?????????????????????????????????????????????????? (Precast) ???? ?????????????????? ????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????????????????????????????
ประโยชน์ของเครื่องถ่ายเอกสาร
????????????? ??????????????????????????? ???????????????????????????????????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ???????? ???????????????????????????????????? ? ????????????????????? ????????????????
การรีดเกลียวโลหะมีกี่รูปแบบ
???????????????? ???????????? (Thread rolling) ?????????????????????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????? 2 ??? ??????1. ?????????? ????????