Abstract: The invention discloses a five-axis flank milling system for machining curved surface and the method thereof, the system is capable of generating a tool path that minimizes the undercut error, overcut error, or the total machining error. The amount of the overcut, undercut, or total machining errors can be precisely controlled by adjustment of the cutter locations contained in a tool path. This invention is to transform tool path planning in five-axis flank milling into an optimal matching problem. The proposed mechanism of the invention significantly improves the manufacturing capability of five-axis flank milling. It enhances the machining quality by reducing various machining errors and provides a systematic approach to precise control of machining error in five-axis flank milling.

Abstract: In this investigation, Cu-Sn lead-free solder microbumps on 10-μm pads with a 20-μm pitch are designed and fabricated. The chip size is 5 × 5 mm with thousands of microbumps. A daisy-chain feature is adopted for the characterization and reliability assessment. After pattern trace formation, the microbump is fabricated on the trace by an electroplating technique. A suitable barrier/seed layer thickness is designed and applied to minimize the undercut due to wet etching but to still achieve good plating uniformity. With the current process, the undercut is less than 1 μm and the bump height variation is less than 10%. In addition, the shear test is adopted to characterize the bump strength, which exceeds the specification. Also, the Cu-Sn lead-free solder microbumped chip is bonded on an Si wafer using chip-to-wafer bonding technique. Furthermore, the microgap between the bonded chips is filled with a special underfill. The shear strength of the bonded chips without the underfill is measured and it exceeds the specification. The bonding and filling integrity is further evaluated by open/short measurement, scanning acoustic tomography analysis, and cross-section with scanning electron microscopy analysis. The stacked ICs are evaluated by reliability (thermal cycling) test (-55 to 125°C). Finally, ultrafine-pitch (5-μm pads on a 10-μm pitch) lead-free solder microbumping is explored.

Abstract: Previous studies have shown that machining error in 5-axis flank milling can be systematically reduced by optimization of tool path planning. However, the solution quality of the optimization methods adopted by those studies was not satisfactory, due to the constraint that the cutter must contact the boundary curves of the ruled surface to be machined. This work proposes an improved tool path planning method based on Particle Swarm Optimization (PSO) algorithms without this constraint. The method enlarges the feasible region in the optimization by allowing cutter location to deviate the boundary curves along the normal, tangent, and bi-normal directions. Design of experiment techniques are applied to determine better parameter setting in the PSO. A new objective function is formulated as the weighted sum of the errors induced by overcut and undercut. We can choose to minimize the total machining error, the overcut, or the undercut by properly adjusting the weight value. Compared to previous methods, the improved path planning method produces smaller machining error and offers better planning flexibility.

Abstract: The present disclosure provides computing device implemented methods, computing device readable medium, and molds for filling undercut areas of teeth relative to an axis of placement. Filling undercut areas of teeth relative to an axis of placement can include calculating an undercut area of a tooth relative to an axis of placement of part of a dental appliance over a number of teeth and a height of contour that is defined based on the axis of placement. Filling undercut areas of teeth relative to an axis of placement can also include filling in a part of the undercut area of the tooth with a virtual filler wherein the undercut is filled to within a threshold distance from the tooth that is defined relative to the axis of placement and the height of contour.

Abstract: A semiconductor structure has embedded stressor material for enhanced transistor performance. The method of forming the semiconductor structure includes etching an undercut in a substrate material under one or more gate structures while protecting an implant with a liner material. The method further includes removing the liner material on a side of the implant and depositing stressor material in the undercut under the one or more gate structures.

Abstract: Mechanical properties of silicon nanobeams are of prime importance in nanoelectromechanical system applications. A numerical experimental method of determining resonant frequencies and Young's modulus of nanobeams by combining finite element analysis and frequency response tests based on an electrostatic excitation and visual detection by using a laser Doppler vibrometer is presented in this paper. Silicon nanobeam test structures are fabricated from silicon-on-insulator wafers by using a standard lithography and anisotropic wet etching release process, which inevitably generates the undercut of the nanobeam clamping. In conjunction with three-dimensional finite element numerical simulations incorporating the geometric undercut, dynamic resonance tests reveal that the undercut significantly reduces resonant frequencies of nanobeams due to the fact that it effectively increases the nanobeam length by a correct value ΔL, which is a key parameter that is correlated with deviations in the resonant frequencies predicted from the ideal Euler—Bernoulli beam theory and experimentally measured data. By using a least-square fit expression including ΔL, we finally extract Young's modulus from the measured resonance frequency versus effective length dependency and find that Young's modulus of a silicon nanobeam with 200-nm thickness is close to that of bulk silicon. This result supports that the finite size effect due to the surface effect does not play a role in the mechanical elastic behaviour of silicon nanobeams with thickness larger than 200 nm.

