Abstract: A group of 3D metal printing or Additive metal manufacturing (AMM) processes, officially categorized as ‘directed energy deposition (DED)’ according to American Society for Testing and Materials (ASTM) classification, has enabled the building of full dense metallic tools and parts using metal powders precisely delivered and controlled with no powder bed. Mold making and metalworking are being taken in an entirely new direction. The overhang/undercut problem in DED processes, as much as other Additive manufacturing (AM) processes, has long remained unsolved, and the ones equipped with more than 3-axis tool mechanism turn out to be capable of depositing overhang/undercut features onto the part to be made. Multi-axis machines introduced for resolving the problem, however, require advanced preprocess software support for the process management that controls multi-axis tool paths. This study proposes slicing algorithms, sophisticatedly designed for the control of the tool paths on a 5-axis base table, to build overhang/undercut features. A methodical approach, using an auto-partitioning algorithm for generating three-dimensional layer (3DL) information, is proposed in this study, and various overhang features, as case studies, have been investigated and implemented by using the proposed method.

Abstract: A method includes receiving welding data corresponding to a welding session completed with a welding system, receiving a selected location from an operator, and displaying on a display one or more quality characteristics of the welding session corresponding to the selected location. The welding data includes welding parameters and quality characteristics corresponding to a plurality of points along a path of the welding session. The welding parameters include a work angle of a welding torch, a travel angle of the welding torch, a contact tip to work distance, a travel speed of the welding torch along the path of the welding session, an aim of the welding torch, or any combination thereof. The quality characteristics include porosity, undercut, spatter, underfill, overfill, or any combination thereof. The selected location corresponds to a point of the plurality of points along the path of the welding session.

Abstract: This paper presents the first demonstration of a “zero-undercut” precision formation of ultrafine-line copper conductor patterns for redistribution layers (RDL) and thin film RF passives. This is accomplished by using a highly-anisotropic and uniform copper plasma-etching process to remove the seed layer with no lateral etching of the copper patterns, unlike what is seen with traditional seed-layer removal by wet-etching. Application of this technical breakthrough for large-area panel processes allows demonstration of precision copper patterns demonstrated, for the first time, on organic laminates with no measurable lateral undercut. Two different plasma chemistries, one pure physical sputter-etching, and the other based upon chemical-physical processes with a hydrogen plasma, were investigated and compared.

Abstract: A novel substrate design is presented for scalable industrial production of filamentary coated conductors (CCs). The new substrate, called 'two level undercut-profile substrate (2LUPS)', has two levels of plateaus connected by walls with an undercut profile. The undercuts are made to produce a shading effect during subsequent deposition of layers, thereby creating gaps in the superconducting layer deposited on the curved walls between the two levels. It is demonstrated that such 2LUPS-based CCs can be produced in a large-scale production system using standard deposition processes, with no additional post-processing. Inspection of the conductor cross-section reveals that the deposited superconducting layer is physically separated at the 2LUPS undercuts. Filament decoupling is also seen in maps of the remanent magnetic field and confirmed by transport measurements.

Abstract: A method of manufacturing an OLED device includes providing a first undercut lift-off structure on a device substrate having a first lower electrode array. Next, at least one first organic EL medium layer comprising at least a first light emitting layer is deposited on the first undercut lift-off structure and the first lower electrode array. The first intermediate structure is formed by treating the first undercut lift-off structure and the overlying first organic EL medium layer (s) with a first lift-off agent comprising a fluorinated solvent. The process is repeated using a second undercut lift-off structure, and one or more second organic EL layers are deposited on the second lower electrode array. After removal of the second undercut lift-off structure, a common top electrode is provided in electrical contact with the first and second organic EL mediating layers.

