Slanted guide post side parting and core-pulling mechanism is the most commonly used side parting and core-pulling mechanism. It has advantages of simple structure and reliable operation, and is widely used worldwide. Slanted guide post side parting and core-pulling mechanism uses slanted guide post as a transmission component to transmit vertical mold opening motion to side-joining half-module or side core, causing it to move laterally, thus completing side parting and core-pulling action. Slanted guide post side parting and core-pulling mechanism is preferred core-pulling mechanism; other core-pulling mechanisms are used only in special cases when it cannot meet requirements.

A typical slanted guide post side parting and core-pulling mechanism is shown in Figure 9-11.

 

Figure 9-11 Lateral parting and core-pulling mechanism with inclined guide post
1-A plate; 2-Inclined guide post; 3-7-Wear-resistant plate; 4-Slider; 5-Spring; 6-Limit screw; 8-Core; 9-B plate
Key design points for lateral parting and core-pulling mechanism of inclined guide post are as follows:
① If height H of inclined guide post exceeds 177.8mm (7”), see Figure 9-12, slider should be driven by a hydraulic cylinder;

 

Figure 9-12 Height Limitation of Angled Guide Posts
② Lubrication grooves should be provided at locations with sliding friction. To prevent lubricating oil leakage, grooves should not be "open" but rather "closed," as shown in Figures 9-13 and 9-14;

 

Figure 9-13 Specifications of oil tank

 

Figure 9-14 Schematic diagram of slider oil tank
③ Limit for core-pulling distance of inclined guide post is 70mm, depending on size of slider. If it exceeds 70mm, inclined guide post will be too long and lack strength, requiring use of a hydraulic cylinder for core pulling;
④ Slider movement should be smooth, without dead motion, unevenness, or looseness;
⑤ When designing slider, its center of gravity must be on slider seat. When slider is placed horizontally outside mold, it should not tilt downwards, otherwise jamming will occur during operation. Solution is to appropriately extend length of slider seat tail;
⑥ Sliding portion of slider should be approximately 1.5 times its width. After core pulling, length of slider within guide groove should be 2/3 of its total length.
⑦ Slider wear-resistant plate and pressure strip must have oil grooves, and pressure strip must have positioning or positioning pins.
⑧ Where slider extends into front mold or where larger sliders lock with front mold on both sides, wear-resistant blocks should be added at an angle of 1~5 degrees.
⑨ All sliders must have limit devices.
⑩ All sliders and wedges must have different hardnesses. In most cases, slider cannot use same steel as cavity and core. If this is unavoidable, slider needs to be nitrided.
⑪ For multiple sliders, try to concentrate them as much as possible, and design multiple small sliders on same slider seat.
⑫ Slider locking surface should not be smaller than the glue surface.
⑬ Slider should be easy to install, disassemble, and maintain. Sliding mating surfaces should be grindable, and there should be independent positioning between slider and mating parts.
⑭ All friction surfaces and stress surfaces should be inlaid with wear-resistant blocks as required.
⑮ Before inclined guide post enters slider, guide post has already entered guide sleeve;
⑯ Whether product sticks to slider. If this cannot be avoided, a slider ejector mechanism should be designed.

Installation and locking methods of inclined guide post are shown in Table 9-1. Design points of inclined guide post are as follows:
Table 9-1 Slanted Guide Pillar Locking Method

Head of inclined guide post should be chamfered and polished; Angle of inclined guide post should be less than slope of slider locking surface by 2. Clearance hole of inclined guide post on slider should be diameter plus 1mm; Length of inclined guide post must be less than 10 times diameter; Length of inclined guide post extending into slider must be greater than 2/3 of slider height; Length of fixed part of inclined guide post must be greater than or equal to 1.5 times diameter of inclined guide post.

1) General Rules
Design of a slider driven by angled guide pillars is shown in Figure 9-15. During mold design, ejector pins should be avoided in slider area as much as possible; in special cases, a pre-reset device must be designed. When slider width exceeds 200mm, a guide block needs to be added in the middle of slider, along with two angled guide pillars. When slider width exceeds 300mm, a center guide block is added. All slider guide blocks require heat treatment, quenching, and nitriding. Guide block material should be 1.2510, 56~58HRC, and height of wear-resistant block should be 0.5mm higher than its plane. Angled guide pillar of a large slider should be positioned at a lower point at tail of slider, and process screw holes should be designed at the top of slider.

