46results about How to "Eliminate the step effect" patented technology

A local adaptive method is proposed for automatic detection of microaneurysms in a digital ocular fundus image. Multiple subregions of the image are automatically analyzed and adapted to local intensity variation and properties. A priori region and location information about structural features such as vessels, optic disk and hard exudates are incorporated to further improve the detection accuracy. The method effectively improves the specificity of microaneurysms detection, without sacrificing sensitivity. The method may be used in automatic level-one grading of diabetic retinopathy screening.

A method for synchronous powder-feeding space laser cladding and three-dimensional forming includes: dividing a three-dimensional solid into a plurality of forming units according to a form simplification and nozzle cladding scanning accessibility principle, and dividing each forming unit into a plurality of layers; employing a single-beam gas-carried power-feeding mode in a hollow annular laser; controlling a mechanical arm (7) to drive an in-laser powder-feeding nozzle (1) to move and scan along a predetermined trajectory in a filling area and a boundary area of the layer; and sequentially conducting cladding and stacking formation of the layer for the entire unit. A device includes an inside-laser powder-feeding nozzle (1), a laser generator (6), a mechanical arm (7), a control module (4), a transmission optical fiber (5), a gas-carried powder feeder (3) and a gas source (2).

The present invention discloses a five-freedom-degree rapid forming processing apparatus, which comprises a frame (1), material disks (3) on the top portion of the frame (1), an operating plate (6), a screen (7), and a control plate (8), and further comprises a two-freedom-degree spraying head assembly (2) capable of freely moving along X axis and Z axis, a clamping device (4), and a three-freedom-degree platform assembly (5) capable of freely rotating along Y axis, Z axis and A axis, wherein the operating plate (6) and the screen (7) are arranged on the bottom portion in front of the frame (1). With the five-freedom-degree rapid forming processing apparatus of the present invention, the step effect can be eliminated, the surface quality of the printed inclined plane can be increased, the processing efficiency on the circular cross-section parts is high, the processing on the spherical platform can be achieved, and the space utilization rate is good.

The invention belongs to the field of laser processing, and relates to a near-net forming method and device for composite manufacturing a fine workpiece based on laser additive manufacturing and subtractive manufacturing. According to the method, the construction parameters of a three-dimensional digital-to-layer slicing layer are generated by utilizing software, laser additive manufacturing processing is carried out, and ultrafast pulse laser subtractive manufacturing processing is carried out alternately in the laser additive manufacturing processing process to form a three-dimensional entity. The device comprises a computer control device, a sealing molding chamber, a light path selecting system and an inert protection gas source; during additive manufacturing processing, the computer control device controls the light path selecting system to select the laser emitted by an additive manufacturing laser device and perform laser additive manufacturing processing; and during subtractivemanufacturing processing, the computer control device controls the light path selecting system to select ultrafast pulse lasers emitted by a subtractive manufacturing laser device and perform the ultrafast pulse laser subtractive manufacturing processing. According to the near-net forming method and device, the preparation of complex and fine-structure parts can be completed in a high-precision and integrated manner, the defects that traditional laser additive manufacturing is low in the forming precision, high in roughness and cannot be used for preparing a fine and complex inner cavity areovercome.

The invention discloses an adaptive layering method for preventing feature deviation of 3D printing model, including the creation of three-dimensional models, A mesh process is carried out on that three-dimensional model, to generate the STL file, reading the STL file, and preprocessing the data read from the STL file, to obtain the preprocessed data, recognizing the feature height on the three-dimensional model after gridding, A set of height data is obtained to adjust the spacing between adjacent feature heights, the height data is adjusted, The feature height is sliced at a position of thefeature height, and an adaptive slicing is performed between adjacent feature heights to obtain slice outline information, generate a print file, and print a 3D model. The invention ensures that the layered plane passes through the position where the model features are located, thereby retaining the three-dimensional model features, effectively preventing the feature deviation and loss caused by the layer-by-layer accumulation of materials in the printing process of the 3D printing model, and reducing the step error.

A space path generating methodorientedto multi-freedom-degree 3D printing comprises the steps that a three-dimensional part model is firstly established and an auxiliary model and a supporting model are generated by utilizing computer aided design (CAD) software, and then a part path is generated; then, the part path undergoes reverse ranking to generate a front-inside-to-outside 3D printing path, meanwhile printing action matching parameters required by a motion mechanism moving along the printing path are calculatedby adopting a 3D printing process; then the supporting model is introduced to the 3D printing path to generate software, and a supporting path is generated; normal vector information is added for the supporting path, and a posturecomponent of a printing head in a multi-freedom-degree 3D printing system is calculated through normal vectors; finally the generated supporting path and the part path are introduced to the multi-freedom-degree 3D printing system, and multi-freedom-degree 3D printing is completed. The space path generating method eliminates the step effect existing in an existing 3D printing technology, improves the mechanical properties of parts and increases the isotropy of the parts.