Abstract: The ongoing trend of miniaturization makes hybrid joint also for the micro range necessary. Existing solutions often have restrictions due to the principle of joining. Therefore a new joining technology, which is realized by a plastic forming process based on TEA-CO2-laser induced shock waves, is used at BIAS. This technology enables the joining of different sheet materials with thicknesses between 20 µm and 300 µm. The manufacturing of the joint is an incremental process where several laser induced shock waves are needed to form the undercut, which presents the joint itself. For the analysis of the incremental forming behavior of this process a 50 µm thick forming sheet of aluminum (Al99.5) is joined with a 100 µm thick stainless steel (1.4301) die sheet. The first ten laser pulses are leading to relative high induced strain while for forming of the undercut 200 laser pulses are needed. The incremental induced strain per laser pulse decreases exponentially with the amount of used laser pulses. This behavior is explained by the acting pressure distribution of the induced shock wave and the contact area.

Abstract: This article presents an operation planning method based on a dynamic feature concept for 2.5-axis numerical control machining of complex aerospace structural parts. A dynamic feature consists of information about the machining effects on the feature between various operations carried out during production. To get the information about the machining effects of a machining operation, non-machining configuration spaces are constructed by detecting the intersection regions within the offset machining boundaries. Each non-machining configuration space refers to the machining effect (either an overcut or undercut). In the proposed operation planning method, dynamic features based on a preliminary process plan are first established. Then, an iterative procedure for adjusting the preliminary machining operations is put forward using updated dynamic feature information with various machining effects transitions and validity constraints during different operations. The method is tested using an aircraft structural...

Abstract: The mechanical clinching process combining with hot stamping process for high-strength steel sheets is investigated in this study. Finite elements analysis method and experimental method are applied to analyse the formation of high-strength steel sheet. The connecting strength between two sheets is discussed via the relation between neck thickness and undercut, and the Vickers hardness. The results indicated that the cooling water channels of hot stamping die provided efficiently temperature exchange to control the temperature of sheets. The 15B22 sheet, after being hot stamping process, obtained higher connecting strength than S15C and S45C. At high temperature, the materials properties of 15B22 are similar to that of the S15C. However, due to the hardness of 15B22 is higher than that of S15C and S45C, the undercut is also higher. Hot stamping process means to rapid cooling hot metal, which change the structure from austenite to martensite, so that the hardness will be increased. Hence, the connecting strength of 15B22 is stronger than S15C and S45C.

Abstract: This paper presents a method to reduce the fluctuation of machining strip width by modifying tool position. When the machining strip width varies rapidly within a tool path, the fluctuation of cutting force brings negative influence on the workpiece and cutter. Furthermore, as the tool path interval is always defined conservatively to avoid undercut, the machined strips of adjacent tool paths have unnecessary amount of overlap. Rapid changing machining strip width usually creates too much overlap at some location, which causes repeated cutting. A method is proposed to modify tool position and reduce the fluctuation of machining strip width. Besides, tilt angle smoothness along the tool path is also taken into account. The computation result of a blade surface verified the validity of the proposed method.

Abstract: The effect of welding condition on microstructure and mechanical property of Plasma-MIG Hybrid Weld between Al 5083 plates(thickness : 10mm) was investigated. 1 pass weld without any defects such as puckering, undercut, and lack of fusion was obtained by 150~200A of plasma current and 5~7mm of welding speed. Gas porosities and shrinkage porosities were existed in the weld near fusion line. As welding speed and plasma current were decreasing, the area fraction of porosity was increasing. The hardness of the weld is increasing as welding speed. On the basis of microstructural analysis, Mg segregated region near dendrite boundaries tends to increase with the welding speed. In the result of hardness test, Distribution of hardness in fusion zone showed little change with the plasma current. However, when the welding speed increased, hardness in weld metal markdly increased. It could be considered that effect of heat input to growth of the dendritic solidification structures. Based on tensile test, tensile properties of weld metal was predominated by area fraction of porosities. Consequently, tensile properties can be controlled by formation site and area fraction of porosity.

Abstract: We use optical, thermal, and electrical simulation to evaluate the effects of using varying amounts of undercut etch on wavelength-scale and subwavelength metal-clad semiconductor nanolasers (MCSELs). We find that as MCSEL diameter decreases, the optical performance becomes more sensitive to slight amounts of sidewall tilt. A modest amount of undercut (25%) dramatically improves the optical performance, reducing modal threshold gain to 100 $\mathrm{cm}^{-1}$ or less for lasers with core radius of 225, 550, or 775 nm, even in the presence of significant sidewall tilt (20° gain sidewall or ±8° pedestal sidewall tilt). Finally, we examine the effects of the increased undercut on nanolaser thermal performance and find that the increased resistive heating is insignificant near threshold, even for subwavelength nanolasers.

