In recent years, the role of laser cutting machines in the development of the sheet metal industry has become increasingly prominent.
During the cutting process, there are six practical functions, with these practical functions, the processing efficiency and cutting performance of the laser cutting machine can be greatly improved.
Leapfrog is an idle running of laser cutting machine.
As shown in the figure below, after cutting the hole 1, then the hole 2 is cut.
The cutting head should move from point A to point B.
Of course, the laser should be turned off in the process of moving.
The process of movement from point A to point B, the machine “empty” run, known as idle running.
The idle running of the early laser cutter is shown below, with the cutting head performing three actions in succession: rising (to a safe enough height), leveling (to reach above point B), and descending.
Compressing the idle time will increase the efficiency of the machine.
If the three actions, which are performed in succession, are performed “simultaneously”, the idle time can be reduced.
When the cutting head moves from point A to point B, it rises at the same time; when it approaches point B, it falls at the same time. As shown in the figure below.
The trajectory of the cutting head’s idle running movement is like an arc drawn by a frog jumping.
In the process of the development of laser cutting machine, frog jumping is considered outstanding technical progress.
Frog jumping action, only takes up the time from point A to point B flat movement, eliminating the time of ascent and descent.
Frog hopping, the food is captured.
For frog hopping of the laser cutting machine, the “captures” is high efficiency.
If the laser cutting machine does not have the frog jump function now, it will not be in the mainstream.
2. Auto Focus
When cutting different materials, it is necessary that the focus of the laser beam falls on different parts of the workpiece cross-section.
Therefore, it is necessary to adjust the position of the focal point (focus adjustment).
Earlier laser cutting machines were generally manually focused; today, many manufacturers have machines with automatic focus.
People might say that changing the height of the cutting head is fine; if the cutting head rises, the focus position is high; if the cutting head lowers, the focus position is low. It’s not that simple.
In fact, in the cutting process, the distance between the nozzle and the workpiece (nozzle height) is about 0.5 ~ 1.5mm, may as well be regarded as a fixed value, that is, the nozzle height remains unchanged, so it can raise and lower the cutting head to adjust the focus (otherwise the cutting process can not be completed).
The focal length of the focusing lens is not changeable, so it cannot expect to change the focal length to adjust the focus either.
If the position of the focusing lens is changed, the focus position can be changed:
If the focusing lens goes down, the focus goes down, and if the focusing lens goes up, the focus goes up.
This is indeed one way to adjust focus.
Using a motor to drive the focus lens in an up and down motion allows for automatic focus.
Another method of auto-focusing is:
A variable curvature reflector (or adjustable lens) is placed before the beam enters the focusing lens.
By changing the curvature of the reflector, the divergence angle of the reflected beam is changed, thereby changing the focus position, as shown in the figure below.
With the auto-focus function, the processing efficiency of laser cutting machines can be significantly improved.
The punching time of thick plate is greatly reduced; the machine can automatically and quickly adjust the focus to the most suitable position for workpieces of different materials and thickness.
3.Automatic edge finding
As shown in the figure below, when the sheet is placed on the table, if it is skewed, it can cause waste when cutting.
If the angle and origin of the sheet’s tilt can be sensed, the cutting process can be adjusted to fit the angle and position of the sheet, thus avoiding waste.
So, automatic edge finding has been developed.
When the auto-edge function is activated, the cutting head starts from point P and automatically measures three points on the two vertical sides of the sheet, P1, P2 and P3, and then automatically calculates the angle of inclination A and the origin of the sheet.
Thanks to the automatic edge finding function, the machine’s efficiency is improved by eliminating the time needed to adjust (move) the workpiece earlier, which is not an easy task on the cutting table and weighs hundreds of kilograms.
A technologically advanced and powerful high-powered laser cutting machine is a complex system that integrates light, machine and electricity.
Subtleties are often hidden.
Let’s take a peek at its subtleties.
4. Concentrated perforation
Concentrated piercing, also known as pre-piercing, is a process that is not a function of the machine itself.
When laser cutting thicker plates, each contour of the cutting process undergoes two stages: piercing and cutting.
Conventional process (point A perforation → cutting profile 1 → point B perforation → cutting profile 2 → …).
The centralized perforation is all the perforation process on the entire steel sheet in advance of the centralized execution, and then go back to execute the cutting process.
