A robotic welder can weld at speeds of up to 60 inches per minute (IPM) for standard applications. However, advanced robotic systems can achieve even higher speeds, reaching up to 100 IPM or more. These high speeds, combined with precision and consistency, make robotic welders a valuable asset in various industries.
Introduction of Robotic Welding
Robotic welding, an application of automation technology, refers to the use of mechanized programmable tools (robots) which completely automate a welding process by performing both the weld and handling part. This practice has been gaining prominence since the late 1980s due to the technological advancements and growing industrial requirements.
Robotic welding systems typically consist of a welding machine, robot manipulator, and a controller, which manages operations. Most of these systems are powered by electric energy, and the average power consumption can range from 4.5kW to 13.5kW based on the size and complexity of operations.
The Rise of Robotic Welding
The global robotic welding market was valued at $5.40 billion in 2021 and is projected to reach $10.78 billion by 2027, growing at a CAGR of 8.5% during the forecast period. This growth is driven by the increasing adoption of automation in manufacturing industries and the need for high-quality and efficient welding operations.
In 2021, the arc welding segment held the highest market share of around 62% due to the advantages it offers, such as increased speed, precision, and repeatability. Furthermore, the demand for spot welding robots is anticipated to grow significantly over the forecast period, given their capability of performing high-volume welding operations with great efficiency.
The automotive industry is a significant end-user of robotic welding and accounted for over 32% of the overall market share in 2021. However, sectors such as construction and aerospace are also fast adopting these automated systems due to the myriad of benefits they offer.
Advantages of Robotic Welders
Robotic welders offer several advantages over traditional manual welding. The following are the key benefits:
Increased Efficiency and Productivity
Robotic welders are designed to weld at higher speeds and for longer durations without any breaks. On average, robotic welding can improve productivity by 25-30% compared to manual welding.
Superior Precision and Quality
Robotic welders deliver a high degree of precision, typically achieving a repeatability of ±0.02mm. This precision ensures consistent high-quality welds, reducing the need for rework and associated costs.
Improved Safety
Robotic welders help mitigate various workplace hazards, including exposure to welding fume, extreme heat, and the risk of injury from repetitive tasks.
Cost Savings
Although the initial investment for a robotic welding system can range from $50,000 to $200,000 based on specifications, these systems can provide significant cost savings in the long run. They reduce labor costs, material waste, and energy consumption, offering a return on investment period typically within two years.
5. Flexibility
Robotic welders can be reprogrammed and deployed for different tasks and welding operations, providing flexibility in the production process. This makes them a valuable asset in industries with a wide range of welding requirements.
Factors Influencing Welding Speed
Welding Process and Technique
Manual vs. Automated Welding
Manual welding typically moves at a pace of 3 inches per minute (IPM), depending on the skill of the welder and the complexity of the weld. On the other hand, automated welding systems like MIG or TIG can weld at speeds of up to 120 IPM, significantly reducing the total welding time.
Shielded Metal Arc Welding (SMAW)
SMAW, also known as stick welding, is slower because it requires frequent electrode changes. An experienced welder might achieve speeds of around 5 IPM.
Welding Material and Thickness
Material Type
Materials such as aluminum and stainless steel require slower welding speeds compared to mild steel. For instance, mild steel welding speed can reach 40 IPM, while for aluminum, it might be just 15 IPM.
Thickness
Thinner materials are welded at faster speeds. A 1/4 inch thick plate might be welded at 30 IPM, while a 1-inch thick plate could require a slower speed of around 10 IPM to ensure penetration.
Robot Configuration and Capabilities
Robot Reach and Precision
A robot with longer reach and better precision can increase the welding speed. A robot with a reach of 1.4 meters and repeatability of ±0.02 mm, like the Fanuc ArcMate series, can execute faster, more accurate welds than less capable robots.
Integration with Sensors
Robots integrated with sensors for seam tracking or weld pool control can adjust their operation in real-time, boosting the overall welding speed.
Power Source and Welding Parameters
Voltage and Amperage
The power source directly impacts the welding speed. For example, a 350-ampere power source can accomplish a weld up to 3 times faster than a 150-ampere source, given the same welding conditions.
Pulse Frequency
Higher pulse frequencies result in quicker travel speeds. In pulse MIG welding, for example, using a frequency of 150 PPS (Pulses Per Second) may enable speeds of 40 IPM, while lowering the pulse frequency to 50 PPS could reduce the speed to around 15 IPM.