 

Figure 9-15 General Example of Slider Design
1 - Cavity; 2 - Angled Guide Post; 3 - Angled Wedge; 4 - Plate A; 5 - Wear-resistant Plate; 7 - Slider; 6 - Slider; 8 - Limiting Screw; 9 - Plate B; 10 - Positioning Ball; 11 - Core; 12 - Pin; 13 - Screw; 14 - Pressure Strip
Design of a very small slider is shown in Figure 9-16. When mold space is very limited, slider must be designed very small; this method is the most space-saving and simplest. Bent pin serves both to lock slider and, during mold opening, to act as an angled guide pillar. However, due to small size of slider, as shown in Figure 9-16(a), a through-hole is cut on slider, through which bent pin passes; as shown in Figure 9-16(b), inclined groove on slider is a through groove, which greatly reduces strength of slider.

 

Figure 9-16 Miniature slider design
When designing this type of slider, angles of front and back sides of bent pin are consistent, and tilt angle should be as small as possible to reduce force on slider and bent pin. Rounded corners should be added to all parts of inclined groove of slider to facilitate insertion of bent pin and increase strength. Due to structural limitations, this type of slider generally has a small stroke and low force, making it suitable for situations with very small strokes, such as snap-fit parts.
2) Slider Angle
End of slider closest to molded part, along its two sides in direction of movement, needs a 3°~5° angle to ensure smooth movement when mating with cavity and core. There are two types of this angle, as shown in Figure 9-17: (a) shows an angle X on both sides of slider's orthographic projection, suitable for fit between slider and core. (b) shows slider protruding above parting surface and mating with cavity, with angle X° shown in right view. Only one angle should be used in this direction of movement to avoid adding angles in both horizontal and vertical directions.

 

Figure 9-17 Slider Angle and Direction Selection
3) Oil Groove Design
Oil grooves are required for sliding parts, such as sliders, angled ejectors, and wear-resistant blocks. Refer to Figures 9-13 and 9-14 for oil groove construction. Groove depth is 0.8mm. Figure 9-18 shows advantages and disadvantages of various oil groove shapes. Figure (a) shows optimal structure, where oil groove is formed by intersection of concentric circles. During machining, it should not extend beyond edge. Practice shows that shapes in Figures (b) and (c) are inferior, as oil easily overflows from slider surface, contaminating product. Avoid using shapes shown in Figures (b) and (c) whenever possible.
Occasions requiring oil grooves: bottom, sides, and back (sloping surfaces) of sliders, and mold base that contacts bottom surface when slider slides. Surfaces of inner mold, inserts, etc.; sides near slider and part of bottom surface of pressure strip; four sides of lifter; sides of inserts that need to move during injection molding; friction surfaces of all wear-resistant blocks, etc.
Oil grooves are all circular in shape. Dimension D is reasonably selected according to size of surface to be machined, ensuring that boundary is not broken, and depth is 0.8mm. When width of surface to be machined is small, circular oil grooves can be arranged in a straight line according to width (in this case, ratio of distance between adjacent centers to D should be smaller, and recommended value is 0.7); when width of surface to be machined is large, dimension D should be larger (in this case, ratio of distance between adjacent centers to D can also be larger), as shown in Figure 9-13.

 

Figure 9-18 Oil tank shape selection

Pressure bar is guide element for slider. Commonly used guide elements are inverted L-shaped and straight-shaped. Inverted L-shaped pressure bar is shown in Figure 9-19. During design, fixing groove should be deepened as much as possible, sinking pressure bar into B plate, and two locating pins should be added to each pressure bar. Straight-shaped pressure bar is shown in Figure 9-20. Guide parts are on both sides of bottom, and guide parts slide against B plate without gaps. Height T of guide parts is at least 15mm. Oil grooves should be added to guide parts of pressure bar. Pressure bar material should be alloy steel and heat-treated and quenched.

