Technology Research Report
Posted by admin as Research papers
Free Technology research report:
To effectively compete in the global marketplace, a manufacturing firm will likely be required to develop both a mixed product or service strategic orientation and highly flexible manufacturing processes. Today’s information and manufacturing technologies provide aggressive market-driven manufacturers with the capabilities to prosper at levels not experienced since the first industrial revolution. This column examines two common marketing strategies and explains how manufacturers can use changing technologies to implement the best combination of these strategies.
In today’s competitive world, current, relevant, and accurate information has become increasingly critical for assessing customer needs. As these needs become increasingly sophisticated, successful firms aggressively attempt to more accurately identify and then uniquely serve those needs. Executives face the challenge of developing strategies and tactics that promote the manufacturing flexibility necessary for consumer responsiveness.
Welding jobs are complex. However, manufacturers of welding robots and third-party developers are steadily improving the capabilities and range of software for programming robotic welding operations. Welding is an orchestration of angles, movements, materials, voltages, and temperatures. The process of following a seam or hitting a spot is complicated by numerous factors, each of which has to be’ precisely calibrated. On the factory floor, the welding torch has been passed from human to robotic hands. Where craftsmen once assured quality welds by virtue of their skill, software systems have been developed for automated control of industrial welding. (Puttre)
Unlike other computer-aided manufacturing operations such as milling and lathing, welding has not benefited from a wealth of third-party software development. Most of the control software for robotic welders is written by the manufacturers of the robots themselves. In general, this software is proprietary and engineered for specific machines. “There are not many generic controllers and none that handle all welding functions,” said David Yapp, section manager for fusion welding and automation at the Edison Welding Institute (EWI) in Columbus, Ohio. He indicated that while CAM systems have a number of standards for modeling and data transfer inherited from their CAD forebears, such as NURBS, IGES, and ACIS, there are no corresponding standards for computer-aided welding software. (Puttre)
However, Yapp pointed out that organizations such as EWI and The Welding Institute (TWI) in Cambridge, U.K., as well as some private companies, are developing software systems for automating welding functions that are applicable to a broad range of welding robots. Advanced Manufacturing Engineering Technologies (AMET) in Rexburg, Idaho, for example, has developed a welding data-acquisition and control system for graphical program creation and editing of high-end welding operations. Matra Datavision in Paris markets a welding control program in Europe based on its Euclid-IS design system. (Puttre)
Traditional programming of robotic welders is done through teach pendants and control panels on the machines themselves. Users effectively pantomime a desired welding operation with the teach pendant, which transfers the coordinate point logic of the motions to the controller’s memory. At key points of the process the user inputs data via the control panel to regulate the amperage of the discharge from the welder’s electrodes and the rate at which wire welding material feeds, in the case of seam welding. Spot welding is similar, except that precise points rather than contours are programmed. In all cases, the angle and travel speed of the welding gun have to be specified. Equipment for spatter cleaning, venting, and cooling also have to be programmed. All of these variables may change dynamically during the course of the procedure, and the programming has to reflect this. In addition, other devices in the welding work area, called a cell, have to be programmed with instructions controlling the movement of the parts to be welded through the cell.
These functions involve a mix of analog and digital signals. Reference voltages for the current source and wire feed units are typically controlled by analog signals while on/off commands, contour following and coordinate point data, gun angles, and supervisory data are typically expressed digitally. According to Chris Anderson, an applications developer with Motoman Inc., a welding robot manufacturer in West Carrollton, Ohio, the complex mix of analog and digital signal processing and programming specific to each robot is one of the key factors discouraging generic software solutions.
