How set the parameters of plasma cutting machine?

How set the parameters of plasma cutting machine?

1.Cutting electric current

The cutting electric current is the most importante parameter.It decide the cutting thickness and speed directly,also the cutting ability.
Influence
The cutting current increases, the arc energy increases, the cutting ability is improved, and the cutting speed is increased.
The cutting current increases, the arc diameter increases, the arc becomes thick and the cutting line becomes wide.
But if electric current is too big,the nozzle is easy to hurt.The hurt nozzle give bad influence to cutting result.So before cutting,we should set suitable electric current and nozzle according the metal thickness.

2.Cutting Speed

The best cutting speed needs test with certain machine and certain metal thickness.Because the different material,different thickness,diffrent melting point and thermal conductivity ,so the cutting speed is different.The main performance:
Increase the cutting speed appropriately can improve the result of cutting,the cutting line becomes narrow,the cutting surface becomes smooth and reduce the distortion.
If the cutting speed is too fast,the cutting line energy is lower than the required value, cut seam in the jet can't quickly melted cutting melt immediately blew and the formation of larger drag, accompanied by incision slag hanging, the surface quality of the incision down.
When the cutting speed is too low, because the cut is plasma arc anode, in order to maintain the stability of the arc's, anode spot or anode region must from recent arc cutting seam found near the conduction current place, at the same time will pass more heat to a radial jet, so make the incision became wide, on both sides of the notch of molten material in the bottom flange aggregation and coagulation, form is not easy to clean the slag hanging, and incision margin due to excessive heating and melting and the formation of fillet.
When the velocity is extremely low, as the incision is too wide, or even extinguished arc. Thus, good cutting quality and cutting speed are inseparable.

3.Arc voltage

We generally believe that the power supply is normal output voltage for cutting voltage.
Plasma arc cutting machine usually have high no-load voltage and working voltage, the use of high ionization energy in gas such as nitrogen, hydrogen or air, stability needed for the plasma arc voltage will be higher. When the current and voltage of the means of improvement of arc enthalpy and cutting ability. If the increase in the enthalpy, reduce the diameter of the jet and increase the gas flow, often can get faster cutting speed and cutting quality is better.

4.Work gas and gas flow

Working gas include cutting gas and auxiliary gas, some equipment also requires arcs gas, usually according to the types of cutting material, thickness and cutting method to choose proper working gas.Cutting gas need ensure the formation of plasma jet, but also need ensure the removal of molten metal oxides and incision.A large gas flow will take more heat from the arc, making jet length becomes shorter, resulted in cutting capacity is decreased and arc instability; too small gas flow the plasma arc lost due to the straightness and the cutting depth shallow, but also easy to produce hang slag; so the gas flow must with cutting current and speed very good cooperation.Now most plasma arc cutter control the gas flow according the gas pressure,because when the gun body aperture when the gas pressure control will control flow.When we choose different gas pressure of different thickness metal usually according the parameters from manufacture.If there are other special application, the gas pressure need to be determined by the actual cutting test. The most commonly used working gas: argon, nitrogen, oxygen, air, H35, ar - N2 etc..

Argon

Argon is hardly any reaction of metal at high temperature, argon plasma arc is stable. And the use of nozzle with electrodes have higher service life. But the argon plasma arc voltage is low, the enthalpy value is not high, cutting ability is limited, and cut the air than the thickness of the cut about 25% lower. In addition, in argon, protect the environment, the surface tension of molten metal is larger, about 30% higher than that in nitrogen environment, so there'll be more hang slag problem. Even using the mixture of argon and other gases will be cutting slag sticking tendency. Therefore, it is rarely used alone in pure argon plasma cutting.

Hydrogen
Hydrogen is often used as auxiliary gas and other gas mixed functions, such as the famous gas H35 (the volume fraction of hydrogen is 35%, the rest of the argon) is one of the strongest gas plasma arc cutting, the main enrichment in hydrogen. Because the hydrogen can significantly improve the arc voltage, the hydrogen plasma jet has high enthalpy, when mixed with argon plasma jet, the cutting ability is greatly improved. General of metal materials with the thickness of more than 70mm, commonly used as argon + hydrogen gas cutting. If the use of water jet to further compress argon + hydrogen plasma arc, also can obtain higher cutting efficiency.

