Robots Impact Production at Mennie's Machine Company, Inc.
Robots Impact Production at Mennie's Machine Company, Inc.
At Mennie's Machine, the term 'innovation' is not a buzzword it is business as usual. The Illinois-based manufacturer of machined castings and forgings now uses robotic automation to meet their customers' stringent demands for speed and quality. Previously a manual process, human limitations had prevented Mennie's from achieving throughput and consistency requirements for a major contract to manufacture automotive drive shaft components for sport utility vehicles and full size trucks. In addition, the company had safety and ergonomic issues for employees due to repetitive activities. Consequently, frequent employee absenteeism made production planning nearly impossible.
Operating three shifts per day, the company used a manual operation for one year before Mennie's determined that automation was needed. The manual system, which typically yielded 80 pieces per hour, did not achieve production goals of 118 pieces per hour.
'We realized that in order to position ourselves as a world class manufacturer, we needed to implement leading-edge technology,' said Mennie's vice president Bill Mennie. 'On this project, speed and quality were the highest priorities because when it comes to automotive manufacturing, there is no margin for error.'
According to Mennie, production complexity was another key factor in the decision to go with robotics. In addition to the many different processes and types of machinery involved in the production of finished parts, the company was challenged to balance cycle times between each process. With the manual operation, it became difficult to overcome bottlenecks in the system, preventing Mennie's from achieving its desired production goals.
Mennie's selected FANUC Robotics America, Inc. for a turnkey solution because of FANUC Robotics' reputation for having reliable products and systems expertise. In addition, Mennie's appreciated having a supplier within close proximity to their manufacturing facility. Although FANUC Robotics is headquartered near Detroit, its full-service facility located just outside of Chicago took complete responsibility for the design, build, installation and service of the system.
Mennie's has a system design philosophy of: 'Factory within a factory.' This meant that they needed a series of robotic work cells linked through a common part transfer conveyor. 'FANUC Robotics understood what we were trying to accomplish and encouraged an atmosphere of teamwork,' said Mennie.
The fully automated system incorporates nine material handling robot models. Mennie's provided the pallets, part fixtures, safety fencing, conveyor equipment, PLC hardware and other peripherals.
Each robot is equipped with HandlingTool and Collision Guard software, custom grippers and a control interface to the equipment and conveyor. The HandlingTool software package provides built-in functions, menu-driven prompts and point-and-shoot position teaching, making it easy for operators to create and run programs. Collision Guard allows a robot to sense a potential collision along any axis and stops robot operation in time to minimize damage to the end-of-arm-tooling, the part or the robot.
The entire system consists of ten consecutive processes that are linked via conveyor. Raw parts are first manually loaded into a 'face and center' machine before being conveyed downstream through nine automated machining processes. At each 'stop' along the conveyor, parts are automatically loaded and unloaded by robots. First, an M-6i, capable of lifting up to 13.2 pounds, picks raw parts and places them into a CNC lathe for machining. The robot then places finished parts onto a part pallet that is located on the conveyor. Next, each full part pallet makes its way to an LR Mate 100i table top model robot which loads and unloads parts into and out of a small broach machine. In the next process, another M-6i alternately loads and unloads parts onto one of two fixtures of a large broach machine for further processing. A third M-6i moves parts into and out of a boring operation.
In the final processes, an S-430iF, which can lift up to 286 pounds, sequentially loads and unloads parts into and out of four machines that perform various groove and ream operations. Following this operation, parts are loaded and unloaded by a forth M-6i robot to and from a drilling operation, then conveyed to another LR Mate 100i for a spline roll machining process. Next, an M-16i robot, capable of lifting up to 35 pounds, handles parts two at a time into a heat-treat operation. Finally, a fifth M-6i is used to load and unload parts for grinding.
At Mennie's, production quality is assessed by tracking scrap dollars. During final inspection, each part attribute is examined for dimensional tolerance and cosmetic appearance. Rejects are tagged and then further evaluated to determine how to eliminate inaccuracy. Robotic automation has contributed to a reduction in scrap rates. In addition, as a result of the robotic system, Mennie's has experienced significant competitive advantages including:
- accurate and consistent part loading
- a reduction in part defects
- increased productivity - typically 120 pieces per hour
- improved control of the entire manufacturing system
- less cost per piece
- flexibility to meet future production demands
The close working relationship established between Mennie's and FANUC Robotics was a major factor in the success of the project. 'Our expectations were met and responsibilities were understood without experiencing any unexpected surprises,' said Mennie. 'I credit open and honest customer/supplier communication for that.' Another contributing factor to the successful system was the commitment that Mennie's had to using automation to achieve their goals. 'We put our trust in FANUC Robotics' engineering team to supply a turnkey solution that would help us achieve our vision of 'factory within a factory' and they didn't let us down,' said Mennie.
Production is humming at Mennie's. The three shift operation is running at 95 percent uptime, a 15 percent increase over the previous manual operation. In fact, Mennie's estimates that the robotic system has helped the company reduce total production costs by approximately 25 percent. Robotic automation has also helped Mennie's increase production flexibility.
Not only is the system expandable to accommodate additional machines, but with slight modifications to fixtures, the system could easily accommodate new part designs. Another flexible feature of the system is that Mennie's can switch to manual production during routine preventive maintenance. Since the original robotic cells were installed in 1997, Mennie's has expanded the system twice, including the purchase of an additional robot for a drilling operation and an additional machine tool to increase throughput in a turning operation.
Mennie's Machine Company is a privately held Illinois corporation specializing in low- to high-volume sub-contract manufacturing for the heavy construction & off-road equipment and automotive OEM markets. Founded in 1970, by Hubert and Cheryl Mennie, the company is QS 9000 and ISO 9002 certified and has achieved approximately $25 million in annual sales. For additional information contact Mennie's Machine Co. at (815) 339-2226 or visit their website at www.mennies.com.