Robotic Welding Systems

Robotic welding is suitable for any welding process designed for automation in that it requires repetitive tasks on similar pieces. Robotic welding also works well when there are welds on more than one axis, or where access to the pieces is difficult. When programmed, robots perform the same welds every time on workpieces of the same dimensions and specifications. In about 80 percent of applications, robotic welding is used with the solid wire GMAW process.

Throughout the years, D/F Machine Specialties’ MIG & TIG torches were used exclusively on the following FANUC Robotics System 100 Models - ArcMate 100, ArcMate 100i, ArcMate 100iB, and ArcMate 100iB/6S. The typical power source used with the D/F Torches on the Fanuc robotic cell was a Lincoln Powerwave 450 power supply.

QUALITY: Higher quality welds are maintained with the mechanical consistency of the robot. Consistency is provided by the precise movement of the robot arm and torch, as well as the wire feed speed and travel speed. Robotic welding creates a more consistent weld strength and better weld appearance.

PRODUCTION COSTS: Robotic Welding reduces productions costs by using fewer welding consumables and producing fewer scrapped parts.

RETURN ON INVESTMENT: The ROI for an industrial welding robot usually appears after about 6 months. Increased productivity, decreased labor, and many other benefits of automated welding factor into faster ROI times.

PRODUCTIVITY: The repeatability and speed of the robotic welding system provides increased productivity. Robotic welding can produce at a higher rate than human welding, and allow for a more productive workforce.

SAFETY: Employers find that they have fewer employee accidents and lower Workers Comp claims when they change to robotic welding.

There are two popular types of industrial welding robots, articulating robots and rectilinear robots. Robotics control the movement in each of these robot types by rotating a wrist in space. These two types are defined as follows:

1. Rectilinear robots move in line in any of three axes (X, Y, Z). In addition to linear movement of the robot along axes there is a wrist attached to the robot to allow rotational movement. This creates a robotic working zone that is box shaped.

2. Articulating robots employ arms and rotating joints. These robots move like a human arm with a rotating wrist at the end. This creates an irregularly shaped robotic working zone. Most articulated welding robots feature six axes and function as part of a robotic system or workcell.

Robotic welding systems reduce production costs and improve quality with consistency and repeatability. Consistency is provided by the precise movement of the robot arm and torch, as well as the wire feed speed and travel speed. The repeatability of the welding robotic system provides increased productivity. To create a successful robotic welding system, you need an integrator who can properly design a program that integrates the parts to be welded and the robotic cell and tooling. Robotic welding is simpler than one might think, but it requires precise measurements and an understanding of parameters of the equipment. It is important to team with an integrator with the experience and customer service demanded by your robotic needs.

Benefits of Robotic Welding:

• Reduce Production Costs - Fewer scrapped parts, reduced amount of welding consumables needed
• Improved Product Quality - More consistent weld strength, better weld appearance and consistent quality
• Increased Productivity - Robotic welding produces at a higher rate than human welding
• Cost Justification - Lower costs of robotic equipment, scarcity of highly skilled labor
• Improved Safety - Fewer employee accidents / Lower Workers Comp claims, more productive workforce

Things to consider before beginning a new robotic welding project:

• The parts to be welded
• Weld joint accessibility
• Repeatability of the parts
• Fixture requirements

Benefits:

• Features highest motion speeds in class for maximum performance and productivity.
• Best in class reach versus stroke ratio.
• Compact design simplifies installation and transportation of system.
• Fastest wrist axes in class minimizes air cut time by quickly reorienting the weld torch.
• High axis speeds maximize product throughput.
• Design allows for extremely small weld cells or a high density of arc welding torches in a given area.

Features:

• Slim wrist size enables the robot to enter into smaller openings in the work space.
• 951 mm reach.
• 622 mm stroke.
• 6 kg payload on faceplate.
• All axes mechanical brakes.
• Absolute encoder positioning.
• TurboMove^TM advanced servo control features allow quick and smooth point-to-point motion, which increases arc on-time and throughput.
• “Plug and play” simplicity with Lincoln Electric's Power Wave or STT^TM (Surface Tension Transfer) power sources.
• Compatible with all major brands of welding equipment.
• Arc welding teach pendant with application-specific hard keys offers intuitive control over the process.
• Interfaces with most types of servo-driven or indexing positioners.
• Multiple mounting positions include upright, inverted, wall or angle mount with no changes to the mechanical unit.
• Sealed bearings and drives provide protection and improve reliability.
• RV reducer drivetrain with integral bearings provides rigidity and performance in a compact package.