Abstract: The present invention is a method that (i) allows for creating micro and/or nanostructures on either planar or non-planar three-dimensional surfaces in a single molding step, and (ii) allows for the molded production of complex high-aspect ratio micro and/or nanostructures including but not limited to cylinders, conical structures, low aspect-ratio channels, bumps, or posts. An example of such a complex structure are high aspect ratio pillars with enlarged "mushroom-shaped" or undercut tips which demonstrate enhanced, repeatable adhesion and shear strength on a variety of substrates when compared with other micro and/or nanostructures and unstructured materials. The mold of such a material requires an "undercut" feature that cannot be produced using typical micro/nano-molding processing techniques.

Abstract: A microelectromechanical system (MEMS) device includes a substrate and an oxide layer formed on the substrate. A cavity is etched in the oxide layer. A microstructure device layer is bonded to the oxide layer, over the cavity. The microstructure device layer includes a substantially solid microstructure MEMS device formed in the microstructure device layer and suspended over a portion of the cavity. An anchor is formed in the device layer and configured to support the microstructure device, the anchor having an undercut in the oxide layer. The undercut has a length along the anchor that is less than one-half a length of an outer boundary dimension of the microstructure MEMS device.

Abstract: Photochemical Machining is a novel machining process capable of processing wide range of hard-to-machine materials. This research addresses modelling and optimization of the process parameters for this machining technique. To model the process a set of experimental data has been used to evaluate the effects of various parameter settings in machining of SS316L. The process variables considered here include etchant temperature, time and concentration. Undercut, as one of the most important output characteristics, has been evaluated based on different parameter settings. The full factorial method and regression modelling are used in order to establish the relationships between input and output parameters. The effect of control parameters on undercut was analysed using Analysis of Variance (ANOVA) technique and their optimal conditions were evaluated. It was found that etchant temperature and etching time are the most significant factors for undercut.

Abstract: The invention provides a double-gun horizontal automatic welding device and a welding method thereof. The welding device comprises a trolley body which comprises a control box, a cross-shaped sliding block, a gun wire fixing frame, an angle adjusting mechanism and oscillators, wherein the positions of the oscillators can be adjusted upwards, downwards, forwards and backwards by the cross-shaped sliding block; the angles of the oscillators are adjusted by the angle adjusting mechanism; oscillating shafts of the oscillators are connected with gun clamps and oscillate along with the oscillators; and the gun clamps are used for fixing welding guns. In the double-gun horizontal automatic welding device and the welding method thereof provided by the invention, the rail positioning and tracking are adopted, the welding stability is greatly improved, the control and the operation are simple, and the parameter adjustment is easy; in the welding process, the melting penetration of welding is improved by adjusting the angles and the oscillating amplitude of the welding guns; and in the process of filling welding and cosmetic welding, the double guns are adopted for welding simultaneously, so that the efficiency is improved by at least two times, no undercut exists on welding seams, the melting penetration is good and the attractiveness is achieved.

Abstract: An apparatus and method in which an insert with an undercut is mechanically coupled to a lay up mold for translated movement between an engaged position for molding with an undercut engaging the material to be molded and a remote position in which a resultant molded product maybe removed and the material may be laid up without interference with the undercut, preferably with the mechanical coupling allowing for hinged movement of the insert relative the lay up mold.

Abstract: A semiconductor device includes a semiconductor die having first and second opposing faces and an edge surface. The edge surface has an undercut under the first face. The second face of the semiconductor die is bonded to a bonding surface of a die support member, such as a thermally conductive flag of a lead frame, with a die attach material. A fillet of the bonding material is formed within the undercut.

