A multivariable decoupling pressure control method for flexible circuit board welding

Abstract

The present invention relates to the field of pressure control technology, and in particular to a multivariable decoupled pressure control method for flexible circuit board welding. First, the temperature and pressure are set, and the pressure setting is corrected according to the temperature-pressure model. The regulator adjusts the pressure of the pressure actuator on the welding object according to the corrected pressure. The pressure detection sensor detects the pressure on the welding object and feeds back to the regulator of the sliding mode variable structure control to achieve pressure control based on two variables: welding temperature and mechanical deformation. The present invention adjusts the pressure in real time according to the shape of the solder during the temperature change process. This is a typical dual-input single-output multivariable system. The algorithm semi-quantitatively fits the relationship between temperature and deformation, that is, pressure demand, according to the characteristics of the solder to achieve decoupling control of temperature and pressure. Because different solder shapes have different responsiveness requirements for the system, the regulator introduces a parameter adaptor to set different adjustment parameters according to different temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure control, and in particular to a multivariable decoupling pressure control method for flexible board welding. Background Art

[0002] Circuit boards, also known as printed circuit boards, are essential components in electronics, as they hold numerous electrical components together and provide electrical connections. Flexible printed circuit boards (FPCs), a type of circuit board, are made from polyimide or polyester film and offer high reliability and excellent flexibility. They are primarily used in a wide range of products, including mobile phones, laptops, PDAs, digital cameras, and LCMs.

[0003] The production of flexible printed circuit boards requires soldering, and controlling the pressure during soldering is crucial. In practice, changes in soldering temperature and solder morphology cause pressure fluctuations. Existing pressure control techniques cannot adapt to these changes, leading to excessive or insufficient pressure during soldering, impacting soldering quality. To address this issue, we propose a multivariable decoupled pressure control method for flexible printed circuit board soldering. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a multivariable decoupling pressure control method for flexible circuit board welding, which has the characteristic of adjusting the pressure in real time according to the shape of the solder during the temperature change process, and solves the problem that in flexible circuit board welding, the change of temperature during welding and the change of solder shape will affect the pressure, resulting in poor welding quality.

[0005] The present invention provides the following technical solution: a multivariable decoupling pressure control method for flexible circuit board welding, comprising the following steps: first, temperature and pressure settings are performed, the pressure setting is corrected according to a temperature-pressure model, a regulator adjusts the pressure applied to the welding object by a pressure actuator according to the corrected pressure, a pressure detection sensor detects the pressure applied to the welding object and feeds back to the regulator of the sliding mode variable structure control to form a closed-loop feedback, thereby realizing pressure control based on the two variables of welding temperature and mechanical deformation.

[0006] Preferably, a parameter adaptor is introduced according to the responsiveness requirements of the system for different solder forms. The parameter adaptor sets different adjustment parameters according to different temperatures. The regulator adjusts the pressure of the pressure actuator on the welding object according to the temperature-pressure model and the adjustment parameters.

[0007] Preferably, the pressure actuator controls the displacement of the pressure device and the pressure applied by the pressure device to the welding object.

[0008] Preferably, the parameter adaptor sets different pressure adjustment parameters according to the changes in the five states of the solder, namely, solid, solid-liquid mixed state, liquid, solid-liquid mixed state, and solid state.

[0009] Preferably, the welding temperature change during the flexible board welding process is determined according to the temperature change of laser heating.

[0010] The present invention provides a multivariable decoupled pressure control method for flexible circuit board welding. Pressure changes are influenced by two variables: welding temperature and mechanical deformation. At low temperatures, the solder is solid, resulting in significant deformation of the welded object. At high temperatures, the solder melts, minimizing deformation. As the temperature increases, the solder gradually melts, assuming a mixed state of solid and liquid. To achieve optimal welding results, the present invention adjusts the pressure in real time based on the solder's morphology during temperature changes. This is a typical dual-input, single-output multivariable system. The algorithm semi-quantitatively fits the relationship between temperature and deformation, and thus pressure requirements, based on the solder's characteristics to achieve decoupled control of temperature and pressure. Because different solder morphologies require different system responsiveness, a parameter adaptor is incorporated into the regulator to set different adjustment parameters based on different temperatures. This method addresses the issue of poor welding quality during flexible circuit board welding, where changes in temperature and solder morphology can affect pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the control principle diagram of the present invention. DETAILED DESCRIPTION

