Corundum ceramic composite steel pipe production device

Abstract

The utility model relates to the technical field of steel pipe production equipment discloses a corundum ceramic composite steel pipe production device, including base, the upper end fixed mounting of base is provided with the first support and second support of interval, rotatably installed with rotating shaft on the first support, one end fixed mounting of rotating shaft has the clamping device for clamping steel pipe. The utility model in the use process, can drive the rotation of driving gear through the second motor drive of setting clamping device, drive gear ring rotation, utilize the cooperation of arc -shaped groove and slide, make the movable card block along the radial, self -adaptation adjustment clamping radius, realized can to a variety of pipe diameter's steel pipe clamping, make in actual production, need not frequently change the fixture, reduced equipment adjustment time, improved production efficiency significantly, expanded the application scope of device simultaneously, reduced production cost, satisfied the diversified production demand.

Description

Technical Field

[0001] This utility model relates to the technical field of steel pipe production equipment, and in particular to a corundum ceramic composite steel pipe production device. Background Technology

[0002] In the industrial sector, corundum ceramic composite steel pipes are widely used in material conveying systems in mining, power, and chemical industries due to their excellent wear resistance, corrosion resistance, and high strength. Currently, the industry mostly uses the traditional centrifugal self-propagating high-temperature synthesis method to produce this type of steel pipe. The principle is to utilize the high temperature generated by the aluminothermic reaction to instantly melt the raw materials. Under centrifugal force, the molten corundum ceramic uniformly adheres to the inner wall of the steel pipe, forming a composite layer. The production steps are as follows: First, the aluminothermic agent and other reaction raw materials are filled into the steel pipe. Then, the steel pipe is horizontally fixed to a simple rotating device. The motor is started to drive the steel pipe to rotate at high speed. The aluminothermic agent is ignited by an ignition device. The heat released by the reaction causes the materials to react and melt rapidly. Under centrifugal force, the denser molten iron adheres to the outer layer of the inner wall of the steel pipe, while the corundum ceramic layer is located in the inner layer, finally cooling and solidifying.

[0003] However, this production method has significant drawbacks. In the steel pipe fixing stage, conventional clamps are difficult to adapt to steel pipes of different diameters. Frequent replacement or adjustment of clamps not only reduces production efficiency but may also cause the steel pipe to shift during high-speed rotation due to unstable clamping, affecting the uniformity of the ceramic layer. Furthermore, the lack of effective filtration devices means that the high-temperature fumes generated during the aluminothermic reaction are rich in dust and harmful gases. Without effective filtration devices, this will not only seriously pollute the workshop environment and threaten the health of operators but also accelerate equipment aging due to the corrosive components in the fumes, significantly increasing equipment maintenance costs.

[0004] Therefore, it is necessary to provide a corundum ceramic composite steel pipe production apparatus to solve the problems mentioned above in the background art. Utility Model Content

[0005] To address the aforementioned problems, this application provides a corundum ceramic composite steel pipe production apparatus to solve the problems of difficulty in matching steel pipe diameter and insufficient flue gas treatment in the prior art mentioned in the background section.

[0006] To achieve the objectives of this application, the following technical solution is provided:

[0007] This application provides a corundum ceramic composite steel pipe production device, including a base, with a first support seat and a second support seat fixedly installed at an interval on the upper end of the base; a rotating shaft is rotatably installed on the first support seat, a clamping device for clamping steel pipe is fixedly installed at one end of the rotating shaft, and a driven wheel is fixedly installed at the other end; a driving wheel is rotatably installed on the second support seat, the driving wheel is connected to the driven wheel through a track, and the driving wheel is connected to the drive shaft of a first motor; an ignition device is provided at the upper end of the base, and a flue gas emission device is placed on one side of it; the clamping device includes a gear ring, a first limiting ring and a second limiting ring arranged coaxially, the gear ring being rotatably sleeved on one end of the first limiting ring, and the second limiting ring being fixed to the other end of the first limiting ring by a bracket.