Key Performance Indicators (KPIs) for Robotic Welding Speed
Travel Speed
Significance of Travel Speed
Travel speed, measured in inches per minute (IPM), is the speed at which the welding torch moves along the joint. It is directly proportional to productivity; higher travel speeds yield more welds per hour. For instance, increasing travel speed from 20 IPM to 30 IPM can result in a 50% increase in productivity.
Determinants of Optimal Travel Speed
Choosing the optimal travel speed is crucial. Too slow, and there can be excessive heat input leading to warping. Too fast, and there may be insufficient penetration. A common range for travel speed in automated MIG welding is 15-40 IPM, but this varies with material type and thickness.
Deposition Rate
Deposition Rate Explained
The deposition rate refers to the amount of filler metal deposited in the weld joint over time, typically measured in pounds per hour (lbs/hr). An average deposition rate for an automated MIG process might be 8 lbs/hr.
The Role of Deposition Rate in Cost Estimation
Knowing the deposition rate is crucial for cost estimation. If a pound of filler wire costs $2, and the deposition rate is 8 lbs/hr, the welding cost for filler metal will be $16 per hour.
| Deposition Rate (lbs/hr) | Cost per lb of Filler ($) | Cost per hour ($) |
|---|---|---|
| 8 | 2 | 16 |
Arc On-Time
Definition of Arc On-Time
Arc On-Time refers to the percentage of total operation time the welding arc is active. If a welding operation lasts for an hour and the arc is active for 30 minutes, the Arc On-Time is 50%.
Efficiency and Arc On-Time
Higher Arc On-Time signifies more efficient operation. For example, an increase in Arc On-Time from 50% to 70% signifies a 40% increase in productive work.
Dwell Time
Understanding Dwell Time
Dwell time refers to the time the welding torch pauses at the end of a weld. Reducing dwell time can significantly increase productivity. For instance, reducing dwell time from 3 seconds to 1 second on a weld cycle of 30 seconds (including dwell time) can increase productivity by about 7%.
Dwell Time and Quality
However, reducing dwell time too much may compromise weld quality, potentially leading to increased costs due to rework. Therefore, an optimal balance between speed and quality is required.
Robotic Welding vs. Manual Welding Speed
Comparative Analysis of Speed
Manual Welding Speed Metrics
The speed of manual welding varies significantly based on the welder’s expertise, the type of joint, and the welding process used. However, a skilled welder using a common technique like Shielded Metal Arc Welding (SMAW) can average around 3-5 inches per minute (IPM).
Robotic Welding Speed Metrics
Robotic welding, particularly processes like MIG or TIG, can consistently maintain higher speeds, often ranging from 50 to 120 IPM.
| Welding Type | Average Speed (IPM) |
|---|---|
| Manual | 3-5 |
| Robotic | 50-120 |
Efficiency Gains with Robotic Welding
Work Hours and Welding Speed
Robotic welding systems can operate continuously without fatigue, effectively multiplying the work hours compared to human welders. If a manual welder works an 8-hour shift, achieving an average speed of 4 IPM, a robotic system operating 24/7 at 80 IPM would accomplish the equivalent of 240 human work hours in a single day.
Cost Efficiency
Assuming the wage for a welder is $20 per hour, the labor cost for manual welding for a day (8 hours) would be $160. However, the 24/7 operation of the robotic system, accomplishing 240 human work hours in a day, would represent a labor cost equivalent of $4,800, providing significant cost savings when considering the high initial investment for robotic systems.
Complex Joints and Difficulties in Speed
Manual Welding with Complex Joints
Manual welders have the advantage of adaptability when dealing with complex or irregular joints. Suppose a specific complex joint takes a manual welder 7 minutes to complete.
Robotic Welding with Complex Joints
The same joint might initially take a robotic system 10 minutes due to the programming and adjustments needed for precision. However, after the initial setup, the robotic system can reproduce the weld at a consistent speed, without breaks or reduction in quality.
Long-term Efficiency in Complex Welds
In a scenario where 1,000 similar complex joints are required, the manual welder would take approximately 7,000 minutes (assuming no decrease in speed), while the robot would take about 10,000 minutes. However, factoring in breaks and working hours for the manual welder, the robotic system would complete the job in a much shorter real-time period, once again highlighting the efficiency of robotic welding for large-scale or repetitive tasks.