WO2020075198A2

WO2020075198A2 - Multi-station multi-axis hybrid layered manufacturing system

Info

Publication number: WO2020075198A2
Application number: PCT/IN2019/050756
Authority: WO
Inventors: Karunakaran POOPATHI K.P.; Sajan Kapil; Seema Negi
Original assignee: Indian Institute Of Technology Bombay
Priority date: 2018-10-10
Filing date: 2019-10-10
Publication date: 2020-04-16
Also published as: WO2020075198A3

Abstract

According to the present disclosure, a Multi-Station Multi-Axis Hybrid Layered Manufacturing (MSMA-HLM) system is disclosed. The present disclosure enables different levels of process hybridization and integration of multiple technologies. The Multi-Station Multi-Axis Hybrid Layered Manufacturing system comprises a base-structure (2000). Further a super-structure (1000) may be mounted on the base-structure (2000). The system may further comprise a 4-axis platform (3000) mounted on the base structure (2000). The 4-axis platform (3000) may be further configured to traverse in Y and Z direction and further comprises a tilting table (3400). The various levels of process hybridization may comprise of an optimal use of: different modes of manufacturing like subtractive(-)/additive(+)/ transformative(0); different joining methods like thermal (MIG/TIG/laser/EB), or non-thermal (Binder); different kinematics like 3-axis, 5-axis, serial, or parallel); different layering strategies like horizontal/conformal; and different form(wire/powder)/size of raw-stock.

Description

MULTI-STATION MULTI-AXIS HYBRID LAYERED

MANUFACTURING SYSTEM

TECHNICAL FIELD

[0001] The present invention relates to a Hybrid Layered Manufacturing

(HLM), and more particularly to a system and method for improved hybrid layered manufacturing combining other levels of process hybridization and multiple technologies to produce near neat shape of an object.

BACKGROUND

[0002] Most of the existing hybrid-Additive Manufacturing systems combine additive and subtractive manufacturing in order to exploit the benefits of both and avoid their limitations. It is achieved by retrofitting a cladding torch on the spindle head of a CNC machine.

[0003] The spindle head moves up/down and therefore increases the chance of clogging the wire by the cladding torch. Further another limitation of the system is space available for the realization of near-net shape, which is reduced by the distance of offset distance between the spindle and other units. This also add to the possibility of collision and over travel.

[0004] There is a need of a system, that optimally combines (i) different modes of manufacturing like subtractive/ Additive/Transformative (ii) thermal/non- thermal joining methods, (iii) 3/5-axis, serial/parallel kinematics, (iv) planar/non- planar layering strategies and (v) different forms/size of raw stock. The system should also be able to accommodate multiple technologies for relieving the residual stresses, inspection etc. SUMMARY

[0005] In an aspect of the present disclosure, a Multi-Station Multi-Axis

Hybrid Layered Manufacturing (MSMA-HLM) system to fabricate/manufacture near-net shape of an object is disclosed.

[0006] In an implementation of the present disclosure, a Multi-Station

Multi-Axis Hybrid Layered Manufacturing (MSMA-HLM) system is disclosed. The present disclosure enables different levels of process hybridization and integration of multiple technologies.

[0007] The various levels of process hybridization may comprise of an optimal use of: different modes of manufacturing like subtractive(-)/additive(+)/ transformative(O); different joining methods like thermal (MIG/TIG/laser/EB), or non-thermal (Binder); different kinematics like 3-axis, 5-axis, serial, or parallel); different layering strategies like horizontal/conformal; and different form(wire/powder)/size of raw-stock.

[0008] The various technologies may comprise of: face milling for surface management, pneumatic hammering and induction preheating for residual stress management, and optical inspection for crack and surface porosity detection.

[0009] In an implementation of the present disclosure a Multi-Station

Multi-Axis Hybrid Layered Manufacturing system is disclosed. The system comprises a base-structure (2000). Further a super- structure (1000) may be mounted on the base-structure (2000). The system may further comprise a 4-axis platform (3000) mounted on the base structure (2000). The 4-axis platform (3000) may be further configured to traverse in Y and Z direction and further comprises a tilting table (3400). BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The detailed description is described with reference to the accompanying figures.

[0011] Figure 1 illustrates an exemplary embodiment of the present disclosure.

[0012] Figure 2a, illustrates an exemplary embodiment of the super structure, in accordance with the present disclosure.

[0013] Figure 2b, illustrates an exemplary embodiment of a retractable fixture in accordance with the present disclosure.

[0014] Figure 3a, illustrates a base-structure, in accordance with the present disclosure.

[0015] Figure 3b, illustrates a 4-axis platform, in accordance with the present disclosure.

[0016] Figure 4 illustrates another exemplary embodiment of a 4-axis platform, in accordance with the present disclosure.