[0008] In one possible implementation, multiple guide blocks are fixed at adjacent ends of the first and second limiting rings, and vertical guide grooves are formed at corresponding positions of the guide blocks; a slide rod is slidably installed in each of the vertical guide grooves, and a locking block is fixedly installed on the outer wall of the slide rod. The locking block consists of two sets of locking blocks that are slidably disposed in the guide blocks of the first and second limiting rings respectively; multiple sets of arc-shaped grooves penetrating both sides are formed on the gear ring, and one end of the slide rod extends into the corresponding arc-shaped groove; a drive gear is rotatably installed at one end of the first limiting ring, and the drive gear meshes with the gear ring, while its other end is connected to a second motor drive shaft fixed at the other end of the first limiting ring.

[0009] In one possible implementation, the curvature of the arc groove matches the rotation trajectory of the gear ring, and the slide rod achieves linear movement along the vertical guide groove through the guidance of the arc groove.

[0010] In one possible implementation, the flue gas emission device includes a filter box and an exhaust pipe. The exhaust pipe is fixed to the upper end of the filter box, and its other end is connected to an induced draft fan. A first retaining ring is fixedly installed at the front end of the filter box, and a maintenance plate is detachably installed at its rear end. Multiple filter bags are horizontally arranged inside the filter box and are all located at the bottom of the exhaust pipe.

[0011] In one possible implementation, a mesh hole is formed on the inner side of the first retaining ring, and the filter bag is made of high-temperature resistant needle-punched felt material with a filtration accuracy of ≤10μm.

[0012] In one possible implementation, the ignition device is fixed to the upper end of the slide plate, and a second retaining ring is fixedly installed at the front end of the ignition device. The slide plate is slidably installed on the inner side of the U-shaped carriage. The U-shaped carriage is slidably installed on the upper end of the base. A limit bolt is provided at the upper end of the U-shaped carriage to limit the slide plate on its inner side. The rear end of the U-shaped carriage is rotatably connected to a threaded rod, and a support block is threadedly connected to the outer wall of the other end of the threaded rod. The support block is fixedly installed on the upper end of the base.

[0013] In one possible implementation, the bottom of the U-shaped carriage is provided with a guide rail that slides with the base, and the threaded clearance between the threaded rod and the support block is ≤0.1mm.

[0014] The beneficial effects of this utility model are:

[0015] 1. This utility model utilizes a second motor in its clamping device to drive a gear, which in turn rotates a gear ring. The arc-shaped groove and sliding rod work together to allow the clamping block to move radially, adaptively adjusting the clamping radius. This enables the clamping of steel pipes of various diameters, eliminating the need for frequent fixture changes in actual production, reducing equipment adjustment time, significantly improving production efficiency, expanding the device's applicability, reducing production costs, and meeting diverse production needs.

[0016] 2. This utility model uses a multi-stage filtration and negative pressure extraction method to treat high-temperature flue gas through a flue gas emission device. The high-temperature flue gas generated by the steel pipe firing process enters the filter box through the first baffle ring, and then uses multi-layer high-temperature resistant needle-punched felt filter bags to intercept dust and harmful particles. Finally, it is discharged by the induced draft fan, which effectively avoids the direct emission of high-temperature flue gas into the workshop, greatly improves the working environment, and reduces the threat of dust and harmful gases to the health of operators. Attached Figure Description

[0017] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0018] Figure 1 This is a schematic diagram of the main structure of a corundum ceramic composite steel pipe production device according to the present invention;

[0019] Figure 2 This is a schematic diagram of the main structure of the rotating shaft and clamping device in the corundum ceramic composite steel pipe production device of this utility model;

[0020] Figure 3 This is a schematic diagram of the main structure of the gear ring, the first limiting ring, and the second limiting ring in the clamping device of the corundum ceramic composite steel pipe production device of this utility model;

[0021] Figure 4 This is an exploded structural diagram of the clamping device in a corundum ceramic composite steel pipe production apparatus of this utility model.

