Automated Cell Phone Housing Assembly Line Combines Robotics & Vision Guidance

Reprinted by permission from Robotics World Magazine
 
Spectra Technologies Inc. of Euless, Texas, recently designed an automated cell phone housing assembly line for Triple S Plastics Inc. The assembly line consists of 12 stations that combine to automatically load, assemble, process and unload parts. Ten of the stations use SpectraFlex Modular Process Platforms equipped with Stäubli RX-60 six-axis robots and CS7B controllers. An asynchronous conveyor transfers pallets between stations. Processes at the major stations include loading/unloading parts from/to a tray, picking and placing gaskets or protective covers to the cell phone housing and two gluing operations.

A SpectraFlex Tray Handler on three stations presents parts to the robot. The robot picks the parts from the tray and places them onto the working pallet. The end effector is single or double tooled, depending on the application. The tray handler automatically cycles full trays into the workstation and empty trays out of the workstation and stacks them. An operator periodically loads full trays into the handler and removes the stack of empty trays.

Three workstations pick parts from a tape-and-reel feeder and use vision guidance for accurate placement onto the cell phone housing. The robot acquires the part from the tape and presents the part to a vision camera. A second camera captures the location of the subassembly as the working pallet transfers into the station. The part is then placed onto the subassembly. Gluing operations are performed on two workstations to permanently join parts of the subassembly. The glue is dispensed as the robot traces the required paths. Another workstation places a protective cover onto a lens/housing subassembly. A tape-and-reel feeder presents the protective cover to the robot. The robot picks the cover and places it on the completed lens/housing subassembly. An unload station incorporates a Tray Handler to supply empty trays to the robot work area. The robot picks the completed assembly from the pallet and places it into pockets in the tray. When full, the tray indexes out and is stacked. Another empty tray is then indexed into the station.

In the SpectraFlex MPP machine platform, each workcell is identical except for custom tooling, process devices and process specific programming. The stations can be quickly reconfigured for new processes. The MPP features a SpectraFlex modular I/O panel and a standard bolt pattern is supplied on the tabletop work surface and the upper mounting surface. Full guarding is provided and safety switch protected doors allow the work area to be accessed easily. The SpectraFlex I/O panel connects to the system enclosure using plug and play cabling. Each panel provides 32 local inputs and 32 local outputs via Eurofast connectors. Multiple I/O panels can be mounted in various locations in the MPP to provide increased expandability and flexibility.

For this cell phone housing assembly line, the RX-60 robot is mounted to the upper mounting plate in the MPP, which provides an open tabletop in the work area. The Stäubli CS7B controller is mounted in the base of the machine along with the control enclosure for easy access and maintenance. Each MPP assembly cell is positioned next to the conveyor. A removable hood guards the robot work area over the pallet. A lift-and-locate unit is attached to the MPP to lift the pallet from the conveyor and precisely locate it for the assembly operations, which allows the workstation to be set up and run offline, if desired, before mating it with the conveyor.

An operator interface for each workcell is provided via a 15-inch touch screen panel PC running WIN 2000 and Adept Windows. A SMEMA interface is used to connect each workcell. Each workstation is connected via an ethernet cable to a supervisory station where line data is collected and displayed/stored.