[0017] Figure 5 illustrates a parallel kinematics-based scissor lift mechanism in accordance with the present disclosure.

[0018] Figure 6 illustrates a common lead-screw for Y&Z axes on bottom frame in accordance with the exemplary embodiment of the present disclosure.

[0019] Figure 7a and 7b, illustrates motion along Y axis by moving both motors at same speed, and along Z axis by moving only one motor in accordance with the exemplary embodiment of the present disclosure.

[0020] Figure 8 illustrates a method in accordance with exemplary embodiment.

DETAILED DESCRIPTION

[0021] The present disclosure relates to a Multi-Station Multi-Axis Hybrid

Layered Manufacturing (MSMA-HLM) system to fabricate/manufacture near-net shape of an object. [0022] In an implementation of the present disclosure, a Multi-Station

Multi-Axis Hybrid Layered Manufacturing (MSMA-HLM) system is disclosed. The present disclosure enables different levels of process hybridization and integration of multiple technologies. The various levels of process hybridization may comprise of an optimal use of: different modes of manufacturing like subtractive(-)/additive(+)/ transformative(O); different joining methods like thermal (MIG/TIG/laser/EB), or non-thermal (Binder); different kinematics like 3-axis, 5- axis, serial, or parallel); different layering strategies like horizontal/conformal; and different form(wire/powder)/size of raw-stock. The various technologies may comprise of: face milling for surface management, pneumatic hammering and induction preheating for residual stress management, and optical inspection for crack and surface porosity detection.

[0023] In an exemplary embodiment Multi-Station Multi-Axis Hybrid

Layered Manufacturing, system may comprise a face milling module mounted on the super structure along the X-axis of the machine. The face milling module may utilize to achieve Z-accuracy, to remove the scallops and to create a nascent surface. In an alternate embodiment, a slab milling, or grinding may be used.

[0024] In an exemplary embodiment Multi-Station Multi-Axis Hybrid

Layered Manufacturing, system may comprise a preheating module mounted on the super structure along the X-axis of the machine. The preheating module may utilize induction heating to heat the pre-built layer and hence to reduce the residual stresses. In an alternate embodiment arc heating, flame heating, or resistance heating may be used.

[0025] The exemplary embodiment system may further comprise cladding units mounted on the super structure along the X-axis of the machine. The cladding may comprise MIG, TIG, and/or Laser cladding. The cladding, MIG, TIG and laser, are may be utilized in the increasing order of precision and cost and decreasing order of speed. These can be deployed optimally to build objects fast without any sacrifice in quality and cost.

[0026] In an exemplary embodiment Multi-Station Multi-Axis Hybrid

Layered Manufacturing, system may comprise a cold working module mounted on the super structure along the X-axis of the machine. The cold working module may utilize pneumatic hammer to remove the residual stress from the layers. In an alternate embodiment laser shock peening, cold rolling, or pressing may be used.

[0027] In an exemplary embodiment Multi-Station Multi-Axis Hybrid

Layered Manufacturing, system may comprise an inspection module mounted on the super structure along the X-axis of the machine. The inspection module may utilize an optical camera to detect the cracks and porosities on the surface of layers. In an alternate embodiment, laser scanning or ultrasonic scanning may be used.

[0028] Referring to Figure 1, illustrates an exemplary embodiment of the present disclosure. The Multi-Station Multi-Axis Hybrid Layered Manufacturing system as illustrated may comprise a super- structure (1000), a 4-axis platform (3000), and a base-structure (2000). The base- structure (2000) may primarily enable motion along X-axis for the 4-axis platform (3000). The 4-axis platform (3000) may traverse in order to commute among the different stations that may be mounted on the super-structure (1000). A substrate may be mounted on a table of the platform (3000) and the near-net shape will be created in a layer-by-layer manner.

[0029] Referring to Figure 2a, illustrates an exemplary embodiment of the super- structure, in accordance with the present disclosure. The super-structure may further comprise an assembly of a preheating unit (1200), a MIG cladding unit (1300), a TIG cladding unit (1400), a laser cladding unit (1500), a pneumatic hammering unit (1600), an optical Inspection unit (1700), and/or a Face-Milling unit (1800). Further at least one power source (1900) for the various units may be mounted on a roof of a frame (1100).

[0030] The different units mounted on the super-structure (1000) may be tightly packed for optimal utilization of the available space. In an exemplary embodiment the minimum length of the system can be 2300 mm, with all units placed within the 2300 mm length. For e.g. the preheating unit (1200) may occupy 650 mm; the MIG cladding unit (1300), along with the TIG cladding unit (1400), and the laser cladding unit (1500) may occupy 750 mm; the pneumatic hammering unit (1600) may occupy 250mm; the optical Inspection unit (1700) may occupy 250 mm; and the Face-Milling unit (1800) may occupy 400mm.

