Assembly system selection

Assemblies involve two or more combined components of varying degrees of build complexity and spatial configuration. The assembly technologies used range from simple manual operations through to dedicated and fully mechanized systems. The final system or combination of systems selected has the task of reproducing the product at the volume dictated by the 

In practice, assembly selection is a very difficult task. It does not mean, however, that we cannot make a sound decision about the most appropriate assembly teehnology to use for a given set of conditions or requirements. A number of researehers have proposed strategies for assembly system selection. The reader interested in this topie ean find more information in References (2.7-2.9). 

Prior to the selection of an assembly technology, a number of aetivities should be undertaken and factors considered, some of which also help drive the final quality of the assembly  

From the above, a number of drivers for assembly technology selection can be highlighted  

Availability of labor Operating costs Production quantity Capital cost of assembly equipment Production rate required Number of components in the assembly Number of product variants 

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Self-assembling systems selectively produce the most thermodynamically stable products and therefore both the enthalpic and entropic contributions towards the final species must be considered. The formation of a self-assembled product, by definition, necessitates the formation of new, favourable interactions, i.e. the process is enthalpically favourable. However, the formation of aggregate species occurs at an entropic cost as many degrees of freedom in the system are lost. The entropic penalty is offset somewhat by the release of solvent molecules that were previously interacting with the binding areas of the assembly components, in a solvophobic effect (see Chapter 1, Section 1.3.5). 

A particular type of support assembly is selected according to the amount of restraint tolerable by the piping system and the movement to be allowed at each location. Support types ate classified as rigid, resiUent, and constant-effort hanging and resting are the two basic arrangements. 

We will describe two mesoscale, self-assembling systems in which the interactions between objects are based on capillary forces. The first is based on polyhedral polydimethylsiloxane (PDMS) objects at a perfluorodecalin (PFD)/H20 interface. These objects have their faces patterned to be either hydrophobic or hydrophilic, and they assemble via lateral capillary forces that originate from interactions between these faces (Fig. 4. la). The second system uses polyhedral objects that are suspended in water and have selected faces covered with a water-insoluble liquid - either a hydrophobic organic liquid or a liquid metal solder these objects assemble via capillary forces into three-dimensional (3D) structures (Fig. 4.1b). 

Having presented the general aspects of micellar catalysis with its interesting features but also with its limitations, I will focus on a personal selection of examples of reactivity in aggregates and to show how these self-assembling systems may reveal, in some instances, unique properties that cannot be totally explained with the simple concept introduced above. 

Selective Ion Recognition with Durable Sensors (Lugtenberg and Reinhoudf) Self-Assembling Systems on Scales from Nanometers to Millimeters Design and Discovery (Issues, Chin, Bowden, Xia and Whitesides)... 

PERFORMANCE EVALUATION AND ECONOMIC JUSTIFICATION IN SELECTING THE ASSEMBLY SYSTEM... 

In the planning and realization of assembly systems, it is not only the selection of the correct operating materials which is important for the project success but also the optimal composition of the project... 

The confocal epifluorescent detection scheme we use is common among many who use this detection mode and features a cube-and-rail assembly system, specifically the microbench system from LINOS Photonics (Milford, MA) on an optical breadboard to maintain proper alignment of components (Figure 45.13). The excitation source is a multiline argon ion gas laser (model Reliant 150 m. Laser Physics, West Jordan, UT) that features user-selectable wavelengths (457,488, and 514 nm)... 

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