阅读说明：本技术 一种用于对接塑料工件的激光焊接方法 (Laser welding method for butt-joint plastic workpiece ) 是由 林资凯 其他发明人请求不公开姓名 于 2019-10-25 设计创作，主要内容包括：本发明属于激光焊接技术领域,公开了一种用于对接塑料工件的激光焊接方法,将两束相互交叉成一定角度的激光光束同时透过第一塑料工件和第二塑料工件透射到所述第一塑料工件和所述第二塑料工件相互对接形成接触焊接面,并将所述激光光束沿所述接触焊接面上来回移动,同时,在压力的作用下,所述第二塑料工件与所述第一塑料工件粘结为一体；该技术方案中采用两束激光同时对接触焊接面的两侧进行激光照射,在激光焊接面的发生热反应,在压力作用下,使得两塑料工件粘结在一起,该工艺具有熔接速度快、熔接痕小的有益效果,同时,防止了上下塑料工件的变形。(The invention belongs to the technical field of laser welding, and discloses a laser welding method for butting plastic workpieces, wherein two laser beams which are mutually crossed to form a certain angle are transmitted to the first plastic workpiece and the second plastic workpiece through the first plastic workpiece and the second plastic workpiece to be butted mutually to form a contact welding surface, the laser beams move back and forth along the contact welding surface, and simultaneously, the second plastic workpiece and the first plastic workpiece are bonded into a whole under the action of pressure; according to the technical scheme, two beams of laser are adopted to simultaneously carry out laser irradiation on two sides of a contact welding surface, thermal reaction is generated on the laser welding surface, and under the action of pressure, two plastic workpieces are bonded together.)

1. A laser welding method for butt-jointed plastic workpieces is characterized in that two laser beams which are mutually crossed to form a certain angle simultaneously penetrate through a first plastic workpiece and a second plastic workpiece to be transmitted to the first plastic workpiece and the second plastic workpiece to be mutually butt-jointed to form a contact welding surface, the laser beams move back and forth along the contact welding surface, and meanwhile, the second plastic workpiece and the first plastic workpiece are bonded into a whole under the action of pressure.

2. The laser welding method for butted plastic workpieces as recited in claim 1, wherein an included angle between said laser beams is 25 to 70 degrees.

3. The laser welding method for butted plastic workpieces as recited in claim 1, wherein said first plastic workpiece and said second plastic workpiece are coated with a layer of a photosensitizer on butting faces of said first plastic workpiece and said second plastic workpiece, respectively, before butting to form a contact welding face.

Technical Field

The invention relates to the technical field of laser welding, in particular to a laser welding method for butting plastic workpieces.

Background

The connection method of plastics and composite materials thereof generally has three methods: mechanical attachment, adhesive bonding and welding. Mechanical connections include rivet or compression joint connections using separate fasteners such as metal or plastic screws. (2) Adhesive bonding is the application of an adhesive between the parts to be joined to join the parts. (3) The welding is to melt or soften the polymer at the interface by heating, so that the polymer molecular chains are diffused through the interface to form chain entanglement under the action of certain pressure and time, and finally the strength of the welding point is obtained. The welding methods are divided into two main categories according to the heating mode adopted: external heating and internal heating. External heating methods heat the weld surface by convection or conduction, including hot tool welding, hot gas welding, extrusion welding, implant induction welding, and implant resistance welding. The internal heating method is a method of directly generating a heat source inside a material by a technique, thereby replacing external heating. It is divided into two categories: mechanical heating and electromagnetic heating. Mechanical internal heating is the conversion of mechanical energy into heat by surface friction or intermolecular friction, including ultrasonic, vibration and spin welding. Electromagnetic internal heating methods rely on the absorption of electromagnetic radiation for conversion to heat, including infrared, laser, radio frequency and microwave welding.

The traditional thermoplastic plastic connecting method has many defects, the mechanical connecting strength of adopting screws, snap rings and the like is not easy to meet the requirement and can not have the requirement on the quality of the connecting surface; the adhesive bonding method needs the procedures of surface roughening, gluing, bonding, curing, ironing by an electric iron, finishing and the like, all the procedures are manually operated, the labor intensity is high, the procedures are multiple, the production efficiency is low, the quality is difficult to ensure, and the volatile components of the adhesive pollute the environment and influence the body health of operators; the plastic part is easy to be bonded with a heating source by adopting external heating welding, and air pollution can be caused; the strength of a welding joint is influenced when an implant for implant welding is left on a welding surface; mechanical internal heating can leave the final product with residual vibrational and thermal stresses that accelerate the aging of the product.