Abstract: The present subject matter relates to method(s), system(s) and device(s) for cladding of materials, and in particular to an undercut clip anchor system. The system comprises a horizontal rail which mounts both an upper undercut clip and a lower undercut clip for attaching an upper cladding panel and a lower cladding panel, respectively. Serrations on the undercut clips and on a nut bar serrated washer allow for the accurate vertical adjustment of the cladding panels.

Abstract: This project work focuses on the reduction of weld undercuts using the Taguchi method. The phenomenon of weld undercuts constitutes a major problem for the welding industry. When undercuts occur, and particularly when such cuts are deep, it has a negative impact on the weld as it lowers the integrity and quality of the weldment. Therefore, efforts are made globally to reduce the depth of such weld undercuts to the barest minimum. Several optimization methods have been adopted; however, in this study, the Taguchi method is applied. “The smaller the better components” of the Taguchi method is applied. From the results obtained from applying this Taguchi method, the optimum process parameters obtained are A2-B1-C2, which are a voltage of 20 V, a current of 180 A, and a welding speed of 130 mm/s, required to form an undercut of 0.03 mm. Whereas the existing process parameters used by the company are A1-B3-C, which make an undercut to a depth of 0.09 mm. It is concluded that the use of Taguchi method has been able to reduce the depth of undercut as shown in this study. A step-by-step approach is presented in the study.

Abstract: In this paper we report the results on the optimization of the bi-layer lift-off resist (LOR) SiO2 sputter-deposition technique which is ideal for obtaining damage-free multi-electrode array (MEA). To optimize the bi-layer overhang formation, we have examined the undercut formation kinetics of LOR bottom layer and the dependence of the SiO2 sputter-deposition lift-off processed electrode structure on the undercut length. Crater-shaped and recessed electrode structure is obtained when the undercut length is short (≤2 μm) and longer than 3 μm, respectively. To optimize the SiO2 sputter-deposition process, we have examined the dependence of Au electrode passivation on the SiO2 sputtering parameters in terms of electrochemical cyclic-voltammogram (CV), impedance, electrical noise, sputter-deposition rate and in vitro neuronal activity recording property. The MEAs passivated under pure argon supply condition showed poor barrier properties, poor neuronal signal recording performance, and cytotoxic property. The CV of MEAs passivated under oxygen mixing ratios above 5% showed traditional sigmoidal CV and long-term recording of neuronal activities, probing the excellent barrier property and cytocompatibility of the SiO2 films sputter-deposited under oxygen mixing conditions. We have also issued thermal damaging aspect of bi-layer overhang structure which is tightly coupled with the detailed electrode structure and the high sputter-deposition rate. Finally, it was suggested that measurement of CV, electrochemical impedance and electrical noise can be a viable tool in evaluating the barrier performance of a passivation layer.

Abstract: A semiconductor device and a method of manufacturing a semiconductor device, the device including an active fin protruding from a substrate and extending in a first direction, a first device isolation region disposed at a sidewall of the active fin and extending in a second direction, the second direction crossing the first direction, a normal gate electrode crossing the active fin, a first dummy gate electrode having an undercut portion on the first device isolation region, the first dummy gate electrode extending in the second direction, and a first filler filling the undercut portion on the first device isolation region, wherein the undercut portion is disposed at a lower portion of the first dummy gate electrode.

