Mechanical precision machining

Figure 2.4 Hard metal drill for mechanical precision machining.

With copper or brass as base material, the best surface quality is obtained with mechanical precision machining, followed by an electropolishing step. By this means, a surface roughness of down to 30 nm can be reached. Figure 2.7 shows the surface of a single O F copper microchannel after the electropolishing step. For all techniques, details can be found in [1, 4,14—20]. 

By using brass or copper structural material, the best surface quality is obtained with mechanical precision machining. Then, an electropolishing step... 

In a batch analyzer, each discrete sample is assigned a container (sample cup or sample bag), within which it is held through all the steps necessary to perform the analysis. The advantage of this approach is that crosscontamination between samples is not possible the samples preserve their identity and cannot be mismatched, since each container carries an identification label. The disadvantage of all batch analyzers is that they are mechanically very complex, have many moving parts that may become worn, and include components that must be precisely machined therefore, they have limited lifetimes. Three types of batch analyzers have been suggested [1.2-1.4]. 

Mechanical Design. Typically, each battery will have a thermal sleeve around each cell. The cells are mechanicily restrained by clamping them in a precision-machined sleeve. These sleeves can be made of either a metal such as aluminum or a composite made in a manner to provide electrical isolation, high thermal conductivity and strength. The sleeve is isolated electrically from the cell by a blanket, such as CHO-THERM which allows thermal transfer, wrapped around the cylindrical portion of the cell between the cell and sleeve. The space between the sleeves, blanket and cell is normally filled with a material such as an RTV 566 to provide better thermal transfer as well as to bond the interfaces mechanically. The sleeves are then either attached mechanically to a base plate which is the interface to the satellite structure or are attached to an interface such as extruded heat pipe assemblies which are a part of the satellite structure. The exposed surfaces of the cells are protected by a coating of Solithane or a combination of paint on the cell pressure vessel and Solithane. The desired battery voltage defines the number of cells used for the assembly. 

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