A.冷卻機(jī)針B.提高縫紉線強(qiáng)度C.降低縫紉線捻度D.防止扎斷紗
A.差動送料牙/送料牙B.送料牙/差動送料牙
A.背景噪聲聲壓級應(yīng)小于縫紉機(jī)噪聲聲壓B.縫紉機(jī)噪聲聲壓級與背景噪聲聲壓級之差應(yīng)大于10dBC.縫紉機(jī)噪聲聲壓級與背景噪聲聲壓級之差應(yīng)大于20dB