Robot welders have payload capabilities ranging from a dozen to hundreds of pounds and repeatability performances measuring from hundredths to hundred-thousandths of an inch. Since every robot and work cell is different, it is difficult for a generic program to capture all of the variables required for each installation. “Calibrating the power sources, positions, and other data for a welding job requires considerable expertise on the part of the operator,” Anderson said. (Puttre)
However, the robot vendors do use software to expand the capabilities of their products and make tasks easier for their users. Motoman, for example, designs its controllers with CRT screens and keypads that assist operators when entering the welding data that accompanies the teach point data. Motoman’s control software also allows operators to program welding operations on a personal computer, which can be downloaded to robot controllers. (Le Blanc)
The AS controller language developed by Kawasaki Robotics of Farmington Hills, Minn., for its A Controller systems permits welding tasks to be defined by user-written programs. The programs can be based on block/step diagrams or a programming language. Programming is shown on the controller plasma display or the teach pendant display screen. The software features high-level functions such as off-line program editing and multitask execution during robot operation. A process-control program that does not initiate robot motion can be executed simultaneously with a robot-control program, allowing greater flexibility in altering processes in progress and controlling peripheral equipment in the work cell. Signal-monitoring programs can be written that suspend operations when defined parameters are violated. (Puttre)
Efforts are being made by some robot vendors to move programming functions away from the teach pendants and control panels onto personal computer platforms. The Offline software package from ABB Robotics Inc. of New Berlin, Wis., a division of Asea Brown Boveri that manufactures welding robots, allows users to develop programs for its robots on a PC. Control programs are created and modified in OffLine using commands similar to those used by ABB teach pendants. Alternatively, CAD data can be downloaded to OffLine and converted to robot position data. ABB’s TagPoint product is an interface between OffLine and AutoCAD from Autodesk Inc, of Sausalito, Calif. Control programs can be transferred to the robot welder’s controller by disk or sent across a network using ABB’s Computer Link communications software. (Puttre)
In addition to its programming software, ABB Robotics has developed its Pre-View software for simulating the motion of ABB robots and peripheral equipment on Iris workstations from Silicon Graphics Inc. of Mountain View, Calif. Pre-View has much the same function as tool path verification packages available from CAM software vendors. Users can create simulations of welding work cells to identify potential problems and optimize layout before initiating a job. Models of robots and equipment are positioned on the screen along with their intended motions. The models can be built from scratch or imported from CAD systems as IGES or DXF files. The Pre-View software automatically performs collision-detection calculations. Simulation programs can be converted to robot-control programs and transferred to robot controllers by disk. (Puttre)
These programs were developed by manufacturers of welding robots to improve the performance and usability of their particular systems. AMET developed its Advent welding process-control and data-acquisition system to be used with a broad range of welding equipment, with emphasis on high-end operations. Advent is a Macintosh-based system for graphic creation and editing of control programs. In addition, the program has data-acquisition and real-time performance-monitoring capabilities for quality assurance.
The Advent programs can be used to control most power sources and can be integrated with most torches, fixtures, feeders, seam trackers, and video equipment. Arc and beam welding processes can be programmed using teach pendant-like commands or by drawing contours that are converted to coordinate point data. All control parameters, such as current, voltage, torch travel speed, and wire feed rate, can be programmed using mouse clicks in the Macintosh user interface. Remote-control functions permit operators to override any welding parameter using joystick and mouse-driven commands.
Vision systems and seam trackers can be used to ensure that a welding operation is proceeding according to defined parameters. Advent accepts data from these systems to perform real-time quality-assurance monitoring. A data summary facility gathers information on parameters and reports on them. In addition, screens can be saved to a VCR during a welding operation, providing a record of each individual weld as part of a quality-control and quality-assurance program. (Le Blanc)
Quality assurance is one such area where welding engineering software can be used with nearly any robot environment. The EWI’s Weld spec Plus package is a database program designed to store welding procedures for analysis or future use. The program can be used to trace welding procedures from specific jobs. Traces are made using a sketching tool for drawing the sequence of passes in a given weld preparation. These procedures can be recalled to avoid duplication and for producing welding procedure documentation. (Le Blanc)
Although the difficulties in programming a robotic work cell have slowed the development of broadly applicable third-party software solutions, manufacturers of welding robots have actively been improving techniques for programming their controllers. Interfaces to CAD systems, communications links to desktop computers, and improved control panels and teaching pendant displays all have made it easier for operators to tell their robots what to do. Modeling software for simulating work cells and graphically creating programs that can be downloaded to robot controllers also have made welding jobs easier to orchestrate.