CN1775448A - Laser cutting head - Google Patents

Abstract

The present invention provides a new-type gas-aided laser cutting head. The mounting mode of said laser cutting head lens seat adopts a plug-in type V-shaped groove structure, it can be applicable to lenses with different focal distances, and the axiality of the laser beam and nozzle can be regulated by adopting four-point regulation method, and its cutting nozzle adopts a newly-designed supersonic nozzle.

Description

A kind of laser cutting head

Technical field

The present invention relates to the laser cutting technique field, refer in particular to a kind of laser cutting head, can be used for thin plate and three-dimensional cutting, assist gas can adopt oxygen, nitrogen, carbon dioxide or inert gas.

Background technology

At present traditional laser cutting head adopts series arrangement, lens mount could be taken out after promptly cutting head will being taken apart fully, and the installation of lens mount discharges with the maintenance of lens very inconvenient, has wasted process time, has reduced working (machining) efficiency.The control method that keeps laser beam and nozzle axiality: " 3+1 " structure, promptly there are three to adjust the screw strong point in unified direction, another strong point is at the offside of this direction, and this structure is comparatively complicated, adjusts trouble; Two orthogonal directions are respectively with a handwheel adjustment, and this structure is comparatively heavy.Nozzle in traditional laser cutting head generally adopts convergent type nozzle or simple fold line scaling nozzle, owing to do not pass through aerodynamic optimization, so when adopting gases at high pressure cutting slab, there is shock wave phenomena to exist in the gas of ejection, the radially substep gradient of cutting pressure is little, effectively cutting distance is short, to cutting nozzles to the variable in distance sensitivity between the workpiece, cutting speed is slow, joint-cutting is wide, roughness is high, perpendicularity is low, dross is often arranged at the bottom, thereby has reduced cutting speed, cutting thickness and cut quality.

Summary of the invention

The invention provides a kind of laser cutting head, to overcome traditional defective that laser cutting head was brought at present.A kind of laser cutting head comprises laser cutting head housing, lens mount and lens mount end cap, bottom end cover and axiality adjustment screw, connector.This laser cutting head has improved lens inserted mode, nozzle and laser beam axiality regulative mode, cutting head nozzle, it is characterized in that: have the bottom in laser cutting head housing side and be that the slot of V-arrangement, lens mount bottom shape are the V-arrangement that cooperates with it; Nozzle and laser beam coaxiality adjusting method are four-point structure method, promptly all have one by the screw adjustment laser beam of cutting head axis and the axiality of nozzle bore axle on the position of bottom end cover four side mutually perpendicular directions, and this method is simple and reliable; Cutting nozzles adopts the continuous type superonic flow nozzzle of crossing through aerodynamic optimization, is made up of stable section, contraction section, throat and expansion segment, and stable section is designed to straight line, its length L ₀Be not less than 10 times of throat diameter D _c, stable section diameter D ₀According to formula $\frac{{D_0}^2}{{D_C}^2}=\frac{A_0}{A_c}=\frac{M_c}{M_0}{\left(\frac{1+\frac{k-1}{2}{M}_0^2}{1+\frac{k-1}{2}{M}_c^2}\right)}^{\frac{k+1}{2(k-1)}}$ Value, k is specific thermodynamics coefficient, for example gaseous state N ₂, k=1.4; Gaseous state Ar, k=1.658, the Mach number Mc=1 of throat, nozzle entrance place Mach number $M_0=\frac{P_C}{P_0}{M}_C,$ P _cBeing throat's gas pressure, is 1 atmospheric pressure, P ₀Be nozzle entrance place gas pressure; Linear hot this base curves in Vito that is designed to of contraction section; Throat is for connecting the circular arc of contraction section and expansion segment, throat diameter according to $D_c=1.43\sqrt{\frac{V}{P_0+1}}\left(\mathrm{mm}\right)$ Value, V is the volume flow (m of cutting gas under the status of criterion ³/ h), P ₀Be porch gas pressure (kg/mm ²), reduce throat diameter and can reduce gas consumption, but the too little laser beam of throat diameter also burning out nozzle inner walls easily, throat diameter is value between 1.0～2.5mm, and expansion segment designs according to Fu Ershi (Foelsch) method.

