What is the difference between TIG and MIG welding done by robots?

Robotic TIG welding focuses on precision and quality, often used for delicate tasks, while robotic MIG welding emphasizes speed .

Introduction

Welding stands as a cornerstone of modern manufacturing and construction, bridging gaps between materials to create structures, products, and machinery that serve an array of purposes. With technological advancements, robotic welding has surfaced, integrating automation into this age-old practice. This transition not only heralds a new era of efficiency but also underscores the importance of understanding the nuances of different welding techniques when executed by robots.

Brief Overview of Welding

Welding is the process of joining metals by melting the parts and adding a filler material to form a joint. There are various welding techniques, each with its own set of advantages and disadvantages. Some common methods include Shielded Metal Arc Welding (SMAW), Gas Tungsten Arc Welding (GTAW or TIG), and Gas Metal Arc Welding (GMAW or MIG). These methods differ in power requirements, with TIG welding typically demanding a power range of 10 to 300 amps, while MIG welding operates between 40 to 700 amps. They also have distinct speed capabilities; for instance, MIG welding is generally faster, achieving speeds up to 10 inches per minute, in contrast to TIG’s 2 to 5 inches per minute. Furthermore, each welding method varies in material compatibility, quality of weld, and cost. For instance, TIG welding produces high-quality welds but often comes at a higher cost, sometimes amounting to $15-$50 per hour, depending on factors like material and labor.

The Importance of Robotic Welding

Robotic welding has revolutionized the industrial landscape, bringing about unprecedented levels of precision, consistency, and speed. These robotic systems can achieve welding speeds of up to 50 inches per minute, depending on the specific application and robot model. Additionally, they offer a remarkable efficiency of around 90-95%, minimizing waste and maximizing production rates. From a cost perspective, the initial investment for a robotic welding system can range from $50,000 to $200,000. However, the return on investment is compelling, given the reduced labor costs, increased throughput, and improved product quality. Another notable advantage is the longevity of these robotic systems. With proper maintenance, a robotic welding system can serve an industrial setting for 8-12 years. With these merits in view, it’s evident that robotic welding not only paves the way for enhanced production metrics but also ensures that products meet rigorous quality standards consistently.

Basics of TIG Welding

TIG (Tungsten Inert Gas) welding, also known as GTAW (Gas Tungsten Arc Welding), is a method that utilizes a non-consumable tungsten electrode to produce the weld. It’s renowned for producing superior quality welds and is especially useful for welding thin sections of stainless steel, non-ferrous metals like aluminum, magnesium, and copper alloys.

MIG

TIG

Principles of TIG Welding

At the heart of TIG welding is the tungsten electrode that carries the current to the welding arc. The heat generated from the arc melts the base metal and forms a molten weld pool. Shielding is provided by an inert gas, typically argon or helium, which protects the electrode and the molten weld pool from atmospheric contamination. The result is a clean, spatter-free weld with precision. The power requirements for TIG welding can vary, with most commercial applications falling within a range of 10 to 300 amps.

Components Used in TIG Welding

TIG welding systems consist of several key components:

• Tungsten Electrode: This is a non-consumable electrode used to conduct the current. Its diameter can range from 0.010″ to 1/4″, with the specific size selected based on the material thickness and type.
• Welding Torch: Houses the tungsten electrode and directs the shielding gas. It comes in various designs, with some allowing for water cooling.
• Shielding Gas Supply: Typically argon or helium. These gases protect the welding area from atmospheric contamination. A typical flow rate is around 10-20 cubic feet per hour.
• Power Supply: Provides the necessary current for welding. TIG welding units can operate on both alternating current (AC) and direct current (DC). The specific power and polarity used depend on the material being welded.
• Foot or Hand Remote Control: This component allows the welder to adjust the current during the welding process, offering better control over the weld.

Advantages and Limitations

Advantages:

• Quality: TIG welding is known for producing high-quality welds, especially on thinner materials.
• Flexibility: It can be used on a wider variety of metals than most other welding methods.
• Control: The welder has greater control over the weld compared to other methods, leading to cleaner, more precise welds.
• No Spatter: Unlike some other welding methods, TIG produces no spatter, reducing post-weld cleanup.

Limitations:

• Speed: TIG welding is generally slower than methods like MIG welding. For instance, while MIG can achieve speeds up to 10 inches per minute, TIG typically ranges between 2 to 5 inches per minute.
• Skill Requirement: TIG welding demands a higher skill level and more training compared to other methods.
• Cost: The equipment and gases used in TIG welding can be more expensive. A typical TIG welding setup might range from $1,500 to $5,000, not including ongoing costs for consumables and shielding gases.

