Moulding tool for a thermoplastic polyester socket structure
Patent Information
- Application Number
- CN202522609275.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-09
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-12-09
AI Technical Summary
Traditional molding dies are prone to uneven temperature distribution when molding deep recessed structures, leading to quality problems such as burrs, cracks, or insufficient filling.
The design employs a lower mold base and an upper mold base, with independently controlled heating elements installed on the outside of the mold cavity and around the groove, respectively. Combined with a spirally arranged cooling pipeline, this achieves uniform temperature distribution and gradient control. Through the coordinated heating of the mold cavity and the molding section, the temperature uniformity within the molded sleeve is ensured.
It improves the quality of the molded cavity, avoids the problem of material scorching or incomplete melting caused by excessively high or low local temperatures, extends the service life of the mold, and reduces maintenance costs.
Smart Images
Figure CN224928338U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of molding die technology, and in particular to a molding die with a thermoplastic polyester nest structure. Background Technology
[0002] In some furniture products and pet supplies, nesting structures are frequently designed. These nesting structures are often complex and deep due to their design requirements. Thermoplastic polyester material, with its strong plasticity, is widely used in these applications. For deeper nesting structures, the traditional molding die design can easily lead to uneven temperature distribution during the heating and molding process. This can result in quality problems such as burrs, cracks, or insufficient filling at the edges or in areas with excessively high or low temperatures. Utility Model Content
[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a molding die that improves the control of the molding temperature field and the molding quality of thermoplastic polyester nest structure.
[0004] The objective of this utility model is achieved through the following technical solution:
[0005] A molding die for a thermoplastic polyester cavity structure, characterized in that it comprises:
[0006] The lower mold base has a receiving cavity on its bottom surface and a mold cavity on its top surface. The mold cavity is recessed into the receiving cavity. A recessed forming sleeve is provided on the inner side of the mold cavity. The outer side of the recessed forming sleeve is sealed and fitted to the inner side of the mold cavity. A first heating element is provided in the receiving cavity and surrounds the outside of the mold cavity.
[0007] The upper mold base is provided with a groove, and a molding part is provided on the bottom of the groove. The molding part protrudes in a direction away from the groove. When the mold is closed, the outer side of the molding part presses against the inner side of the socket forming sleeve. A second electric heating element is arranged around the molding part at the bottom of the groove.
[0008] The first heating element and the second heating element are connected to an external control device.
[0009] In a preferred embodiment, the centerlines of the molding part, the recess forming sleeve, and the mold cavity coincide.
[0010] In a preferred embodiment, the top edge of the cavity forming sleeve is provided with an outward flange, and the outward flange is fitted and connected to the edge of the top surface of the mold cavity.
[0011] In a preferred embodiment, the surface of the socket forming sleeve is coated with a polytetrafluoroethylene coating.
[0012] In a preferred embodiment, the socket-shaped sleeve is made of rubber material.
[0013] In a preferred embodiment, the socket forming sleeve is provided with an exhaust hole.
[0014] In a preferred embodiment, the first heating element is spirally arranged around the outer side of the mold cavity.
[0015] In a preferred embodiment, the first heating element is connected to a PID temperature controller, which controls the temperature in the height direction of the mold cavity in segments.
[0016] In a preferred embodiment, a cooling pipe is further included, which is connected and fixed inside the accommodating cavity, and the cooling pipe and the first heating element are arranged at intervals along the axial direction of the outer side of the mold cavity.
[0017] Compared with the prior art, the present invention has at least the following advantages:
[0018] 1. In the molding die of this utility model, a first heating element is arranged around the outside of the mold cavity, and a second heating element is arranged around the bottom of the groove and the molding part. The two heating elements can be independently controlled by an external control device to make the temperature distribution in the cavity more uniform. This avoids molding defects caused by excessively deep recesses, such as local overheating or underheating at the longitudinal direction and irregular edges, which can lead to material scorching or incomplete melting. The heating of the thermoplastic polyester material by the first heating element forms an outer layer on the mold cavity forming sleeve, improving the temperature uniformity within the mold cavity forming sleeve. The second heating element, together with the first heating element, creates a coordinated heating effect from top to bottom, achieving temperature gradient control and constructing a temperature field from the mold cavity to the molding part. This avoids local temperature differences that can occur during molding due to the inability to transfer heat to the molding part pressed against the top of the forming sleeve, resulting in internal stress or adhesion, caused by complex recess structures or deep recesses. Furthermore, the first heating element is arranged in a spiral pattern, which allows for more flexible matching of the recess structure and zoned control.