Nitrogen

Nitrogen is a kind of common work gas, under the conditions of higher voltage and nitrogen plasma arc has better stability and higher than the argon gas jet power, even if is cutting liquid metal viscosity materials such as stainless steel and nickel base alloy, incision of inferior hanging slag quantity are few. Nitrogen can be used alone, also can use with other gas mixture, such as automatic cutting often use air or nitrogen as the working gas, the gas has become the standard high speed cutting carbon steel gas. Sometimes nitrogen is also used as an oxygen plasma arc cutting of arc gas.

Oxygen

The oxygen can improve the low carbon steel material cutting speed. Use oxygen cutting, cutting mode and flame cutting is difficult to imagine, plasma arc of high temperature and high energy of the cutting speed faster, but must with the use of high temperature oxidation resistance of electrode, and the electrode for arc anti impact protection, to prolong the electrode life.

Air containing volume fraction of about 78% of the nitrogen, so use air cut formed by the hanging slag and nitrogen for cutting very imagine; air also contains a volume fraction of about 21% oxygen, because the existence of oxygen, air cutting speed of low carbon steel material is also very high; at the same time the air is the most economical working gas. But the single use of air cutting, will hang slag and incision oxidation, nitrogen, and the electrode and the nozzle of the lower life will also affect the work efficiency and cutting costs. Five, the nozzle height: refers to the nozzle surface and the cutting surface distance, it constitutes a part of the whole arc length. Due to the power supply of plasma arc cutting generally use constant current or steep drop characteristic, nozzle height increased, the change in current is very small, but will the arc length increased and resulted in the increase of arc voltage, so that the arc power increase, but also to expose in the environment of arc length growth, increased energy loss in the arc column. In the two factors of the case, the former is completely offset by the latter, but will make the cut of the effective energy decreases, and the cutting capacity decreased. The performance is often a cut of the jet blow force is abate, incision of the lower residual slag increased, the upper edge of the melt and appear a round. In addition, considering the shape of plasma jet, jet diameter is expanded outward from the gun in, increase the height of nozzle will inevitably cause incision width increase. Therefore, selecting the nozzle height as small as possible to improve the cutting speed and cutting quality is beneficial, but may cause double arc phenomenon of the nozzle at low altitude. The ceramic nozzle can be set to zero nozzle height, or nozzle end direct contact surface is cut, you can get a good effect.

5.Cutting power density

In order to obtain high shrinkage of plasma arc cutting arc, cutting nozzles have adopted the smaller nozzle aperture, longer channel length and strengthen the cooling effect, which can increase the effective section of the nozzle in the current, arc power density increases. But at the same time compression also makes the arc power loss increase. Therefore, the actual used to cut energy efficient to smaller than the power output of the power and the loss rate generally between 25% - 50%, some methods such as water constricted plasma arc cutting energy loss rate will be greater, and in the cutting process parameter design or cutting the cost of economic accounting should consider this issue.

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What auxiliary gas can be used laser cutting?

What auxiliary gas can be used laser cutting?

Laser cutting machine can use the auxiliary gas when cutting, mainly oxygen, nitrogen, air and argon, and the following we will introduce its use and characteristics for different auxiliary gases.

1.Atmosphere

Air can be supplied directly from the air compressor, so the price is very cheap compared with other gases. Although the air contains about 20% of the oxygen, but the cutting efficiency is far less than oxygen, cutting capacity and nitrogen. The cutting surface will appear micro film, but it can be used as a measure to prevent the film from falling off. Cut end face yellow.
The material is mainly applicable to aluminum, aluminum alloy, stainless steel, brass, galvanized steel, non metal and so on.

2.Nitrogen

Some times,when we cut some metal material,the cutting surface will form oxide film,adopt nitrogen can invoide the oxide film.The non oxidation cutting mask has the characteristics of direct welding, coating, corrosion resistance and so on. Cut face is white.
The main application of the plate are stainless steel, galvanized steel, brass, aluminum, aluminum alloy, etc.

3.Oxygen

Mainly used for cutting carbon steel in laser cutting machine. Using oxygen reaction heat large format improve cutting efficiency at the same time, resulting in the oxide film can improve the reflective material beam spectrum absorption factor. Cut face is black or dark yellow.
Is mainly used for rolling steel, solution and connecting structure of rolled steel, mechanical structure with carbon steel, high tension version, tools in, stainless steel, galvanized steel, copper and copper alloys.