Description of drawings

Fig. 1 laser cutting head outside drawing

Fig. 2 laser cutting head assembling explosive view

Fig. 3 laser cutting head housing outside drawing

Fig. 4 laser cutting head housing outside drawing

Fig. 5 laser cutting head shell air inlet, water cooling pipeline cutaway view

Fig. 6 laser cutting head housing revolved sectional view

Fig. 7 bottom end cover outside drawing

Fig. 8 bottom end cover revolved sectional view

Fig. 9 connector outside drawing

Figure 10 connector cutaway view

Figure 11 nozzle outside drawing

Figure 12 nozzle cutaway view

Figure 13 superonic flow nozzzle ideograph

Figure 14 contraction section curved profile

Figure 15 axial symmetry expansion segment curved profile

1, compress gasket, 2, lens mount, 3, gasket seal, 4, housing screw, 5, the cutting head housing, 6, connecting ring, 7, screw, 8, screw, 9, the lens mount end cap, 10, gasket seal, 11, gasket seal, 12, connector, 13, pad, 14, adjustment screw, 15, attachment screw, 16, cutting nozzles, 17, gasket seal, 18, bottom end cover.

The specific embodiment:

Part compress gasket (1), lens mount (2), gasket seal (3), housing screw (4), cutting head housing (5), connecting ring (6), screw (7), screw (8), lens mount end cap (9), gasket seal (10) are the laser cutting head main part.Housing screw (4) acts on compress gasket (1), lens mount (2) and the gasket seal (3), has guaranteed the air-tightness of assist gas passage; Gasket seal (10) prevents that dust from immersing; The two bottom sides of lens mount (2) is V-shaped, is convenient to go up accurate in locating at part (5), and connecting ring (6) is convenient to be connected with laser generator with screw (7).

Nozzle and laser beam axiality are regulated partly and are made up of adjustment screw (14) and bottom end cover (18), and connector (12) is held on the T stage rank of bottom end cover (18).Cutting nozzles (16) and connector (12) are for being threaded, and gasket seal (11), (17) guarantee air-tightness.

Screw (15) links together the cutting head each several part, and the centre is lined with gasket seal (11).

Part (12) four side screwed holes are installed and are adjusted screw (14), adjust the axiality of laser beam and lens.Accompanying drawing 8 is its rotation profile.

Novel supersonic speed cutting nozzles among Figure 11, top regular hexagon shape is convenient to screw up with a wrench, and inside is continuous type convergent-divergent cross section, is divided into four sections of stable section, contraction section, throat and expansion segments.

Stable section

The function of stable section is to make the gas that enters from gas tank comparatively even, has low turbulence level, and makes the speed of stable section every bit not have cross stream velocity component near paralleling to the axis.Stable section diameter D ₀Depend on throat diameter D _cD in theory ₀Diameter is the bigger the better, but in the reality, owing to reasons such as nozzle arrangements manufacture method and focal length and spot diameter, D ₀Limited often.For the air-flow that guarantees into is stable, the length L of stable section ₀Generally should be not less than 10 times of throat diameter D _c

Contraction section

The function of contraction section is to make air-flow quicken to guarantee that entraining air stream speed reaches velocity of sound, but keep simultaneously flowing evenly with parallel.Can set up A by one dimension stabilizing gas kinetics equation ₀/ A _cEquation:

$\frac{A_0}{A_c}=\frac{M_c}{M_0}{\left(\frac{1+\frac{k-1}{2}{M}_0^2}{1+\frac{k-1}{2}{M}_c^2}\right)}^{\frac{k+1}{2(k-1)}}$

K is specific thermodynamics coefficient (gaseous state N ₂, k=1.4; Gaseous state Ar, k=1.658), Mc=1.

According to A ₀/ A _cCan be in the hope of R _c/ R ₀, set the contraction section length L ₁, will remove to design contraction section with a kind of simple but practical equation in this patent:

$R=\frac{R_c}{\sqrt{1-[1-{\left(\frac{R_c}{R_0}\right)}^2]\frac{{(1-a^2)}^2}{{(1+\frac{a^2}{3})}^3}}}$

R ₀, R _c, R is respectively the section radius at contraction section import, outlet and any X place, α=x/L1.The air-flow that it is the throat porch that such shrinkage curve has an advantage is very uniform.

