阅读说明：本技术 一种高温激光选区烧结装备的高温活动式密封机构 (High-temperature movable sealing mechanism of high-temperature selective laser sintering equipment ) 是由 闫春泽 陈鹏 王卫 史玉升 于 2021-07-31 设计创作，主要内容包括：本发明于先进制造配套设备技术领域,公开了一种高温激光选区烧结装备的高温活动式密封结构,包括成形腔、铺粉辊、运动通道、碳纤维布、碳纤维夹层、碳纤维密封刷、金属臂、石墨隔层板、步进电机、同步传送带、晶格散热片。高温活动式密封结构主要针对高温铺粉辊的运动机构进行活动式密封,实现装备内部成形时的氧含量低于0.8％,同时隔绝装备内部热量外散,保证成形腔内的温度均匀性、以及外部步进电机和同步传送带的使用寿命。(The invention discloses a high-temperature movable sealing structure of high-temperature selective laser sintering equipment, belonging to the technical field of advanced manufacturing corollary equipment. The movable seal structure of high temperature mainly spreads the moving mechanism of powder roller to high temperature and carries out movable sealed, and the oxygen content when realizing equipping inside shaping is less than 0.8%, and isolated simultaneously equips inside heat and looses outward, guarantees the temperature homogeneity in the shaping intracavity and outside step motor and synchronous conveyor's life.)

1. A high-temperature movable sealing mechanism of high-temperature selective laser sintering equipment is characterized by comprising a forming cavity 1, a powder spreading roller 2, a moving channel 3, carbon fiber cloth 31, a carbon fiber interlayer 32, a carbon fiber sealing brush 33, a metal arm 4, a graphite interlayer plate 5, a stepping motor 6, a synchronous conveyor belt 7 and a crystal lattice cooling fin 8. Wherein:

the dusting roller 2 is placed inside the forming chamber 1 and is connected by a metal arm 4 through a movement channel 3 to a graphite interlayer sheet 5 outside the forming chamber 1. The graphite interlayer plate 5 is fixed on the synchronous conveyor belt 7, the stepping motor 6 drives the synchronous conveyor belt 7 to move through gear transmission, and then the graphite interlayer plate 5, the metal arm 4 and the powder spreading roller 2 are driven to be linked.

2. The high-temperature movable seal mechanism according to claim 1, wherein the moving passage 3 is provided with a carbon fiber sandwich layer 32 and a carbon fiber cloth 31 arranged on the outer wall of the forming chamber 1 in sequence from inside to outside. The carbon fiber interlayer 32 is of a two-layer structure, is fixed on the outer wall of the forming cavity 1, is internally provided with a double-layer carbon fiber sealing brush 33, and can be movably sealed when the metal arm 4 drives the powder spreading roller 2 to move. The outer carbon fiber cloth 31 is fixed to the metal arm 4 and is interlocked with the metal arm 4.

3. The high-temperature movable seal mechanism according to claim 1, wherein the carbon fiber seal brush 33 has a revolving ring structure, is partially overlapped in the upper, lower, left and right directions, and has a double-layered built-in structure.

4. The high temperature movable seal mechanism of claim 1, wherein the metal arm 4 is attached to the outside of the forming chamber 1 and the lattice heat sink 8 is disposed thereon.

Technical Field

The invention belongs to the technical field of advanced manufacturing corollary equipment, and particularly relates to a high-temperature movable sealing mechanism of high-temperature selective laser sintering equipment.

Background

High Temperature-Selective Laser Sintering (SLS) is an important branch of Additive Manufacturing (AM) technology, and the biggest characteristic of the High Temperature-Selective Laser Sintering (SLS) technology is the forming Temperature compared with the traditional SLS technology. At present, SLS technology at home and abroad is mainly used for forming thermoplastic polymer materials with lower melting points (such as nylon 12, nylon 11, TPU, PP, PS and composite materials thereof). For special polymer materials such as high performance Polyaryletherketones (PAEKs) and polyaramides (aromatic Polyamides), the melting point of the polymer material is generally higher (for example, polyetheretherketone PEEK material, which has a melting point of about 340 ℃). In order to prevent the buckling deformation of the part during the forming process, the preheating temperature of the cavity during the HT-SLS forming process is required to be set within the range of 330-337 ℃ (laser sintering window). Whereas for aged PEEK powder the melting point is higher, the sintering window is narrower and the preheat temperature is set closer to 400 ℃.