Concentrated piercing process (complete piercing of all contours → return to starting point → cut all contours).
The total trajectory length of the machine is increased in the case of concentrated piercing compared to the conventional machining process.
So, why centralized piercing is used?
Concentrated piercing can avoid overheating.
During the piercing process of the thick plate, heat is collected around the piercing point, for example, if it is followed by cutting, the overheating phenomenon will occur.
With the centralized piercing process, when finishing all the piercing and returning to the starting point to cut again, due to enough time to dissipate heat, the overheating phenomenon is avoided.
Centralized piercing can improve processing efficiency.
Currently, there are still many laser cutting machines that do not have auto-focusing.
With thick plates, the process parameters (laser mode, power, nozzle height, auxiliary gas pressure, etc.) are different in the piercing and cutting stages.
The nozzle height is higher in the piercing process than in the cutting process.
In the case of conventional processes (profile 1 piercing → profile 1 cutting → profile 2 piercing → profile 2 cutting → …), the focus of the laser beam can only be adjusted manually to the optimum position required for the cutting process in order to guarantee cutting quality and efficiency.
(Imagine that: at first, the focus is manually set to the position required for piercing, and the hole is pierced; then, the focus is set to the position required for cutting, cutting; then adjust it to the position for piercing, piercing; …; until the process is complete – it’s a nightmare).
As a result, the focal point for piercing will necessarily not be in the optimal position and the piercing time will be longer.
However, with a concentrated piercing method, the focus can be adjusted to a suitable piercing position first.
When the perforation is complete, it should pause the machine and adjust the focus position to the best position required for the cut.
As a result, the piercing time can be reduced by more than half, greatly increasing efficiency.
Of course, if necessary, other process parameters can be adjusted or changed between concentrated piercing and cutting (e.g. air and continuous wave can be used for piercing, while oxygen can be used for cutting, with enough time to complete the gas changeover in between).
We generally refer to the drive focus lens autofocus as the F-axis.
Is it possible to call it “H” (Hand) axis “zoom” by using manual zoom for concentrated piercing and cutting like this?
Concentrated perforation is also a risk.
If a collision occurs during the cutting process, causing the sheet to change position, the uncut part may be scrapped.
The concentrated perforation process requires the help of an automatic programming system.
During the laser cutting process, the sheet is held in place by a serrated support bar.
If the cut parts are not small enough, they cannot fall from the gap of the support bar;
If it is not large enough to be supported by the support bars, it may lose its balance and warp.
A high speed cutting head can collide with it, resulting in a stoppage or damage to the cutting head.
This can be avoided by the bridge (micro-joint) cutting process.
When programming laser cutting on graphics, the closed contour is intentionally broken in several places, so that after the cutting is completed, the parts adhere to the surrounding materials without falling, these disconnects are bridging location.
This is also known as a breakpoint, or microjunction (a term derived from a rigid translation of MicroJoint).
The distance of the break, about 0.2 to 1mm, is inversely proportional to the thickness of the sheet.
Based on different perspectives, there are these different calls:
Based on the contour, if it is broken, so it is called a breakpoint;
Based on the part, if it adheres to the base material, so it is called a bridge location or micro-connection.
Bridges connect the part to the surrounding material, and sophisticated programming software automatically adds the appropriate number of bridges according to the length of the profile.
It is also possible to distinguish between internal and external contours and decide whether to add bridging positions, so that internal contours (scrap) without bridging positions fall off, while external contours (parts) with bridging positions remain attached to the base material and do not fall off, thus eliminating the need for sorting.
6. Common edge cutting
If the contours of adjacent parts are straight and have the same angle, they can be combined into one straight line and cut only once.
This is known as a common edge cut.
Obviously, cutting with a common edge reduces the length of the cut and significantly increases the efficiency of the process.
Common edge cutting does not require the part to be rectangular in shape, which is shown in the figure below.
The azure lines are common edges.
Common edge cutting not only saves time in cutting, but also reduces the number of perforations.
Therefore, the benefits are clear.
If 1.5 hours per day are saved due to common edge cutting, that’s about 500 hours per year, which equates to an additional $50,000 per year at a combined cost of $100 per hour.
Common edge cutting needs to rely on intelligent automatic programming software.