Throat

Throat's design is important comparatively speaking, because it is that subsonic speed is converted into ultrasonic excessive interface zone.As mentioned above, the variation of the cross-sectional area of close critical interface zone can not be too fast, pacifies the arc that this transitional region of aerodynamics will be designed to a long radius like this.

In the aerodynamics, secondly throat radius is the calculated gas flow equation by the cutting steam decision of corresponding cutting thickness.If air-flow is T at porch absolute temperature ₀=273K considers the ponding of throat, is selecting flow coefficient μ=0.93, and computing formula is as follows:

$D_c=1.43\sqrt{\frac{V}{P_0+1}}\left(\mathrm{mm}\right)$

V is the volume flow (m of cutting gas under the status of criterion ³/ h), P ₀Be porch gas pressure (kg/mm ²).Reduce throat diameter and can reduce gas consumption, but the too little laser beam of throat diameter also burns out nozzle inner walls easily, general throat diameter is between 1.0～2.5mm.

Expansion segment

The function of expansion segment is to expand by gas to quicken to have reached in throat the air-flow of velocity of sound, up to obtaining satisfied Mach number.This section is in the superonic flow nozzzle most important one section.According to throat diameter D _cWith the outlet Mach number Me that will design be Foelsch (Fu Ershi) analysis meter formula according to a simple and practical method.Figure 15 is the ideal curve figure with the design of Foelsch method.The throat interface has comprised a circular arc that radius is R.The expansion curve of diffuser comprises that one is prolonged born circular arc C D and one and isometric straightway DA of arc section and reduced curved profile circular arc AB from the throat section.A equals the radius at nozzle exit interface to the vertical range of x axle.

The embodiment 1 newly-designed cutting head cutting galvanized sheet that superonic flow nozzzle is housed

Designs of nozzles Mach 2 ship 1.5, theoretical supply gas pressure are 4bar, and galvanized sheet thickness is 1mm, cutting gas is a nitrogen, and supply gas pressure is 5bar, and cutting speed is when 4.8m/min, the otch end face is very bright, and zinc coat does not almost destroy in incision, only has the wide remelting of 0.2mm to solidify zinc coat; Joint-cutting lower floor does not have dross; The roughness of otch end face is Ra=2.4812 μ m.

Utilize the thick galvanized sheet of said nozzle cutting 1.2mm, cutting gas still is a nitrogen, and supply gas pressure is 4bar, laser power is 1500w, cutting speed is respectively 2.0m/min, 2.5m/min, 3.0m/min, and nozzle is 1.1mm to the distance of workpiece, and focus is 0.5mm to the distance of workpiece surface.The roughness of the kerf width of upper and lower surface, otch section (measuring distance joint-cutting upper surface 1/2 thickness of slab place during roughness here), measured values such as dross amount, inclination angle size are as shown in the table:

Cutting speed (m/min)	Upper surface seam wide (mm)	Lower surface seam wide (mm)	The inclination angle (°)	Dross	Roughness Ra (μ m)
						2.0	0.19	0.18	0.239	Few	6.0
2.5	0.18	0.17	0.239	Seldom	5.4
						3.0	0.18	0.17	0.239	Almost do not have	3.9

By above result as can be seen, utilize new type of continuous type superonic flow nozzzle to carry out laser cutting, cutting speed is fast, and cut quality is good.When nozzle was big to workpiece surface distance, cut quality was still better simultaneously, and this point is difficult to accomplish concerning the conventional laser cutting nozzles the time.