4.Argon

Argon is inert gas, used in the laser cutting machine to prevent oxidation and nitriding, also used in welding, compared with other processing gas, the price of Japonica rice, the corresponding increase in cost. Cut face is white.

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Operating process of fiber laser cutting machine

Operating process of fiber laser cutting machine

Today, the fiber laser cutting machine has become an indispensable processing equipment in the modern sheet metal industry, with industrial upgrading, processing requirements upgrade, not only improve the efficiency, the operation is also optimized, below, I will introduce the concrete operation of the process for you.

Operation procedure of optical fiber laser cutting machine:

1.Make sure the material of working,and put the material on the table of machine and fix it.Then pls make sure the material is stable in the table of machine,lest it moves when cutting,cause bad accuracy of working.

2.Operate the control system and import the design of cutting,set the thickness and other parameters in software.Then adjust the laser head and nozzle for getting good laser focus position.

3.Start the manostat and water chiller,pls set the suitable water temperature and pressure.

4.Start the laser generator and start laser cutting machine.

The above 4 points are easy and short,but in the actual operation need more thim for exercise.We should be very familiar with all details of operation,invoide the problem even fault in the cutting.Below,i will share some fault experiences.

When you start the machine,but no response.

1.Pls check whether the power insurance burn,if yes,pls change new one.
2.Power input is normal: check the power input and make it normal.
3.Total power switch is damaged: replace the total power switch.

No laser or laser is weak

1.If laser path is shifting,pls adjust the laser path.
2.If the laser focus is right,pls check and change it.
3.If laser generator is demaged,check and change it.
4.If laser generator is power on,make it power on.

The size of working is not right or be in wrong action.

1.pls check if the signal line.
2.The power supply is not stable or be in interference signal.Pls use the manostat and eliminating interference signal.
3.Check the parameters of working.
4.Check the preparation of the processing procedures, and modify it to make it normal

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3 focus of laser cutting machine

3 focus of laser cutting machine

1.Cutting focus is above the material

This way we are also known as the negative focal length, because the cutting point is not located in the surface of the cutting material is not located in the inside of the cutting material, but positioned at the top of the cutting material. This method is mainly used in the material with high cutting thickness. This approach is focused on the cutting material, mainly because of the need to cut a large plate, otherwise the nozzle delivery of oxygen is extremely prone to lead to problems and the resulting cut temperature. But one drawback of this approach is that the cutting surface is rough and less practical for the cutting of high precision.

2.Cutting focus is in material

This way is also known as the positive focal length. When you need to cut the workpiece for the stainless steel or aluminum plate when the cutting point in the workpiece inside the model. But one drawback of this approach is that, due to the focus principle of cutting surface, the cutting surface of the workpiece is larger than the cutting point at the same time, and this mode requires the cutting gas flow to be large, the temperature should be sufficient, and the time of cutting is slightly longer. So when you choose the material of the workpiece is mainly for stainless steel or aluminum lamp of the material selection of high hardness.

3.Cutting focus is on surface of material

This method is also known as the 0 focal length, usually in the SPC, SPH, SS41 and other parts of the cutting, the use of the cutting machine is used to focus on the workpiece surface, which is not the same as the upper and lower surface of the workpiece surface smooth, generally close to the focus of the cutting surface is relatively smooth, and far from the cutting of the lower surface is rough. This model should be based on the actual application of the upper and lower surface of the process requirements and set.

To sum up, we should use different focus mode when cutting different material or parts, can more play the performance advantages of laser cutting machine.

Advantages of laser cutting machine in the shipping industry

Advantages of laser cutting machine in the shipping industry

There are four main types of ship hull plate parts, which are flame cutting, plasma cutting, cutting and laser cutting.
1.Equipment performance comparison
The cutting performance of the flame cutting machine can be carried out by the cutting machine. The plasma cutting machine is fast and the cutting machine has high efficiency, but it can only be limited to the machining of the linear side parts. But the cutting plate speed is relatively slow. It is due to the advantages of high precision, laser cutting machine in high sheet product construction, block construction process without allowance precision management, build merchant ships of welding groove line of demanding process: such as FCB puzzle, double wire submerged 4 arc automatic welding and other aspects, has irreplaceable advantages, the laser cutting machine is to change the smooth implementation of the method has laid an important foundation.