Basics of MIG Welding

MIG (Metal Inert Gas) Welding, also known as GMAW (Gas Metal Arc Welding), is a process where a continuous solid wire electrode is fed through a welding gun and into the weld pool, joining the two base materials together. A shielding gas is also sent through the welding gun to protect the weld pool from contaminants. It’s a popular welding method due to its adaptability and speed.

Principles of MIG Welding

The core principle behind MIG welding is the use of a wire electrode that’s continuously fed into the weld joint, and it’s electrically heated by the current. The heat melts the wire, creating a weld pool which then cools, joining the base materials. The role of the shielding gas in MIG welding is to prevent atmospheric contamination of the weld pool. Typically, carbon dioxide or a mix of carbon dioxide and argon are used for this purpose. The power range for most MIG welding processes usually falls between 40 to 700 amps.

Components Used in MIG Welding

Several components make up a standard MIG welding system:

• Wire Electrode: A spool of wire that’s continuously fed to the weld joint. The wire diameter often ranges between 0.023″ to 0.045″, depending on the material and the desired weld characteristics.
• Welding Gun: A handheld tool that feeds the wire electrode and shielding gas to the weld joint.
• Shielding Gas Supply: Common gases include carbon dioxide and mixes of carbon dioxide and argon.
• Power Supply: Provides the required current. MIG welding units operate using direct current with the wire electrode connected to the positive terminal (DCEP).
• Wire Feed System: This system continuously feeds the wire electrode to the welding gun at a controlled speed. Depending on the material and the application, feed rates might range from 100 to 800 inches per minute.

Advantages and Limitations

Advantages:

• Speed: One of the primary benefits of MIG welding is its speed. It can achieve welding speeds of up to 10 inches per minute, which is faster than many other welding techniques.
• Versatility: MIG welding can be used on a wide array of metals and is suitable for both thick and thin materials.
• Ease of Use: MIG welding is often considered easier to learn and execute than TIG welding, making it a popular choice for beginners.

Limitations:

• Shielding Gas: The requirement for shielding gas can increase operational costs. A standard-sized cylinder of CO2/Argon mix might cost around $50-$200, depending on regional pricing and cylinder size.
• Weld Appearance: While MIG welds are strong, they may not be as clean or aesthetically pleasing as TIG welds.
• Porosity Risks: If the shielding gas is disrupted or if there are contaminants on the material, there’s a risk of porosity in the weld.
• Initial Cost: A basic MIG welding setup can range from $500 to $2,000, but professional-grade systems can be significantly more expensive.

Robotic Welding Systems

As manufacturing processes evolve, so too do the methods by which we construct and assemble products. One such development that has revolutionized the welding industry is the introduction of robotic welding systems. These systems combine the precision of robotics with the foundational practices of welding to create products faster, more efficiently, and with greater consistency than ever before.

Evolution of Robotic Welding

Robotic welding began its journey in the 1960s, with the advent of the first electrically powered industrial robots. These machines were rudimentary by today’s standards but marked a significant leap forward in automated manufacturing. By the 1980s, advances in computer technology and engineering facilitated the development of robots specifically designed for welding tasks. As the technology matured, we witnessed a shift from manual or semi-automated welding processes to fully automated robotic systems in industries ranging from automotive to aerospace. This transition was driven by the desire for faster production rates, higher quality welds, and a reduction in human error and workplace injuries.

Features and Capabilities

Modern robotic welding systems are marvels of engineering, offering a range of features that make them indispensable in contemporary manufacturing:

• Precision: Robots can achieve accuracy levels within a fraction of a millimeter, ensuring consistent and high-quality welds.
• Speed: Robotic systems can achieve welding speeds upwards of 50 inches per minute, depending on the specific application.
• Repeatability: Unlike human welders, robots can reproduce the exact same weld over and over, ensuring product consistency.
• Adaptability: Many modern robotic systems come with adaptive welding technology, allowing them to adjust parameters in real-time based on sensor feedback.
• Multi-Process Capability: Some advanced robots can switch between welding processes (like TIG and MIG) in a single operation.

The initial investment for such systems can range between $50,000 to $200,000, but the ROI in terms of speed, quality, and efficiency makes them a valuable asset for many manufacturers.

Safety and Efficiency Considerations

While robotic welding systems offer many advantages, they also introduce new considerations in terms of safety and efficiency:

• Safety Protocols: It’s crucial to establish safety protocols to protect workers. This includes barriers, safety interlocks, and emergency stop mechanisms. Additionally, training workers to operate and maintain these robots safely is paramount.
• Efficiency: While robots are inherently efficient, their maximum potential is realized only when integrated into a well-optimized workflow. This involves considering factors like part positioning, accessibility for the robot, and the sequencing of welding operations.
• Maintenance: Regular maintenance is vital for ensuring the long lifespan of a robotic welding system, which can be between 8-12 years with proper care.
• Cost Efficiency: While the initial cost might be high, the efficiency gains, reduced wastage, and higher quality often lead to significant cost savings in the long run.

