High-density sponge forming process based on layered temperature control

Abstract

The invention discloses a high-density sponge forming process based on layered temperature control, which specifically comprises the following steps: S1, curing and forming: carrying out heating curing and forming on a foamed material in a curing area, and keeping the environment temperature of the curing area at 48-53 DEG C all the time; s2, cooling and forming: conveying the cured and formed sponge into a cooling area in a breakpoint manner, wherein the conveying direction of the cured and formed sponge from the curing area to the cooling area is from left to right; wherein the sponge subjected to curing forming is divided into m layering areas from left to right, the width of each layering area is h, the breakpoint type conveying distance of the sponge subjected to curing forming each time is h, the cooling area adopts a graded cooling mode, n independent temperature areas with the temperature gradually decreased are sequentially arranged from left to right, and n is larger than or equal to m. The problems of uneven density, concentrated thermal stress and the like easily occurring in the cooling process of the high-density sponge are solved, and the product percent of pass and the structural stability are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sponge production, and more specifically, the present invention relates to a high-density sponge forming process based on hierarchical temperature control. Background Art

[0002] Due to its excellent cushioning, resilience and durability, high-density sponge is widely used in furniture, automotive interiors, medical equipment and other fields. However, there are significant technical bottlenecks in the curing and cooling processes of traditional high-density sponge forming processes, resulting in problems such as uneven product density distribution and poor structural stability, which are specifically manifested in the following aspects:

[0003] 1. Insufficient temperature control accuracy:

[0004] Existing processes mostly adopt a single temperature zone curing or uniform cooling mode, making it difficult to achieve precise control of temperature gradients. Temperature fluctuations during the curing stage are likely to cause insufficient cross-linking reactions, while insufficient temperature differences during the cooling stage result in uneven distribution of internal thermal stress in the sponge, ultimately forming density deviations (the deviation rate of traditional processes is as high as ±8%).

[0005] 2. Conflict between cooling efficiency and uniformity:

[0006] Conventional cooling processes usually rely on continuous conveying or uniform temperature zone design. Although they can improve production efficiency, they cannot adapt to the cooling requirements of different layers of the sponge. The upper layer cools too quickly while the lower layer retains residual heat, easily causing local shrinkage or expansion and affecting the dimensional accuracy of the product.

[0007] 3. Lack of dynamic adjustment mechanism:

[0008] Existing technologies lack the ability to monitor and feedback real-time data during the production process. For example, key parameters such as density distribution entropy value and abnormal temperature gradient cannot dynamically adjust process parameters, resulting in a low process fault tolerance rate and difficulty in coping with complex working conditions.

[0009] 4. Limited level of equipment intelligence:

[0010] Traditional production lines mostly adopt fixed sensors and static control strategies, unable to automatically optimize parameters such as the number of hierarchical zones and fan speeds. Frequent manual intervention increases production costs and the risk of quality fluctuations.

[0011] In view of the above problems, the industry urgently needs a high-density sponge forming process that can achieve hierarchical temperature control, dynamic correction and intelligent monitoring. Summary of the Invention

[0012] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a high-density sponge forming process based on hierarchical temperature control.

[0013] To achieve the above object, the innovation points of the present invention are as follows: Specifically, it includes the following steps:

[0014] S1. Solidification and molding: Heat and solidify the foamed material in the solidification area, and the ambient temperature of the solidification area is always maintained at 48°C - 53°C;

[0015] S2. Cooling and molding: Convey the solidified and molded sponge into the cooling area in a breakpoint manner. The conveying direction of the solidified and molded sponge from the solidification area to the cooling area is from left to right;

[0016] Among them, the solidified and molded sponge is divided into m stratified areas from left to right. The width of each stratified area is h, and the distance of each breakpoint conveyance of the solidified and molded sponge is h. The cooling area adopts a hierarchical cooling mode, and n independent temperature zones with gradually decreasing temperatures are arranged from left to right, n ≥ m; The cooling time of the stratified area in the independent temperature zone is set as t1, t2, t3....t n , and the interval time of the breakpoint conveyance of the solidified and molded sponge is p1, p2, p3.....p m .

[0017] Further, the cooling time sequence satisfies an exponential decay relationship: t k = t1 × e -0.12(k-1) , where, t k represents the value at the kth moment, t1 is the initial value (the value when k = 1) which is 8 - 10 min, e ≈ 2.71828 is the natural constant, k is the number of terms (k = 1, 2,..., n, n ≤ 6), and -0.12 is the decay coefficient.

[0018] Further, the above-mentioned conveyance interval time sequence is a linearly increasing relationship: p j = p1 + 0.6(j - 1), where, j is the number of breakpoint conveyances required for the solidified and molded sponge to be completely conveyed into the cooling area, j = 1, 2,..., m, p1 is the interval time of the first breakpoint conveyance of the solidified and molded sponge, and p1 = 3 - 5 min.

[0019] Further, the correction formula for dynamically adjusting the interval time of the breakpoint conveyance on the premise of maintaining a linearly increasing trend: P′ j = P j × [1 + 0.05 × (T 实测 - T 设定 )], where, p j is the original value of the conveyance interval time, T 实测 is the actually measured temperature value of the corresponding independent temperature zone, and T 设定 is the theoretically set temperature value of the corresponding independent temperature zone.