Abstract: * 부산대학교 융합학부 ** 부산대학교 재료공학과 *** 대우조선해양 산업기술 연구소 **** 부경대학교 기계공학과 Abstract The effect of welding condition on microstructure and mechanical property of Plasma-MIG Hybrid Weld between Al 5083 plates(thickness : 10mm) was investigated. 1 pass weld without any defects such as puckering, undercut, and lack of fusion was obtained by 150~200A of plasma current and 5~7mm of welding speed. Gas porosities and shrinkage porosities were existed in the weld near fusion line. As welding speed and plasma current were decreasing, the area fraction of porosity was increasing. The hardness of the weld is increasing as welding speed. On the basis of microstructural analysis, Mg segregated region near dendrite boundaries tends to increase with the welding speed. In the result of hardness test, Distribution of hardness in fusion zone showed little change with the plasma current. However, when the welding speed increased, hardness in weld metal markdly increased. It could be considered that effect of heat input to growth of the dendritic solidification structures. Based on tensile test, tensile properties of weld metal was predominated by area fraction of porosities. Consequently, tensile properties can be controlled by formation site and area fraction of porosity.

Abstract: FIELD: machine building.SUBSTANCE: welded shell and rings are made out of structural complex-alloyed steel for cold strain. Initially blank of the shell is subjected to rotation drawing by several transitions with intermediate recrystallisation annealing and thermal deformation hardening and annealing reducing stress. The rotation drawing of the shell at each transition is made by rollers, installed in same plane of cross-section with displacement between each other in radial direction. After rotational drawing edges for welding are produced, they further are undercut. The ring blanks are initially subjected to heat strengthening as per modes of hardening and annealing of the shell blanks, then to machining providing ring thickness and ring edges for welding. Then shell and ring edges are prepared for welding. Then assemblage and welding of shell with rings are performed on expanding mandrel. The automatic welding is performed by GMAW using low-alloyed wire by single pass.EFFECT: increased accuracy of dimensions.6 dwg, 2 tbl, 1 ex

Abstract: A novel SOI-MEMS process with galvanic protection technique is presented in this paper. After front-end-of-line processes and metallization with Au on SOI wafers, the moving structures and release trenches are patterned by using a single mask. A combination of RIE and DRIE was employed to define the moving structures and release trenches. In the releasing process, the silicon substrate was etched normally while the exposed silicon on SOI layer was passivated by the galvanic cell that consisted of top silicon layer and Au electrode in TMAH solution. Compared with other methods, this is a simplified process. As no protection layer on the sidewalls was required for TMAH etching, all of the lithography was performed on the plain surface instead of the high topography surface. Aside from this, the released cavity has a large space that provides less air damping. The undercut of the anchor is controlled by anisotropic etching which results in desirable anchors. A double-ended tuning fork resonator was fabricated to verify the processes. The resonant frequency of the resonator was measured as 3.098 MHz with a quality factor of 730 in an atmospheric environment.

Abstract: The present invention relates to an injection mold having a core extraction device, comprising a guide mold through which an ejector pin is penetrated and which has an undercut withdrawing device installed therein. The undercut withdrawing device, comprises: an inserting groove which is embedded in the guide mold, has a bottom flange for supporting the lower end of the spring provided on an outer circumferential surface, and a lower end of a molding core inserted thereinto; a spring bracket which is penetrated through the lower part of the inserting groove and has a coupling hole into which a coupling means is inserted; a withdrawing unit which is coupled to the upper part of the spring bracket and moves vertically according to the operation of the spring bracket so as to enable withdrawal of an undercut part of a mold product; a molding core which has a stopper limiting the range of vertical movement of the molding core, and a taper part enabling the upper end part to be escaped from the undercut part; a guide holder which is fixed into the guide mold such that the molding core penetrates and moves vertically, has the upper part which controls the operation of the molding core by being in contact with the stopper, and prevents the collision between the spring bracket and an ejecting plate; a coupling means for coupling the molding core with the spring bracket by being inserted into the coupling hole of the spring bracket; and a supporting bush which supports the head part of the coupling means, allows the double coupling between the coupling means and the spring bracket, and absorbs the vibration delivered from the molding core so as to prevent the decline of the coupling force between the molding core and the spring bracket.

