47results about How to "Eliminate the "step effect"" patented technology

The invention discloses a synchronous powder feeding space laser machining and three-dimensional forming method and device. A three-dimensional solid is divided into a plurality of forming units according to the form simplification and nozzle fusion covering scanning accessibility principle, each forming unit is divided into a plurality of laminates, a mode for single-beam gas-carried powder feeding in a hollow annular laser is adopted, a mechanical arm is controlled to drive an in-laser powder feeding nozzle to move for scanning in filling areas and boundary areas of the laminates according to a preset trajectory, and forming fusion covering and stacking forming of the laminates are sequentially completed, so that forming fusion covering and stacking forming of the whole unit are completed. The device comprises the in-laser powder feeding nozzle, a laser generator, the mechanical arm, a control module, a transmission optical fiber, a gas-carried powder feeder and a gas source. The control module is connected with the mechanical arm, the laser generator and the gas-carried powder feeder. The in-laser powder feeding nozzle is fixed to the front end of the mechanical arm and can make spatial motion along with the mechanical arm. Through the method and device, fusion covering and three-dimensional stacking forming on any surface of the space can be achieved, and supportless three-dimensional forming of parts with complex structures such as a hanging structure and a cavity can be achieved.

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.

The invention discloses a high-precision laser additive and subtractive material combined manufacturing device. 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, a lead screw is arranged at the bottom of the machining forming platform,the machining forming platform is fixed to a sliding block of the lead screw, the lead screw is connected with a lead screw motor, and the machining forming platform can be driven by the lead screw motor to slide forwards and backwards on the lead screw. The light path selection system comprises an additive material independent laser light path and a subtractive material independent laser light path. The additive material independent laser light path and the subtractive material independent laser light path are parallel to each other, are arranged in the direction of the lead screw and do notshare equipment. According to the device, the laser additive and subtractive material technology is integrated, the forming precision, the surface quality, the structure 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 manufacturing operation is achieved.

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 present invention relates to an equidistant curved surface layering method based on the point cloud model of additive remanufacturing, which includes the following steps: ① Fitting the cylindrical surface: selecting the point cloud of the undamaged area of ​​the shaft part to fit the cylindrical surface, as a standard The model is the standard cylindrical surface; ② Extract the point cloud model of additive remanufacturing: select the point cloud of the defective part, calculate the distance from each point to the standard cylindrical surface as the defect amount e of each point, and follow the principle to extract the data points with serious defects Cloud and its e, as the point cloud model of additive remanufacturing; solve the distance from any point P(x,y,z) of the defective point cloud to the standard cylindrical surface, that is, the defect amount e, and convert it into the point P to the axis L. The difference between the distance and the radius of the cylinder; ③Establish the equidistant surface family of the standard cylindrical surface; ④Construct the contour data P'(x',y',z'), traverse all the points in the additive remanufacturing point cloud, and find out The corresponding contour data is layered, and the equidistant surface layered model diagram of the shaft parts is obtained.

The invention belongs to the technical field of three-dimensional (3D) printing, and particularly discloses a construction method for a three-dimensional (3D) printing path with the real-time variablewidth. The method comprises the following steps of constructing a 3D model of a part to be manufactured; layering the 3D model, and obtaining a slice at each layer; obtaining a central axis and a skeleton line of each slice; dividing the skeleton line into two parts by adopting the corresponding central axis as a center, and recording as a first half area and a second half area; sequentially ranking the skeleton lines along the directions of the central axes; calculating the maximum skeleton line length and the minimum skeleton line length in the skeleton lines at the first half area and thesecond half area, and determining the optimal path points of the first half area and the second half area; and determining the position of each path point according to the optimal path points, and then sequentially connecting the path points so as to generate the printing path. According to the construction method for the 3D printing path with the real-time variable width provided by the invention, the occurrence of a step effect and a cavity can be reduced, the idling stroke during the processing process is less, and the method has high processing efficiency.

The present invention relates to a gradient surface layering method based on additive remanufacturing point cloud model, comprising the following steps: ① forming distance calculation; calculating the Euclidean distance d of the centroid point corresponding to the grid: the distance d reflects the defect point cloud in the The degree of defect at the point, that is, the forming distance that needs to be remanufactured by additive; ②The determination of the gradient distance; ③The generation of layered data; when the gradient is layered, the real layered surface family does not need to be accurately described. It is enough to interpolate the layered data on each surface; the layered data includes two parts: contour data and contour internal data; for the layered data of the i-th layer, its contour data is directly recorded as the layered interval number num=i data points; the internal data P'(x', y', z') of the contour can be obtained by the lower layer surface (num

The invention relates to the field of additive manufacturing, and discloses a laser selective melting scanning method. In the laser selective melting scanning method, the layer scan includes the following area scans: contour scan: scan along the outer contour line of the layer; internal filling line scan: perform filling scan in the inner area of ​​the layer; upper epidermis scan: scan inside the contour line The upper epidermis area is scanned, and the width D1 of the upper epidermis area satisfies the following relationship: D1=ah·tanα, the lower epidermis scan: the lower epidermis area inside the contour line is scanned, and the width D1 of the upper epidermis area satisfies the following Relational formula: D2=bh·tanβ. Using this method, the surface of the formed part has obvious metallic luster, and the surface quality is better; the combination of powder metallurgy is sufficient, and the performance of the formed part is better; the scanning speed can also be improved, and the forming efficiency is higher, especially for the overhanging surface of the formed part. , can reduce the step effect of its surface, thereby improving its molding quality.