Assembly process Lines

Operational qualification (or verification with the existing line) for each processing machine and assembled processing line. Operational qualification is required to confirm that all machines and equipment can be operated in the designed manner within the intended range. Preventive and corrective maintenance programs are established. 

Efficiency trials, which means developing specific operational conditions of the machinery and equipment in the assembled process line to manufacture the intended product. When needed, process control parameters for monitoring and acceptance criteria must be developed. 

Component Packaging Formats. Odd-form components come in a variety of sizes, geometries, and I/O configurations that determine the ease with which the component can be automated into the assembly process line. Another important variable is the component placement machine. Typical component packaging formats for the placement machine include tape and reel (radial and axial leaded), extruded tube, tray, continuous strip, and bulk containers. Each of these formats has benefits and drawbacks, as noted in the following subsections. Industry specifications have standardized nearly all of these packaging schemes. For example, there is EIA-468-B for radial deviees and EIA-296-E for axial components. 

Defects are most often detected by visual inspection or automated optical inspection (AOI). Other means of nondestructive evaluation (NDE) include electrical testing, x-ray inspection, and ultrasonic inspection. The preferred NDE inspection technique for BGA and CSP solder joints is x-ray inspection. Automated x-ray inspection equipment is often placed directly into the assembly process line for circuit board products having a large number of area-array components. 

When there is only one process line and one MCC alone is adequate to control the entire process, it is possible to combine the PCC and the MCC into one unit to save on space and cost. The assembly may now be called a PMCC (power-cum-motor control centre). 

For example, the characteristic dimension A on the cover support leg was critical to the success of the automated assembly process, the potential failure mode being a major disruption to the production line. An FMEA Severity Rating (S) = 8 is allocated. See a Process FMEA Severity Ratings table as provided in Chrysler Corporation et al. (1995) for guidance on process orientated failures. The component cost, Pc = 5.93 and the number planned to be produced per annum, N = 50000. 

Feedback provided by on-line monitoring of self-assembling processes will play an increasingly important role in controlling the microscopic and macroscopic architecture of molecular assemblies. Successful adaptation of char-... 

As scientists and engineers, natural self-assembly processes represent a tremendous resource, which we can use to create our own miniature materials and devices. Our endeavors are informed by hundreds of years of curiosity-driven research interested in the natural world. Our toolbox is further expanded by modem synthetic chemistry which extends beyond the realm of natural molecules. We can also create artificial environments to control and direct assembly and use computer-based tools and simulations to model and predict self-assembly pathways and their resulting protein structures. Many researchers believe we can use these modern tools to simplify, improve, and refine assembly processes. We have much to do in order to reach this ambitious goal but the next 10 years are likely to be filled with exciting discoveries and advances as self-assembling polypeptide materials move from the laboratory to the clinic or the manufacturing assembly line. 

The gear teeth were stripped for a 9/16-inch length from the ends of each gear rod. The first and last 3/16 inch of each rod were threaded to fit the 1 /4 inch female threads in the ends of the catcilyst boats. Thus, the reactor core assembly was joined securely for accurate positioning in the reactor tube. The reactor was designed so that the boats and gear sections could be inserted or removed individually when a fitting in the process line below the reactor was opened. 

This paper presents results from a study of assemblies composed of glass fibre reinforced epoxy composites. First, tests performed to produce mixed mode fracture envelopes are presented. Then results from tests on lap shear and L-stiffener specimens are given. These enabled failure mechanisms to be examined in more detail using an image analysis technique to quantify local strain fields. Finally the application of a fracture-mechanics-based analysis to predict the failure loads of top-hat stiffeners with and without implanted bond-line defects is described. Correlation between test results and predictions is reasonable, but special attention is needed to account for size effects and micro-structural variations induced by the assembly process. 

Figure 4.18 depicts a typical flow-injection pervaporation assembly. Solid lines represent fixed parts and the dashed lines, parts included when liquid samples are to be processed. 

Poly(dimethyl siloxane) (PDMS) stamps with protruding features (e.g., 1-pm lines or 10 pm squares on a side) may be inked with hexadecyl amines and pressed on smooth substrates covered with carboxylic acid anhydride surfaces. These in turn are obtainable by SAMs of fatty acids and subsequent dehydration. Hexadecylamide patterns are thus formed on carboxylate surfaces. Unreacted sites still contain anhydrides for further self-assembly processes to fill the voids ( micrometer or nanometer printing thiols or Kumar et al., 1995). 

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