Fixtures are essential to most machining processes and can have a direct impact on productivity, cost and quality. However, the level of efficiency of automation depends upon the design and manufacturing of the fixturing. In fact, according to Assembly Magazine, inappropriate fixtures contribute to 40 percent of rejected parts, so it is important to realize that without proper fixturing to hold parts in the right position and orientation, robots can’t make accurate welds.
The variety of possibilities for a weld’s intended shape, size, and profile requires unique, custom engineered fixturing solutions for each application. Praxair can provide many types of ﬁxtures for your automation needs. Depending on the complexity of the part and the level of interface you require, a tool can be designed to seamlessly integrate into your welding cell.
Tooling ﬁxtures usually are made of wear-resistant materials to help ensure long life and part accuracy and can come in a variety of forms including:
It is common to manually load and unload parts while needing clamps to hold all the parts in place. The beneﬁt of this simplicity is that hand clamps are relatively inexpensive and can be easily replaced after wear.
Progressive tooling is used when a part’s components cannot all be welded at once due to either a need for repositioning, the robot cell may not have the ability to rotate parts, or sub-components needing to be welded separately for a ﬁnal part to be completely.
When designed, there may be several part ﬁxture cavities on the load side of the robot. As a part gets welded in the ﬁrst ﬁxture cavity, it is moved manually to the next ﬁxture cavity and so on, until a part is completed in the ﬁnal ﬁxture cavity. Each rotation of the robot cell table would produce a ﬁnished part in the ﬁnal ﬁxture cavity. This conﬁguration would be mirrored on both sides of the robot.
Cut through base plates are commonly used when a tooling plate is on a rotating headstock tailstock positioner. These access holes simply allow the welding torch access to be able to weld the bottom of the part.
Smart tooling is used to give ﬁxtures a level of automation for purposes to help ensure quality and productivity of the robot cell such as: