All kinds of thermal laser cutting technology, except a few cases can start the edge of the plate, generally must be in the plate through a small round hole. Previously, in the laser stamping die compound machine, punch needle was used to break a hole, then laser was used to start laser cutting the small hole. There are two basic ways to break holes in fiber laser cutting without stamping die equipment

(1) Blast drilling

After the raw material is directly irradiated by the continuous laser, a dent is produced in the management center, then the melted raw material is quickly removed by the oxygen flow coaxial with the particle beam to produce a hole. Generally, the size of laser cutting holes in precision sheet metal is related to plate thickness, the average diameter of engineering blasting holes is half of the thickness. Therefore, the diameter of engineering blasting holes with partial thickness is very large round, which is suitable for the application of high specified parts (such as crude oil screen slotted pipe), only for waste. In addition, because the common working pressure of CO2 is the same as that of laser cutting, the splash is very large.

(2) Single pulse hole breaking: (pulsedrilling) professional sheet metal laser cutting selects the pulse light with peak output power to melt vaporize a small amount of raw materials, common gas N2 is used as auxiliary vapor to reduce the hole expansion due to causticization, the air pressure is lower than the CO2 working pressure during laser cutting. Each pulse light only causes small particles to gush gradually deepens. Therefore, the time to break a hole in thick steel plate must be several seconds. Once the hole is broken, the auxiliary steam is replaced by CO2 to carry out laser cutting. As a result, the hole diameter is smaller, the hole quality is better than that of engineering blasting. Therefore, the laser generator used should only have high power, but also the time space characteristics of time line, so the general stray CO2 laser generator can be incorporated into the provisions of fiber laser cutting. In addition, a reliable air supply automatic control system is needed to complete the conversion of vapor type, air pressure hole breaking time.