AUTOMATED MOLD MANUFACTURING UNLOCKS THROUGHPUT FOR STRATTEC SECURITY CORPORATION

STRATTEC Security Corporation of Milwaukee, Wis., has the automotive market locked down. Since the early days of the automobile, the company has been a leading supplier of vehicle locks and keys, and it produces these components for the majority of vehicles built in North America. In fact, the company's efforts in globalization have resulted in STRATTEC being a worldwide market leader.

In recent years, a greater number of vehicle-access systems have gone from purely mechanical components to integrated electromechanical systems. To remain a market leader, STRATTEC has been on top of this new technology, providing quality, cost-effective, innovative solutions to its clients in the shortest possible time.

A primary component of the company's success has been its implementation of an automated mold manufacturing cell that combines graphite milling, hard milling and EDM capabilities into one seamless manufacturing process. According to STRATTEC, the performance and reliability of this cell have been a direct result of the cooperative integration efforts between Makino and System 3R. By working closely together throughout the installation process, the companies have ensured that all systems communicate effectively, leading to significant improvements in cutting performance, part quality and dramatic lead-time reductions from days to hours in some cases.

STRATTEC SECURITY CORPORATION

As a former division of Briggs & Stratton, STRATTEC has been in the automotive industry for over a century. In 1995, it broke away from Briggs & Stratton to form its own company, serving the "Big Three" U.S. car manufacturers with design, development and manufacturing of various automotive security components, such as mechanical and electronically enhanced locks and keys, ignition lock housings and access-control products.

"For many years we were content with being a North American market leader, but it wasn't long before our clients began globalizing their operations. At that point, we were suddenly competing against overseas companies and trying to combat their low labor costs and near endless manpower. It was a whole different business climate that required a new approach to how we managed our operations," said Broetzmann.

In 2001, STRATTEC formed an alliance with German lock, latch and door-handle manufacturer, WiTTE, to expand its business globally, forming what was referred to as WiTTE-STRATTEC LLC. The WiTTE-STRATTEC alliance was strengthened in 2006 with the addition of ADAC Automotive of Grand Rapids, Mich., a privately held, full-service automotive supplier with manufacturing operations in Muskegon, Mich. Together, these three companies formed the VAST Alliance, which continues to grow its global footprint in Brazil, China, Korea and Japan.

"This alliance has enabled us to adopt new manufacturing capabilities, increase market share and solidify ourselves as a global manufacturer; however, along with these opportunities came new challenges in the form of increased customer demand," said Broetzmann. "Lead-times were becoming a growing concern that often led to costly outsourcing. We knew there was only so much time that could be cut out of our R&D and design procedures, so in order to address capacity limitations, we began to evaluate our manufacturing process."

ENTERING THE AGE OF AUTOMATION

To overcome its lead-time constraints, STRATTEC pursued technology solutions that would reduce errors, minimize manual labor and slash cycle times.

In 2006, the company purchased a Makino SNC64 vertical machining center for graphite milling operations. Broetzmann recalls the efficiencies gained with the SNC64 providing the speed, reliability and repeatability necessary to produce finer electrode details under tighter time frames with little to no operator attendance.

In seeing the unattended operational benefits of the SNC64, STRATTEC decided to also move forward with an investment in an EDGE3 sinker EDM. The two machines were then joined together within a robotically managed cell for lights-out operation. The automated mold manufacturing cell worked flawlessly. However, when it came time for STRATTEC to expand, the company was confronted with a difficult decision.

“There were two options on the table for expansion: We could duplicate the configuration we had grown accustomed to, or take a whole new approach to automation that would allow for more fluid expansions,” said Broetzmann. “While the familiarity and simplicity of our current cell design was certainly the easy way out, we knew we needed an automated system with more modularity—a cell that could grow with us.”

In 2011, STRATTEC purchased a linear, robotically managed cell system. The cell incorporated the SNC64 and EDGE3, as well as new investments in a Makino F5 vertical machining center for hard milling, and two EDAF3 sinker EDMs for unattended EDM operations. Designed for modular growth, the new automated mold manufacturing cell provided STRATTEC with the opportunity to expand its manufacturing capacity on a per-machine basis.

“The modular capabilities of the cell enabled simplified expansion that was practically plug and play,” explained Broetzmann. “We were quickly able to grow the cell to a point where all of our work was being performed in-house with additional capacity remaining for more throughput.”

FLEXIBLE CELL DESIGN AND WORKFLOW MANAGEMENT

STRATTEC’s cell system is designed to manage workflow across all machine processes, and it contains storage space for all necessary cutting tools, electrodes and pallets. Its rail-guided robot features interchangeable grippers to transfer these various components between work-setting stations, storage racks, machining centers and a coordinate measuring machine (CMM).

Material distribution is managed by the cell’s control software, which tracks electrodes and pallets using ID chips that operators scan and program into the cell. Individual machine and equipment controls share a direct line of communication with the cell control software, supporting the system with notifications of work progress, tool monitoring and alarms.

“Thanks to the flawless integration efforts between Makino and System 3R, all components of the cell are able to fluidly communicate with one another, providing operators with a single interface to monitor cell and machine activity,” said Broetzmann. “There are very few vendors we’ve dealt with that have worked together so closely, purely with our best interest top of mind.”