[0031] An optimum distance between the various units is required to be kept in order to avoid collision of the units with a tilting table (3400) during working. In the exemplary embodiment the MIG cladding unit (1310) can mounted on a retractable fixture (1320). Similarly, the TIG cladding unit (1410) can be mounted on a retractable fixture (1420), and the Laser cladding unit (1510) can be mounted on a retractable fixture (1520). Further the hammering unit (1610) can be mounted on a retractable fixture (1620), and the inspection unit (1710) mounted on a retractable fixture (1720). In accordance with the embodiment pneumatic arrangement (1320, 1420, 1520, 1620 and 1720) can retract and keep the corresponding unit (1310, 1410, 1510, 1610 and 1710) to a desired position at a safe height. For e.g. Figure 2b illustrates the exemplary embodiment, wherein the retractable fixture (1420) with the TIG torch (1410) mounted in a retracted and an extended position. The TIG cladding unit (1400) may further comprise of at least two guide rods (1421) to constrain the rotation and to guide in the vertical motion. Further, a piston cylinder arrangement (1422) may make a 300 mm stroke to retract and extend a hammer unit, and a housing unit. The embodiment may further comprise an end fixtures of the at least two guide rods and piston cylinder (1423), a base plate (1424) to hold the entire retractable fixture on the frame (1100). Further, a plate (1425) may offset the TIG cladding gun (1410) from the centre of cylinder and a mounting block to hold the pneumatic hammer (1426). Similar to the retractable fixture (1420), the other retractable fixtures can be fabricated.

[0032] Referring to Figure 3a, illustrates the base-structure (2000), in accordance with the present disclosure. The base-structure (2000) may be configured to accommodate a moving 4-axis platform (3000) and the super structure (1000). The base-structure may further comprise a frame (2500). Further a motor (2100), for driving a leadscrew (2200) of X-axis with approximate 3.0m traverse is mounted on the frame (2500). The base structure (2000) may further comprise at least two liner motion guideways (2300) with the hubs (2400) to carry the 4-axis motion unit (3000) on top of it. The total length of the frame (2500) of base-structure may be about 4.7 m (including the additional space for motor and gear box etc.). Further the width of the frame (2500) can be about 2.0 m to accommodate the base of 4-axis platform (3000) which may have the Y-Z axes.

[0033] The 4-axis platform (3000) may further comprise a bottom frame

(3100) mounted on the liner motion hubs (2400) and may be configured to move in X-direction with the help of the X-axis leadscrew (2200). The remaining 4-axes (Y, Z, A and C) can be accommodated on the bottom frame (3100) as shown in Figure 3b.

[0034] Referring to Figure 3b, a conventional trunnion table (3400) may be attached to the top frame (3300) of the 4-axis platform (3000). Further, the trunnion table (3400) may be configured to rotate about X-axis that is known as A-axis (3410), and a rotary axis about Z-axis can be referred to as C-axis (3420). The near net shape of the object (3430) is realize on a substrate mounted on the C-axis (3420).

[0035] Referring to Figure 4, illustrates at least two single wall blocks

(3310) welded on one side of the top frame (3300). Further on another side of the top frame (3300), at least two linear motion guides (3320) are attached. A connecting plate (3350) may be configured to slide on the at least two linear motion guide rails (3320) with the help of LM hubs (3330) mounted. Further two double wall blocks (3340) can be welded to the bottom of the connecting plate (3350). [0036] Referring to Figure 5, illustrates a parallel kinematics-based scissor lift mechanism (3200) configured to achieve movement along Y and Z axis. The parallel kinematics-based scissor lift mechanism (3200) comprises scissor links 3230 and 3240 that are similar to conventional scissor links. Further other two scissor-links (3210 and 3220) may be split into four linkages. Such configuration of the scissor links and other two scissor-links enables top ends blocks (3310) to be are fixed with top frame (3300) and any load acting along Y-axis will be taken by only these two links. Further the scissor-links (3210 & 3230) may be connected to each other with the thrust bearing (3260). Similarly, the scissor-links on another side (3220 & 3240) can be connected with the thrust bearing (3260). The top ends of the scissor-lift linkages are connected to the blocks (3310 and 3340) by thrust bearing (3250). Similarly, the bottom of the scissor-lift linkages are connected to the blocks (3160 and 3150) by thrust bearing (3250).

[0037] The common leadscrew (3120) for Y&Z axes may be placed along the Y-axis as shown in Figure 6. It will be a stationary leadscrew. The bottom carriages (3170 and 3180) may be mounted on the linear guide rails (3110). Further at least two motors (3140 and 3130) can be mounted on these two bottom carriages (3170 and 3180). These motor (3140 and 3130) are connected to respective nuts (3141 and 3131) which are mounted on the common leadscrew of Y&Z axes (3120). Both the carriages (3170 and 3180) can slide along the Y-axis with help of their respective motors (3140 and 3130). The bottom of the scissor-lift linkages can be connected to the blocks (3160 and 3150) by thrust bearing (3250). These blocks (3160 and 3150) are welded on the bottom carriages (3170 and 3180) respectively.