 

Pressure bar design for large slider is shown in Figure 9-21. Pressure bar material is 2510, heat-treated to 52~54HRC, contact gap between pressure bar and slider side is 0.2mm, and center guide block material is 2344, heat-treated to 46~48HRC.

 

Figure 9-21 Design of pressure bar for large slider

Molds with a lifespan exceeding 300,000 cycles require wear-resistant blocks. For small sliders with a width of less than 30mm, this can be omitted. Wear-resistant block design is shown in Figure 9-22.

 

Figure 9-22 Wear-resistant block design
Wear-resistant blocks are typically fixed to inclined surface and bottom of slider. Their function is to increase wear resistance, thereby increasing mold life. Designing wear-resistant blocks also facilitates mold assembly and maintenance. Wear-resistant blocks are usually made of 2510 alloy steel with a heat treatment hardness of 52HRC or higher. When slider area is large, wear-resistant block needs to be divided into multiple pieces for easier manufacturing. Wear-resistant block is fixed to bottom of slider groove on plate B using flat-head screws. Wear-resistant block at inclined surface of slider can be fixed to slider or wedge. In mold design, wear-resistant block should protrude 0.2~0.5mm above fixed plane for easy adjustment during assembly. Before heat treatment, oil grooves need to be machined on friction surface. Standard thickness dimensions are 5mm, 6mm, 8mm, 10mm, and 12mm. Allowance should be left in thickness direction before heat treatment, and surface should be ground smooth after heat treatment.
Oil grooves on wear-resistant block are designed in same way as oil grooves at the bottom of slider, requiring intersecting circles with a depth of 0.8mm. A grinding allowance must be added to depth before heat treatment, and circles must not be broken at edges to prevent oil from seeping out.

There are generally five types of slider positioning methods, as shown in Figure 9-23. Figure (a) shows a spring-embedded positioning method, suitable for sliders facing upwards or tilted upwards; or sliders with protruding small inserts or pins; or sliders with push rods at the bottom. Figure (b) shows an external spring when spring installation length is greater than 50mm. For wider sliders, more than two springs can be installed. Figure (c) shows a ball bearing positioning method when slider is small and not facing upwards. Slider positioning ball bearing specifications are shown in Table 9-2. Figure (d) shows a SUPERIOR slider lock, widely used in European molds. Its usage position is similar to that of a positioning ball bearing, but its force is slightly greater. SLK-8A is suitable for sliders under 3.6kg, and SLK-25A is suitable for sliders under 11kg. Figure (e) shows a DME standard slider clamp, commonly known as a tiger clamp. Appropriate clamp should be selected according to slider weight; specifications are shown in Table 9-3.

 

Figure 9-23 Positioning method of slider
Table 9-2 Specifications of Slider Positioning Balls

Table 9-3 DME Slider Clamp Specifications

To prevent interference with other parts of mold during mold closing and damage, all sliders must be reliably positioned.
Positioning of split-type half-slider uses an interlocking mechanism, as shown in Figure 9-24. Figure (a) is a product drawing, Figure (b) shows two half-sliders, and Figure (c) is a plan view of two sliders combined. Two half-sliders are locked together at a 10° angle.

 

Figure 9-24 Split-type half-slider

Injection pressure in cavity causes slider to move backward. Wedge's function is to resist this backward force, ensuring slider is in correct position. Figure 9-25 shows various wedge forms. Figure 9-25(a) shows a wedge protruding from mold base's A plate. This type of wedge has the greatest force and is often used when slider mechanism is higher than parting surface and slider experiences significant lateral force. Figure 9-25(b) shows a wedge embedded in A plate, often used when mold base's A plate is thin or for smaller sliders. Figure 9-25(c) shows another type of wedge embedded in A plate, with a backscraper at the bottom of wedge, with a slope of 5-10 degrees. This is often used when slider experiences significant lateral force and can effectively prevent burrs from forming on slider.

 

Figure 9-25 Various forms of wedge blocks
Slider must have sufficient locking area, and height of wedge must be greater than 2/3 of height of glue area. For sliders with a large glue area, as mentioned above, wedge needs a backscraper.