[0012] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0013] See also Figure 1 The present invention provides a technical solution: a multivariable decoupling pressure control method for flexible board welding, comprising the following steps:

[0014] First, the temperature and pressure settings are set. The pressure setting is corrected according to the temperature-pressure model. The change in welding temperature during flexible board welding is determined by the temperature change during laser heating. The regulator adjusts the pressure applied to the welding object by the pressure actuator based on the corrected pressure. The pressure actuator controls the displacement of the pressure device and the pressure applied to the welding object.

[0015] To meet the system's responsiveness requirements for different solder states, a parameter adaptor was introduced. This adaptor sets different adjustment parameters based on different temperatures. The regulator adjusts the pressure applied by the pressure actuator to the soldering object based on the temperature-pressure model and the adjustment parameters. The adaptor sets different pressure adjustment parameters based on the solder's transitions through five states: solid, solid-liquid mixed, liquid, solid-liquid mixed, and solid.

[0016] The pressure detection sensor detects the pressure on the welding object and feeds it back to the regulator of the sliding mode variable structure control to form a closed-loop feedback, realizing pressure control based on two variables: welding temperature and mechanical deformation.

[0017] Sliding mode variable structure control is essentially a special type of nonlinear control, whose nonlinearity manifests as control discontinuity. This control strategy differs from other control strategies in that the system's "structure" is not fixed, but can be purposefully and continuously changed during the dynamic process based on the system's current state (such as the deviation and its derivatives of various orders), forcing the system to move along a predetermined "sliding mode" state trajectory. Because the sliding mode can be designed and is independent of the object parameters and disturbances, variable structure control has the advantages of fast response, insensitivity to parameter changes and disturbances, no need for online system identification, and simple physical implementation. After adopting sliding mode variable structure control, this solution can quickly and in real time adjust the pressure according to the shape of the solder during temperature changes.

[0018] In this invention, pressure is adjusted in real time based on the solder's morphology during temperature changes. This is a typical dual-input, single-output, multivariable system. The algorithm semi-quantitatively fits the relationship between temperature and deformation, and thus pressure requirements, based on the solder's characteristics to achieve decoupled temperature and pressure control. Because different solder morphologies require different system responsiveness, the regulator incorporates a parameter adaptor to set different adjustment parameters based on different temperatures. This solves the problem in flexible circuit board soldering, where changes in temperature and solder morphology affect pressure, leading to poor soldering quality.

[0019] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A multivariable decoupling pressure control method for flexible circuit board welding, characterized by: The method includes the following steps: first, setting the temperature and pressure, correcting the pressure setting according to the temperature-pressure model, a regulator adjusting the pressure applied by the pressure actuator to the welding object based on the corrected pressure, a pressure detection sensor detecting the pressure applied to the welding object and feeding it back to the regulator of the sliding mode variable structure control, forming a closed-loop feedback loop to achieve pressure control based on the two variables of welding temperature and mechanical deformation; According to the responsiveness requirements of different solder forms to the system, a parameter adaptor is introduced. The parameter adaptor sets different adjustment parameters according to different temperatures. The regulator adjusts the pressure applied by the pressure actuator to the welding object according to the temperature-pressure model and the adjustment parameters. The parameter adaptor sets different pressure adjustment parameters according to the changes in the five states of the solder, namely, solid, solid-liquid mixed state, liquid, solid-liquid mixed state, and solid state.

2. The multivariable decoupling pressure control method for flexible circuit board welding according to claim 1, characterized in that: The pressure actuator controls the displacement of the pressure device and the pressure applied by the pressure device to the welding object.

3. The multivariable decoupling pressure control method for flexible circuit board welding according to claim 1, characterized in that: The welding temperature change during the flexible board welding process is determined by the temperature change of laser heating.

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