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What is a MOPA Laser and how does it work?

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A MOPA (Master Oscillator Power Amplifier) fiber laser engraving machine is an advanced type of laser engraver that utilises fiber laser technology along with a two-stage process for amplifying the laser signal.

In the first stage, the master oscillator generates a highly coherent laser signal with the desired pulse shape and length. This signal is then amplified by the power amplifier, which increases the power of the laser signal while maintaining its original characteristics.

This technology enables precise control over the pulse width and frequency, which is crucial for a wide variety of applications, including engraving, marking, cutting, and welding.

MOPA fiber laser machines offer superior performance in terms of engraving quality and flexibility compared to traditional fiber laser engraving machines. They can be used to engrave a broad spectrum of materials, including sensitive ones, without causing thermal damage, thanks to their adjustable pulse durations. Moreover, they can create different colours on certain metals, such as stainless steel, by manipulating pulse durations and frequencies.

n-lase desktop laser machine on transparent background

What Can I Engrave With a MOPA?

Due to this larger range in pulse duration, the scope of applications is larger for a MOPA laser. A MOPA laser can produce precise, high contrast engravings on the following materials:

  • Metals: This includes stainless steel, aluminium, brass, copper, titanium, gold, silver, and other alloys. The MOPA laser can also achieve colour marking on stainless steel and titanium.
  • Coated Metals: This refers to metals coated with materials such as paint, anodised aluminium, or other surface treatments. The machine can selectively remove the coating to create high-contrast markings.
  • Plastics: Certain types of plastics, especially those that are engineered for laser marking, can be engraved with MOPA laser technology. The results may vary depending on the type of plastic, with some achieving a high-contrast, readable mark.
  • Sensitive Materials: MOPA lasers are suitable for marking sensitive materials that may be damaged by the higher heat input of other laser types. This includes materials such as certain thin plastics and films, some types of anodised aluminium, and silicon.

However, it's important to note that the engraving quality and effects can vary based on the specific type of material and the settings used. Always run tests before processing large batches of material.

needham laser engraved plate

How Does the MOPA Laser Allow for Greater Control Over Pulse Duration?

In a MOPA fiber laser system, the structure is divided into two distinct parts: the master oscillator and the power amplifier.

The master oscillator generates the initial laser signal. This signal has a low power level, but it's highly coherent and carries the desired pulse shape and duration. By adjusting the settings of the master oscillator, users can control the pulse shape and duration, having a direct influence over the laser's interaction with various materials.

Once the initial signal is generated, it's sent to the power amplifier, which dramatically increases the output power of the laser signal without affecting its original characteristics, like pulse shape and duration.

The ability to control pulse duration is particularly useful when engraving materials that react differently to heat, as it can minimise thermal damage and discolouration, leading to a better quality of engraving.

For example, shorter pulses can be used to achieve high contrast marking on plastics or to mark sensitive materials, whereas longer pulses can be useful for engraving certain types of metals or for applications like deep engraving or colour marking on stainless steel.

QR code engraved on metal by a laser

What are the Advantages of Using a MOPA Fiber Laser Engraving Machine Over Other Types of Engraving Machines?

The MOPA marking machines offer several advantages over other types of laser technology. These include:

  • Adjustable Pulse Durations: This provides a greater degree of control over the laser's interaction with materials, leading to optimal results for various applications.
  • High Precision and Quality: They are known for producing higher contrast engravings on certain materials, like plastics, improving visibility and readability.
  • Material Compatibility: MOPA fiber lasers can engrave a wider range of materials than many other laser types, including sensitive materials that may be damaged by higher heat input.
  • Colour Marking: MOPA lasers can create assorted colours on certain metals, such as stainless steel and titanium, by manipulating pulse durations and frequencies, a feature not available in many other laser types.
  • Reduced Heat Damage: Because pulse durations can be shortened, MOPA lasers reduce the heat-affected zone on the material being processed. This reduces thermal damage and discolouration, which is particularly important when working with sensitive materials.
  • Efficiency and Longevity: Fiber lasers, including MOPA lasers, are known for their energy efficiency and long operational life, often up to 100,000 hours. This leads to lower running costs over the lifetime of the machine.
  • Minimal Maintenance: MOPA fiber lasers have no moving parts or consumables and are fully sealed against dust and dirt, leading to lower maintenance requirements compared to other types of lasers.

Each of these advantages makes the MOPA fiber laser engraving machine a versatile and valuable tool for businesses across a range of industries, from manufacturing and engineering to retail and creative.

Men at work around a laser machine

Can a MOPA Fiber Laser Engraving Machine be Used for Industrial-Scale Engraving?

These machines are designed for high-precision, high-speed engraving, which makes them ideal for industrial applications. Here are a few reasons why MOPA fiber lasers are well-suited to industrial-scale operations:

  • High Speed and Efficiency: MOPA fiber lasers can operate at high speeds without compromising the quality of the engraving. This allows for increased productivity, making them suitable for large-scale industrial applications.
  • Durability and Reliability: These lasers are built for durability and can run for prolonged periods without breaking down, reducing downtime in industrial settings.
  • High-Quality Results: Despite their speed, MOPA fiber lasers can produce high-quality, consistent results, which is essential in industrial applications where precision and repeatability are crucial.
  • Versatility: They can be used to engrave a wide range of materials, including various metals and certain plastics, making them adaptable to different industries.
  • Low Maintenance: MOPA fiber lasers have few consumables and require less maintenance compared to other types of engraving lasers. This results in less interruption, contributing to more efficient industrial production.

However, the suitability of a MOPA laser system for a specific industrial application also depends on the specific requirements of that application, such as the volume of items to be engraved, the type and thickness of the material, and the required depth of the engraving. Get in touch with our knowledgeable team to discuss your laser requirements and find the right machine for you.

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