Workholding equipment is critical to welding, as it is to all areas of the metal working trades, and sales of workholding equipment for welding, seems to be holding its own despite some downturn in shipments of primary equipment.

The Association for Manufacturing Technology’s Workholding Product Group recently said shipments of workholding equipment from the U.S. were 20.8 percent in the third quarter of 2007, compared to shipments in the same period in 2006. The 35 companies that participate in the Association for Manufacturing Technology Workholding Product Group’ said workholding equipment shipments in the U.S. totaled $55.1 million while exports amounted to $12.8 million for the third quarter of last year. The Workholding Product Group comprises AMT members who produce fixtures and other workholding equipment.

Domestic workholding equipment orders increased 12.0 percent and U.S. exports increased 82.8 percent from year-earlier levels, boosted by record exports in July. The July shipments were followed by strong exports in the second two months of the quarter, according to the report.

The Midwest remained the largest domestic destination, with 42.8 percent of total domestic shipments going to that region.

Driving the demand for innovations in workholding equipment is the need for ease of use, and designs that allow welders to perform close-tolerance welds with easy setup and part removal.

The line of Strong Hand Tools from Valtra Inc. (www.stronghandtools.com) features the company’s 3-Axis Welders Angle Clamp. For welders who currently use 90 degree welders angle clamps, 90 degree vise clamps, 90 degree angle miter clamps or 90 degree jig and fixture clamps, the company said its 90 degree 3-Axis Welders Angle Clamp provide a third axis. Valtra said that allows work to be positioned in a 3-axis workpiece in one easy setup, and enables welders to hold the workpiece in position during the cool down period to minimize distortion from contraction. The third axis arm is a swing arm that allows easy part removal because the work swings away from the third axis arm.

Ray Strickland, vice president of sales for Valtra Inc., said the 3-Axis Welders Angle Clamp is revolutionary in the way the company integrated the standard 2-axis vice with an added an upper bracket for use in both 2-axis and 3-axis welds.

“You can hold parts in the traditional horizontal position but, with the upper bracket, you can do vertical positioning as well. With one set up you can tack weld it all in one operation,” Strickland said.

Magnetic workholding is becoming a popular alternative to workholding equipment, and Valtra’s Strong Hand tools also feature the company’s Adjust-OMatic magnetic squares.

The company said its Adjust- O-Mat ic squares feature an easily accessed on/off switch. The company’s magnetic workholders are made with rare earth magnets, and are designed to hold work in 45-degree or 90-degree positions.

New collision sensors for robotic arms are designed to help the robots to avoid crashes with work pieces and fixtures. The red arrow in the photographs point to the sensors that are added unobtrusively near the torches on the end of the robotic arm. (Photos courtesy of Applied Robotics.)

Peerless Industrial Equipment Corp. (www.peerlessusa.com) distributes a range of magnetic welding clamps for positioning and workholding for welding and general fabrication applications. The company said its magnetic welding clamps can be used on pipe, plate, sheet and other ferromagnetic materials.

Most of the clamps for welding are triangular to keep the clamp away from the actual point of the weld, and provide a temporary hold on the workpiece and not during the entire welding operation.

Workholding Equipment for Robotic Cells
Applied Robotics has developed workholding fixtures designed specifically for robotic welding applications. The company said its workholding products are designed to ensure quality and prevent scrap.

Applied Robotics said the end of arm tooling that holds the torch is critical to producing a high-quality weld, and it has developed an auxiliary collision sensor for arc welding to ensure that the torch avoids crashes with the workpiece and work fixtures. The Applied Robotics collision sensor is designed for arc welding, and is attached to a robot arm.

The company said collision protection devices do not hold the torch rigid enough in normal operation, causing proximity switches to give false reset signals. That compromises repeatability and weld quality, the company said.

Applied Robotics (www.arobotics.com) said its two QuickStop (AW Models) collision sensors are designed specifically for for arc welding, laser and plasma cutting, and avoid the problem of having false reset signals.

The company said its QuickStop units have pneumatic chambers that incorporate metal-to-metal seals to hold the units rigid during articulated robot motion. Air pressure to the unit can be adjusted to ensure correct breakaway resistance, and a fast-acting pressure switch monitor air pressure to reset the sensor and put it into the proper position before resuming operation.

Applied Robotics also has developed a collision sensor for laser- beam welding, for applications which the laser-beam welding heads are attached robotic arms.

Applied Robotics said its collision sensor is designed to protect laser tooling and the robotic arm, and to avoid collisions.

Applied Robotics said its QuickStop collision sensors are dynamically variable with a regulated air supply to provide positive pressure that holds the unit rigid. In a collision, the air chamber seal is opened while the shut-down signal is sent to the robot controller.