The PEEK powder material has serious aging problem during high-temperature forming at 330-400 ℃, and the stepping motor of the equipment is extremely easy to damage, and the reason is mainly the sealing property of the powder paving roller movement mechanism of the HT-SLS equipment. On the one hand, the oxygen content is increased due to poor motion sealing of the powder spreading roller in the equipment, PEEK powder is seriously aged and can be solved only by improving the flow of argon, but dispersed dust in a cavity is easily caused, a laser protective mirror is polluted, and the actual sintering power is reduced. The whiteness of the aged PEEK powder is seriously reduced, the fluidity is reduced, and new PEEK powder must be mixed for printing, so that the reuse rate of the PEEK powder is greatly reduced, and the HT-SLS processing cost is greatly increased. On the other hand, the stepping motor and the synchronous conveyor belt have thermal convection with a forming cavity at a high temperature of 330-400 ℃ in the equipment due to poor sealing of a powder spreading roller moving mechanism, and are easy to damage as long-time working parts, and the replacement cost also causes the whole processing cost to be greatly increased. Therefore, the tightness of the powder laying roller movement mechanism of the whole HT-SLS equipment must be effectively controlled, and the technical difficulties are mainly focused on the following two points: (1) when the powder spreading roller moves in the forming process, the smoothness and the sealing of a moving channel are difficult to ensure at the same time, and the oxygen content is ensured to be lower than 0.8 percent; (2) spread the powder roller and be connected to the step motor who equips the outside through the metal arm, equip inside heat on the one hand and carry out heat convection to outside motor through the motion passageway, on the other hand also carries out heat transfer to conveyer belt and motor through the metal arm, consequently seriously influences conveyer belt and step motor's life.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a high-temperature movable sealing mechanism of high-temperature selective laser sintering equipment, which mainly aims at movably sealing a movement mechanism of a high-temperature powder spreading roller, realizes that the oxygen content is lower than 0.8 percent when the inside of the equipment is formed, simultaneously isolates the heat inside the equipment from being dissipated, and ensures the service lives of an external stepping motor and a synchronous conveyor belt.

The invention provides a high-temperature movable sealing mechanism of high-temperature selective laser sintering equipment, which comprises a forming cavity, a powder spreading roller, a moving channel, carbon fiber cloth, a carbon fiber interlayer, a carbon fiber sealing brush, a metal arm, a graphite interlayer plate, a stepping motor, a synchronous conveyor belt and a lattice cooling fin.

The powder spreading roller is arranged inside the forming cavity and is connected to each part outside the forming cavity through a moving channel by a metal arm.

The moving channel is provided with a carbon fiber interlayer and carbon fiber cloth from inside to outside in sequence on the outer wall of the forming cavity. The carbon fiber interlayer is of a two-layer structure, is fixed on the outer wall of the forming cavity, is internally provided with a double-layer carbon fiber sealing brush, and can be movably sealed when the metal arm drives the powder spreading roller to move. The outer side carbon fiber cloth is fixed on the metal arm and is linked with the metal arm.

The carbon fiber sealing brush is of a rotary annular structure, is partially overlapped up and down, left and right, and is of a double-layer built-in structure, so that heat insulation can be carried out while movable sealing is carried out, the oxygen content in the forming cavity is controlled, and an external stepping motor and a synchronous conveyor belt are protected.

The lattice radiating fins are arranged after the metal arms are connected to the outside of the forming cavity, so that the radiating efficiency of the metal arms is improved, and the further external conduction of heat is slowed down.