[0020] Further, h = 12 cm.

[0021] Further, a 16×16 infrared temperature measurement matrix is set at the outlet of the curing area, with a spatial resolution of 2 cm×2 cm. The number of layers m in the layering area is dynamically adjusted according to the density distribution entropy value H. When H > 2.8, m increases to the maximum value of 6.

[0022] Further, each independent temperature zone is equipped with a dual-channel temperature / wind speed sensor. The temperature gradient ΔT from top to bottom in the independent temperature zone is 5 - 8 °C, where ΔT is the temperature difference between adjacent independent temperature zones.

[0023] Further, when it is detected that the adjacent temperature gradient ΔT is greater than 8 °C or ΔT is less than 5 °C for a single time, the cross-layer balanced cooling mode is triggered, and the rotational speeds of the left and right two-layer fans are synchronously adjusted to: V′ 上 = 1.2V 上 V′ 下 = 1.2V 下 .

[0024] Further, when it is continuously detected that ΔT exceeds the set value of 8 °C three times in a row, the fan reverse purge program is automatically executed, and the purge time τ = 2.5×m (min), and the wind speed is 150% of the normal value.

[0025] The technical effects and advantages of the present invention: Through the layer-by-layer temperature control and dynamic correction mechanism, the present invention solves the problems such as uneven density and thermal stress concentration that are prone to occur during the cooling process of high-density sponges, significantly improves the product qualification rate and structural stability. Experimental data shows that after adopting this process, the density deviation rate of the sponge is reduced from ±8% of the traditional process to within ±2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the process flow chart of the present invention.

[0027] Figure 2 is the layout schematic diagram of the infrared temperature measurement matrix of the present invention.

[0028] Figure 3 is the relationship diagram between the correction amount and the temperature deviation of the present invention.

[0029] Figure 4 is the comparison diagram of the transmission interval time before and after correction of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figures 1 to 4 A specific implementation manner of the present invention specifically includes the following steps:

[0032] S1. Curing and forming:

[0033] Place the foamed material in the curing area, and the ambient temperature is kept constant within the range of 48°C - 53°C. During the curing process, the material is uniformly heated through heat conduction to form a preliminary cross-linked structure.

[0034] Among them, the temperature fluctuation needs to be controlled within ±0.5°C to ensure sufficient curing reaction and uniform density.

[0035] S2. Cooling and forming:

[0036] Breakpoint transfer: The cured sponge is transferred to the cooling area in a breakpoint manner in the vertical direction (from top to bottom). The transfer distance each time is the stratification width h (12 cm), and the transfer interval time is dynamically adjusted according to the linear increasing relationship.

[0037] Stratified cooling control: The cooling area is divided into n independent temperature zones (n ≥ m, m is the number of stratification zones). The temperature decreases from left to right, and the temperature difference between adjacent temperature zones ΔT = 5 - 8°C.

[0038] The cooling time of each stratification zone is allocated according to the exponential decay formula:

[0039] t k = t1 × e -0.12(k-1) , where t k represents the value at the k-th moment, t1 is the initial value (the value when k = 1) which is 8 - 10 min, e ≈ 2.71828 is the natural constant, k is the number of terms (k = 1, 2,..., n, n ≤ 6), and -0.12 is the decay coefficient

[0040] The interval time p of the breakpoint transfer j satisfies the linear increasing relationship:

[0041] p j = p1 + 0.6(j - 1)

[0042] where j is the number of breakpoint transfers required for the cured and formed sponge to be completely transferred into the cooling area, j = 1, 2,..., m, p1 is the interval time of the first breakpoint transfer of the cured and formed sponge, and p1 = 3 - 5 min.

[0043] Dynamic correction: According to the real-time temperature monitoring data, through the formula

[0044] P′ j =P j ×[1 + 0.05×(T 实测 -T 设定 )]

[0045] where p j is the original value of the transfer interval time, T 实测 is the temperature value actually measured in the corresponding independent temperature zone, and T 设定 is the theoretically set temperature value in the corresponding independent temperature zone.

[0046] Key parameters and control logic

[0047] Dynamic adjustment of the layering zone: A 16×16 infrared temperature measurement matrix (resolution 2cm×2cm) is set at the outlet of the curing zone to calculate the density distribution entropy value H in real time. Among them, when H > 2.8, the number m of layering zones increases to the maximum value of 6 to ensure uniform cooling.

[0048] Temperature gradient anomaly handling

[0049] Single overlimit: If the temperature difference ΔT between adjacent temperature zones is > 8°C or < 5°C for a single time, trigger the cross-layer balanced cooling mode and synchronously adjust the fan speeds of the upper and lower layers to:

[0050] V′ 上 =1.2V 上

[0051] V′ 下 =1.2V 下

[0052] Continuous overlimit: If ΔT > 8°C for three consecutive times, start the fan reverse purge program, the purge time τ = 2.5×m (min), and the wind speed is increased to 150% of the normal value to eliminate local heat accumulation.