[0019] 2. The molding die of this utility model features a fitting design between the die-forming sleeve and the mold cavity and molding part, which reduces the wear of the die during the molding process and allows for replacement. At the same time, the reasonable heating method and temperature control avoid thermal fatigue damage caused by local overheating of the die, which can extend the service life of the die and reduce the maintenance cost of the die.
[0020] 3. The molding die of this utility model is also provided with a cooling pipe that is spirally arranged around the outside of the mold cavity. Compared with the traditional method of cooling the mold by external cooling device after molding, the heat conduction distance between the cooling medium and the mold is shortened. The cooling pipe is arranged at intervals with the first heating element along the axial direction of the outer side of the mold cavity, which can match the temperature field of the first heating element for cooling. Moreover, there is no need to add clamps to fix or flip the mold to cool a specific part. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.
[0022] Figure 1 This is a three-dimensional schematic diagram of a molding die in one embodiment of the present invention;
[0023] Figure 2 This is a schematic diagram of the upper mold structure in one embodiment of the present invention;
[0024] Figure 3 This is a schematic diagram of the lower mold structure in one embodiment of the present invention;
[0025] Figure 4 This is a schematic diagram of the back structure of the lower mold in one embodiment of the present invention. Detailed Implementation
[0026] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be given below with reference to the accompanying drawings.
[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly.
[0028] It should also be understood that the terms "top", "bottom", "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0029] See Figures 1 to 4A thermoplastic polyester cavity molding die includes a lower mold base 100 and an upper mold base 200. The bottom surface of the lower mold base 100 is provided with a receiving cavity 110 facing the top surface of the lower mold base 100. The top surface of the lower mold base 100 is provided with a mold cavity 120. The receiving cavity 110 is recessed in the mold cavity 120. A cavity forming sleeve 130 is provided on the inner side of the mold cavity 120. The outer side of the cavity forming sleeve 130 is sealed and fitted with the inner side of the mold cavity 120. A first electric heating element 140 is provided in the receiving cavity 110. The first electric heating element 140 surrounds the mold cavity 120. The outer side of cavity 120; the upper mold base 200 is provided with a groove 210, and a molding part 220 is provided on the bottom of the groove 210. The molding part 220 protrudes in a direction away from the groove 210. When the mold is closed, the outer side of the molding part 220 presses against the inner side of the socket forming sleeve 130. The bottom of the groove 210 is provided with a second electric heating element 230 around the molding part 220. The axis of the molding part 220, the socket forming sleeve 130 and the mold cavity 120 coincide. The first electric heating element 140 and the second electric heating element 230 are connected to an external control device.
[0030] It should be noted that the lower mold base 100, as the basic support structure of the mold, has a receiving cavity 110 on its bottom surface that provides space for the installation of the first heating element 140, allowing the first heating element 140 to surround the outside of the mold cavity 120 and achieve uniform heating of the mold cavity 120. The shape and size of the mold cavity 120 are set according to the outline of the thermoplastic polyester nest structure. It forms a molding cavity by sealing and fitting with the outside of the nest forming sleeve 130, ensuring the sealing of the cavity and the mold closing accuracy. The nest forming sleeve 130 is a key component in forming the nest structure. Its outer side is sealed and fitted with the inner side of the mold cavity 120. When the mold is closed, its inner side is pressed against the outer side of the molding part 220, forming a double seal (mold cavity 120-forming sleeve-molding part 220), reducing the risk of molten material leakage and ensuring accurate molding. It is understandable that the material of the nest forming sleeve 130 can be selected based on its compatibility with thermoplastic polyester materials, wear resistance, and thermal conductivity. The first heating element 140 and the second heating element 230 are respectively arranged around the outside of the mold cavity 120 and around the bottom of the groove 210 near the molding part 220. The heating temperature is independently controlled by an external control device. In this way, the heating of the thermoplastic polyester material (inside the socket forming sleeve 130) in the mold cavity by the first heating element 140 is achieved by the mold cavity 120 forming an outer layer inside the socket forming sleeve 130, which improves the temperature uniformity in the mold cavity. The second heating element 230 and the first heating element 140 are independently controlled from top to bottom. It can also synergistically heat the material, further improve heating efficiency and temperature gradient control, and construct a temperature field from the mold cavity 120 to the molding section 220. This ensures the overall temperature uniformity of the molding section 220 and avoids the occurrence of local temperature differences, internal stress, or adhesion caused by the complex structure or depth of the cavity during the molding process, which may result in the temperature of the molding cavity not being able to be transferred to the top of the molding section 220 or the top of the molding section 220 being in contact with the outside. This avoids problems such as material burning or incomplete melting that could cause molding defects.