A unique job number organizes all work assigned to the cell. An operator assigns specific programs, pallets and electrodes to the job number by scanning his respective ID chips into the cell control software. Due to potential issues with tool balance, ID chips are not assigned to cutting tools; cutting tools are instead pre-assigned to specific slots within the cell’s tool carousel and each machine’s tool magazine. The location for the cutting tools is then referenced within each machine program.

The cell’s robot contains an ID chip scanner to identify the correct assets pertaining to specific jobs listed within its production queue. The cell software gives the operator the ability to change the production queue by distinguishing whether a job must run on a specific machine or the first available machine. In addition, the operator is able to associate different priority levels for specific jobs and may run them sequentially, schedule jobs simultaneously, or just change the order of the list of jobs based on urgency. Once a job is completed, the operator can simply call the pallet to the workstation and move on to the next job. The only manual labor involved is the loading and unloading of workpieces. Once loaded, the cell can run overnight.

“In the past, operators used to rush through the day to produce as many parts as possible before turning off the machine at the end of their shift. This is no longer the case,” said Broetzmann. “During the day, we are hustling—not to produce parts during our shifts, but to load the cell with new jobs to make sure everything is set up and ready to run throughout the evening and night. The cell and machine software handle all of the intelligence and automatically manage all other procedures that are required before performing a task. It’s like having a car that drives itself. Just type in your destination and it gets you there.”

REMOVING HUMAN ERROR

To further reduce lead-times and minimize human error, STRATTEC programs its workpieces offline using Makino’s EDcamTM software. This software enhances the capabilities of the company’s sinker EDMs through the direct reception and proper calibration of workpiece data as a critical relay between the machines and CAD-CAM systems. It receives all necessary peripheral information from the CAM systems and adds the necessary burning technology and tool-change data to output a final program for the EDM machine to use.

“By integrating EDcam software into our internal network, we can completely eliminate the need for programming at the machine,” said Broetzmann. “All of our programs are loaded directly into EDcam without inconsistencies between jobs. Today, we only have one operator and one programmer to manage three sinker EDMs, and we’re seeing higher throughput, better quality and more consistency. In fact, this offline programming has enabled us to even further reduce errors by 90 percent.”

Electrode life is built into the EDcam software and monitors how many electrodes a specific workpiece is going to require for roughing, semi-finishing and finishing. If a defect is found in one of the electrodes or an electrode is depleted, the machine software will deliver a notification to the cell control software to notify the operator that additional materials and electrode production are required in order to complete the workpiece. To conserve electrodes, the shop also has the option to program the cell control software to send the electrode back for additional machining so that it can be used again for a similar job.

“Our rotary magazine holds up to 200 electrodes, and some jobs may require up to 50 electrodes,” said Broetzmann. “Oftentimes, we will have 15 to 20 jobs in different stages of electrode development, including standby in work queue, milling, CMM verification and EDM burning. This is simply too much for an operator to handle alone. The EDcam software has helped us manage our processes without mixing up electrodes.”

STRATTEC’s recent addition of a CMM from Hexagon Metrology provides an additional layer of quality assurance to the process, inspecting electrodes and workpieces between machining processes and prior to exiting the cell. This has enabled the company to perform pickups outside of the machine for greater machine utilization.

“The CMM wasn’t just added to the cell. It was fully integrated into the system through the cell control, adding yet another layer of automation to our manufacturing process,” said Broetzmann. “With every step of the process, individual components of the machining process are automatically verified to ensure the highest level of quality and consistency. Whether it’s an electrode from the SNC64 or a rough-machined workpiece from the F5, any instances of deformity are addressed before moving to the next stage. As a result, we’ve noticed vast improvements in our tool assembly processes.”

STRATTEC has also included built-in tool-monitoring systems into its milling process. When cutting tool stocks are low, the machine systems notify the operator to load the tool magazines before downtime becomes an issue. The machine control also receives tool-length data that can prompt the machine operator to replace used or broken tools with either spare tools in the machine’s tool changer or to program the robot to deliver a new tool from the storage carousel outside of the machine.

LOCKING-IN FUTURE GROWTH

Automation to this degree isn’t for every die/mold manufacturer, but for those who demand high productivity and rapid deployment, this type of system offers the flexibility and versatility needed to grow. Through the use of this automated machining cell and advanced control software, STRATTEC has brought all of its jobs back in-house and still has the capacity for additional work and expansion.

The company has plans to add more pallets and wire EDM machines to the cell. Additionally, STRATTEC plans to continue to work with Makino to ensure a fluid integration with the new equipment and the cell system.

“We are still in our early development stages, but we are striving to get better and have plenty of room to expand,” said Broetzmann. “The automated cell has been a magnet for work. We just completed a large tooling project in which we tooled up 25 parts in a very short amount of time. Throughput has increased so much that we could actually use an extra hand or two just to keep the machines fed. This would never have been possible for us in the past without the investments we’ve made in our cell.”

With shorter lead-times, increased efficiency and enhanced workpiece quality, STRATTEC intends to remain an exemplary market leader for many more years to come.