The graphite interlayer plate is fixed on the synchronous conveyor belt on the outer side and is connected with the metal arm at the inner side up and down, so that heat transfer of the metal arm can be isolated in the height direction, heat is prevented from being transferred to the synchronous conveyor belt, and aging of the fixed part of the synchronous conveyor belt is slowed down.

The stepping motor drives the synchronous conveyor belt to move through gear transmission, and then drives the graphite interlayer plate, the metal arm and the powder spreading roller to be linked.

Generally, compared with the prior art, the above technical solution of the present invention mainly has the following technical advantages:

1. for the forming cavity, the high-temperature movable sealing mechanism can well control the oxygen content in the powder spreading roller during movement, and the isolation between the high-temperature movable sealing mechanism and the outside air is guaranteed. Meanwhile, heat dissipation is avoided, and the uniformity of a temperature field is ensured, which is of great importance for high-temperature forming;

2. for parts outside the cavity, the aging of the stepping motor caused by heat dissipation can be avoided, the aging of the synchronous conveyor belt is slowed down, and the maintenance and depreciation cost of the whole equipment is reduced;

drawings

FIG. 1 is a schematic diagram of the overall construction of a high temperature movable seal constructed in accordance with the present invention;

FIG. 2 is a schematic view of the carbon fiber structure inside the high temperature moving seal mechanism;

1-forming cavity, 2-powder spreading roller, 3-moving channel, 31-carbon fiber cloth, 32-carbon fiber interlayer, 33-carbon fiber sealing brush, 4-metal arm, 5-graphite interlayer plate, 6-stepping motor, 7-synchronous conveyor belt and 8-lattice radiating fin.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The following description of the overall operation is made in conjunction with fig. 1 and 2. In general, the dusting roller 2 is placed inside the forming chamber 1 in a high temperature environment and is connected to the external parts by a metal arm 4 through a movement path 3 of the outer wall of the forming chamber 1.

After the metal arm 4 extends out of the forming cavity 1, the lattice radiating fins 8 are arranged for primary heat dissipation, so that the heat dissipation efficiency of the metal arm 4 is improved, and the heat is slowed down to be further conducted to the outside. And then the graphite interlayer plate 5 is connected below the metal arm 4 for longitudinal heat insulation, so that heat is prevented from being transferred to the synchronous conveyor belt 7, and the aging of the synchronous conveyor belt 7 is slowed down. The graphite interlayer plate 5 is arranged on a synchronous conveyor belt 7 and driven by a stepping motor 6 to run, so that the internal powder paving roller 2 is driven to pave powder in a linkage manner.

On the moving channel 3 of the outer wall of the forming cavity 1, a carbon fiber interlayer 32 and a carbon fiber cloth 31 are arranged in sequence from inside to outside. The carbon fiber interlayer 32 is of a two-layer structure, is fixed on the outer wall of the forming cavity 1, is internally provided with a double-layer carbon fiber sealing brush 33, and can be movably sealed when the metal arm 4 drives the powder spreading roller 2 to move. The outer carbon fiber cloth 31 is fixed to the metal arm 4 and is interlocked with the metal arm 4. The carbon fiber sealing brush 33 has a revolving ring structure, is partially overlapped in the upper, lower, left and right directions, and has a double-layer built-in structure. During the forming process, when the powder laying roller 2 moves, the opening of the carbon fiber sealing brush 33 moves following the metal arm 4, and the unmoved position maintains the seal. Meanwhile, the carbon fiber cloth 31 fixed outside is tightly attached to the carbon fiber interlayer 32 on the inner side and the built-in carbon fiber sealing brush 33 when the metal arm 4 moves, so that the multi-layer sealing in the forming cavity 1 is ensured. Therefore, the movable sealing and heat insulation can be carried out at the same time, the oxygen content in the forming cavity is controlled, and the external stepping motor and the synchronous conveyor belt are protected.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.