[0022] Figure 5 This is a schematic diagram of the main structure of the flue gas emission device in a corundum ceramic composite steel pipe production device according to this utility model;

[0023] Figure 6This is a schematic diagram of the internal structure of the filter box in a corundum ceramic composite steel pipe production device according to this utility model;

[0024] Figure 7 This is a schematic diagram showing the connection relationship between the base, the sliding plate, and the U-shaped slide in a corundum ceramic composite steel pipe production device of this utility model;

[0025] Reference numerals: 1. Base; 2. First support seat; 3. Second support seat; 4. Rotating shaft; 5. Clamping device; 6. Driven wheel; 7. Drive wheel; 8. Track; 9. First motor; 10. Ignition device; 11. Smoke emission device; 12. Gear ring; 13. First limit ring; 14. Second limit ring; 15. Bracket; 16. Guide block; 17. Vertical guide groove; 18. Slide rod; 19. Locking block; 20. Arc groove; 21. Drive gear; 22. Second motor; 23. Filter box; 24. First retaining ring; 25. Exhaust pipe; 26. Exhaust fan; 27. Inspection plate; 28. Filter bag; 29. ​​Second retaining ring; 30. Slide plate; 31. U-shaped slide; 32. Limit bolt; 33. Threaded rod; 34. Support block. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this application, unless otherwise stated, "multiple" means three or more.

[0028] Figures 1-7A corundum ceramic composite steel pipe production apparatus provided in this application includes a base 1. A first support 2 and a second support 3, spaced apart, are fixedly mounted on the upper end of the base 1. A rotating shaft 4 is rotatably mounted on the first support 2. A clamping device 5 for clamping the steel pipe is fixedly mounted on one end of the rotating shaft 4, and a driven wheel 6 is fixedly mounted on the other end. A driving wheel 7 is rotatably mounted on the second support 3. The driving wheel 7 is connected to the driven wheel 6 via a track 8 and is connected to the drive shaft of a first motor 9. An ignition device 10 is provided on the upper end of the base 1, and a flue gas emission device 11 is placed on one side of it. The clamping device 5 includes a coaxially arranged gear ring 12, a first limiting ring 13, and a second limiting ring 14. The gear ring 12 is rotatably fitted onto one end of the first limiting ring 13, and the second limiting ring 14 is fixed to the other end of the first limiting ring 13 via a bracket 15. The base 1 serves as the basic load-bearing structure of the entire apparatus, providing a stable mounting surface for the first support 2, the second support 3, and other components. The first support seat 2 and the second support seat 3 are fixedly installed on the base 1 at intervals, respectively supporting the rotating shaft 4 and the drive wheel 7. They maintain a precise relative position to ensure the accuracy of the transmission of the track 8. During production, the corundum ceramic composite steel pipe is inserted into the inner wall of the clamping device 5. The clamping device 5 forms an annular clamping space through the coaxially arranged gear ring 12, the first limiting ring 13, and the second limiting ring 14. After the first motor 9 starts, the drive shaft drives the drive wheel 7 to rotate, and the drive wheel 7 transmits power to the driven wheel 6 through the track 8. Since the driven wheel 6 is fixedly connected to the rotating shaft 4, the rotating shaft 4 rotates accordingly, thereby driving the clamping device 5 fixed at one end to rotate. During this process, the toothed structure of the track 8, the drive wheel 7, and the driven wheel 6 meshes with each other, ensuring smooth power transmission. This, in turn, drives the steel pipe to rotate at high speed, providing centrifugal force conditions for the aluminothermic reaction. The ignition device 10 is aligned with the end of the steel pipe, igniting the internal aluminothermic agent and other reactants. The high-temperature molten material produced by the reaction adheres to the inner wall of the steel pipe under centrifugal force, forming a ceramic layer.

[0029] In one possible implementation, multiple guide blocks 16 are fixed to adjacent ends of the first limiting ring 13 and the second limiting ring 14, and vertical guide grooves 17 are formed at corresponding positions of the guide blocks 16. Sliding rods 18 are slidably installed within each vertical guide groove 17, and locking blocks 19 are fixedly installed on the outer wall of each sliding rod 18. Two sets of locking blocks 19 are slidably disposed within the guide blocks 16 of the first limiting ring 13 and the second limiting ring 14, respectively. The gear ring 12 has multiple sets of arc-shaped grooves 20 extending through both sides, and one end of each sliding rod 18 extends into the corresponding arc-shaped groove 20. A drive gear 21 is rotatably mounted on one end of the first limiting ring 13, meshing with the gear ring 12, and its other end is connected to the drive shaft of a second motor 22 fixed to the other end of the first limiting ring 13. The second motor 22 drives the drive gear 21 to rotate, meshing and causing the gear ring 12 to rotate around the first limiting ring 13. The arc-shaped groove 20 on the gear ring 12 engages with one end of the slide rod 18. When the gear ring 12 rotates, the arc of the arc-shaped groove 20 forces the slide rod 18 to slide up and down along the vertical guide groove 17. The two sets of locking blocks 19 on the outer wall of the slide rod 18 are respectively limited by the guide block 16 connected to them, and can only converge towards or move away from the center of the corresponding first limiting ring 13 and second limiting ring 14, thereby adaptively adjusting the clamping radius: when the slide rod 18 moves towards the center, the locking block 19 clamps the outer wall of the steel pipe; when the slide rod 18 moves away from the center, the steel pipe is released, realizing the clamping and fixing of steel pipes of different diameters.

[0030] In one possible implementation, the curvature of the arc groove 20 matches the rotation trajectory of the gear ring 12, and the slide rod 18 achieves linear movement along the vertical guide groove 17 through the guidance of the arc groove 20. The precise match between the curvature of the arc groove 20 and the rotation trajectory of the gear ring 12 ensures that when the gear ring 12 rotates, the force exerted by the arc groove 20 on the slide rod 18 is decomposed, generating an effective component force only along the direction of the vertical guide groove 17. This ensures that the slide rod 18 can only move linearly along the vertical guide groove 17, avoiding jamming or impaired movement due to uneven force distribution.

[0031] In one possible implementation method, such as Figure 5 and Figure 6As shown, the flue gas emission device 11 includes a filter box 23 and an exhaust pipe 25. The exhaust pipe 25 is fixed to the upper end of the filter box 23, and its other end is connected to an induced draft fan 26. A first baffle ring 24 is fixedly installed at the front end of the filter box 23, and a maintenance plate 27 is detachably installed at its rear end. Multiple filter bags 28 are horizontally arranged inside the filter box 23, all located at the bottom of the exhaust pipe 25. The high-temperature flue gas generated during the steel pipe firing process is discharged from both ends and enters the filter box 23 through the mesh holes inside the first baffle ring 24. The flue gas passes through multiple layers of horizontally arranged filter bags 28 inside the filter box 23. The filter bags 28 are made of high-temperature resistant needle-punched felt material, which uses its fiber structure to trap dust and harmful particles in the flue gas. The purified gas is discharged from the device through the exhaust pipe 25 under the negative pressure generated by the induced draft fan 26. After the filter bags 28 have been used for a period of time, they can be replaced and cleaned by removing the maintenance plate 27.

[0032] In one possible implementation, the inner side of the first baffle ring 24 has mesh holes, and the filter bag 28 is made of high-temperature resistant needle-punched felt material with a filtration accuracy of ≤10μm. The mesh holes are evenly distributed on the inner side of the first baffle ring 24, allowing the high-temperature flue gas discharged from the steel pipe to be evenly dispersed into the filter box 23. The filter bag 28, made of high-temperature resistant needle-punched felt material, has a microporous structure formed by its interwoven fibers, which can efficiently intercept dust particles with a diameter of ≤10μm, while also withstanding the impact of high-temperature flue gas, ensuring long-term stable filtration.

[0033] In one possible implementation method, such as Figure 1 and Figure 7 As shown, the ignition device 10 is fixed to the upper end of the slide plate 30. A second retaining ring 29 is fixedly installed at the front end of the ignition device 10. The slide plate 30 is slidably installed inside the U-shaped slide 31. The U-shaped slide 31 is slidably installed on the upper end of the base 1. A limit bolt 32 is provided at the upper end of the U-shaped slide 31 to limit the slide plate 30 inside it. The rear end of the U-shaped slide 31 is rotatably connected to a threaded rod 33. A support block 34 is threadedly connected to the outer wall of the other end of the threaded rod 33. The support block 34 is fixedly installed on the upper end of the base 1. When placing the steel pipe, first slide the slide plate 30 laterally to move it inside the U-shaped slide 31 to make room for the steel pipe to be placed. After the steel pipe is placed, reset the slide plate 30 and fix the position of the slide plate 30 by the limit bolt 32 at the upper end of the U-shaped slide 31. Subsequently, rotating the threaded rod 33 causes its threaded engagement with the support block 34 to push the U-shaped slide 31 forward along the guide rail of the base 1, thereby causing the second retaining ring 29 at the front end of the ignition device 10 to engage with the steel pipe end, ensuring precise alignment of the ignition device 10 and completing the ignition operation of the reactants inside the steel pipe. The second retaining ring 29 engaging with the steel pipe end seals one end of the steel pipe, forcing all gases to escape from the other end.