[0031] When the thermoplastic polyester nest structure molding die is working, the thermoplastic polyester material is placed in the cavity. The first heating element 140 and the second heating element 230 are activated by the control device. The first heating element 140 heats the nest forming sleeve 130 from the outside of the mold cavity 120, and the second heating element 230 heats the inside of the nest forming sleeve 130 from the top of the molding part 220. When the preset temperature is reached, the upper mold base 200 moves down and closes with the lower mold base 100. The molding part 220 presses the inside of the nest forming sleeve 130. Under the pressure, the softened thermoplastic polyester material flows and fills the entire cavity, ensuring the complete molding of the nest structure. After the material is fully filled in the cavity and reaches a certain degree of solidification, the heating is stopped. After cooling, the control device controls the upper mold base 200 to move up, open the mold and take out the molded thermoplastic polyester nest structure product.
[0032] During the molding process of the thermoplastic polyester cavity structure, a certain pressure and temperature environment needs to be maintained within the cavity to ensure that the material is fully melted and uniformly filled. This effectively prevents leakage of the thermoplastic polyester material from the joints during heating, melting, and molding, ensuring the smooth progress of the molding process and the integrity of the product. It is understood that the cavity molding sleeve 130 and the mold cavity 120 are press-fitted together, firmly fixing the cavity molding sleeve 130 within the mold cavity 120. During molding, the cavity molding sleeve 130 and the mold cavity 120 are less prone to displacement or loosening, enhancing the overall stability of the mold. Thus, during heating, the heat generated by the first heating element 140 can be more efficiently transferred through the mold cavity 120 to the cavity molding sleeve 130, thereby uniformly heating the thermoplastic polyester material within the cavity. This allows the material to reach the appropriate molding temperature in a shorter time, while also ensuring the uniformity of the material temperature, which is beneficial for improving product quality.
[0033] In some embodiments, the top edge of the housing molding sleeve 130 is provided with an outward flange 131, which is fitted and connected to the top edge of the mold cavity 120. During the molding process, the thermoplastic polyester material becomes more fluid after being heated and melted. The fit of the outward flange 131 blocks the material overflow path, preventing molten material from seeping into the mold gap and causing flash or burrs on the product. The fit of the outward flange 131 increases the contact area between the housing molding sleeve 130 and the mold cavity 120, reduces local stress concentration, and prevents the housing molding sleeve 130 from shifting or deforming due to pressure under high-pressure molding environment, ensuring the dimensional accuracy of the housing structure.
[0034] To facilitate easier demolding and prevent sticking after molding, the surface of the housing molding sleeve 130 is coated with a polytetrafluoroethylene (PTFE) coating. The PTFE coating is non-adhesive, preventing melt residue from easily adhering to the mold surface. In some embodiments, the PTFE coating thickness is 5-8 μm.
[0035] To further improve sealing and spill prevention during the molding process, the cavity molding sleeve 130 is made of rubber. The rubber fits tightly against the edge of the mold cavity 120, forming a dynamic seal that effectively prevents the thermoplastic polyester melt from overflowing during molding, avoiding flash or burrs on the finished product. It should be noted that, in addition, rubber has good plasticity, which ensures that the melt fully fills the molding cavity for irregular cavity shapes, improving the dimensional accuracy and surface quality of the product. Furthermore, its low adhesion makes the molded product easy to peel off, reducing demolding resistance.
[0036] In some embodiments, the housing forming sleeve 130 is provided with several through holes (not shown in the figure). It should be noted that the through holes are provided to discharge air and gases generated by the material being heated in the forming cavity, preventing problems such as high-temperature combustion, charring of molten material, or reduced strength at weld lines caused by gas compression leading to localized high temperatures in the forming cavity. In some embodiments, the diameter of the through holes is controlled between 0.01-0.03 mm.
