How to adjust various perforation processes in laser cutting?

1. The most commonly used is segmented perforation. The perforation height of each level needs to use corresponding parameters. The perforation action is performed within the set time. You can refer to the following when debugging:

(1) Nozzle height: The nozzle height gradually decreases as the perforation action is performed. Level 1: 6-8 Level 2: 10-15 Level 3: 18-20 Air pressure corresponds to cutting air pressure;

(2) Duty cycle: Level 1: 50% Level 2: 55% Level 3: 60% Start by setting half of it, and then adjust it slightly according to the situation;

(3) Pulse frequency: Level 1: 300 Level 2: 300 Level 3: 1000;

(4) Focus position: The focus position of perforation is the same as the cutting focus. It is generally recommended to be in the middle of the plate thickness;

(5) Dwelling time: The dwelling time increases according to the plate thickness. It is necessary to ensure penetration and slag removal. Level 3 opening is 200-300, and level 2 and level 1 are 1000 (can be extended appropriately);

(6) Stop light and blow: Stop light and blow mainly play a cooling role. Generally 200-500. Novices can slightly increase the size of the protective lens. The nozzle progressive is to continuously emit light during the perforation action.

2. Inductive perforation, the cutting head will leap to the perforation position, quickly zoom to the focus of inductive perforation, and continuously emit light to the progressive focus. For specific settings, please refer to the following:

(1) Piercing height: 6mm

(2) Piercing time: 30ms

(3) Piercing focus: -5mm

(4) Laser adjustment:

Laser power: 100%; 12000w

Duty cycle: 40%

Frequency: 2000HZ

3. Lightning perforation, also called variable frequency perforation. Thick plates can be penetrated by quickly changing the frequency, zoom and power. For specific settings, please refer to the following:

(1) Perforation time: about 300ms-500ms

(2) Nozzle height: above 15, increase by 5 with the thickness of the plate and power, otherwise it is easy to burn the lens

(3) Air pressure: about 1, focus negative, take the middle part of the plate thickness, stop the light and blow, and the dwell time is 100-300 milliseconds

(4) Frequency 3000HZ to frequency 1000HZ, duty cycle 55 to duty cycle 45%

It should be noted that when adjusting the frequency and duty cycle, the thickness of the plate increases and decreases by about 5% each time.

FAQ

1. What are the two main methods for laser piercing (perforation), and what is the key difference in their application?

The two main methods are Pulse Piercing (or Burst Piercing) and Ramp Piercing (or Dynamic Piercing). Pulse piercing uses successive high-energy pulses and is better for thicker materials where controlled material removal is needed. Ramp piercing uses a continuous, gradually increasing laser power, which is faster and better suited for medium-thickness materials.

2. When adjusting the piercing process for thick mild steel, what are the three most critical parameters to control?

The three most critical parameters are: 1. Piercing Time (or Pulse Count): Allowing enough time for full penetration. 2. Piercing Pressure: Typically low oxygen pressure to initiate the oxidation reaction. 3. Focus Position: Usually set slightly above the material surface to distribute energy and prevent spatter.

3. How should the piercing process be adjusted to minimize spatter and protect the nozzle/optics, especially on thick stainless steel?

To minimize spatter, use a multi-stage pulse piercing process with gradually increasing power and low initial pressure. Crucially, the focus position should be kept slightly higher above the material to keep the molten material away from the cutting head and protective lens.

4. What is “Flight Piercing” (or Fly Cut Piercing), and how is it adjusted for high-speed thin-sheet production?

Flight Piercing is a technique where the laser beam starts piercing while the cutting head is already moving. It is adjusted by precisely synchronizing the power-on signal and the piercing time to ensure full penetration is achieved just as the head reaches the programmed cutting speed, maximizing throughput on thin sheets.

5. If the machine frequently fails to achieve full penetration during piercing (piercing failure), what should be the first parameters checked and adjusted?

If piercing fails, the first steps are to increase the Piercing Time (or pulse count) to ensure sufficient energy input, and then verify the Piercing Focus Position. The focus position must be calibrated accurately to concentrate enough energy to initiate melting and vaporization.

6. How does the auxiliary gas pressure used during the piercing phase differ from the pressure used during the final cutting phase?

The gas pressure during the piercing phase is generally set lower than the final cutting pressure. Low pressure is used to control the expulsion of material and prevent excessive spatter, allowing the laser to efficiently drill the keyhole. Once the hole is established, the pressure is ramped up to the higher cutting pressure to efficiently expel slag and maintain speed.