please remember, generally the rotary mold systems are more expensive, and the mold need two cavities and the injection machine need a large distance between tie bars in order to be rotatable, but rotary mold will offer greater design freedom.

this kind of molding method has following disadvantages:

the most important thing is that kind of molding method does not need to open the machine and further transport of a molded part in one mold. It just need core-back technique. It works like this, when the first material is injected, then movable inserts or cores close the cavity spaces for the second material. After it complete, then the spaces for second material are opened.

do you know core-back mold? I mean a mold with retractable slides and cores, that kind of mold structure has some attractive advantages: 1) low mold cost. 2) it is possible to produce multicolor or multi-component injection molded parts.

but that kind of mold with transfer or insert technique has it’s own disadvantages, because it needs precise centering of the pre-molding, complicated rotary device and more cavities accommodated on the mold platen, so because of economic reason, these molds are preferred to rotary molds.

here is a mold with transfer or insert technique, it also can mold two-colored materials or two different materials in one mold, after the pre-molding is made in the first cavity, it is transferred by a handing device or by hand into the second cavity and molded to produce the final part with a second material.

as for mold with rotary cores, how does it work? Let me tell you some details, in this technique, the quite different part is that both mold plates remain in position, only part of the ejector or nozzle side cavity with injected pre-molding is rotated.

for example, for a two-colored part, mold with rotating mold platen or rotating mold half, the first colored section is created by injection at the first mold position. After sufficient time has lapsed for the melt to cool, the mold opens and the mold part section turns 180 degree into the section position. The mold closes to form the second cavity and the second color or another material is injected via a second injection position.

today you ask me some things about the structure of two-colored mold, yes! Now I have a project like this at hand. Actually, the key of that kind of structure requires special mold techniques, during two-component combination injection molding, two melts are introduced into the cavity in succession via separate gating system. When the first material is injected, the second melt must be blocked off. The rotating mold systems and the non rotating core-back systems are their separation methods.