Pipe Defect
Pipe defect is also known as tail pipe or fishtailing. In many cases, during extrusion the surface oxides and impurities are driven twards the cenre of the bilet , much like a funnel (called pipe). The length of the extruded part with this defect has to be discarded and cut off as scrap. The piping defect can be minimized by proper designing of the die so that a more uniform metal flow pattern may be obtained.
(Kaushish,J.P., Manufacturing Processes, Eastern Economy Edition, pg. 407)
Arrowhead Crack
Internal cracking, also called center-cracking, center-burst, arrow head, fracture or chevron cracking in which the extruded product develops cracks in its centre. To reduce this defect, the die angle and impurities in the billet should be reduced.
(Kaushish,J.P., Manufacturing Processes, Eastern Economy Edition, pg. 407)
Hot Spinning
The hot spinning process is schematically shown in fig. the process is carried out on thick steel sheets to form a dish or other circ
ular cross-sectional shapes which are symmetrical about the axis of rotation. In hot spinning,
metal blank is heated to forging temperature and then it is held on lathe with the help of metallic form or chuck attached to the lathe spindle. The adapter at the tail stock end helps in the holding the hot blank against the chuck. Blunt hand spinning tools when fed forward(or pushed with pressure), bend and give shape to the revolving hot blank. Thin sheets are formed to various shapes by ‘cold spinning’ process discussed later.
(Kaushish,J.P., Manufacturing Processes, Eastern Economy Edition, pg. 411)
SCARA is an acronym for Selective Compliance Assembly Robot Arm. This configuration is similar to the jointed arm robot except that the shoulder and elbow rotational axes are vertical, which means that the arm is very rigid in the vertical direction, but compliant in the horizontal direction. This permits the robot to perform insertion tasks (for assembly) in a vertical direction, where some side-to-side alignment may be needed to mate the two parts properly.
(Groover,M.P., Automation, Production Systems and Computer-Integrated Manufacturing, 3rd Edition, pg.217)
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