[0038] When both motors (3140 and 3130) run at the same speed, there will be no Z motion but only Y. When their speeds are unequal, one can achieve the required velocity ratios along Y and Z including only Z motion. Noted that the motor (3130) shall rotate to achieve only the vertical Z motion as illustrated in Figure 7a and 7b (see Figure 17). [0039] Referring to Figure 8, illustrates a method in accordance with exemplary embodiment. The 4-axis platform (3000) moves to the induction heating system at the left extreme for preheating the prebuilt layer. The 4-axis platform (3000) may further move to a laser cladding system where the boundary loops of a few slices of fine layer thickness (say, 0.5mm) are deposited in 5-axis mode. Then it may move to the arc cladding system to fill the interior in one thick layer in 2.5- axis mode. This will be done by MIG or TIG head depending on the size of the part and precision. Further, it may move to the face milling head at the right extreme for flattening the scalloped clad surface to the required height. Then it may move to the station for optical inspection where camera shoots the surface and an image processing software looks for any cracks arising out of a possible process instability such as spatter. If any crack is found larger than the pre-set permissible limit, it goes back to the face milling head where the entire recently built layer is milled off to rebuild it again right from preheating. Further after the layer will pass the inspection, it will move to the hammering station to relieve the residual stresses.

[0040] After the near-net shape is ready, if required, it may be sent for a heat/pressure treatment after which it will be finish-milled on an accurate CNC machine.

Claims

We Claim:

1. A Multi-Station Multi-Axis Hybrid Layered Manufacturing system comprising:

a base- structure (2000);

a super-structure (1000) is mounted on the base-structure (2000); and a 4-axis platform (3000) mounted on the base structure (2000), wherein the 4-axis platform (3000) is configured to traverse in Y and Z direction and further comprises a tilting table (3400).

2. The system as claimed in claim 1 wherein the super- structure (1000), further comprise an assembly of a preheating unit (1200), and a Face-Milling unit (1800) mounted on the super-structure (1000).

3. The system as claimed in claim 1, wherein the super-structure (1000), further comprises a frame (1100), wherein at least one power source (1900) is mounted on a roof of the frame (1100).

4. The system as claimed in claim 1 wherein the super- structure (1000), further comprise a MIG cladding unit (1300), a TIG cladding unit (1400), a laser cladding unit (1500), a pneumatic hammering unit (1600), and an optical Inspection unit (1700), wherein the MIG cladding unit (1300), the TIG cladding unit (1400), the laser cladding unit (1500), the pneumatic hammering unit (1600), and the optical Inspection unit (1700), are mounted on a retractable fixture (1320, 1420, 1520, 1620, 1720).

5. The system as claimed in claim 4, wherein the retractable fixture (1320, 1420, 1520, 1620, 1720) further comprises at least two guide rods (1421).

6. The system as claimed in claim 4, wherein the retractable fixture (1320, 1420, 1520, 1620, 1720) a piston cylinder arrangement (1422).

7. The system as claimed in claim 4, wherein the retractable fixture (1320, 1420, 1520, 1620, 1720) further comprise an end fixtures to hold the retractable fixture (1320, 1420, 1520, 1620, 1720) on the frame (1100).

8. The system as claimed in claim 1, wherein the base- structure (2000) further comprises a frame (2500).

9. The system as claimed in claim 1, wherein the base structure (2000) further comprise at least two liner motion guideways (2300) with a liner motion hubs (2400).

10. The system as claimed in claim 1, wherein the 4-axis platform (3000) further comprises a bottom frame (3100) mounted on the liner motion hubs (2400) and configured to move in X-direction.

11. The system as claimed in claim 1 further comprises a parallel kinematics- based scissor lift mechanism (3200) configured to achieve movement along Y and Z axis.

12. The system as claimed in claim 11 wherein the parallel kinematics-based scissor lift mechanism (3200) further comprises scissor links (3230) and (3240).

13. The system as claimed in claim 11 wherein the parallel kinematics-based scissor lift mechanism (3200) further comprises other two scissor-links (3210 and 3220) that are split into four linkages, wherein the other scissor- links (3210 & 3230) are connected to each other with a thrust bearing (3260).

14. The system as claimed in claim 11, wherein the parallel kinematics-based scissor lift mechanism (3200) achieve Y and Z motions through a stationary lead screw (3120), wherein the stationary lead screw (3120) further comprises two motors (3130 & 3140) connected to respective nuts (3141 & 3131).