Fabrication Requirements

Fabrication and Processing. PVDF is available in a wide range of melt viscosities as powder or pellets to fulfill typical fabrication requirements latices are also commercially available. 

Many fluorochemical finishes for fabrics require curing at up to about 175°C. Curing aUows melt-spreading of the fluorochemical to ensure maximum leveling of the finish on the fibers and to promote optimum orientation of the pendant fluorinated portion of the molecules on the fibers. 

The agar-based impression materials are used extensively for dupHcating casts. Frequendy, it is desired to retain the original model for reference and do the actual work on a dupHcate cast. Partial-denture fabrication requires that the original stone cast be dupHcated in an investment. For dupHcating, the agar-based impression material is usually diluted with water, boiled, cooled to the desired temperature, and carefully poured over the model to be dupHcated. 

Polyester fabrics and many other hydrophobic synthetic fabrics require the appHcation of an antistatic agent prior to printing to prevent the buildup of static charges at rapid printing speeds (see Antistatic agents). 

The code assigns to the owner the respousibihty for identifying those flmd services which are in Categories D and M. The design and fabrication requirements for Class M toxic-service piping are beyond the scope of this Handbook. See ANSI B31.3—1976, chap. T11. 

Unsuitable. Not available in form required or not suitable for fabrication requirements or not suitable for corrosion conditions. 

Particular fabrication requirements, including the need to assemble or plate parts. 

Helically wrapped fins are fabricated such that the fm height can be between about 3/8 to 3/4 of the tube diameter, but limited because of fabrication requirements to a maximum of about 2.54 cm (1.0 in.) in height. Fin spacings vary between about 275 and 450 fins per meter of tube length, while fin thicknesses range from 0.025 to 0.075 cm. For particular cases these parameters may be varied further. 

Alloys or tempers chosen should be free of susceptibility to corrosion and should meet strength and fabrication requirements. Often a weaker alloy must be selected than one that cannot be reliably heat treated and whose resistance to a particular corrosion is low. 

Composite structures fabrication requires levels and types of expertise for layup and curing that are not typically found in metals fabrication industries. Therefore, a composite structure is more of a specialist-produced structure than is a metallic structure. Layup is a totally different process that is absolutely foreign to metals production technologists. We must somehow get those people into the mainstream of composite structures manufacturing before we will see widespread composite structures production. 

Most companies have a detailed general specification for the construction of pressure vessels, which defines the overall quality of fabrication required and addresses specific items such as ... 

All these alloys are characterised by high hardness values and low resistance to impact. In this they are probably more similar to stoneware than to other metals but they are superior to stoneware in thermal conductivity and in their resistance to thermal shock, which, however, is poor compared with that of other metals. Moreover, it is usually easier to make castings of silicon iron than to fabricate required parts from stoneware. 

BS 6374 Part 5 1985 gives full details of design and fabrication requirements and it is advisable to consult this document as well as the lining contractor prior to arriving at the final design. 

Design drawings Detail or fabrication drawings Materials requirements including composition, quality standards, and minimum structural properties Fabrication requirements and standards, including dimensional tolerances, allowable defects, and minimum structural properties Requirements for prototype and quality control tests and procedures Shipping and handling... 

An eight minute cycle time does not allow any tolerance for error. Fabricators require a part success rate of approximately 95% therefore, the actual operating conditions chosen were more conservative than the ones optimized here. The conditions used in the actual process were as follows an A/E ratio of 1.05, a wind time of 3.8 minutes and mold and press temperatures of 90 and 115 C, respectively. These conditions resulted in a cycle time of eleven minutes which is three minutes more than the optimized cycle time. Figures 6a-9b, which were previously... 

All the nickel alloys are readily fabricated and welded. Their design strengths allow use to elevated temperatures and with relatively thin wall thicknesses. The Nickel Institute (http7Avww.nickelinstitute.org) has excellent publications available that detail the properties and fabrication requirements for both stainless steels and nickel-based alloys, as does SSINA (http //www.ssina.com) and so do many of the manufacturers of these alloys. 

Since engineering plastics are difficult to process under normal conditions and occasionally require special equipment, it is essential that commercial fabricating requirements be resolved early in the development program. This helps insure proper acceptance once the polymer is introduced to the market. 

Membrane design and fabrication requires more optimization than the synthesis of the right type of polymer. For example, those phosphazene polymers that contained the highest ratios of methylamino groups were too brittle to be used as membranes (because of the high glass-transition temperatures) and too soluble in aqueous media. However, the polymers could be made insoluble in water by radiation cross-linking as shown in reaction (54). 

Consider general ways in which the design criteria can be achieved, specification of other types of equipment, manufacturer s data, economic considerations, materials and fabrication requirements for the design, etc. 

A complete design includes consideration of all aspects of the equipment specification such that the item could be built and operated. These aspects include the mechanical design, materials selection, fabrication requirements, operational details, safety features, versatility (e.g. turn down), economic considerations, etc. The scope (i.e. depth) of the design should be clearly specified by the supervisor. 

Many durable flame retardants for cotton have been developed to convey open-flame resistance [344,346,360,361]. The vertical flame test for determining the U.S. children s sleep-wear flammability (16 CFR 1615 and 1616) is a rather severe test and cotton fabrics require a FR treatment to pass the test. The test method requires treatments that are durable to 50 hot water wash and dry cycles. Currently there are relatively few commercially available FR chemistries that are durable under these conditions required today. Some of the reasons include low commercial availability of the chemicals, costs, safety concerns, process control issues, and difficulty in application. 

Two major improvements in the fabrication of an ion-sensitive FET that avoid most of the tedious polymer encapsulauon process have been reported. Matsuo and his coworkers (4, 37) fabricated a probe-type FET with a three-dimensional silicon nitride passivation layer around most of its surface, as shown in Fig. 2. The probe-type FET has one disadvantage Its fabrication requires a three-dimensional process that is uncommon for semiconductor construction facilities. An alternative approach utilizes a silicon-on-sapphire (SOS) wafer for FET fabrication (38, 39). The structure of a SOS-FET is depicted in Fig. 3. It has an island-like silicon layer on a sapphire substrate, in which an ion-sensitive FET is fabricated. The bare lateral sides do not need encapsulation because of the high insulation property of sapphire. 

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