Flash welding
Flash welding is a process used to produce butt welds between similar or dissimilar metals in solid or tubular form. The two pieces of metal are first secured in current carrying grips and lightly touched together. An electric current may be passed through the joint to provide optional preheat, after which the pieces are withdrawn slightly. An intense flashing arc forms across the gap, which melts the material on both surfaces. The pieces are then forced together under high pressure (on the order of 70 MF'a, or 10,000 psi), expelling the liquid and oxides, and upsetting the softened metal. The electric current is turned off, and the force is maintained until solidification is complete. If desired, the upset portion can then be removed by machining.
(MATERIALS AND PROCESSES IN MANUFACTURING 10th edition, J. Temple Black, Ernest Paul DeGarmo, Ronald A. Kohser, p.897)
Mock-up
This is a proven and old technique in model making. It involves making a false model to simulate the real product or prototypes. It is made in wood or plastic instead of, say, cast iron or plastic. The mock up has to be painted in suitable metallic or other paint to create an impression of the actual future product.
(Product Design and Manufacturing, A. K. Chitale,R. C. Gupta, p.39)
Capability maturity model
The software sector has adopted a unique quality certification programme developed by the Software Engineering Institute (SEI) at the Carnegie Mellon University, known as the Capability Maturity Model (CMM). CMM is a model used by many organizations to identify best practices useful in helping them increase the maturity of their processes. According to SEI, the goals in developing CMMs include addressing software engineering and other disciplines that have an effect on software development and maintenance and providing integrated process improvement reference models. Moreover, the models will also enable efficient improvement across disciplines relevant to software development and maintenance.
(Operations Management: Theory and Practice, Mahadevan, p.130)
Shaft-Basis System (for dimensioning and tolerancing)
In the Shaft-Basis system, the different clearances or interferences are obtained by associating various holes with a single shaft, whose upper deviation is zero. In this system, the size of shaft is the basic size, while the clearance or interference is applied to the dimensions of the hole. The system is denoted by the symbol 'h'. The shaft-basis system is popular in industries using semi-finished or finished shafting, such as bright bars, as raw material.
Shaft-basis system
(a) Clearance Fit
(b) Transition Fit
(c) Interference Fit
(Design of machine elements, Bhandari, p.77)
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