The result of the appearance of laser pointer is good enough

 The result of the appearance of laser pointer is good enough.
In theory, usually to change the acceleration section of the cutting conditions: such as focal length, nozzle position, gas pressure, but in fact because of the time is too short to change the above conditions is unlikely. Used mainly in industrial production in the average laser power to change the way more realistic, there are three specific ways: changing the pulse width; change the pulse frequency; while changing the pulse width and frequency. Actual results show that (3) kinds of the best. Laser cutting of steel, oxygen, and a focused laser beam shines through a nozzle at the material to be cut to form a gas beam. The basic requirements of the air entering the gas flow to a large incision, the speed must be high, so that the oxidation of the cut material sufficient to fully carry out an exothermic reaction; It also has enough momentum to blow the molten material jet. The director will be directly in charge of the new production line of laser pointer .
The laser pointer company is calculating the profit of laser pointer . In addition to the beam quality and therefore directly affect the cutting quality control, nozzle design and flow control (such as the nozzle pressure, the position of the workpiece in the air, etc.) is also very important factors. Use of laser cutting nozzles a simple structure, that is a tapered hole with a small hole end (Figure 4). Commonly used to design experiments and error method. As the nozzle is generally made with copper, smaller, is vulnerable parts, need to be replaced, so not to computational fluid dynamics and analysis. Nozzle in the side with access from a certain pressure Pn (gauge pressure of Pg) of gas, said nozzle pressure ejected from the nozzle exit, after a certain distance to reach the surface, said cutting pressure, the pressure Pc, the last expansion of the gas to atmospheric pressure Pa. The laser pointer company has a long development history of laser pointer .
Research indicates that with the increase in Pn, flow velocity increase, Pc continue to increase. For different gases have different pressure threshold, when the nozzle pressure exceeds this value, the flow of normal oblique shock, subsonic to supersonic gas flow rate from the transition. This threshold value Pn, Pa ratio and the freedom of gas molecules (n) two factors: such as oxygen, air, n = 5, so the threshold value Pn = 1bar × (1.2) 3.5 = 1.89bar. When the nozzle pressure higher Pn / Pa = (1 +1 / n) 1 + n / 2 时 (Pn; 4bar), normal flow is oblique shock wave into the shock seal, cutting down pressure Pc, air flow rate reduction, and eddy currents in the workpiece surface, weakening the role of air to remove molten material affect the cutting speed. Therefore, the use of tapered bore with a small hole of the nozzle tip, the nozzle pressure of oxygen often 3bar below.