The comparison of the parameters of the laser cutting machine and the other two kinds of cutting equipment is listed:
Application of laser cutting machine in the actual production of shipping industry
Through comparison of the performance of laser cutting equipment and other equipment, the main advantages of the laser cutting equipment are cutting high precision and small thermal deformation. This feature has a broad application prospect in the practical production.
There is no allowance for advancing the process of building a new high tech ship
High precision requirements for ship hull zhuanpei high frame, zhuanpei gap must be controlled in the range of 1mm. In a bottom part EB02 for example, formerly in the plasma of floor plate material, in order to ensure the assembly gap, in the coal floor are set to mow the margin (as shown in the following picture), the allowance of the ribbed plates are is in the field assembly manual to mow, mow the quality parameter difference not neat inner slotted oxides are not clear and easy to, but also increase the workload of the assembly, assembly cycle of growth, resulting in the block construction period is prolonged. Using laser cutting machine to improve the accuracy of parts, in the relative to cancel the assembly margin, the structure of the assembly speed is significantly accelerated. The assembly quality of the whole block is improved obviously, and the precision of the construction is also improved at the same time. The fact proves that the more accurate parts are good for the main dimensions of the segmented.
Promote the change of thin plate cutting
Section thin-walled superstructure construction division is an important part of the whole high engineering hull construction, the thinnest thickness coaming of only 2mm; in the superstructure segment in the process of the construction, expect from the next parts manufacturing, block manufacturing, total group equipped with a series of processes are in the hands of the process, thin wall plate is very easy to lose stability deformation. So section thin-walled superstructure construction of each process are key control, and it is the introduction of laser cutting machine, promote the thin-walled material engineering change. To ensure the quality of the construction of the sub construction.
Before the introduction of laser cutting machine, the cutting of the 2-3mm cutting of the sheet is mainly through the manual line. Through Zhaping were leveling; artificial marking and shear cumulative error in 3mm, resulting in in wall imposition assembly of ultra poor gap, unable to realize the assembly gap in the range of 1 mm requirements, tend to have a lot of modification cutting phenomenon; and for 4 6mm steel plate, using ion cutting, because of the thin sheet metal, the cutting heat, steel plate edge straightness is not up to the requirements, after cutting Zhaping, still need the edge planing machine for edge processing, an increase of machining process.
To the Ministry of loading stage, there are a large number of wall due to the material error or scrap or rework, and in the sub wall assembly, the wall edge potential repair or assembly gap is endless, and the material is not used in the cutting machine before the material scrap rate is high. Introduction of laser cutting machine thick, it is using its high processing precision, small heat input, all thin wall are used laser cutting and blanking, step in place, eliminating the need for the lineation, Zhaping, planing process; to eliminate the problems caused by plate's loss, greatly improve the processing efficiency.
It is clear that the use of laser cutting machine for thin plate cutting is a process of change. Greatly improve the efficiency and quality of the thin wall segment processing.
In short, laser cutting machine as a new type of hull parts cutting equipment, compared with other conventional cutting equipment, with high machining accuracy, small thermal deformation, good stability, low loss rate, small environmental pollution and other advantages, in the shipbuilding industry has great potential for application. Currently in in section of high ship building without remainder, sheet cutting method change has good application, greatly improving the processing efficiency, eliminating the on-site repair cut phenomenon, reduce the labor and material waste. The advantage of laser cutting machine will be wider and deeper application in ship manufacturing.

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Teach you how to easily distinguish the quality of laser cutting machine

Teach you how to easily distinguish the quality of laser cutting machine

1.Roughness

Laser cutting section will form the vertical lines, the depth of the lines determines the cutting surface roughness, the more shallow the lines be, the more smooth cut section be.Roughness not only affects the appearance of the edge, but also affects the friction characteristics, in most cases, we need to minimize the roughness, so the more shallow, the higher the quality of cutting.

2.Verticality

If the sheet metal thickness is more than 10mm, the verticality of cutting edge is very important. Away from the focus, the laser beam becomes divergent, based on the focus of the position, cutting toward the top or bottom of the width. When the cutting edge deviates from the vertical line of a few millimeters, if the edge is more vertical, the cutting quality is better.

3.Cutting width

Generally cutting width does not affect the cutting quality, cutting width is important only cutting special precision contour in internal parts of components, Because the cutting width determines the minimum of the outline, When the thickness of the plate increases, the cutting width increases. So if you want to ensure that the same high accuracy, regardless of the width of the cut, the workpiece in the laser cutting machine processing area should be constant.

