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CN-121988757-A - Self-adaptive composite scraper for powder bed powder and powder laying device

CN121988757ACN 121988757 ACN121988757 ACN 121988757ACN-121988757-A

Abstract

The invention relates to the technical field of powder bed melting, in particular to a self-adaptive composite scraper for powder bed powder and a powder laying device. Comprises a doctor blade holder, a central wiper blade and a pair of lateral sealing units. The self-adaptive driving device comprises a scraper frame, a base material, a central scraping blade, a pair of side sealing units and an adaptive driving assembly, wherein the central scraping blade is connected with the scraper frame, working gaps are reserved between two sides of the central scraping blade along the length direction of the central scraping blade and the side walls of the base material, the pair of side sealing units are symmetrically arranged on two sides of the central scraping blade, each side sealing unit comprises a sealing piece and the adaptive driving assembly, the sealing piece is used for being elastically abutted against the side wall of the corresponding base material, and the adaptive driving assembly is connected between the scraper frame and the sealing piece and used for driving the sealing piece to move so as to adaptively seal the corresponding working gaps. When the base material is displaced, the seal member is allowed to retract or follow the base material by the elastic contact, thereby maintaining the contact state with the side wall of the base material and dynamically closing the working gap. Solves the problem of fixed clearance caused by thermal displacement, so that the powder cannot leak from the side direction.

Inventors

  • WANG HOUQIN
  • WANG ZEPENG
  • JIN JUN
  • ZHANG BINGGANG
  • WANG YIFAN

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260508
Application Date
20260310

Claims (10)

  1. 1. An adaptive composite doctor blade for powder bed powder, comprising: A scraper rest (1); The central scraping blade (2), wherein the central scraping blade (2) is used for paving powder, the central scraping blade (2) is connected to the scraper frame (1), and a working gap is reserved between two sides of the central scraping blade (2) along the length direction and the side wall of the base material (01); a pair of lateral sealing units (3), wherein the pair of lateral sealing units (3) are symmetrically arranged at the two sides of the central scraping blade (2); Wherein each lateral sealing unit (3) comprises a sealing member (31) and an adaptive driving assembly, wherein the sealing member (31) is used for being elastically abutted against the corresponding side wall of the base material (01), and the adaptive driving assembly is connected between the scraper frame (1) and the sealing member (31) and used for driving the sealing member (31) to move so as to adaptively seal the corresponding working gap.
  2. 2. The adaptive composite doctor blade according to claim 1, characterized in that each lateral sealing unit (3) further comprises a lateral spacer (33), the lateral spacer (33) being connected to the doctor blade holder (1) and being located at the rear side of the central doctor blade (2) in the direction of the doctor blade movement, the lateral spacer (33) comprising a first side wall (331) and a second side wall (332) arranged at intervals and a third side wall (333) connecting the two, the second side wall (332) being located at the rear side of the central doctor blade (2), the second side wall (332) being provided with a sealing surface for cooperating with the sealing element (31) for blocking leakage of powder from the rear side of the central doctor blade (2).
  3. 3. An adaptive composite doctor blade according to claim 2, characterized in that the sealing member (31) is a floating cylinder, the axial direction of which is arranged parallel to the doctor blade holder (1) for elastic abutment against the corresponding side wall of the parent material (01) by its first end, and the sealing surface is an arcuate sealing surface (3321) for cooperation with the outer circumferential surface of the floating cylinder.
  4. 4. An adaptive composite doctor blade according to claim 3, characterized in that the adaptive drive assembly comprises a guide bar (321) and a resilient element (322); The guide rod (321) is parallel to the scraper frame (1), the floating roller is slidably sleeved on the guide rod (321), and the elastic element (322) acts on the second end of the floating roller and is used for providing elastic pressing force towards the side wall of the base material (01) for the floating roller.
  5. 5. The adaptive composite doctor blade according to claim 4, wherein the guide rod (321) is penetrated through a pair of the first side walls (331) supported to a pair of the side spacers (33) by a bearing, and the pair of the first side walls (331) are adjacent to each other and connected by a pin.
  6. 6. The self-adaptive composite scraper according to claim 4, wherein limiting rings (3211) are arranged at two ends of the guide rod (321), and the limiting rings (3211) are used for limiting the axial movement of the corresponding floating roller.
  7. 7. The self-adaptive composite scraper according to claim 4, wherein the elastic element (322) is a compression spring, the compression spring is sleeved on the guide rod (321), one end of the compression spring is abutted with the first side wall (331) of the corresponding side baffle (33), and the other end is abutted with the second end of the floating roller.
  8. 8. The adaptive composite doctor blade according to claim 5, further comprising a connecting member (11), one end of the connecting member (11) being connected to the doctor blade holder (1), the other end extending between the first side wall (331) and the second side wall (332) of the side spacer (33), the third side wall (333) of the side spacer (33) being fixedly connected to the other end of the connecting member (11) by means of a fastener.
  9. 9. The adaptive composite doctor blade according to claim 2, characterized in that the sealing member (31) is a lateral doctor blade, a side of which facing the central doctor blade (2) is planar and is in abutment with the sealing surface of the second side wall (332), and an end of the lateral doctor blade corresponding to the side wall of the parent material (01) is rounded in shape curved towards the central doctor blade (2).
  10. 10. A powder spreading device comprising an adaptive composite doctor blade according to any one of claims 1 to 9.

Description

Self-adaptive composite scraper for powder bed powder and powder laying device Technical Field The invention relates to the technical field of powder bed melting, in particular to a self-adaptive composite scraper for powder bed powder and a powder laying device. Background In powder bed melt additive manufacturing, a powder spreading scraper is a basic core component for ensuring uniform powder spreading and determining molding quality. The powder spreading scraper in the prior art is a rigid metal scraper, a floating roller scraper or an improved design with vibration or heating function, and the connection mode of the powder spreading scraper and the powder spreading device is basically rigid or integral floating connection. The common premise of such designs is that the boundaries of the powder placement area remain constant during the process, so that reliable operation is possible in conventional powder placement scenarios, which accumulate layer by layer from the substrate. However, in the current emerging "additive-joining" special process, powder laying is required in the region between two base materials which have been previously placed in the forming cylinder, and in order to meet the process requirements of materials such as nickel-based superalloys, the powder bed equipment needs to preheat the substrate to a very high temperature (e.g., 750 ℃ to 850 ℃), which causes the base materials placed on the high temperature substrate to shift as the substrate thermally expands. Resulting in a necessarily dynamically varying, millimeter-sized gap between the doctor blade and the sidewall of the parent material. In the powder spreading process, metal powder can seriously leak from the gaps, not only is raw material waste and equipment pollution caused, but also a uniform, compact and accurate-thickness powder layer cannot be obtained in a to-be-connected area between two base materials, so that the subsequent melt forming step can not be carried out, and the whole additive-connection process fails in the initial stage. Disclosure of Invention The invention solves the problem that the rigid connection type scraper cannot adapt to the dynamic boundary conditions generated by the thermal expansion of the substrate. In order to solve the problems, the invention provides a self-adaptive composite scraper for powder bed powder and a powder laying device. In one aspect, the present invention provides an adaptive composite doctor blade for powder bed powder comprising: A scraper rack; The central scraping blade is used for paving powder, is connected to the scraper frame and leaves a working gap between two sides of the central scraping blade along the length direction and the side wall of the base material; a pair of lateral sealing units symmetrically disposed on the both sides of the central wiper blade; Each lateral sealing unit comprises a sealing element and an adaptive driving assembly, wherein the sealing element is used for being elastically abutted against the corresponding side wall of the base material, and the adaptive driving assembly is connected between the scraper rest and the sealing element and used for driving the sealing element to move so as to adaptively seal the corresponding working gap. Preferably, each lateral sealing unit further comprises a side baffle connected to the doctor blade holder and located at the rear side of the central blade in the direction of powder spreading movement, the side baffle comprises a first side wall and a second side wall which are arranged at intervals, and a third side wall connecting the first side wall and the second side wall, the second side wall is located at the rear side of the central blade, and a sealing surface is arranged on the second side wall and is used for being matched with the sealing piece to prevent powder from leaking from the rear side of the central blade. Preferably, the sealing element is a floating roller, the axial direction of the floating roller is parallel to the scraper rest and is used for elastically abutting against the corresponding side wall of the base material through the first end of the floating roller, and the sealing surface is an arc sealing surface and is used for being matched with the peripheral surface of the floating roller. Preferably, the adaptive drive assembly comprises a guide rod and a resilient element; The guide rod is parallel to the scraper rest, the floating roller is sleeved on the guide rod in a sliding manner, and the elastic element acts on the second end of the floating roller and is used for providing elastic pressing force towards the side wall of the parent material for the floating roller. Preferably, the guide rod is penetrated and supported on the pair of first side walls of the pair of side separation plates through a bearing, and the pair of first side walls are close to each other and are connected through a pin shaft. Preferably, limiting rings are arranged at two ends of the guid