Jigless Welding: The Next Competitive Edge

In the search for another advantage in an ever-changing production environment, this method offers shops an alternative for reducing their costs, improving their quality and improving their manufacturing flexibility.

The marriage of robotics to welding has reached a stage in its evolution that allows manufacturers to leverage a process called “jigless welding” to reach new levels of productivity and quality at a point in time where the industry faces a shortage of skilled labor.

Jigless welding pairs a robotic welder with a material handling robot that presents the workpiece to the welding robot. Optimal weld quality, lower cost and smaller system footprints are the significant returns on a company’s investment when pairing a welding arm with a material handling robot.

The practice of using a second robot to hold a robotic welding workpiece is a more precise way of accomplishing the same end result. A gripper or some sort of holding tool is placed on the material handling robot to grab or mount the workpiece and present it to the welding robot. By automating this process it is easier to maintain preset tolerances and quality standards on the finished part.

In traditional robotic welding cells, a part is placed on a fixture table and the welding robot works on the static part. The cell is generally manned by an operator who is charged with setting materials into a preset jig to be accessed by the robotic welding arm. The same operator would then progressively rotate the part about the work table to prepare for required welding on sides of the workpiece that were unreachable in the original position.

The drawbacks to this method include the process and handling time consumed by setting and resetting parts and fixtures; uneven welding due to limitations in access caused by the static part positions; and operator error in placing the parts through the various stages of robot welding.

Another limitation to the traditional approach: The part becomes its own roadblock — a welding robot cannot weld what it cannot reach. Some conventional welding systems offer two dedicated axes of part positioning equipment to alleviate these reach constraints, but the cost of these two positioning axes can add up — particularly when contrasted with the access freedom provided by a six-axis handling robot.

FEATURES AND BENEFITS OF JIGLESS WELDING
The benefits of jigless welding should be attractive to a multitude of manufacturers and shops looking to:

• Maintain and improve quality
  • Weld joints are positioned optimally to maximize throughput and quality
  • Consistency of welds and weld location
• Lower costs
  • Reduce manhandling and re-fixturing of parts
  • Smaller welding robot arm may suffice when paired with a handler
  • Work completed in less time
  • Multiple processes can be completed in a single cell
  • Fewer robotic welding arms needed
  • Future expandability
  • Safer environment for workers
• Save space
  • System footprint smaller
  • Parts can be stacked or palletized
• Increase production
  • System can read and “know” the part and path for welding
  • Offline programming allows for programming the next line while keeping production flow
  • Future functions can be modeled and simulated before production begins

MORE CONSISTENCY, LESS HANDLING
If a part is welded on multiple planes with a six-axis handling robot, the workpiece can be held with minimal reach restrictions and limitless part positions to maximize the welding robot’s operations. The handling robot literally turns the part to an infinite number of positions, exposing the welding areas and presenting it to the welding robot in the optimum procedural location.

Jigless welding permits the manipulation of parts to occur in a smaller envelope, reducing the need for larger or multiple work areas. The part can be picked up by the material handling robot and brought and presented to the welding arm in preset coordinates. The part is then rotated through the entire welding process without the need for human intervention. The handling robot can even stack a finished part on a pallet or other area further reducing the man-hours involved in production.

Capital investment can be less and return on investment improved, because you decrease the need to purchase multiple positioning axes and extra welding robots. Due to the almost limitless positions a handling robot can articulate, the potential to reuse this equipment in the future is increased. The limitations are the payload of the material handling robot and the imagination of the production team.

Throughput flexibility to the jigless approach is increased by adding a static process tool (like a stationary spot welder that the handling robot would present the part to) or placing a tool changer on the welding robot.

Through identifiers such as barcoding, jigless welding is adjustable to varied production lines where one part to the next may have different design parameters or makeup. The system can recognize the part and through subroutines change the movement programs and welding parameters to accommodate a mix in parts. This supports automated changeover of a production line.

An additional benefit of jigless welding is the opportunity to leverage offline programming (OLP). The harmonization of the handling robot and the welding robot can easily be programmed offline with special software routines, even while another part is under production.

Simulating the process between robots provides engineers and management a picture of what production will look like, offering the chance to troubleshoot issues before production begins. OLP, combined with jigless welding, gives operations of all sizes the ability to quote, plan, and prepare for production runs with minimal overhead investment.

ROBOTIC HANDLER, STATIONARY WELDER
Another form of jigless welding is to pair a static welding gun with a material handling robot. This robot can hold the workpiece and run the weld paths of the part over the stationary weld torch. This doesn’t have all the functionality of two robots doing jigless welding, but can offer improvements over positioning the workpiece manually and can afford a higher level of quality than traditional automation.

For manufacturers looking for a competitive edge in this ever-changing production environment, jigless welding offers an alternative for reducing costs, improving quality, and offering manufacturing flexibility. Durability and consistency bookend the benefit package of jigless welding — which quietly produces part after part.