Search Results for chemical milling

This article discusses the principal process steps, specifications, defects, applications, advantages, and disadvantages of chemical milling (CM) in aerospace industries. The process steps include precleaning, masking, scribing, etching, final cleaning, stripping, and mechanical finishing. The article describes the variables that affect undercut and surface finish obtained by CM. The mechanical properties of chemically milled parts are also discussed.

This article discusses the wrought product forms of titanium and titanium-base alloys, which include forgings and the typical mill products with tabulations for various specifications, and compares specifications for pure titanium, titanium alloys for mechanical, physical properties and chemical properties, including chemical composition, corrosion resistance, and chemical reactivity. The article discusses the effects of alloying elements in titanium alloys, and describes the classes of titanium alloys, namely, alpha alloys, alpha-beta alloys, and beta alloys. It also describes the typical applications of various titanium-base materials, and explains the crystal structure, effect of impurities, and microstructural constituents of titanium alloys. The article provides a brief description on the processing of wrought titanium alloys, including primary fabrication in which ingots are converted into general mill products and secondary fabrication (forging, extrusion, forming, machining, chemical milling and joining) of finished shapes from mill products and the heat treatment of titanium alloys.

This article discusses the properties of beryllium metals that require special attention when machining. It provides information on the considerations of S65 and selects 65 beryllium materials that are used for conducting tool wear studies and surface damage studies. The article highlights some of the precautions to be followed while machining beryllium metals. Information on the cutting oils, cutting tools, and speeds and feeds used in turning the beryllium are also provided. The article describes the chemical milling and photochemical machining methods that are used for etching beryllium components.

This article focuses on the machining of reactive metals which refer collectively to the elements titanium, hafnium, and zirconium. It provides guidelines for machining titanium and titanium alloys and describes machining operations, such as turning, milling, drilling, tapping, reaming, grinding, and sawing, performed on titanium and its alloys. The article also provides information on electrochemical machining (ECM), chemical milling (CHM), and laser beam machining (LBM) for titanium and titanium alloys. Guidelines for machining zirconium alloys and hafnium are also provided. The article provides a short description of turning, milling, and drilling operations performed on zirconium alloys and hafnium. It also discusses health and safety considerations related to zirconium and hafnium.

Titanium metal passes through three major steps during processing from ore to finished product: reduction of titanium ore to sponge (porous form), melting of sponge and scrap to form ingot, and remelting and casting into finished shape. This article describes primary fabrication, including all operations that convert ingot into general mill products, such as billet, bar, plate, sheet, strip, tube, and wire. The section on secondary fabrication describes processes such as die forging, extrusion, hot and cold forming, machining, chemical milling, and joining. The article presents a short note on powder metallurgy products of titanium. Casting processes and properties are covered in the final section.

The combination of high strength-to-weight ratio, excellent mechanical properties, and corrosion resistance makes titanium the best material choice for many critical applications. This article commences with a description of the historical perspective of titanium casting technology. It discusses the various types of molding methods, namely, rammed graphite molding, and lost-wax investment molding. The article provides information on the casting design, melting, and pouring practices, and describes the microstructure, hot isostatic pressing, heat treatment, and mechanical properties of Ti-6AI-4V alloy. It also talks about the chemical milling and weld repair, and describes the product applications of titanium alloy castings. Tensile properties, standard industry specifications, and chemical compositions of various titanium alloy castings are tabulated.

This article discusses coating products available for use in the aerospace industry that are compliant with regulations requiring reductions in emissions from organic solvents. The coating products addressed include primers, topcoats, and chemical milling maskants. It describes their characteristics and limitations compared to conventional noncompliant materials. The article addresses the methods and products commonly used achieve regulatory compliance: waterborne coatings, exempt-solvent-based coatings, high-solids coatings, powder coating, and electro-deposition.

This article is a comprehensive collection of summary charts that provide data and information that are helpful in considering and selecting applicable processes alternative to the conventional material-removal processes. Process summary charts are provided for electrochemical machining, electrical discharge machining, chemical machining, abrasive jet machining, laser beam machining, electron beam machining, ultrasonic impact grinding, hydrodynamic machining, thermochemical machining, abrasive flow machining, and electrical discharge wire cutting.

This article presents general design principles for different types of surface-finishing processes, such as cleaning, organic coatings, and inorganic coatings applied by a variety of techniques. It discusses the factors that influence the selection of surface-finishing processes. These include fabrication processes, size, weight, functional requirements, and design features. The article discusses the design as an integral part of manufacturing. It contains tables that summarize the design limitations for selected surface-preparation, organic finishing, and inorganic finishing processes.

Both surface finish and surface integrity must be defined, measured, and maintained within specified limits in the processing of any product. Surface texture is defined in terms of roughness, waviness, lay, and flaws. This article illustrates some of the designations of surface roughness and the symbols for defining lay and its direction. In addition, it describes the applications of surface integrity, typical surface integrity problems created in metal removal operations, and principal causes of surface alterations produced by machining processes. The article tabulates the effect of some machining methods on fatigue strength, and low-stress grinding procedures for steels, nickel-base high-temperature alloys, and titanium alloys.