Embodiment 2 utilizes the high pressure nitrogen cutting stainless steel

Designs of nozzles Mach 2 ship 2, stainless-steel sheet thickness is 2mm, the trade mark is 304 (1Cr18Ni9), laser power is 1400W, distance between nozzle and the workpiece is 0.75mm, and supply gas pressure is 7bar, focus to surface of the work apart from the time 0.8mm, cutting speed is respectively 2.0m/min, 2.5m/min, 3.0m/min, and the cutting test result is as shown in the table:

Cutting speed (m/min)	Upper surface roughness (mm)	Lower surface seam wide (mm)	The inclination angle (°)	Dross	Roughness Ra (μ m)
						2.0	0.20	0.15	0.716	Seldom	3.1
2.5	0.19	0.13	0.859	No	1.7
						3.0	0.18	0.12	0859	Seldom	2.8

The cut quality of above-mentioned each group test is all relatively good.The kerf width of upper and lower surface is very little, and the inclination angle is also very little simultaneously, the perpendicularity height of joint-cutting, and the otch section is smooth, and roughness Ra is very little.

The thick corrosion resistant plate of cutting 5mm, the trade mark is 304 (1Cr18ni9), and laser power is 2000W, and the distance between nozzle and the workpiece is 1.2mm, nitrogen is as cutting gas, supply gas pressure is 8bar, and cutting speed is when 1.8m/min, and the otch section is very bright, roughness is very little, apart from upper surface 1/3 thickness of slab place, roughness is Ra=3.0 μ m, apart from the lower surface 1/3 roughness Ra=4.1 μ m of thickness of slab place.The first half of otch section is more smooth than the latter half.The joint-cutting lower limb does not have dross.According to relevant document record, when utilizing the thick corrosion resistant plate of conventional spout cutting 5mm, the supply gas pressure of nozzle reaches 14bar and could blow away motlten metal and slag inclusion thereof from joint-cutting, new design supersonic speed continuous type superonic flow nozzzle cutting head is housed just cuts and can reduce air consumption so utilize.

When top actual cutting test utilization is equipped with novel supersonic speed continuous type superonic flow nozzzle and is cut, cutting effect is fine, the speed height, fine, the joint-cutting lower limb low as the section roughness of cut quality do not have dross, perpendicularity height, kerf width narrow, can also reduce air consumption simultaneously.Especially for molten state, the corrosion resistant plate that surface tension is very big utilizes newly-designed superonic flow nozzzle effectively to blow away and melts metal and slag inclusion thing thereof, improves cut quality.

Claims (2)

1, a kind of laser cutting head, comprise laser cutting head housing (5), lens mount (2) and lens mount end cap (9), bottom end cover (18) and axiality adjustment screw (14), connector (12), lens inserted mode, nozzle and laser beam axiality regulative mode, cutting head nozzle have been improved, it is characterized in that: have the bottom in laser cutting head housing (5) side and be that the slot of V-arrangement, lens mount (2) bottom shape are the V-arrangement that cooperates with it; Adjustment screw (14) by the cutting head axis is all arranged on the position of bottom end cover (18) four side mutually perpendicular directions, and cutting nozzles (16) is made up of stable section, contraction section, throat and expansion segment, and stable section is designed to straight line, its length L ₀Be not less than 10 times of throat diameter D _c, stable section diameter D ₀According to formula $\frac{{D_0}^2}{{D_C}^2}=\frac{A_0}{A_c}=\frac{M_c}{M_0}{\left(\frac{1+\frac{k-1}{2}{M}_0^2}{1+\frac{k-1}{2}{M}_c^2}\right)}^{\frac{k+1}{2(k-1)}}$ Value, k is specific thermodynamics coefficient, the Mach number Mc=1 of throat, nozzle entrance place Mach number $M_0=\frac{P_C}{P_0}{M}_C,$ P _cBeing throat's gas pressure, is 1 atmospheric pressure, P ₀Be nozzle entrance place gas pressure; Linear hot this base curves in Vito that is designed to of contraction section; Throat is for connecting the circular arc of contraction section and expansion segment, throat diameter according to $D_c=1.43\sqrt{\frac{V}{P_0+1}}\left(\mathrm{mm}\right)$ Value, V is the volume flow (m of cutting gas under the status of criterion ³/ h), P ₀Be porch gas pressure (kg/mm ²); Expansion segment designs according to Fu Ershi (Foelsch) method.

2, a kind of laser cutting head according to claim 1, it is characterized in that: throat diameter is between 1.0～2.5mm.

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