Case Studies: Wireless Data Collection Provides Long Memory
A wireless remote data collection process designed and built by Weldun International Ltd. (Bridgman, MI) is making that possible.
“When a module leaves Metaldyne, it leaves behind a detailed electronic file showing how that particular module was assembled and its performance at every test station,” says Jay Fluegel, engineering manager at the Metaldyne plant in Middleville, MI. “We’ll know every bolt that is supposed to be there, is there, and was assembled with the correct torque. Ten years from now, we can strip a water pump from a module, and from its serial number, we’ll be able to access a lot of information. And if we want, we can pull up all the data from every pump assembled that same day or hour.”
During production, Metaldyne checks for porosity and casting cracks, but its main concern is assembly failure.
Pumping informationWeldun supplied an assembly and test machine to produce water pumps, and a system to produce front cover modules. The water pump is a component of the front cover module. A wireless Ethernet allows part process data to be transferred from a radio frequency (RF) tag memory system to a wireless local area network (LAN) bridge.
The RF tag is attached to every pallet conveyed through the facility. Each tag contains an inductive coupling and a microchip. During the manufacturing process, load cells and transducers measure forces, torques and distances used in the assembly and then send them to each station. At every station, this information and various test data is communicated to each tag by radio frequency with an antenna that is mounted some 4 inches from the side of the pallet.
As a pallet containing one water pump or module passes through all the stations, additional data is written to the tag.
At the final station, all the stored data is read off the tag and combined with a time, date and serial number to create an electronic file. The serial number is pin stamped onto the individual water pump or module, and the file is transmitted to a host computer.
These host servers have a backup process and CD-ROM burners to automatically back up production data.
The wireless LAN allows seamless data transfer from the production equipment to the servers. The effective range of the wireless LAN is 300 feet indoors. This enables the company to install the servers in a convenient location without affecting data transfer.
The production data is processed using Rockwell RSSQL and RSLINX Professional software. After the data is processed, it is placed in a database where end users can manipulate the data.
Through a dedicated phone line or connection to the Web, Weldun can offer remote programming support for all equipment linked to the wireless LAN. This also gives Metaldyne the capability to view production reports and other data on the Internet.
The assembly and test machine for the water pump conveys 6-inch square pallets. Each holds a single machined aluminum casting. As the pallets move to the first station, each part is checked for positioning and for porosity with a pressure decay test. A shaft and bearing is then pressed into each casting. The press force and travel distance is measured and recorded. Further down the line, a hub, an impeller, plugs and seals are assembled to the pump.
After the water pump assembly is finished and given its serial number, it is ready for assembly as a component of the front cover module.
Pick and placeThe assembly and test system for the front cover module begins with a pallet receiving a machined aluminum casting from a pick-and-place unit. After being cleansed, the casting is at an elevated temperature. The pallet then follows a serpentine path to allow the casting to cool over time to ambient temperature.
At the system’s first cell, the part is clamped up, all port orifices are plugged, and the part is subjected to a pressure decay leak test of three separate cavities. This is followed by a blockage test using air and a differential system to determine if any sand from the casting process has remained within the casting. If porosity leakage or blockages are detected, it is rejected at the next cell. The validating, fastening or pressing of all parts is done automatically. Torques and press forces are written into the pallet tags.
After all assembly is completed, additional cells run leak tests on the water pump to ensure the gaskets are functioning. A torque test is performed that ensures that there is no binding on the pump’s shaft. This is followed by an air-verification test of the oil pump to validate the assembly process and to ensure its correct operation.
The final cell of the system gets all rejects, other than for porosity. An operator decides whether each reject should be scrapped or repaired. Those modules with missing or defective parts are sent back through the system for repair. Again, the same data is collected for each of the finished and serialized modules. Should any cell signal failures for three consecutive modules, the entire system shuts down. The operating rate for the system is targeted at 410,000 units a year.
Weldun International Ltd.
- A detailed electronic file is created that shows how that particular module was assembled and its performance at every test station. This information can be accessed at any point in the future.
- A radio frequency tag is attached to every pallet through the facility that contains an inductive coupling and a microchip. Production data is written to the tag through each process.
- A wireless Ethernet allows part process data to be transferred from a radio frequency tag memory system to a wireless local area network bridge.
- Through a dedicated phone line or Web connection, Weldun can offer remote programming support for all equipment linked to the Wireless local area network.
- After assembly, lead tests, torque tests and air-verifications tests are performed. Rejects are sent to a work cell where an operator determines whether the part can be repaired or if it should be scrapped.