The invention relates to an adaptive plane layering method based on an additional material remanufacturing point cloud model. The method comprises: step one, a layering direction is determined; step two, a layering height is determined; to be specific, traverse of point cloud coordinates is carried out to obtain a zmin and a zmax, difference processing is carried out on the zmin and the zmax to obtain a layering height; step three, an inter-layer point cloud mapping relationship is constructed; step four, a surface error is defined; to be specific, a surface error P is defined to express a surface difference degree between two slices, wherein sigma is equal to Rmax and the Rmax expresses a maximum value a radial width R of a projection point cloud; and step five, a layering thickness is determined. According to the adaptive plane layering method, the maximum value of the radial width R of the projection point cloud is used as a surface error and thus an adaptive layering height is determined by iteration; the algorithm implementation process is clear; and both efficiency and precision are considered.

The invention discloses a preparation method and application of a silicon-based ceramic core. Mixed slurry obtained according to the mixing ratio is formed by using a photocuring method to obtain a mold core biscuit, the mold core biscuit is degreased and then impregnated with a ceramic slurry, the impregnated mold core biscuit is dried, and the dried mold core biscuit is sintered in an air atmosphere by using a buried powder sintering method to obtain the silicon-based ceramic core. By means of the method, forming of a high-surface-precision silicon-based ceramic core blank can be achieved, the forming precision of the silicon-based ceramic core is improved, the production process of the ceramic core is accelerated, and the forming difficulty of the silicon-based ceramic core of a complexstructure is lowered. Degreasing and sintering treatment are carried out on the mold core biscuit obtained through the photocuring method, dipping lifting treatment is carried out on the mold core biscuit through the silicon oxide inorganic slurry, and the surface precision of the silicon-based ceramic mold core blank can be effectively improved. The method is simple, and the forming difficulty of the silicon-based ceramic mold core with a complex structure is reduced.

The invention discloses a novel method and device for carrying out electrical discharge machining on a thin-sheet microelectrode array. The thin-sheet microelectrode array comprises a plurality of thin-sheet microelectrodes which are arrayed in sequence, and machining end faces of the thin-sheet microelectrodes are worn to form convex arc shapes under the influence of the skin effect. The novel method for carrying out the micro electrical discharge machining on the thin-sheet microelectrode array comprises the step of carrying out the micro electrical discharge machining on the positions, corresponding to the thin-sheet microelectrodes in a one-to-one mode, on a workpiece through the thin-sheet microelectrodes of the thin-sheet microelectrode array to form a fitting surface on the machined surfaces. According to the novel method for carrying out the micro electrical discharge machining on the thin-sheet microelectrode array, the characteristic of the filleted corner wear of the machining end faces of conventional thin-sheet microelectrodes is fully utilized to effectively eliminate the step effect of the fitting surface with a three-dimensional microstructure, so that the precision of the machined fitting surface is improved; and the step effect of the fitting surface with the three-dimensional microstructure and filleted corner discharge marks of the fitting surface with plane characteristics can be eliminated.

The invention belongs to the technical field related to 3D printing, and discloses a 3D printing forming method based on skeleton line contour recognition and area segmentation. The method comprises the following steps: S1, calculating a skeleton line in each slice layer forming contour; S2, calculating and solving the length of the main skeleton line, the diameter of the end point of each skeleton line, the deflection angle between every two adjacent skeleton lines and the deflection angle between every two adjacent edges in each forming contour; S3, dividing the area types in each forming contour into a straight square area, a smooth area, a transition smooth area, a smooth thin-wall area and a rough area, establishing an area division standard by multiple parameter values obtained through calculation in the step S2, and dividing the areas in each forming contour; and S4, planning a forming path of each area for 3D printing forming. According to the method, the problems of contour recognition and segmentation of complex contour parts are solved, and a complex path planning method with high efficiency and high robustness is provided.

The invention discloses a device conducting composite manufacturing on the basis of a laser technology. The device comprises a sealed forming chamber, an inert protective gas source and a machining forming platform. The inert protective gas source is connected with the sealed forming chamber. The machining forming platform is arranged in the sealed forming chamber, and a light path selection system is arranged over the machining forming platform. A machining station is arranged on the machining forming platform, and the machining forming platform is arranged on a guide rail and can slide forwards and backwards through the guide rail. The light path selection system comprises a shock reinforcing independent laser light path, an additive independent laser light path and a subtractive independent laser light path. The light paths are arranged in the direction of the guide rail, and all the independent laser light paths do not share equipment and are arranged over the machining forming platform. According to the device, the laser shock reinforcing technology and the laser additive and subtractive technology are integrated, the forming precision, the surface quality, the organization performance and the residual stress state of a complex fine additive workpiece are improved, and one-stop high-efficiency high-precision and high-performance additive workpiece preparation is achieved.