Abstract: PROBLEM TO BE SOLVED: To provide a weld joint part of a steel member that can prevent a weld defect and a welding procedure failure at the weld joint part of the steel member by fillet welding.SOLUTION: Both tip faces of the other steel member 3 are provided with grooves 4, and the outside of a weld metal 5 in each groove is provided with an overlay metal 6 for reinforcement, forming the surface of a substantially elliptic arc shape that reaches the surface of the other steel member 3 from one steel member 2. The overlay metal 6 for reinforcement of the substantially elliptic arc shape is provided at a weld joint part 1 of the steel member to prevent a build-up weld size from becoming excessively large. Also, an excess weld metal height for securing the strength of the weld joint part 1 is easily secured, and bead irregularity on the surface of the weld metal can be eliminated to hardly cause a fatigue fracture. Furthermore, the weld defect such as an undercut is hardly formed near the groove end B on the surface of the steel member 3 to prevent a brittle fracture.

Abstract: The invention relates to a retaining and anchoring device forming a retaining and anchoring section on a metal plate (1), in particular on a reflector, having the following features: a recess (19) provided in the metal plate (1), wherein the recess (19) has on the upper face (1a) of the metal plate (1) a peripheral edge or edge sections (23') spaced apart from one another, an undercut (25) or several undercut sections (25) are formed below the peripheral edge or the edge sections (23'), and the recess (19) is free of bores or passages.

Abstract: The method for detecting undercut of an abutment for fixing a denture, which comprises the following steps: (1) taking an initial impression with impression material, pouring gypsum, adding coagulant to accelerate solidification; (2) taking out the solidified gypsum and shaping, placing the mold on a dental observation instrument, and adjusting an observation platform on the observation instrument to keep the long axis of the abutment or the common path of insertion of a plurality of abutments to be in line with the direction of an analyzing rod of the observation instrument; (3) enabling the analyzing rod with a pencil core to draw a circumference along the neck edge line and the occlusion edge line of each abutment; (4) molding a tapered analyzing head on the analyzing rod, and estimating the occlusion convergence angle of each axial plane of each abutment; and (5) taking off the analyzing mold, using the mold as a temporary bridge-crown of the abutment, when the temporary bridge-crown is tried on, observing the in-place situation of the temporary bridge-crown, and confirming again whether the abutment undercut is completely eliminated. The method of the invention is simple and feasible, has accurate detection, and solves the technical problem that whether the abutment undercut is completely eliminated can not be accurately detected in the prior art.

Abstract: The invention aims to provide a method for controlling root chained pores in a part with a bottom lock structure by using electron beam welding. The method is characterized by adopting a method combining circular wave welding and triangular wave modified welding phase to weld the part with the bottom lock structure. The method comprises the following steps: firstly using circular wave welding to weld the welded joint of a main body; and then using triangular wave welding to perform modified welding on the welding surface with an undercut defect. The method can be used for solving the problem of chained pores at the root of the welded joint, enhancing the surface state of the welded joint, eliminating the undercut defect, greatly improving the usability of the part, improving the welding efficiency and saving the cost.

Abstract: Copper pillar bumps show a wide-ranging application for assembly and packaging according to the "More than Moore" roadmap. For the demand of higher input/output (I/O) densities and consequently smaller bump pitches the requirements on each process step in producing 6 μm pitch Cu-Sn bumps increase. In this case the removal of seed layer with wet etchants is no longer practicable due to high undercut. A sacrifical Ion Beam Etching (IBE) process was developed for removing the TiW/Cu seed layer without any undercut. Due to the high etching rate of the rough Sn surface a sacrificial layer of Ni was used to protect the solder layer. To optimize the layer thicknesses etch rates were characterized. Special attention was directed to the etched material which covered the bumps on the sidewalls after the etching process step. Energy-dispersive X-ray spectroscopy (EDX) measurements and reflow processes revealed the influence of the redepositioned material on the melting behavior and hence on the following bonding process.

Abstract: An aluminum-based diesel engine piston and a method of making the piston. The method involves casting the piston with complex geometries, including undercut or reentrant features. The casting uses an aggregate disposable mold that can be removed from the as-cast part. In one form, the complex geometry includes an undercut combustion bowl formed in the piston dome, while in another, it may include an internal cooling passage. The undercut bowl and internal passages may be produced using the aggregate disposable mold.

Abstract: A method for fabricating a semiconductor device includes forming a silicon-containing layer; forming a metal-containing layer over the silicon-containing layer; forming an undercut prevention layer between the silicon containing layer and the metal containing layer; etching the metal-containing layer; and forming a conductive structure by etching the undercut prevention layer and the silicon-containing layer.

