壓實式造型機利用氣壓或液壓通過壓頭或模樣對砂箱內(nèi)的型砂施加壓力來緊實型砂。其壓強一般為0.25～0.4兆帕。這種造型機﹐使遠離施壓面的砂型緊實度差。20世紀50年代初出現(xiàn)了高壓造型機﹐砂型平面上的壓強在 0.7兆帕以上。高壓造型機的壓頭分為平壓頭﹑成形壓頭和多觸頭壓頭等幾種結(jié)構(gòu)形式。其中以高壓多觸頭造型機應(yīng)用最為廣泛。高壓多觸頭造型機壓頭分割成許多可上下運動的小方塊──觸頭﹐通過液壓缸可獲得很大的壓實力。壓實時﹐各觸頭按其下面的模樣高度(即受壓砂層厚度)施加相應(yīng)的壓力﹐使砂型獲得很高的﹑均勻的緊實度和硬度。這類造型機都設(shè)有微震震擊機構(gòu)﹐能夠適應(yīng)復(fù)雜模樣的造型。高壓多觸頭造型機多采用四立柱結(jié)構(gòu)﹐有單工位式和雙工位式。為了適應(yīng)中小批量鑄件的生產(chǎn)﹐這種造型機多附有模板快換裝置﹐更換模板時﹐造型機不必停機。采用高壓多觸頭造型﹐砂型鑄造能澆出薄壁﹑尺寸精確﹑表面光潔的鑄件。
The compaction molding machine uses air or hydraulic pressure to apply pressure to the molding sand in the sand box through the indenter or pattern to compact the molding sand. Its pressure is generally zero point two five ~ Zero point four Megapascals. This kind of molding machine makes the sand mold far away from the pressure surface have poor compactness. In the early 1950s, a high-pressure molding machine appeared, and the pressure on the sand mold plane was Zero point seven More than megapascals. The head of high pressure molding machine is divided into flat head, forming head and multi contact head. Among them, the high-voltage multi contact molding machine is the most widely used. The press head of high pressure multi contact molding machine is divided into many small blocks that can move up and down - the contact, and a large compaction force can be obtained through the hydraulic cylinder. During compaction, the corresponding pressure is applied to each contact according to the pattern height (i.e. the thickness of the sand layer under pressure), so that the sand mold can obtain a high and even compactness and hardness. This kind of molding machines are equipped with micro shock mechanism, which can adapt to the shape of complex patterns. The high-voltage multi contact molding machine adopts four column structure, including single station type and double station type. In order to adapt to the production of small and medium-sized castings, this kind of molding machine is often attached with a quick change device of the template. When changing the template, the molding machine does not need to stop. With high pressure and multi contact molding, sand casting can cast thin-walled, precise size and smooth surface castings.