Product diagram of front shell of temperature controller is shown in Figure 1. Maximum size of product is 365.00 mm * 230.00 mm * 54.00 mm, average thickness of plastic part is 2.72 mm, material of plastic part is ABS, shrinkage rate is 1.005, and weight of plastic part It is 311.40 grams. Technical requirements for plastic parts are that there must be no defects such as peaks, underfilling of injection molding, flow lines, pores, warpage deformation, silver streaks, cold materials, jet lines, etc.

 

Figure 1 Product picture of front shell of temperature controller
It can be seen from Figure 1 that structure of plastic part is a closed shell, two ends have one and two side through holes respectively. It is necessary to design front mold slider to pull core. Edge of plastic part has a ring of notches, which is completely anastomosed with the other part. There are two round holes on the top of plastic part, edge of round hole has a bone position facing movable mold. Top of plastic part is appearance surface, and there is an assembly stopper around the edge, which is also a part of appearance with higher requirements. Therefore, location of gate design can only be selected in a round hole at the top.
This is a set of molds based on British NB400-ton injection molding machine. Due to large size of product, need to design slider cores on both sides of sky and earth, mold design cavity ranking is 1 cavity, mold base is a non-standard mold base 4560, size of panel and bottom plate is large, which acts as a code mold plate. Bottom of the two boards is designed with two code mold slots. Opening width of slot is 54 and bottom is R20. Here, it cooperates with code module of injection molding machine to bear weight during code mold. Code mold support block of NB injection molding machine is divided into two pieces, which are arranged on both sides of mold plate. There is one positioning block for large-scale mold in Japan, which is arranged in the center of mold. This is the biggest difference between British NB injection molding machines and Japanese injection molding machines in terms of code patterns.
For small molds, code mold method can be a method of pressing code mold with a pressing plate, and a method of fixing screw on the top surface of mold plate to tighten it. Various methods are not much different, just different from user's injection molding machine design habits. For large molds, coding method will affect efficiency of mold replacement, will affect safety of coding operation, and effectively protect mold. Now many large-scale mold injection manufacturers in the world have invented quick-change mold systems, as well as electromagnetic code mold systems. For these advanced technologies, it is worth learning and researching.

 

 

 

After movable and fixed mold panel, bottom plate are enlarged, in addition to facilitating coding of mold, it can also play a role in supporting mold to omit mold foot. Because of need to design slider core-pulling on the world side of mold, there is no space to design taper positioning block. Two taper positioning blocks perpendicular to each other are respectively designed on left and right sides. Movable mold and fixed mold are respectively designed with positioning pins. A U-shaped prying slot must be designed between two mold plates that are in contact with each other to facilitate disassembly of mold. See figure 2 of mold design.
When size of plastic part is large, design of front and rear mold cores is very important. Front and rear mold cores belong to core part of mold, their processing volume accounts for more than 80% of the entire mold processing. Reasonable design of inserts of mold core is conducive to obtaining the best processing efficiency, ensuring processing accuracy, prolonging life of mold. I have introduced design method of full inlay mold before. This mold uses design method of the whole mold core. Due to large size of plastic part, size of front mold core is 439.87*299.87*95; size of rear mold core is 439.87*299.87*101.76; for such a large mold core, it is usually difficult to directly lower frame. When designing mold, front and back mold fine frames need to be designed as oblique frames, as shown in Figure 4. It should be noted that front and rear molds are based on reference angle, two sides adjacent to reference angle are vertical sides, the other two sides far away from reference angle are hypotenuses. One side can also be designed as a hypotenuse as required. Same slope is also designed at corresponding position of mold core. Angle is generally 3゜ or 5゜.
Core-pulling of three holes on the side of plastic part is all fixed-mold core-pulling. There is no movable mold plate for fixed mold of this set of molds. Core-pulling uses an oil cylinder to pull core. Cylinder is not locked by shovel base. With such a structure, cylinder core can only be used for small holes without locking. It is not suitable for core pulling occasions with large area and large lateral force.
Top and edge of plastic part cannot be designed with gates. Gate is designed in one of round holes at the top, glue is inserted latently around hole at two points. Main runner is an inclined main runner. When designing export molds, application of inclined runners must be confirmed by customers.
Front and back molds of mold are designed with cooling water circuits, schematic diagram is shown in Figure 3.

 

Ejection system of mold is structural form of strong tension and strong roof in Europe. Ejector element is a thimble. There is no spring on the back needle, and a screw hole is designed at the position of KO hole at the bottom of thimble bottom plate. In addition, a travel switch needs to be designed on thimble board to ensure timely return.

 

Figure 2 Mold diagram of front shell of temperature controller

 

Figure 3 3D mold water transportation diagram

 

Figure 4 Structure of slope precision frame