| 摘要 |
PURPOSE: A die apparatus for fins of a hot water heat exchanger for boiler are provided in which two or more female grooved parts are formed on corner portions of heat exchanger fins in a cross or parallel direction using one die apparatus by improving structure of die bushes and forming punches. CONSTITUTION: The die apparatus for fins of a hot water heat exchanger for boiler comprises first receiving grooves(53) which are formed on corner portions of a restriking punch(52) so that die bushes(61,62) are received and installed in the first receiving grooves(53), wherein the die bushes(61,62) are removably installed in the first receiving grooves(53) in such a manner that the die bushes(61,62) are consisting of a first die bush(61) the upper surface of which maintains the same surface as the upper surface of the restriking punch(52) in case of positions where female grooves parts are not formed, and a second die bush(62) the upper surface of which is stepped concave as deep as a forming depth of the female grooves parts compared with the upper surface of the restriking punch(52) in case of positions where the female grooves parts are formed; and second receiving grooves(57) which are formed on corner portions of a restriking pad(56) so that forming punches(71,72) are received and installed in the second receiving grooves(57), wherein the forming punches(71,72) are removably installed in the second receiving grooves(57) in such a manner that the forming punches(71,72) are consisting of a first forming punch(71) the lower surface of which maintains the same surface as the lower surface of the restriking pad(56) in case of positions where female grooves parts are not formed, and a second forming punch(72) the lower surface of which is projected as deep as a forming depth of the female grooves parts compared with the lower surface of the restriking pad(56) in case of positions where the female grooves parts are formed.
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