Automated Cell Phone Assembly Line
Stäubli Robotics Posted 03/14/2012An automated vision cell phone-housing assembly line was designed by SPECTRA TECHNOLOGIES, Inc. of Euless, Texas for Eimo Americas (formerly Triple S Plastics, Inc.) of Vicksburg, Michigan.
The assembly line consists of twelve stations that combine to automatically load, assemble, process and unload parts. Ten of the twelve stations utilize SpectraFlex™ Modular Process Platforms™ (MPP) equipped with Stäubli RX60 six axis robots and CS7B controllers. An asynchronous conveyor transfers pallets between stations. 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.
When Preston Patnoude , Advanced Manufacturing Engineering Leader at Eimo Americas, first looked at a 6 axis solution, he already had a good working knowledge of 4 axis robots.They were not afforded the luxury of floor space, and surprisingly with a new layout they saved floorspace with the new six axis configuration. Along with moving the secondary operation to the press side they increased throughput, and maintained their staffing level while more than doubling their sales. The first order for seven RX90’s came in June 2001, and within 6 weeks four of the six were running production with the remaining two up in the coming two weeks. The robots were field wired to communicate with the press and other auxiliary equipment, tray stacker, gasket machine and final packaging.
A SpectraFlex Tray Handler™ is incorporated on three stations to present 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.
Don Murray, Vice President of Engineering at Spectra Technologies says "Staubli provides a complete motion solution that is easy to integrate and requires minimal setup time. The RX60 was capable of being ceiling mounted which provided an unobstructed table surface for tooling, workflow, part presentation,etc.."
Three workstations pick parts from a tape and reel feeder and utilize 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.
This integration of robots by Preston and his team in such a short time shows the ease of transition between 4 and six axis. In the coming months they would go on to integrate an additional 20 plus robots , mainly performing secondary ops, at the press side.
Gluing operations are also performed on two workstations to permanently join parts of the subassembly. The glue-dispensing valve is carried on the end effector to accurately deliver the desired amount of adhesive. 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.
The SpectraFlex™ MPP machine platform introduces a new standard in flexibility. Each MPP work cell is identical except for custom tooling, process devices and process specific programming. The stations can be quickly and efficiently reconfigured for new processes as required. The MPP features a SpectraFlex modular I/O panel and a standard bolt pattern is supplied on the table top work surface and the upper mounting surface. Full guarding is provided and safety switch protected doors allow the work area to be accessed easily.
Murray said "The small size of the CS7B allowed our design team to mount the controller in the machine base to provide a compact and space efficient workcell. The vision guidance integrated seamlessly into the MPP cell"
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. The inputs are PNP or NPN selectable. The outputs consist of 4 high power relay outputs (sink or source), 2 high power solid state relay AC outputs and 26 sinking 100ma outputs. Standard connectors are provided for up to two 8-station pneumatic manifolds using plug and play wiring. The output’s ESTOP operation mode is user selectable on the panel. Multiple I/O panels can be mounted in various locations in the MPP to provide the ultimate in expandability and flexibility.
For this cell phone housing assembly line, the RX60 robot is mounted to the upper mounting plate in the MPP. This 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. Attaching this lift and locate unit to the MPP allows the workstation to be set up and run off line if desired before mating it with the conveyor.
An operator interface for each work cell is provided via a 15-inch touch screen panel PC running WIN 2000 and Adept Windows. A SMEMA interface is used to connect each work cell. Each workstation is connected via an ethernet cable to a supervisory station where line data is collected and displayed/stored.
Preston indicated that whether injection mold press tending, or assembly, we have had zero downtime after installation for robot related problems, most of our arms have 2 million plus cycles on them currently. We have in house 3 size ranges RX 60, RX 90, and RX 130.
The team effort of all 3 companies (Spectra Technologies, Eimo Americas, Staubli Corporation) on this project made it a technical success.
Murray praised the combined effort. "The entire Staubli team was a joy to work with; from a knowledgeable sales staff to an outstanding technical support team.
"The technical support team was quick to respond to our questions, even following up on a Sunday when required."