Differences in Robotic TIG and MIG Welding

Both TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding are popular arc welding processes. When integrated into robotic systems, they offer enhanced precision and efficiency. However, there are distinct differences between robotic TIG and MIG welding that influence their suitability for various applications and the overall outcome of the weld.

Technical Differences

Robotic TIG welding employs a non-consumable tungsten electrode to produce the weld. Shielding is provided by an inert gas, typically argon. On the other hand, robotic MIG welding uses a continuously fed wire electrode, with shielding provided by a gas or gas mixture, often carbon dioxide or a mix of carbon dioxide and argon.

TIG welding generally requires a more complex power supply, capable of alternating current (AC) for welding materials like aluminum, or direct current (DC) for steels. The typical power range for TIG welding can span from 5 to 600 amps. MIG welding predominantly uses DC with a power range between 40 to 700 amps.

Material Suitability and Applications

TIG is often chosen for its versatility. It’s suitable for welding a wider range of materials, from aluminum, steel, bronze to even exotic metals like titanium. Due to its precision, TIG is the go-to choice for critical applications in the aerospace, nuclear, and food industries, among others.

MIG, with its faster deposition rates, is favored for applications where speed is essential. This makes it ideal for the automotive sector, construction, and large-scale manufacturing. MIG is highly effective for welding steel, stainless steel, and aluminum, but might not be the best choice for more exotic or thin materials.

Cost Implications

TIG welding typically has higher equipment costs due to its sophisticated power supply and tungsten electrodes. The cost of tungsten can be around $3 to $15 per electrode, depending on the type and size. However, the non-consumable nature of the electrode can offer long-term savings.

PLASMA

ROBOT

MIG welding’s consumable wire electrodes and potentially more expensive shielding gas (when using mixes) can lead to higher recurring costs. Wire electrodes can range in price from $5 to $50 per spool, depending on the material and quality.

However, the faster welding speeds associated with MIG can result in labor and production time savings, offsetting some of the material costs.

Quality and Finish Considerations

TIG welding is renowned for its superior weld quality and aesthetic finish. It offers clean, spatter-free welds, making it ideal for visible and critical welds where appearance matters.

MIG welding, while faster, can sometimes result in spatter, which may require post-weld cleaning. However, advancements in robotic welding technology have significantly improved MIG’s finish over the years.

Case Studies

The application of robotic welding in industries worldwide has seen a surge due to its undeniable advantages in precision, consistency, and speed. To understand its real-world impact, it’s crucial to dive into case studies that highlight its success and challenges in specific scenarios.

Real-world Applications of Robotic TIG Welding

Aerospace Industry: Precision in Aircraft Parts

In the aerospace sector, the margin for error is minimal. A leading aircraft manufacturer adopted robotic TIG welding for producing components of its commercial jets. The goal was to ensure a consistent quality of welds for parts that undergo extreme pressure and temperatures during flights.

With an investment of approximately $1.2 million in advanced robotic TIG welding equipment, the manufacturer increased its welding speed by 40% compared to manual processes. The precision achieved resulted in welds that met the rigorous quality standards of the aerospace sector, with an almost zero-defect rate. This not only improved the safety and reliability of the aircraft but also saved an estimated $300,000 annually in reduced rework and scrap costs.

Medical Devices: Stainless Steel Components

A medical device company that specializes in surgical tools faced challenges with welding thin stainless steel parts. Robotic TIG welding was their solution. The delicate nature of these tools required pinpoint accuracy, a strength of TIG welding.

The company reported a reduction in production time by 30% and a significant improvement in the quality of their products. Moreover, the consistency achieved through automation ensured that every tool met the stringent health and safety standards, a vital aspect in the medical field.

Real-world Applications of Robotic MIG Welding

Automotive Industry: Car Frame Assembly

A renowned car manufacturer was aiming to ramp up its production without compromising on the quality of welds on their car frames. By integrating robotic MIG welding into their assembly line, they achieved an astounding production speed of welding a car frame in just under 90 minutes.

This faster production rate led to an annual output increase of 15%. Even with the speed, the quality of the welds remained top-notch, with the company noting a decrease in weld-related defects by 20%. With an initial setup cost of around $2 million for the robotic systems, the company estimated an ROI in just under three years, thanks to increased production and reduced defect rates.

Construction: Large Scale Infrastructure

In the construction of a major overpass bridge, a construction company opted for robotic MIG welding to join large steel beams. Given the size and weight of these beams, manual welding was not only time-consuming but also posed safety risks.

Through the adoption of robotic MIG welding, the company managed to cut down the welding time by half. Additionally, the strength and quality of the welds were consistent across all beams, ensuring the longevity and safety of the bridge structure. The company reported a savings of around $500,000 in labor costs and project timeline reductions.