Conventional structure of injection molded inclined slider
The conventional structure of an injection molding slant slider is a common mechanism used in molds to form undercuts or oblique structures on the outside of the product. Its structure primarily consists of a slant slider, a guide runner, a wedge block, a positioning device, and a reset mechanism. These components work together to achieve core pulling and reset functions. The slant slider is the component directly involved in the product molding process, with its working surface matching the undercut or oblique surface on the outside of the product. It typically adopts a split structure, consisting of a slider body and a molding insert, for ease of processing and replacement. The guide runner, located on either the movable or fixed platen, guides the movement of the slant slider. Its cross-section is typically T-shaped or dovetail, and it mates with a boss on the bottom of the slant slider to prevent the slider from disengaging from the guide runner during movement. The wedge block, mounted on the fixed platen, locks the slant slider in the molding position when the mold is closed, withstanding the melt pressure during the injection molding process and preventing the slider from moving.
The inclination angle of the inclined slider is a core parameter of conventional structural design, which directly affects the core pulling effect and the stability of the mechanism. The inclination angle is usually 15°-25°. If the angle is too small, the core pulling stroke will be insufficient or the length of the inclined slider will be too large, which will increase the mold size; if the angle is too large, the lateral force on the inclined slider will increase, aggravating the wear of the guide groove and even causing the inclined slider to get stuck. For example, for a product with an outer undercut depth of 10mm, if the inclination angle is 20°, the core pulling stroke of the inclined slider must reach about 27.5mm to completely disengage from the undercut. The design must be reasonably determined based on the product size and mold space. The length of the inclined slider must be calculated based on the core pulling stroke and the inclination angle to ensure that it will not fall out of the guide groove during the core pulling process. Usually, the length extending out of the guide groove does not exceed 1/3 of the total length of the inclined slider.
The matching structure of the guide groove and the inclined slider is the key to ensuring the movement accuracy of the mechanism. In conventional structures, the matching clearance between the guide groove and the inclined slider must be strictly controlled between 0.02-0.05mm. A too loose fit will cause the inclined slider to shake during movement, affecting the dimensional accuracy of the product; a too tight fit will increase the movement resistance and cause the inclined slider to wear faster. In order to improve the matching accuracy and wear resistance, the matching surfaces of the guide groove and the inclined slider need to be precision machined to a surface roughness of Ra0.8μm or less, and quenched to a hardness of 50-55HRC. For large inclined slider structures, a wear-resistant plate can be installed in the guide groove. The wear-resistant plate is made of bronze or high-strength alloy material and is fixed to the template with screws. This not only improves wear resistance, but also facilitates subsequent replacement and reduces maintenance costs.
The positioning device and reset device are important components of the conventional structure of the inclined slider, ensuring the accuracy of each core pulling and reset of the mechanism. The positioning device usually adopts a positioning pin or a block. When the inclined slider core is pulled into place, the positioning pin cooperates with the positioning hole on the inclined slider, or the block contacts the end face of the inclined slider, limiting its continued movement and preventing excessive core pulling. The reset device mostly adopts a spring or an inclined guide pin. The spring reset structure is simple. The spring installed between the inclined slider and the template provides a restoring force, so that the inclined slider automatically resets during the mold closing process; the inclined guide pin reset relies on the inclined guide pin on the fixed template to be inserted into the guide pin hole of the inclined slider. Under the action of the mold closing force, the inclined slider is pushed back to the molding position. The reset accuracy is high and it is suitable for occasions with strict reset requirements. For example, when molding electronic component housings with high molding accuracy, inclined guide pin reset is often used to ensure the consistency of the reset position of the inclined slider each time.
The material selection for the conventional structure of an injection-molded inclined slider must meet the requirements of strength, wear resistance, and processability. The inclined slider body is typically made of alloy tool steels such as Cr12MoV or SKD11, achieving a hardness of 55-60HRC after quenching and tempering, ensuring sufficient strength and wear resistance. For molded inserts with complex molding surfaces, pre-hardened steels such as 718H can be used to avoid deformation after heat treatment that affects precision. The guide groove and wedge block are made of 45 steel or 40Cr, achieving a hardness of 28-32HRC after quenching and tempering, and 50-55HRC after surface quenching, improving their load-bearing capacity and wear resistance. Through the rational design of the structure of each component and the selection of materials, the conventional structure of an injection-molded inclined slider can stably and reliably perform core pulling, meeting the molding requirements of various products with external undercuts.
