篩(shai)網材質、規格有(you)(you)好多(duo)(duo)種，最(zui)常用的(de)(de)是(shi)以每英寸長的(de)(de)孔(kong)數為(wei)篩(shai)號稱為(wei)目。所謂目數，是(shi)指(zhi)物料(liao)的(de)(de)粒度或(huo)粗細度，一般定(ding)義是(shi)指(zhi)在1平方(fang)英寸的(de)(de)面積(ji)內(nei)有(you)(you)多(duo)(duo)少(shao)(shao)個(ge)網孔(kong)數，即篩(shai)網的(de)(de)網孔(kong)數。物料(liao)能通(tong)過該面積(ji)內(nei)多(duo)(duo)少(shao)(shao)個(ge)網孔(kong)，即定(ding)義為(wei)多(duo)(duo)少(shao)(shao)目數：如50目篩(shai)網，就(jiu)是(shi)篩(shai)分(fen)料(liao)能通(tong)過1平方(fang)英寸內(nei)有(you)(you)50個(ge)網孔(kong)的(de)(de)篩(shai)網。

  以此類推，可(ke)得(de)知(zhi)：篩(shai)網的目數(shu)(shu)(shu)與(yu)孔(kong)(kong)徑(jing)和粒(li)(li)度(du)(du)成反比、與(yu)孔(kong)(kong)數(shu)(shu)(shu)成正比。即：目數(shu)(shu)(shu)越(yue)大(da)，孔(kong)(kong)數(shu)(shu)(shu)越(yue)多，孔(kong)(kong)徑(jing)越(yue)小(xiao)，說明物(wu)料(liao)粒(li)(li)度(du)(du)越(yue)細；目數(shu)(shu)(shu)越(yue)小(xiao)，孔(kong)(kong)數(shu)(shu)(shu)越(yue)少，孔(kong)(kong)徑(jing)越(yue)大(da)，說明物(wu)料(liao)粒(li)(li)度(du)(du)越(yue)大(da)。因此，我(wo)們必(bi)須針對所需(xu)篩(shai)選的物(wu)料(liao)顆粒(li)(li)大(da)小(xiao)，選擇最合適(shi)的篩(shai)網以滿足我(wo)們的工(gong)作需(xu)要。