【正文】
Figure 52 注塑模 注塑模 盡管成型某些熱固性材料的方法取得了一定的進步,但注塑模主要(還是)用來生產(chǎn)熱塑性塑件。C~ 410176。 parts must be allowed to cool in the mold in order or remove them without distortion. Thus thermosetting cycles can be course the mold must be heated rather than chilled,as with thermoplastics. Basic Underfeed Mould A simple mould of this type is shown in Figure31,and the description of the design and the opening sequence mould consists of three basic parts,namely: the moving half,the floating cavity plate and the feed plate respectively. The moving half consists of The moving mould plate assembly,support block,backing plate,ejector assembly and the pin ejection the moving half in this design is identical with the moving half of basic moulds. The floating cavity plate,which may be of the integer or insertbolster design,is located on substantial guide pillars( not shown) fitted in the feed guide pillars must be of sufficient length to support the floating cavity plate over its full movement and still project to perform the function of alignment between the cavity and core when the mould is being bushes are fitted into the moving mould plate and the floating cavity plate respectively. The maximum movement of the floating cavity plate is controlled by stop or similar moving mould plate is suitably bored to provide a clearance for the stop bolt stop bolts must be long enough to provide sufficient space between the feed plate and the floating cavity plate for easy removal of the feed minimum space provide for should be 65mm just sufficient for an operator to remove the feed system by hand if necessary. The desire operating sequence is for the first daylight to occur between the floating cavity ensures the sprue is pulled from the sprue bush immediately the mould is achieve this sequence,springs may be incorporated between the feed plate and the floating cavity springs should be strong enough to give an initial impetus to the floating cavity plate to ensure it moves away with the moving is normal practice to mount the springs on the guide pillars( Figure32) and acmodate them in suitable pocket in the cavity plate. The major part of the feed system( runner and sprue) is acmodated in the feed plate to facilitate automatic operation,the runner should be of a trapezoidal form so that once it is pulled from the feed plate is can easily be that if a round runner is used,half the runner is formed in the floating cavity plate,where it would remain,and be prevented from falling or being wiped clear when the mould is opened. Now that we have considered the mould assembly in the some detail,we look at the cycle of operation for this type of mould. The impressions are filled via the feed system( Figure31( a)) and after a suitable dwell period,the machine platens mence to force is immediately exerted by the pression springs,which cause the f