robotic weldingsystem represents a significant capital investment for a job shop.">robotic weldingsystem represents a significant capital investment for a job shop.">
July 12, 2001
A robotic weldingsystem represents a significant capital investment for a job shop.
A robotic welding system represents a significant capital investment for a job shop. The number and diversity of typical products that job shops produce may discourage any interest in automation, primarily because the company cannot figure out how to justify the system purchase and operation. Ease of programming and quick changeovers have reduced setup time and enabled job shops to automate.
Among the reasons most job shops purchase welding automation are:
A human welder performs countless welding-related tasks and makes adjustments constantly. An automated system, with its axes of motion and computerization, will have a difficult time performing these tasks if the part is presented with any variations, such as joint location or geometry.
Following are a few simple design guidelines to help to improve automated welding results:
Manufacturing processes must be selected that will provide the accuracy required. Springback variances on bend angles must be controlled, even when using die forming. Formed gussets in the part are a good solution. Parts should be located from an edge rather than from a hole, because through-hole locator pins can bind and make it difficult to remove the weldment from the weld fixture.
Job shops should encourage customers to design parts with fillet welds and lap joints. Groove and butt joints are fine but more difficult to control. Outside corner and square butt joints usually are not acceptable, unless serious tooling enhancements are anticipated.
There are instances when it is too expensive to manufacture parts to the tight tolerances and limitations required for automated welding, but that doesn't mean automation is out of the question. It means simply that there are more capital costs involved and a slower welding process. Sensory technology can be used to allow the system to find and follow the joint:
Weld fixtures are required to locate simple parts for the final welded assembly. The shop must integrate fixture quality and cost into the overall cost, lead-time, and complexity of the welding automation project concept.
The following are general guidelines to tooling complexity:
As with any process, simplification is a goal to strive for. The more complex the tooling, the more difficult it may be to program the robot to access part weld joints. Job shops should encourage customers to use part designs that feature self-locating, simple parts to reduce tooling content. Toy tabbing, slot and tab, locating studs, and part interlocking often can be helpful in reducing tooling complexity and cost.
Some sort of fixturing always is required when a new job is brought into the shop. For a one-time part run or a prototype part, angle iron clamped to a stationary or indexing table often is sufficient to locate the parts for robotic welding.
Considering welding automation often means throwing out some traditional ways of working that have been used for years. By staying open to exploring new ideas, job shops can find the level of welding automation most suited to their needs.
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