The CO2 laser cutter is the most popular cutting machine for hobbyists and small businesses.
It can cut on various materials such as wood, acrylic, marble, fabric, etc.
If you want to buy a CO2 laser cutter, do you know what to look for when choosing a machine?
Which is better, the Desktop laser cutter's CO2 glass tube or the RF laser radio frequency tube? This is one of the questions that many beginners would like to know.
In order to give you a better understanding of the difference between the two CO2 laser tubes, this article will delve into the differences between the DC and RF laser tubes.
In this article

1. Components of the CO2 Laser Tube
2. What is DC CO2 laser tube
3. What is RF CO2 laser tube
4. Different between CO2 and RF laser tube
5. Best DC CO2 laser cutter
6. Best RF CO2 laser cutter
7. Which laser tube is better - DC or RF?

Components of the CO2 Laser Tube

The CO2 Laser Tube consists of a gas mixture (laser-active medium), a resonator and a water cooler.

1. Gas mixture (laser-active medium): The laser-active medium is a material that emits part of its energy in the form of laser radiation. There are many different types of laser media, which can be liquid, gaseous, or solid, and the CO2 laser tube is a gaseous media of choice, whether a glass tube or an RF tube.
2. Resonator: The resonator contains the components required to generate the laser beam. The excited gas transmits capacitance through the resonator wall using a current magnetic field.
3. Stimulated components: The DC laser tube excites the gas inside the tube using a strong voltage between the electrodes.
   RF activates the gas inside the tube using an electromagnetic field generated by the electrodes outside the resonator. This type of excitation is not only more pulsatile but also prevents corrosion of the electrodes.
4. Water chiller: Although only a small fraction of the gas is excited into the laser beam, this process generates much heat. The heat generated can interfere with the laser radiation, so a water-cooled tank is required to keep the laser tube at a constant temperature during operation.
   However, glass is a poor thermal conductor, so it must regularly circulate the chiller's water. If there is no coolant or distilled water in the water cooler, the machine will not work.

What is DC CO2 laser tube

The DC CO2 laser tube, also known as a CO2 laser glass tube, is filled with a mixture of gases. The ratio of CO2: nitrogen: helium = 1:0.5:2.5. The role of CO2 is to be the active medium of the laser, the role of helium is to promote heat dissipation, and the role of nitrogen is to promote the excitation of CO2 molecules into photons. Of course, the ratio of gases added to the CO2 laser tube varies from brand to brand, with some adding hydrogen, xenon, carbon monoxide, etc.
The gas inside the tube must meet strict requirements and must not contain impurities that could interfere with the formation of the laser beam and affect the cutting ability and results.
Poor beam quality In simple terms, a DC CO2 laser tube is a machine component that converts electrical energy into light energy.

How does a DC laser tube work

The DC CO2 laser tube works by applying a voltage to both ends of the glass tube and then creating a flowing current inside the tube. As the current flows, the nitrogen molecules are first excited and react. The excited nitrogen gas then accelerates the excitation of the CO2 gas, generating heat.
The excited gas mixture produces ultra-tiny "photons." When a certain number of photons have accumulated, they are released from the laser.
The tube is fully enclosed. At the same time, the DC CO2 laser tube requires a high level of skill in blowing the glass tube. And to keep the temperature constant during operation, the laser tube and water chiller are placed together.

What is RF CO2 laser tube

The RF laser tube, also known as the metal RF tube, produces a laser beam by excitation of a gas, as does the DC laser tube. The difference between the two is that the RF laser tube is powered by the radiation from the antenna and operates at a higher repetition rate (measured by the number of pulses in 1s). The antenna is located outside the resonator and the gas is excited by the electromagnetic field outside the resonator to produce laser radiation.

How does a RF laser tube work

The RF laser tube uses an RF power supply as the pumping source. Two rectangular metal slats are placed parallel to each other, and a total reflector is installed at each end of the metal plate, thus forming the resonator of the RF laser tube. The airflow in the resonator is cooled by convection through the heat exchanger plate only. Therefore, the RF laser tube does not require a water chiller, mainly cooled by air cooling. The RF power is generated by the electromagnetic field outside the resonator, which excites the nitrogen and CO2.

Difference between CO2 and RF laser tube

Both CO2 laser tubes have their characteristics and the following is a list of their differences.

Service life

The DC CO2 laser tube consumes gas during operation, so the air pressure inside the tube decreases after a certain period. There is no way of replenishing the depleted gas, so the tube needs to be replaced after a certain point. Under normal circumstances, the service life of a DC laser tube is less than 10,000h.
It can inflate the RF laser tube several times, so replacing it is unnecessary.

Price

RF laser tubes are much more expensive than DC's, typically 2-5 times more expensive. Currently, replacement CO2 laser tubes are sold for between $300-$500, while RF laser tubes are sold for $1000-$2000.

Manufacturing process

The manufacturing process for RF laser tubes is much more complex than for CO2 laser tubes, and it usually takes a full day to set up an RF laser tube after production. The DC CO2 laser tube is much simpler, taking only a third of the time of the RF.

Cutting ability

Both are capable of high-quality cutting, but when cutting acrylic or glass, the RF metal laser tube produces a slightly rougher edge. The naked eye does not look different.
The DC CO2 laser tube is suitable for cutting non-metallic materials such as wood, paper, acrylic, fabric, etc. The RF can cut non-metallic materials and metals, so the RF is superior in terms of the range of materials it can cut.

Engraving accuracy

The RF has a smaller spot size than the DC CO2 laser tube to engrave finer patterns. It also cuts a narrower slit and has less heat affected area.
Currently, the RF laser source can produce an engraving accuracy of 0.001mm, while the DC laser source will produce an engraving accuracy of approximately 0.25mm.
This shows that the RF laser source has better engraving accuracy.

Laser power

For the same power, the RF laser tube has a higher cutting capacity and can cut thicker sheets.

Best DC CO2 laser cutter

Gweike cloud pro II

This is a standard DC CO2 laser cutter which can easily engrave/cut a wide range of plates.

Best RF CO2 laser cutter

Gweike cloud RF

Pros of DC lasers

1. Low price, no need for high initial cost investment
2. Water-cooled constant temperature control extends the life of the laser tube
3. High engraving accuracy and productivity

Pros of RF lasers

1. Long service life and no need for regular laser tube replacement
2. High laser beam quality for more precise engraving details
3. Faster engraving speeds
4. Less laser power is required for the desired cutting/engraving results.

Which CO2 laser tube is better - DC or the RF?

There is no standard answer to this question. Both machines shine in their respective fields, but for small businesses and beginners, I recommend the DC CO2 laser tube, which is now so powerful and capable of cutting that you can use it for many difficult designs. If you are a professional or require the best performance from your machine, then the RF laser tube is the best choice.

How to maximize the life of the machine

1. Perform regular maintenance, a simple table cleaning after each use of the machine and a fortnightly cleaning of the focus mirror.
   Remember to refill the water cooler regularly.
2. Always check the user manual before use to avoid damage to the laser tube caused by incorrect use.
3. Try to work in an environment of 0~35°C. Too cold an environment will cause the laser cutting machine's viewing window to freeze and crack. And if the water cooling tank is added with distilled water, it will also freeze in the environment below 0°C. This can all affect the service life of the machine.

Conclusion

Suppose you are looking for a professional CO2 laser cutter for your business. The RF CO2 laser tube is your preferred choice, offering the best engraving accuracy, speed and longevity. Of course, if your budget is low, the DC CO2 laser tube is also perfect for cutting/engraving a wide range of materials.