Topic
Undercut
About: Undercut is a research topic. Over the lifetime, 2805 publications have been published within this topic receiving 20214 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this paper, the authors present an approach for controlling the undercut and the minimal overhang angle in density-based topology optimization, which is useful for reducing support structures in additive manufacturing.
Abstract: Summary
We present an approach for controlling the undercut and the minimal overhang angle in density based topology optimization, which are useful for reducing support structures in additive manufacturing. We cast both the undercut control and the minimal overhang angle control that are inherently constraints on the boundary shape into a domain integral of Heaviside projected density gradient. Such a Heaviside projection based integral of density gradient leads to a single constraint for controlling the undercut or controlling the overhang angle in the optimization. It effectively corresponds to a constraint on the projected perimeter that has undercut or has slope smaller than the prescribed overhang angle. In order to prevent trivial solutions of intermediate density to satisfy the density gradient constraints, a constraint on density grayness is also incorporated into the formulations. Numerical results on Messerschmitt–Bolkow–Blohm beams, cantilever beams, and 2D and 3D heat conduction problems demonstrate the proposed formulations are effective in controlling the undercut and the minimal overhang angle in the optimized designs. Copyright © 2016 John Wiley & Sons, Ltd.
236 citations
Patent•
7 Apr 2011
TL;DR: In this paper, a method for manufacturing a high-performance bipolar transistor in which emitter size dependence of the transistor characteristics is reduced was proposed, in which an opening on an N epitaxial layer was provided, and a polysilicon containing boron and in contact with the N epitaxis layer around the opening, a silicon oxide film with a thickness about 60% with respect to that of the BSG film was formed.
Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-performance bipolar transistor in which emitter size dependence of the transistor characteristics is reduced SOLUTION: A silicon oxide film 102 provided with an opening on an N epitaxial layer 101, a polysilicon 103 containing boron and in contact with the N epitaxial layer around the opening, a silicon nitride film 104, a silicon oxide film 105 and a silicon nitride film 106 are formed Next, a base region 108 is formed by depositing and heat-treating a BSG film 107, the BSG film 107 is exposed by depositing and etching back a silicon nitride film 109 with anisotropic etching, and a P-base region is exposed by etching back with anisotropic etching Next, a silicon oxide film with a thickness about 60% with respect to that of the BSG film 107 is formed, an undercut under a lower portion of the silicon nitride film is etched back by embedded isotropic etching, the film thickness of arsenic-doped polysilicon is uniformized by decreasing the undercut, and impurity concentration and depth of an emitter region are uniformized
172 citations
TL;DR: In this paper, the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts.
Abstract: This article correlates laboratory-based understanding in machining of titanium alloys with the industry based outputs and finds possible solutions to improve machining efficiency of titanium alloy Ti-6Al-4V. The machining outputs are explained based on different aspects of chip formation mechanism and practical issues faced by industries during titanium machining. This study also analyzed and linked the methods that effectively improve the machinability of titanium alloys. It is found that the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts. These challenges are correlated and affected by each other. Sawtooth chips cause variation in cutting forces which results in high cyclic stress on cutting tools. On the other hand, low thermal conductivity of titanium alloy causes high temperature. These cause a favorable environment for high tool wear. Thus, impr...
171 citations
Patent•
24 Oct 1991TL;DR: In this paper, a dental undercut application device for producing an undercut on the surface of a tooth for securing a dental appliance is described. But the application device contains an undercut or applique with a curved front side for engagement with the surfaces of the tooth and a stem on the back side attached to a locator tab.
Abstract: A dental undercut application device for producing an undercut on the surface of a tooth for securing a dental appliance. The application device contains an undercut or applique with a curved front side for engagement with the surface of the tooth and a stem on the back side attached to a locator tab. The locator tab can be grasped when applying the adhesive to the front side of the undercut and for locating the undercut on the surface of the tooth while the adhesive cures. When the undercut is secured to the tooth, the stem is cut and the tab removed. The back side of the undercut may then be smoothed to match the contour of the tooth. Clasps on removable orthodontic appliances or removable partial dentures engage with the undercut to retain the dental appliance or denture in the patient's mouth.
149 citations
Patent•
23 Oct 1982
TL;DR: In this paper, a corner is chamfered so that about a center 1C of the outside circumferential edge of a substrate 1 is projected, for instance, by 0.2mm.
Abstract: PURPOSE:To raise poductivity, and also to prevent a protective film from being damaged due to a corner burr by projecting part of the outside circumferential edge of substrate of a recording medium, in the outside diameter direction from the outermost circumference of the surface, and forming a protective a protective layer by extending this projected part. CONSTITUTION:A corner is chamfered so that about a center 1C of the outside circumferential edge of a substrate 1 is projected, for instance, by 0.2mm. in the outside diameter direction from the outermost circumference of one surface having a recording surface 2 of the substrate 1 and the other surface. In case of mold-forming the substrate 1, an undercut 14a is provided on the outside circumference ring 14 of a fixed metallic mold 13. When a depth of this undercut 14a is set to a size corresponding to a molding contraction coefficient of a resin, for instance, 0.2mm., the substrate 1 can be taken out of the metallic molds 11, 13. A metallic reflecting film 5 and a protective film 6 are struck to the upper face of this substrate 1. In this case, the protective film 6 is stuck so as to cover a corner burr 1b and to cover a corner chamfered part 1d. The circumferential edge part of the reflecting film 5 is covered with the protective film 6, and does not touch directly a circumferential atmosphere. Also, when sticking the reflecting film 5, it is unnecessary to use a mask, etc.
135 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2026 | 1 |
| 2025 | 15 |
| 2024 | 34 |
| 2023 | 72 |
| 2022 | 112 |
| 2021 | 42 |