The invention discloses a roughness-controllable polishing method for stereolithographic resin prototype models. According to the invention, the fluid of a prepared chemical etching abrasive particle flow is used on abrasive particle flow equipment for respective polishing of the stereolithographic resin prototype models; then distilled water or deionized water is used for cleaning, surface roughness of the obtained stereolithographic resin prototype models is reduced to Ra 0.8 to 2 mu m from original Ra 8.0 to 20.0 mu m, surface roughness is uniform, texture is regular, postprocessing of the stereolithographic resin prototype models is realized, operation is simple, and labor intensity is reduced. The polishing method eliminates step effects of the stereolithographic resin prototype models, improves surface precision of the resin prototype models and does not influence dimensional precision of the resin prototype models.

A combined additive manufacturing method applicable to parts and molds relates to moldless-growth manufacturing of parts and molds, which includes steps of: S1: layering and slicing a three-dimensional CAD (computer-aided design) model of a workpiece to be formed according to shape, thickness and dimensional accuracy requirements of the workpiece, so as to obtain a plurality of layered slice data; S2: planning a forming path according to the layered slice data, and generating layered slice numerical control codes for forming; and S3: deposition-forming a powder material on a substrate layer-by-layer and performing pressure forming or milling forming according to the layered slice numerical control codes in the step S2, which uses a numerically controlled high-speed cold spray gun to spray the powder material to a determined position for deposition-forming. The method of the present invention overcomes thermally induced adverse effects of hot processing and drawbacks of cold spray deposition.

A manufacture method of a metal grid electrode comprises forming a gate oxide and a substitution grid electrode on a provided semiconductor substrate and then forming lateral wall layers on two sides of the substitution grid electrode; considering the lateral wall layers and the substitution grid electrode as masks and conducting ion implantation on the semiconductor substrate to form a source and drain region; depositing a contact etching stopping layer on the surfaces of the semiconductor substrate, the lateral wall layers and the substitution grid electrode; depositing a first metal front medium layer on the contact etching stopping layer, enabling the height of the deposited first metal front medium layer to be higher than the surface of the substitution grid electrode, polishing to reach the first metal front medium layer, and forming footsteps on the surfaces of the contact etching stopping layer and the first metal front medium layer which are in a same plane; depositing a second metal front medium layer on the surfaces of the first metal front medium layer and the contact etching stopping layer, completely covering the footsteps, polishing again to reach the substitution grid electrode; and etching the substitution grid electrode to obtain a substitution grid electrode channel and filling the metal grid electrode in the substitution grid electrode channel. The manufacture method removes the footstep effect produced in a manufacture process.

The invention discloses a snow sculpture 3D printer integrating snowmaking equipment. The composition structure comprises a base, an information access port, a speed regulation device, a plurality ofmotors, a base end cover, a plurality of rotary pairs, a connection rod 1, a connection rod 2, a connection rod 3, a connection rod 4, a spray head, a spray head frame, a feed hose, the snowmaking equipment, a micro high-pressure gas pump, a gas inlet pipe, a water inlet pipe, a screw nut, a U-shaped clamping piece, an independent support, a small water pump, a gear 1 and a gear 2. The snowmakingequipment is fixed to the connection rod 2, can also be installed on an independent support installation supporting rod and comprises a cold chamber and a cold chamber rear end cover. The snow sculpture 3D printer integrating the snowmaking equipment is simpler in structure, the spray head can complete printing motion of multiple angles, the problem of printing precision of a suspended part is solved, thus the treatment effect of a hollowed-out part is improved, meanwhile, the snow sculpture 3D printer is not limited to X-Y-plane slice type printing, the step effect of the printed part can belowered, and printing efficiency and precision are improved.

The invention relates to a material increase and material decrease comprehensive manufacturing method of a hard alloy part with the complex shape. The method comprises the steps that segmented copolymer is dissolved in organic solvent, and a reversible gelatin system is prepared; hard alloy powder is added into the gelatin system, and slurry is prepared; the slurry is conveyed to a 3D printing device, and a multi-layer green body layer is formed according to the design requirement of a drawing; and a green body layer with a certain thickness is formed, and machined mechanically after being cooled and cured. According to the method, the 3D printing technology is utilized for directly forming the part with the complex shape, a mould does not need to be customized, meanwhile, a mechanical machining method helps to carry out milling machining, the step effect in the 3D printing process is eliminated, and the manufacturing precision of the part is ensured.