[0034] In one possible implementation, the bottom of the U-shaped carriage 31 is provided with a guide rail that slides and engages with the base 1, and the threaded engagement clearance between the threaded rod 33 and the support block 34 is ≤0.1mm. The guide rail at the bottom of the U-shaped carriage 31 slides and engages with the base 1, providing stable sliding guidance for the U-shaped carriage 31. When the threaded rod 33 is rotated, since the threaded engagement clearance between the threaded rod 33 and the support block 34 is ≤0.1mm, the rotational motion of the threaded rod 33 is converted into linear movement of the U-shaped carriage 31 along the base 1 through high-precision thread transmission, thereby achieving precise adjustment of the position of the ignition device 10.

[0035] Working principle:

[0036] First, slide the slide plate 30 laterally, allowing it to move inside the U-shaped carriage 31 to create space for the steel pipe installation. After placing the corundum ceramic composite steel pipe to be processed in place, reset the slide plate 30 and fix its position using the limiting bolt 32 at the upper end of the U-shaped carriage 31. Then, rotate the threaded rod 33, utilizing the high-precision threaded engagement between the threaded rod 33 and the support block 34 to push the U-shaped carriage 31 along the guide rail of the base 1, so that the second retaining ring 29 at the front end of the ignition device 10 is precisely fitted onto the end of the steel pipe. After positioning, the thermite and other reactive materials inside the steel pipe are ignited. The second retaining ring 29 seals one end of the steel pipe, allowing gas to escape from the other end, ensuring the orderly progress of the reaction. Next, place the corundum ceramic composite steel pipe to be processed into the clamping device 5. The second motor 22 in the clamping device 5 drives the drive gear 21 to rotate, which in turn drives the gear ring 12 to rotate. The arc-shaped groove 20 on the gear ring 12 engages with the slide rod 18, causing the slide rod 18 to slide along the vertical guide groove 17. This, in turn, drives the clamping block 19 to achieve adaptive clamping of steel pipes of different diameters. This design ensures the stability and versatility of the steel pipe fixing. Then, the first motor 9 is started, driving the drive wheel 7 to rotate. Power is transmitted to the driven wheel 6 via the track 8, which in turn drives the rotating shaft 4 and the clamping device 5 to rotate, causing the steel pipe to rotate at high speed, providing centrifugal force for the subsequent aluminothermic reaction. This transmission structure ensures smooth power transmission and guarantees the stability of the steel pipe rotation. During the aluminothermic reaction inside the steel pipe, the generated high-temperature molten material adheres to the inner wall of the steel pipe under centrifugal force, forming a ceramic composite layer. Simultaneously, the high-temperature flue gas generated by the reaction is discharged from the openings at both ends of the steel pipe, enters the filter box 23 through the mesh holes inside the first baffle ring 24, and is filtered by multi-layer high-temperature resistant needle-punched felt filter bags 28, trapping dust and harmful particles. The purified gas is then discharged through the exhaust pipe 25 under the action of the induced draft fan 26. This effectively reduces pollutant emissions and protects the production environment and equipment. Finally, after the filter bags 28 have been used for a period of time, they can be replaced and cleaned by disassembling the inspection plate 27 to ensure the flue gas filtration effect. The entire production unit achieves efficient, stable, and environmentally friendly production of corundum ceramic composite steel pipes through the coordinated operation of its various components.

[0037] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. This application is not limited to the exact structures described above and illustrated in the accompanying drawings, and it should not be considered that the specific implementation of this application is limited to these descriptions. For those skilled in the art, various changes and modifications made without departing from the concept of this application should be considered to fall within the protection scope of this application.