Laser transmission welding is a novel plastic welding process developed in recent years, and the principle is that an infrared laser beam (the wavelength is generally 800-. The two parts to be welded must have one transparent to the laser beam, i.e. the laser beam penetrates it without loss of energy, and the other opaque, i.e. absorbs the energy of the laser radiation; in order to increase the ability of the material to absorb radiant energy, the contact surfaces of the two parts to be welded are provided with a laser-absorbing additive coating. The radiation penetrates through a transparent weld part of the two parts to be welded, and the other opaque part absorbs the laser radiation on the contact surface to form a heat-affected zone, and the plastic in the heat-affected zone is melted; during the subsequent solidification process, the melted material forms a joint and the parts to be welded are joined. However, the current laser transmission welding technology only can play a role in connection, and cannot change the properties of the welded thermoplastic plastic material, such as electrical conductivity, thermal conductivity and the like; due to the characteristics of low melting point and easy burning of plastics, the range of laser welding process parameters is difficult to optimize; and neither of the two welded workpieces can be substantially separated.

Disclosure of Invention

The invention provides a laser welding method for butting plastic workpieces, aiming at the defects of the prior art; the laser transmission welding method of the thermoplastic plastics can realize accurate welding path and welding strength control, increase the overall strength and rigidity of a welding part and prevent burning defects.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a laser welding method for butt-jointed plastic workpieces is characterized in that two laser beams which are mutually crossed to form a certain angle are transmitted to a first plastic workpiece and a second plastic workpiece through the first plastic workpiece and the second plastic workpiece to be mutually butt-jointed to form a contact welding surface, the laser beams move back and forth along the contact welding surface, and meanwhile, the second plastic workpiece and the first plastic workpiece are bonded into a whole under the action of pressure.

Furthermore, the included angle between the laser beams is 25-70 degrees.

Further, before the first plastic workpiece and the second plastic workpiece are butted to form a contact welding surface, a layer of photosensitizer is coated on the butting surface of the first plastic workpiece and the second plastic workpiece respectively.

The invention provides a laser welding method for butting plastic workpieces, which is characterized in that two laser beams which are mutually crossed to form a certain angle are transmitted to a first plastic workpiece and a second plastic workpiece through the first plastic workpiece and the second plastic workpiece to be mutually butted to form a contact welding surface, the laser beams move back and forth along the contact welding surface, and simultaneously, the second plastic workpiece and the first plastic workpiece are bonded into a whole under the action of pressure; according to the technical scheme, two beams of laser are adopted to simultaneously carry out laser irradiation on two sides of a contact welding surface, thermal reaction is generated on the laser welding surface, and under the action of pressure, two plastic workpieces are bonded together.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A laser welding method for butt-jointed plastic workpieces, a first plastic workpiece and a second plastic workpiece are welded together, and the method comprises the following specific operation steps:

s11, uniformly coating a layer of photosensitizer on the welding surface of the first plastic workpiece and the second plastic workpiece, wherein the photosensitizer can help the first plastic workpiece and the second plastic workpiece to absorb laser and convert the light energy of the laser into heat energy, so that the utilization rate of the light energy is improved;

s12, after the photosensitizer is uniformly coated, butting the welding surfaces of the first plastic workpiece and the second plastic workpiece, fixing the butting surfaces on a welding station to form a contact welding surface, and setting pressure between the first plastic workpiece and the second plastic workpiece, wherein the pressure value is 60 MPa;

s13, starting a laser emitter, and adjusting the included angle between laser beams and the included angle between the laser beams and the contact welding surface, specifically, the included angle between the two laser beams is 60 degrees, and the included angle between the laser beams and the contact welding surface is 30 degrees; and then the laser beam moves along the contact welding surface, so that the contact surfaces of the first plastic workpiece and the second plastic workpiece are uniformly melted at the same time and are bonded into a whole under the action of pressure.

In the embodiment, two beams of laser are adopted to weld the contact welding surfaces formed by the first plastic workpiece and the second plastic workpiece simultaneously, so that the contact surfaces of the two plastic workpieces are melted simultaneously, the melting of the welding surfaces can be accelerated, the welding speed is accelerated, the plastic degradation is prevented, and meanwhile, the process provided by the embodiment can seal the welding of products; more importantly, the process provided by the embodiment can realize the connection of not only the same material but also different materials.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.