[0053] Example 1

[0054] Process parameters under standard conditions

[0055] The layering height h = 12 cm, the number m of layering zones = 4, and the number n of independent temperature zones = 6.

[0056] Cooling time series: t1 = 10 min, t2 = 8.8 min, t3 = 7.7 min,..., t6 ≈ 4.2 min.

[0057] Transfer interval time: p1 = 4 min, p2 = 5.3 min, p3 = 6.6 min, p4 = 7.9 min.

[0058] When the infrared temperature measurement matrix detects that H = 2.5, maintain m = 4; if H rises to 3.0, then m is automatically adjusted to 6.

[0059] Example 2

[0060] Abnormal condition handling

[0061] When it is detected that the ΔT of a certain adjacent temperature zone is 9 °C (single - time over - limit), immediately adjust the fan speed to the balanced mode. After 10 minutes, ΔT returns to 6 °C.

[0062] If ΔT = 9 °C at the same position for three consecutive times, trigger the reverse purging program. The purging time τ = 15 minutes (m = 6), and the wind speed is 150% of the normal value, effectively eliminating the hot zone.

[0063] Finally, the following points should be noted: First, in the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be understood in a broad sense. It can be a mechanical connection or an electrical connection, or the communication inside two components. It can be directly connected. "Up", "down", "left", "right", etc. are only used to represent the relative position relationship. When the absolute position of the described object changes, the relative position relationship may change;

[0064] Second: In the attached drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. Other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0065] Finally: The above - mentioned are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-density sponge forming process based on hierarchical temperature control, characterized in that: Specifically, it includes the following steps: S1. Curing and forming: Heating and curing the foamed material in the curing area, and the ambient temperature of the curing area is always maintained at 48°C - 53°C; S2. Cooling and forming: Conveying the cured and formed sponge into the cooling area in a breakpoint manner, and the conveying direction of the cured and formed sponge from the curing area to the cooling area is from left to right; The solidified sponge is divided into m layered areas from left to right, the width of each layered area is h, the distance of each breakpoint transmission of the solidified sponge is h, the cooling area adopts a graded cooling mode, and n independent temperature zones with gradually decreasing temperatures are set from left to right, n ≥ m; the cooling time of the layered area in the independent temperature zone is set to t1, t2, t3...t n The interval time of the solidified sponge breakpoint transmission is p1, p2, p3.....p m .

2. The forming process of a high-density sponge according to claim 1, characterized in that: The cooling time series satisfies an exponential decay relationship: t k = t1 × e -0.12(k-1) , where t k represents the value at the k-th moment, t1 is the initial value (the value when k = 1) which is 8 - 10 min, e ≈ 2.71828 is the natural constant, k is the number of terms (k = 1, 2, …, n, n ≤ 6), and -0.12 is the decay coefficient.

3. A high-density sponge forming process based on hierarchical temperature control according to claim 1, characterized in that: The transfer interval time series is a linearly increasing relationship: p j = p1 + 0.6(j - 1), where j is the number of breakpoint transfers required for the cured sponge to be completely transferred into the cooling zone, j = 1, 2, …, m, p1 is the interval time of the first breakpoint transfer of the cured sponge, and p1 = 3 - 5 min.

4. A high-density sponge forming process based on hierarchical temperature control according to claim 3, characterized in that : The correction formula for dynamically adjusting the interval time of breakpoint transmission while maintaining a linearly increasing trend: P j ′ = P j × [1 + 0.05×(T 实测 - T 设定 )], where p j is the original value of the transmission interval time, T 实测 is the temperature value actually measured in the corresponding independent temperature zone, and T 设定 is the theoretically set temperature value of the corresponding independent temperature zone.

5. A high-density sponge forming process based on hierarchical temperature control according to claim 1, characterized in that: h = 12 cm.

6. A high-density sponge forming process based on hierarchical temperature control according to claim 1, characterized in that: An infrared temperature measurement matrix of 16×16 is arranged at the outlet of the curing area, with a spatial resolution of 2cm×2cm. The number m of the layering areas is dynamically adjusted according to the density distribution entropy value H. When H > 2.8, m increases to the maximum value of 6.

7. A high-density sponge forming process based on hierarchical temperature control according to claim 1, characterized in that: Each of the independent temperature zones is equipped with a dual-channel temperature / wind speed sensor, and the temperature gradient ΔT from top to bottom of the independent temperature zone is 5 - 8°C, where ΔT is the temperature difference between adjacent independent temperature zones.

8. A high-density sponge forming process based on hierarchical temperature control according to claim 7, characterized in that: When it is detected that the single adjacent temperature gradient ΔT is greater than 8°C or ΔT is less than 5°C, the cross-layer balanced cooling mode is triggered, and the rotational speeds of the left and right two-layer fans are synchronously adjusted to: V 上 ′upper = 1.2V 上 , V 下 ′lower = 1.2V 下 .

9. A high-density sponge forming process based on hierarchical temperature control according to claim 7, characterized in that: When it is continuously detected that ΔT exceeds the set value of 8°C three times in a row, the fan reverse purge program is automatically executed, and the purge time τ = 2.5×m (min), and the wind speed is 150% of the normal value.

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