Abstract: An wearable electronic connection assembly including a circuit board connected to a garment. The connector of the assembly has, from top to bottom, a tack pin having a head, a shank, and clinch attachment means with an undercut for receiving the cold flow of metal. The head of the pin passes through a hole in the circuit board and is in contact with a top surface of the circuit board. The shank of the pin extends farther downward through a layer of fabric beneath the circuit board. A ring is disposed beneath the fabric layer into which the tack pin is clinched forcing material of the ring into the undercut. A wire is attached to the ring which is electrically connected to the circuit board through its connection to the electrically-conductive pin. The assembly may include a plurality of pins, each of which extends through a separate hole in the circuit board and is clinched by a separate clinch ring.

Abstract: Ti-6Al-4V is an alloy that is increasingly used in aeronautics due to its high mechanical properties coupled with the lightness. An effective technology used to manufacture titanium components with a reduced buy to fly ratio is the laser beam welding. Previous studies showed that the key factor that rules the mechanical properties and the fatigue life of the joint is its morphology. The aim of this paper was to investigate the influence of the main process parameters, such as welding speed and laser power, on the geometrical features of the joint, in terms of undercut, underfill, reinforcement and so on. 3.0 mm thick Ti-6Al-4V rolled sheets were welded in butt joint configuration by using a Nd-YAG laser source. The joint performances were studied in terms of weld morphology, microstructure and Vickers microhardness. Then, defects such as underfill and reinforcement, controlling the whole weld morphology, were observed, and the relationship between the occurrence, the entity of these defects and the process parameters was studied.

Abstract: Lift-off methods for fabricating metal line patterns on a substrate are provided. For example, a method to fabricate a device includes forming a sacrificial layer on a substrate and forming a photoresist mask over the sacrificial layer, isotropically etching a portion of the sacrificial layer exposed through an opening of the photoresist mask to form an undercut region in the sacrificial layer below the photoresist mask, wherein the undercut region defines an overhang structure, and anisotropically etching a portion of the sacrificial layer exposed through the opening of the photoresist mask to form an opening through the sacrificial layer down to the substrate. Metallic material is deposited to cover the photoresist mask and to at least partially fill the opening formed in the sacrificial layer without coating the overhang structure with metallic material. The sacrificial layer is dissolved to lift-off the metallic material covering the photoresist mask.

Abstract: [Problem] In the decorative layer of a resin molding that is simultaneously molded and decorated using a decorative sheet, to improve inhibition of ink running, which occurs due to melted resin injected during molding. [Solution] A gate undercut block (62) is configured so that: during injection of molten resin when a peripheral plate (54) is in contact with the first parting surface and the compression block (60) is retracted with respect to the peripheral plate (54), the gate undercut block is fitted in the cavity (60b) and adheres tightly to the compression block (60); during compression, the gate undercut block fitted in the cavity (60b) compresses the molten resin together with the compression block (60) by means of the second forming surface (52); and during molding removal, the gate undercut block separates from the cavity (60b) and detaches from the gate resin.

Abstract: A method of making a silicon-on-insulator (SOI) semiconductor device includes etching an undercut isolation trench into an SOI substrate, the SOI substrate comprising a bottom substrate, a buried oxide (BOX) layer formed on the bottom substrate, and a top SOI layer formed on the BOX layer, wherein the undercut isolation trench extends through the top SOI layer and the BOX layer and into the bottom substrate such that a portion of the undercut isolation trench is located in the bottom substrate underneath the BOX layer. The undercut isolation trench is filled with an undercut fill comprising an insulating material to form an undercut isolation region. A field effect transistor (FET) device is formed on the top SOI layer adjacent to the undercut isolation region, wherein the undercut isolation region extends underneath a source/drain region of the FET.

Abstract: The present invention relates to a transformation core fixing apparatus for an electric discharge machining using a jig. According to the present invention, the transformation core fixing apparatus for an electric discharge machining using a jig comprises: a mold providing cavity for electric discharge machining for a workpiece to a desired product; a transformation core equipped in a separate portion in accordance with a predetermined setting value for electric discharge machining in a side of the workpiece, and forming an undercut; and a jig installed in a side of the transformation core and fixating the transformation core, thereby fixating acceleration not to be changed in the separate portion for electric discharge machining in a side of the workpiece compared to the other portions, and further, preventing the transformation core from being attached and discharged with a related product after electric discharge machining.