[0037] In traditional setups, the molding cavity is typically heated directly. The heating elements are usually arranged in a ring or block shape, and the heating positions are linear or point-like, which can easily lead to heating blind spots. For the entire cavity structure, the heat conduction path is long, and especially when the cavity structure is irregular, the local temperature can easily become too low or too high. To address this, the first heating element 140 is arranged spirally around the outside of the mold cavity 120. The spiral arrangement ensures that the first heating element 140 is evenly wound around the outside of the mold cavity 120, forming a surface-like heating effect. A smooth temperature gradient transition is achieved through a continuous heating path. The spiral gaps guide the flow of air or heat transfer medium, creating natural convection circulation and further equalizing the surface temperature of the mold cavity 120. Heating then extends from the mold cavity 120 to the recess forming sleeve 130, ensuring coverage of the entire forming area and avoiding uneven local temperatures. For irregular recess structures or deep recesses, the first heating element can flexibly adjust the coil spacing and winding angle according to the recess structure, or be installed in sections. For example, adjusting the spiral spacing of different heating areas or overlapping coils can achieve localized enhanced heating. The first heating element 140 can also be connected to a PID temperature controller for segmented temperature control along the height direction of the mold cavity 120.
[0038] In some embodiments, the molding die is also provided with cooling pipes (not shown in the figure). The cooling pipes are spirally arranged around the outside of the mold cavity 120 and spaced apart from the first heating element 140 along the axial direction of the outer side of the mold cavity 120. Similar to the heating of the first heating element 140, the cooling pipes can be designed for overall cooling temperature control or zoned control. For irregularly shaped or deep recessed structures, when zoned cooling control is required, the spiral pipes can be divided into zones (such as thick-walled zones, corner zones, and thin-walled zones) to independently control the flow rate and temperature of the cooling medium. Compared with the traditional method of cooling through an external cooling device after molding, the cooling pipes are directly located on the outside of the mold cavity 120, shortening the heat conduction distance between the cooling medium and the mold. This allows for cooling that matches the temperature field of the first heating element 140, and eliminates the need to flip the mold to cool a specific area.
[0039] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A molding die for a thermoplastic polyester recess structure, characterized in that, include: The lower mold base has a receiving cavity on its bottom surface and a mold cavity on its top surface. The mold cavity is recessed into the receiving cavity. A recessed forming sleeve is provided on the inner side of the mold cavity. The outer side of the recessed forming sleeve is sealed and fitted to the inner side of the mold cavity. A first heating element is provided in the receiving cavity and surrounds the outer side of the mold cavity. The upper mold base is provided with a groove, and a molding part is provided on the bottom of the groove. The molding part protrudes in a direction away from the groove. When the mold is closed, the outer side of the molding part presses against the inner side of the socket forming sleeve. A second electric heating element is arranged around the molding part at the bottom of the groove. The first heating element and the second heating element are connected to an external control device.
2. The molding die for the thermoplastic polyester nest structure according to claim 1, characterized in that, The centerlines of the molding part, the cavity forming sleeve, and the mold cavity coincide.
3. The molding die for the thermoplastic polyester nest structure according to claim 2, characterized in that, The top edge of the cavity forming sleeve is provided with an outward flange, which is fitted and connected to the edge of the top surface of the mold cavity.
4. The molding die for the thermoplastic polyester nest structure according to claim 3, characterized in that, The surface of the socket forming sleeve is coated with polytetrafluoroethylene.
5. The molding die for the thermoplastic polyester nest structure according to claim 4, characterized in that, The socket molding sleeve is a rubber molding sleeve.
6. The molding die for the thermoplastic polyester nest structure according to claim 5, characterized in that, The cavity forming sleeve is provided with an exhaust hole.
7. The molding die for the thermoplastic polyester nest structure according to claim 1, characterized in that, The first heating element is spirally arranged around the outer side of the mold cavity.
8. The molding die for the thermoplastic polyester nest structure according to claim 7, characterized in that, The first heating element is connected to a PID temperature controller, which controls the temperature in the height direction of the mold cavity in segments.
9. The molding die for the thermoplastic polyester nest structure according to claim 8, characterized in that, It also includes cooling pipes, which are connected and fixed inside the accommodating cavity, and the cooling pipes and the first heating element are arranged at intervals along the axial direction of the outer side of the mold cavity.