Process knowledge about the glue head of an injection molding machine?

The adhesive head, check ring, and adhesive spacer—these components can be made from a variety of materials, including fully hardened powder alloy steel, Japan’s Hitachi SKD61, domestically produced SACM645 alloy steel, domestically produced 38CrMoALA alloy steel, tungsten steel, 45# steel, H13, and others.

Pass through the glue head, the check valve ring, and the glue spacer. The materials can be selected from among fully hardened powder alloy steel, Japan’s Hitachi SKD61, domestically produced SACM645 alloy steel, domestically produced 38CrMoALA alloy steel, tungsten steel, 45# steel, H13, and other materials.

The function of the adhesive head ring meson: The glue-head assembly plays a crucial role in the plastic injection molding process by mixing the molten plastic and ensuring uniform blending of the melt. The glue head also serves to limit the forward and backward movement of the glue ring. The glue ring, when combined with the die, functions as a sealing element. If either component fails, the plastic will flow backward, leading to inaccurate measurement of the molded parts. In severe cases, this can cause discoloration of the product, resulting in yellowing and the formation of black spots.

Introduction to the adhesive ring: From a stylistic perspective, glue rings can be divided into two types: one with prongs and the other without prongs. The glue ring with prongs is inserted into the groove at the screw head during pre-plasticization, and it rotates along with the screw’s rotation. Its advantages include minimal wear on both end faces and excellent plasticizing performance. However, its disadvantages are rapid outer-diameter wear and the potential for the entire screw to become jammed if the clearance between the screw and the barrel inner bore is tight or if foreign objects fall into the barrel. This type of glue ring also accelerates wear on the inner bore of the barrel. On the other hand, the glue ring without prongs exhibits slower outer-diameter wear because it rotates less during pre-plasticization. Nevertheless, its end faces tend to wear more quickly. If you need to process PVC or PC materials as well as other plastics, this type of glue ring is preferable, as it avoids the dead zones created by the prongs, thereby preventing material buildup and black spots caused by such dead zones.

Requirements for the O-ring gasket in transparent product injection molding: The three small components of the screw head must have smooth, continuous surfaces throughout. Except for the assembly areas, no visible surface—whether on the front side or elsewhere—should feature sharp right angles or dead corners. All angular transitions must be smoothly rounded. This is because sharp right angles and dead corners not only increase the likelihood of cracking but also tend to trap material, impeding the smooth flow of raw materials. Over time, such trapped material can lead to the formation of black spots and yellowing. Typically, the three small components are the most prone to yellowing. Many manufacturers of transparent PC and PMMA products experience yellowing precisely because their three-component designs are poorly conceived.