4.Lines

When the high speed cutting plate, the molten metal will not appear in the vertical laser beam below the cut, but will be in the laser beam to spray out. As a result, the curved lines are formed in the cutting edge, and the lines follow the moving laser beam closely. In order to fix this problem, the feed rate can be cut down at the end of cutting.

5.Burr

Burr formation is a very important factor to determine the quality of laser cutting. Because the removal of burr is an additional workload, so the amount of the amount of burr is very serious and the quality of the cutting can be judged visually.

6.Material deposition

The special liquid of a layer of oil on the surface of the workpiece prior to the melting of the perforation. Laser gasification process, the upward or downward discharge will be formed on the surface of the deposition.

7.Sag and corrosion

Depression and corrosion have a negative effect on the surface of the cutting edge. They appear in general this should be avoided in the cutting error.

8.Heat affected zone

In laser cutting, the area near the notch is heated. At the same time, the structure of the material changes. For example, some of the material will harden. Heat affected zone refers to the depth of the region of the internal structure change, the smaller the better.

9.Deformation

If the cutting causes the parts to be heated rapidly, it will deform. This is particularly important in the fine processing, because the contour and the connecting piece is usually only a few millimeters wide. Controlling the laser power and the use of short laser pulses can reduce the heat of the part and avoid the deformation.

Of course, just look at the effect of cutting materials nor each material are suitable, such as you get very poor material, The effect of cutting for each machine is not good, as another example, you take some not suitable for laser cutting of materials may not be able to conclude. We recommend that the materials are: acrylic, organic glass, ABS and other materials

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Maintenance of laser machine

Maintenance of laser machine

Laser machine must be maintained in order to use a more permanent.

1.Replacement of water and clean water tank

Suggestion: wash the laser tank and replace the circulating water once per week
Note: Before open the machine must ensure that the laser tube is filled with circulating water.
The water quality and the water temperature of the circulating water directly affect the service life of the laser tube, it is recommended to use pure water, and the water temperature is controlled at 35 degrees Celsius. For more than 35 degrees Celsius to replace the circulating water, or add ice to water to reduce the water temperature, (recommend that the user choose a water chiller, or use two water tanks).
The tank cleaning: first turn off the power supply, the water inlet pipe is pulled out, so that the laser tube water automatically flows into the water tank, water tank is opened, remove the water pump, clear water pump on the dirt. The cleaning tank clean, replacing the good water circulation, water return tank will connect to pump water pipe is inserted into the water inlet, the joint order. The pump is powered by a single pass and run for 2-3 minutes (the laser tube is filled with circulating water).

2.Fan cleaning

Use the wind turbine for a while, the wind machine inside accumulate a lot of solid dust.The fan produces a lot of noise, but also not conducive to the exhaust and odor. When appear fan inadequate suction exhaust is not smooth, please turn off the power, wind turbine air inlet pipe and an air outlet pipe, remove dust inside, and then inverted fan and pulling the wind leaf relief until clean, and then install the fan.

3.Lens cleaning

There are three mirrors and a focusing mirror (No. 1 mirror is located in the laser tube's launch exit, which is the upper left corner of the machine.
No. 2 is located in the left end of the beam reflector,
No.3 mirror is at the top of the fixed part of the laser head, poly focal lens in the lens barrel is arranged at the lower part of the laser head can be adjusted).
The laser is reflected through the lens, focusing from the laser hair shot out.
Lenses are easily stained with dust or other contaminants, resulting in the loss of laser or lens damage, No. 1 and No. 2 lens cleaning should not be removed, only to be dipped in a clean liquid of the mirror carefully along the central edge of the lens to the edge of the rub.
Note: 1. The lens should be gently wipe, do not damage the surface coating; 2. Clean the process should be handled with care, to prevent the fall; 3. Focusing mirror installation please be sure to keep concave downward.
The 3 lens and the focusing mirror is removed from the frame, use the same method to wipe, wipe after it is put into the can.

4.Cleaning of guide rail

Guide, linear axis, as one of the core components of the device, its function is to guide and support. In order to ensure that the laser machine has higher accuracy, it is required that the guide rail, straight line has a high accuracy and good motion stability. In the process of operation, because of the large amount of corrosive dust and smoke, the smoke and dust in the process of processing will produce a lot of dust and smoke.The smoke and dust be in a long time, a large number of deposits in the rail, linear axis surface, the machining accuracy of the device has a great impact, and will be in the guide line of the formation of pitting, shorten the service life of the equipment.

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