Abstract: PROBLEM TO BE SOLVED: To provide a method for producing a metal powder sintered compact in which cracks and blister generated in a production process are prevented, and further, the removal of a core after injection molding is facilitated.SOLUTION: Regarding a method in which a metal powder compound is injection-molded using a cavity formed by a mold 13 and a core 12, the core 12 is removed from the obtained molded body 14, and the molded body 14 is degreased and sintered to produce a metal powder sintered compact having a hollow part or an undercut part, the core 12 is composed from a water-soluble resin, or composed from a water-soluble resin added with a water-soluble filler or a water-insoluble filler at a prescribed ratio or composed of a water-insoluble resin added with a water-soluble filler at a prescribed ratio, and the removal of the core is performed by eluting a part or the whole of the core 12 at the inside of the molded body 14 using water.

Abstract: The stability of subgrade soils is a major concern during roadway construction with inappropriately soft layers often undercut and replaced by competent or stabilized materials. Systematic undercut criteria are established using numerical modeling with varying the strength and stiffness parameters of the subgrade and representing the mechanistic behavior as an elastic-perfectly plastic medium. Two modes of domain configurations were considered: the plane strain and axisymmetric conditions. The plane strain mode is assumed to simulate proof roller loading with four parallel tires and mainly provides information about excessive pumping response as materials at deeper layers are affected. The axisymmetric mode provides information related to excessive rutting and is used to simulate the effect of single or dual tires representing construction traffic, rather than a series of closely spaced axle loads. Undercut criteria are proposed for meeting a deformation limit state of 25 mm for both pumping and r...

Abstract: The utility model discloses a forming mold for a biomass molding fuel. A first gear (1) generates undercutting to a second gear (2); the second gear (2) is a undercut gear; a tooth root part of the undercut gear is an undercut tooth profile; and the undercut tooth profile is a tooth profile formed after partial standard tooth profile of the tooth root part is undercut, so that undercut areas for storing biomass materials are respectively formed on two sides of each gear tooth root part. During engagement of the gears, a cutting effect is generated on the biomass materials stored in the undercut area, the cutting force can be decomposed into an axial component force along a forming hole, and the biomass materials are pushed into the forming hole; therefore, an extruding effect is obvious enhanced. The externally engaged gear type forming mold disclosed by the utility model has the advantages of simple structure, long service life and less energy consumption and can operate continuously; and a technical problem to be solved in a biomass molding fuel manufacturing technology is solved.

Abstract: The invention relates to the technical field of metal welding, in particular to a welding production technology of a diaphragm type energy accumulator. Light beams are produced by using an electron beam welder in vacuum through high-voltage light condensation, the instant fusion welding of workpiece base metal is utilized, and the defect of undercut left by vacuum electron beam welding is repaired by a laser welder under normal state through the bead welding of a welding material. The temperature of the welded workpiece is between 50 and 60 DEG C, no heat treatment is needed, and a rubber diaphragm can not be damaged due to too high welding temperature. The energy accumulator has simple structure, small product size, high sealing performance and security, energy saving and low cost, widens the effective active area of an isolator, and overcomes the defects of complex interior structure, high production cost and the like of the traditional energy accumulator.

Abstract: Provided in an embodiment is a method for molding, including: providing a molten alloy in a space between a mold cavity and an etchable block shaped to form an undercut on a part formed in the space, cooling the molten alloy to form the part with the undercut, and etching the etchable block. An undercut is a beveled edge caused by an etchant attacking an etchable block laterally and optionally vertically. The formed part can be made of a bulk amorphous alloy. In some cases, the etchable block can also be used to form at least one threaded portion in the part.

Abstract: The connecting arrangement has to-be-connected components (1-3) in which undercut grooves (4) are formed along the connecting surfaces. A tubular packing (5) are provided in undercut grooves by a flexible closable filling element (6). The filling element fills the medium in the tubular packing by applying pressure so that the tubular packing is pressed against the walls of the undercut grooves and the components are connected under pressure.

Abstract: PROBLEM TO BE SOLVED: To provide an apparatus that performs a correction processing of an undercut of a rope groove that is formed to obtain a sufficient frictional force between the rope groove and a rope, without removing the rope from a grooved pulley.SOLUTION: The apparatus for a correction processing of an undercut, includes: a spring tool; a radially driving unit for moving the spring tool in a radial direction of the grooved pulley; an axially driving unit for moving the radially driving unit in an axial direction of the grooved pulley; a fixture to which the axially driving unit is mounted; and a controller for controlling movement amounts of the radially driving unit and the axially driving unit.