| 摘要 |
<p>A ball manufacturing method comprising: a preparation step in which a tube (2) and a foaming material (A), which constitutes a foamed layer, are contained in a forming mold (11) with the foaming material (A) disposed outside the tube (2); a first forming step which, after the preparation step, presses the foaming material (A) against the forming surfaces (17a, 18a) of the forming mold (11); a foaming promoting step which, after the first forming step, reduces the force which presses the foaming material (A) against the forming surfaces (17a, 18a) to promote the foaming of the foaming material (A); a second forming step which, after the foaming promoting step, increases the force which presses the foaming material (A) against the forming surfaces (17a, 18a) to obtain the foamed layer; and a panel applying step which applies panels to the outer surface of the foamed layer.</p> |