Options:

• EMI shielding kits for TIG (GTAW), plasma (PAW) and plasma cutting (PAC) allow operation in harsh EMI (electro-magnetic interference) environments.
• Additional process welding I/O integrates multi-channel welding equipment such as 4 channel TIG and 3 channel MIG (STT).
• Various robot connection cable lengths for flexible cabinet placement and optional track rated cables.
• J1 axis stroke modification kit.
• Auxiliary axis packages for integration into welding.

Note: ARC Mate is a registered Trademark of FANUC LTD.

FANUC Ferris Wheel System - The FANUC Ferris Wheel Workcell is designed to save space and enhance operator safety.

FANUC Gantry System - A gantry robot system mounts a robot arm on an overhead track, creating a horizontal plane that the robot can travel and extending the work envelope.

FANUC Manual Turntable System - A FANUC workcell with a manual turntable is an ideal solution for applications that require loading and unloading parts while the robot is in operation.

FANUC Stationary Table System - FANUC robots offer excellent ROI in welding and handling applications. Realize incredible savings with a FANUC turnkey workcell that includes a single or dual stationary work table.

FANUC Track System - The Dual FANUC Track System allows for nearly 63 feet of travel along a servo controlled track to accommodate applications with large parts and multiple processes.

FANUC Turntable System - Order a workcell that fits your needs! Available in any size, this workcell pairs a 180 degree table with one or two FANUC robot arms for maximum productivity.

Fanuc - Intelligent Robot Solutions

Application: Arc Welding
Industry: Medical Devices
Products Used: (3) Fanuc Arc Mate 100, Fanuc Arc Tool

Challenges:
When a wheelchair manufacturer introduced a new line of lightweight steel and aluminum wheelchairs, eight workers were assigned the job of brazing all of the frame components. Production rates in the first year reached 2,500 wheelchairs, and plant management found that the current project team was unable to keep up without hiring additional workers.

The company was producing about 18,000 wheelchairs per year, and according to the director of operations, “It didn't take long for us to realize that we needed to find a better method to meet production goals.”

Solution:
The company turned to robotic arc welding to help reach its production goals. An industrial distributor in Elyria, Ohio, was enlisted to help the wheelchair manufacturer change from manual to robotic welding. “We needed a robot to weld small diameter tubing with wall thickness of 0.049 to 0.065 inches,” said the director of operations. In addition, the robot would be required to turn tight corners when welding chair joints.

The integrator selected Lincoln Electric and FANUC Robotics to develop a robotic arc welding system to weld mild-steel wheelchair side frames and foot rests. The solution included robots, tooling, welding equipment, software and system integration.

Three Robots Do the Job of 45 Workers

This company is the first wheelchair manufacturer to robotically weld all frame components and currently has three robotic arc welding cells and plans to install a fourth.

According to the director of operations, the company would have needed 45 brazers working on two shifts to meet production goals of 45,000 wheelchairs. With that much labor content, they would have had a hard time remaining profitable.

Each of the three robotic welding cells uses a FANUC Robotics ARC Mate 100 robot, Lincoln NA-5R control and wire drive, a Lincoln Idealarc CV-400 power supply, part-specific tooling and FANUC ArcTool application software. Two cells produce side frames of six components and subassemblies, and foot rests. The third cell welds two side frames and foot rest assemblies to complete the wheelchair structure.

During system operation, workers who previously performed manual brazing are now trained to operate and maintain the robotic system. Following tooling setup, an operator loads a fixture onto a 180-degree turntable positioner. The two-station positioner allows the operator to load parts and remove welded assemblies while the robot welds a second assembly.

After welding, the operator inspects each weld for cosmetic quality. To ensure structural quality, the company performs destructive tests three times per day.

Weld reject rate is less than one percent and weld rejects require only manual touch-up at a manual brazing station. In addition, cosmetic quality has significantly increased.

Production rates have improved as well. Manual brazing of wheelchair frames took as long as 45 minutes; however, robotic welding has reduced frame production time to about 3 minutes.