Quality Magazine

Case Studies: Parallel ID System Improves Quality Control

December 1, 2005
The Balluff read head relays the pallet number to Telesis pin stamper at immediate right which marks parts with date and time, shift number and pallet number. Source: Balluff

The Briggs and Stratton small engine facility (Poplar Bluff, MO) builds 14,000 units per day of the Quantum 4-cycle engine. Billy DePew, manufacturing engineering technician, had a goal to improve traceability of completed engines coming off the line. This meant being able to trace a nonconforming part back to the pallet it was produced on, the date of manufacture and work shift, in order to check other engines of that batch to determine the exact corrective procedure. Working with engineers at Balluff (Florence, KY), a manufacturer of sensors, transducers and ID systems, he added a Balluff parallel passive inductive ID system to help identify specific engines within their production batch. With this system, engines that did not meet Briggs and Stratton's rigid quality standards could be isolated by a time stamp-date and time of manufacture-that was applied to each block, providing traceability and accountability for work performed by Briggs' operators. The ID system helped Briggs and Stratton flag missteps before final engine assembly, and reduce scrap-increasing throughput and the overall quality of its engine components.

Working with the Balluff team, DePew determined that a Balluff 60R read-only passive inductive identification system could provide information to help improve quality tracking on the engine line. The Balluff BISC-60R-001-08P ID system installed at Briggs and Stratton consists of a parallel, self-contained read head, an 8-bit parallel device resembling a 30-millimeter inductive proximity sensor. This read head works with 1,023-byte Balluff BISC-12805/L data carriers, one each mounted on the machining pallets. The data carriers are rated -20 to +70 C.

The 88 data carriers used at Briggs and Stratton have a mounting hole in the center of the tag for easy pallet attachment. Data exchange between the carrier and the read head is noncontact and wear-free. The data and necessary power for the data carrier are inductively coupled and require no battery for operation or data retention, eliminating added cost and the risk of losing data. Precise alignment of the read head and the data carrier is not necessary. The data carrier can be read "on-the-fly" while moving past the read head.



Integrating the Balluff Parallel ID system helped Briggs and Stratton’s Poplar Bluff engine block line achieve a cost-effective method of identifying quality problems. Source: Balluff

After the data carriers were mounted on the engine block pallets and the M30 read heads were mounted and aligned, the system was ready for integration into Brigg's existing control system. DePew integrated the Balluff ID system into his Mitsubishi PLC and Telesis workstation with an LCD screen used for visually checking data. All communications in the network are via RS-232.

Small engine blocks are installed on each of 88 production pallets progressing on a conveyor that moves them through 54 machining stations. Cylinder bores are rough-cut, valve guide holes are bored, oil fill holes are cut, breather bores and cam bores are machined, and heads are tapped in sequence at the various stations. At the third machining station, the pallet number is automatically read off the data carrier on the pallet, and that number, plus the date, time and crew/shift number, is coded by an operator into a pin stamper, which imprints the information on the corresponding engine block. This data is essential in pinpointing any out-of-spec components that must be pulled out of the system. Beyond that, the process provides greater traceability and quality control on the entire machining process.



The engine part is shown with pin-stamped information while still fixtured in the pallet. Source: Balluff

With the integration of the Balluff parallel ID system, the Briggs and Stratton Poplar Bluff engine block line achieved a cost-effective method of identifying quality problems. Briggs and Stratton also achieved a system of "back-tracking" components and accounting for work performed by its employees. The IP67-rated Balluff ID system withstands the rigors typically found in machine tool environments where components are showered with hot chips, coolant and lubricants.

According to DePew, the ID system is simple to install and use, and provides accurate reads. "We've received good support from the Balluff organization. We'd like to expand this system into other plant areas, even in a new plant expansion assembly area that's being implemented in 2005."



Benefits

• Data exchange between the carrier and the read head is noncontact and wear-free.

• The data and necessary power for the data carrier are inductively coupled and require no battery for operation or data retention.

• The data carriers are capable of withstanding hostile manufacturing environments and are rated for -20 to +70 C.

• The ID system withstands the rigors typically found in machine tool environments where components are showered with hot chips, coolant and lubricants.