 17b) using a fillet joint extruder head 102 to extrude a first pass of extrudate which is bonded to each of the two plates 436 and 438 in the bottom of the angled gap 440.

[0333] Next (as shown in FIGS. 18,19a and 19b) a bead-on-plate extruder head 202 may be used to form a bead 242 on the fillet joint 142 in the gap 440 between the two plates 436 and 438. The bead-on-plate extruder head 202 specially designed for a multi-pass join is shown in FIG. 19a and has angled sides so that it can fit in the gap between the two components 436, 438.

[0334] Next a butt joining extruder head 2 (as shown in FIG. 20b) can be used on either side of the deposited bead 242 to form a butt joint 42 between the central bead 242 and one of the plates 438 and a second butt joint 42 between the central bead 242 and the other of the two plates 436 to form a multi pass joint 400 as shown in FIG. 21.

[0335] A multi-pass joint may be used to join thick plates which cannot be joined by a single pass.

[0336] For even thicker plates a double sided multi-pass joint 402 as shown in FIG. 22 may be formed. In this case, a multi-pass joint 400 is formed on either side of the joint (i.e. on opposite surfaces of the two plates) in the manner described above for a single multi-pass join.