In our plastic mold design industry, there are many types of mold structures. For general mold designers, ordinary sliders and inclined roof structures are familiar to everyone, and they can be designed. But for some special and typical molds There will always be a feeling that there is no way to start with the structure. Today I will explain to you the key points of the design of the screw thread mold structure. I hope that the majority of university mold design enthusiasts and partners who want to know more about the screw thread heart pumping structure will be inspired: Plastic products Threads are divided into two types: external threads and internal threads. For external threads with low precision, Huff blocks are generally used to form them, while internal threads mostly need thread unloading devices. Here is a brief introduction to the demoulding method of internal threads and the introduction of gears:

1. According to the action mode:

①The threaded core rotates, and the push plate pushes the product to disengage;

②The threaded core rotates and retreats simultaneously, and the product naturally disengages.

 

 2. According to the driving mode: the types of tooth extraction molds are generally divided into two types: one is the rack driven by the oil cylinder, and the other is the chain driven by the motor. The following picture shows the rack driven by the oil cylinder: The picture below shows the motor driven Chain twitching:

 

3. The twitching principle of the screw mold: the tooth pitch of the braces and the braces must be the same as the tooth pitch of the product, and the braces play a guiding role.The oil cylinder drives the rack 1 to move—the rack 1 drives the gears 2 and 3 to rotate—the gear 3 drives the gear 4 to rotate—the gear 4 and the screw are positioned as one and rotate together, as shown in the figure below:

 

4. When designing the screw tooth mold It is necessary to know the tooth pitch at the time, the definition of the thread pitch is the vertical movement distance of the screw tooth in one revolution, as shown in the figure below:

 

5. The pitch of the product glue and the thread pitch of the screw must be the same, otherwise the product will be easily scratched.

 

6. How to call gears and racks: Hu Bo plug-in can call gears and racks. According to the product ranking in our mold, we can determine the index circle required by our gears directly, and then the gear modules are the same.Then the gear can be called out as shown in the figure below:

 

7. The calling method of the rack: the rule of calling with Hu Bo’s external rack is also to follow the formula (modulus X number of teeth = diameter of the pitch circle)

 

8. Want to design a screw tooth mold , you must understand the relationship between the rack and the gear. The following figure shows the relationship between the rack and the gear and the relationship between each gear:

 

9. Calculation of the number of exit turns required by the product and the length of the rack: the number of turns of the teeth is 5 , then the screw needs at least 5 turns to exit.The screw exits for 6 turns. Then you can reversely calculate the rack twitching distance according to the previous page:

 

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