Method and system for optimizing process parameters for pore inhibition in high-power laser shaping welding

A welding method for pore inhibition in high-power laser shaping welding based on optimized process parameters, comprising:

• calculating, by a processor, a relationship between an adjustable annular laser beam diameter and a first process parameter comprising point-ring laser power ratio, and calculating, by the processor, a relationship between center point linear energy and a second process parameter comprising laser power and welding speed;
• wherein the adjustable annular laser beam is emitted by a programmable spot fiber laser;
• retrieving, by the processor, a reference ISO 11146-1:2021(en) standard for the relationship between the adjustable annular laser beam diameter and the process parameters, for any spot laser beam, and defining D4σ as a beam diameter, wherein a calculation method is to solve a second-order moment of an intensity distribution function by using laser beam intensity information, and detailed calculation steps are as follows:
• obtaining a light intensity distribution E (x, y) of an entire adjustable annular beam by adding a center Gaussian beam of intensity Ec(x, y) and an outer ring annular beam of intensity Er(x, y):
• E
• ⁡
• (
• x
• ,
• y
• )
• =
• E
• c
• (
• x
• ,
• y
• )
• +
• E
• r
• (
• x
• ,
• y
• )
• center coordinates (xc, yc) of the beam may be calculated as follows:
• σ
• x
• 2
• ⁢
• and
• ⁢
• σ
• y
• 2
• represent normalized weighted integrals of a power density distribution, and a calculation formula is as follows:
• for a Gaussian beam with (0,0) as a center and a radius w, a formula is as follows:
• a beam radius used by ISO 11146-1:2021(en) is defined as:
• w
• =
• 2
• ⁢
• σ
• x
• the beam diameter D4a is two times the above beam radius, and an expression is as follows:
• D
• ⁢
• 4
• ⁢
• σ
• =
• 2
• ⁢
• w
• ;
• wherein an expression for the center point linear energy q is:
• where Pc is laser power of a center point light source, and v is the welding speed;
• determining, by the processor, optimization constraint conditions for the adjustable annular laser beam diameter and the center point linear energy;
• and obtaining, by the processor, preset ranges of the process parameters;
• wherein an optimization constraint condition for the beam diameter D4σ is:
• where h is preset target penetration, Mcol represents a collimation coefficient, and Mfocus represents a focus imaging ratio;
• an optimization constraint condition for the center point linear energy is:
• where qmax and qmin are maximum and minimum center point linear energy under an empirical condition;
• and
• inputting, by the processor, process parameter values within the preset ranges into the optimization constraint conditions for the adjustable annular laser beam diameter and the center point linear energy, and then combining, by the processor, the process parameters that simultaneously satisfy the optimization constraint conditions for the adjustable annular laser beam diameter and the center point linear energy as optimized process parameters;
• and
• controlling, by a laser controller, laser energy distribution and the process parameters based on the optimized process parameters, and performing welding on a workpiece via the programmable spot fiber laser.