Claims

1. A corundum ceramic composite steel pipe production device, comprising a base (1), characterized in that, The upper end of the base (1) is fixedly equipped with a first support seat (2) and a second support seat (3) spaced apart; a rotating shaft (4) is rotatably mounted on the first support seat (2), one end of the rotating shaft (4) is fixedly equipped with a clamping device (5) for clamping steel pipes, and the other end is fixedly equipped with a driven wheel (6); a driving wheel (7) is rotatably mounted on the second support seat (3), and the driving wheel (7) is connected to the driven wheel (6) through a track (8), and the... The drive wheel (7) is connected to the drive shaft of the first motor (9); the upper end of the base (1) is provided with an ignition device (10), and a flue gas emission device (11) is placed on one side of it; the clamping device (5) includes a gear ring (12), a first limiting ring (13) and a second limiting ring (14) arranged coaxially. The gear ring (12) can be rotatably sleeved on one end of the first limiting ring (13), and the second limiting ring (14) is fixed to the other end of the first limiting ring (13) by a bracket (15).

2. The corundum ceramic composite steel pipe production device according to claim 1, characterized in that, Multiple guide blocks (16) are fixed at adjacent ends of the first limiting ring (13) and the second limiting ring (14). Vertical guide grooves (17) are opened at corresponding positions of the guide blocks (16). Sliding rods (18) are slidably installed in the vertical guide grooves (17). A locking block (19) is fixedly installed on the outer wall of the sliding rod (18). The locking block (19) consists of two sets of locking blocks (19) that are slidably set in the guide blocks (16) of the first limiting ring (13) and the second limiting ring (14). Multiple sets of arc-shaped grooves (20) are opened on the gear ring (12) that pass through both sides. One end of the sliding rod (18) extends into the corresponding arc-shaped groove (20). A drive gear (21) is rotatably installed on one end of the first limiting ring (13). The drive gear (21) meshes with the gear ring (12). Its other end is connected to the drive shaft of the second motor (22) fixed to the other end of the first limiting ring (13).

3. The corundum ceramic composite steel pipe production device according to claim 2, characterized in that, The curvature of the arc groove (20) matches the rotation trajectory of the gear ring (12), and the slide rod (18) achieves linear movement along the vertical guide groove (17) through the guidance of the arc groove (20).

4. The corundum ceramic composite steel pipe production device according to claim 1, characterized in that, The flue gas emission device (11) includes a filter box (23) and an exhaust pipe (25). The exhaust pipe (25) is fixed to the upper end of the filter box (23), and its other end is connected to an induced draft fan (26). A first retaining ring (24) is fixedly installed at the front end of the filter box (23), and a maintenance plate (27) is detachably installed at its rear end. Multiple filter bags (28) are horizontally arranged inside the filter box (23) and are all located at the bottom of the exhaust pipe (25).

5. The corundum ceramic composite steel pipe production apparatus according to claim 4, characterized in that, The first retaining ring (24) has mesh holes on its inner side, and the filter bag (28) is made of high temperature resistant needle-punched felt material with a filtration accuracy of ≤10μm.

6. The corundum ceramic composite steel pipe production apparatus according to claim 1, characterized in that, The ignition device (10) is fixed to the upper end of the slide plate (30). A second retaining ring (29) is fixedly installed at the front end of the ignition device (10). The slide plate (30) is slidably installed on the inner side of the U-shaped slide (31). The U-shaped slide (31) is slidably installed on the upper end of the base (1). A limit bolt (32) is provided at the upper end of the U-shaped slide (31) to limit the slide plate (30) on its inner side. The rear end of the U-shaped slide (31) is rotatably connected to a threaded rod (33). A support block (34) is threadedly connected to the outer wall of the other end of the threaded rod (33). The support block (34) is fixedly installed on the upper end of the base (1).

7. The corundum ceramic composite steel pipe production apparatus according to claim 6, characterized in that, The bottom of the U-shaped slide (31) is provided with a guide rail that slides with the base (1), and the threaded gap between the threaded rod (33) and the support block (34) is ≤0.1mm.

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