Flexible Manufacturing System Helps Advance the Science of Machining

Imagine removing all of the uncertainty from your manufacturing process, making on-the-fly adjustments to your production schedule with 100 percent success and virtually no downtime. According to Chris Borch, CEO of Micro-Mechanics, this dream has become a reality through what he calls the “science of machining.”

“Our business environment is increasingly volatile and unpredictable, and most customers don’t have the ability to forecast their requirements accurately,” said Borch. “To be successful, we need to align our business to these realities and strive to provide our customers with perfect parts, on time, every time based on a repeatable, scalable and cost-effective flexible manufacturing system. From equipment to tool management, fixtures and programming, we’re working to advance the science of machining and meet customers’ evolving production needs on demand.”

Micro-Mechanics designs, manufactures and markets a wide range of precision tools, assemblies and consumable parts used in the assembly and testing of semiconductors. From a small workshop in Singapore in 1983, the company has expanded to include manufacturing facilities in the Philippines, Malaysia, China, Thailand and the United States. In 2003, Micro-Mechanics became a publically traded company on the Singapore Exchange.

Micro-Mechanics’ facility in Morgan Hill, Calif., serves as a Tier 1 supplier to the semiconductor, medical and high-tech instrumentation industries, in which high-velocity new product introduction (NPI) is paramount to meeting customer demands. To maintain an uninterrupted and top-quality supply chain, the company has applied its in-depth understanding of the machining process to create what it calls “24/7 machining.”

The term “24/7 machining” implies 168 hours of continuous production per week; for practical purposes, Micro-Mechanics defines this process as achieving at least 95 percent spindle utilization, or 160 hours of weekly production. The remaining 8 hours are dedicated to conducting predictive and preventive maintenance. According to Borch, 24/7 machining was developed as a cost-competitive solution for their high-mix, low-volume production requirements.

“Manufacturers in the U.S. have to understand that this is a global business, and that their true strength lies in the process engineering of challenging part applications. With manufacturing facilities throughout Asia, we see our complex, low-volume part production as the perfect opportunity for us to demonstrate our engineering expertise, and successfully and competitively produce manufactured components here in the U.S.,” said Borch.

“By combining skill and ingenuity with the practical principles of engineering and state-of-the-art technology, we’ve made it our goal to better understand all aspects of the manufacturing process with the end goal of producing perfect parts made on time, every time.”

FUNDAMENTALS OF 24/7 MACHINING

Micro-Mechanics’ strategy of 24/7 machining is based on seven fundamental elements that reach across multiple departments: repeatable machining processes, interchangeability and flexibility, offline fixture and tool setting, 7S housekeeping, defined tools, settings and operating parameters, programming standards, and dedicated engineering and production resources. When implemented together, these fundamentals create repeatable, scalable, flexible and cost-effective machining processes.

“On a relative scale, 24/7 machining isn’t complex,” said Borch. “All of the necessary platforms are already in place within the industry. It’s how they are applied and engineered that makes a difference. When the fundamentals are applied, you will see results, but without them in place, you cannot achieve true 24/7 machining.”

According to Borch, establishing the 24/7 machining platform starts with an investment in a reliable and repeatable flexible manufacturing system. Micro-Mechanics’ 24/7 machining line consists of three Makino a61nx horizontal machining centers, an MMC2 track pallet system and the Makino Automated System (MAS-A5) cell control software.

“With the Makino automated system, we had established a flexible and expandable platform for 24/7 machining, but in order to maximize production and achieve the full benefits, we had to eliminate activities that would interrupt production and affect machine utilization,” said Borch. “Two of these factors were fixture and tool setting. And while we couldn’t eliminate these procedures, we have been able to bring them offline to prevent interference with the 24/7 manufacturing process.”

CUTTING-EDGE TOOL CONTROL

Micro-Mechanics established an offline tool management department to control all of the tooling characteristics for consistent and repeatable production. According to Bill Green, manufacturing engineer for Micro-Mechanics’ tool management group, controlling tooling characteristics is accomplished through RFID chips, run-out monitoring, tool balancing, Cpk calculations and standardized operating and tool setup parameters.

“There’s only one factor of the machining process that will always remain constant, and that’s the inevitability of tool wear,” said Green. “Between our tool holders and presetter, we’ve been able to effectively control tooling run-out within 0.0005 inches before the tool reaches the cell. Additionally, our balancing capabilities, complemented by the rigidity of the a61nx machines, have provided higher accuracy, better surface finish and up to three times longer tool life!”

To maintain consistent performance across all 24/7 machining groups, the tooling management department has a set list of tools that can be applied to all programmed machine processes. Detailed information on each of these tools is included in a tooling matrix with tool types, pod numbers and operating parameters. All machines within the flexible manufacturing system are equipped with identical tool magazines to ensure that any part can be produced on any machine at any time. Identical spare tools are also created and loaded in the magazines to ensure uninterrupted machining once the pre-established wear limits on the tool have been met.

One key element to the success of Micro-Mechanics’ offline tool management is the MAS-A5 cell controller, which features a direct link from the line to the tooling department for instantaneous transfer and storage of all tool data.

“The MAS-A5 controller is like the central nervous system to our tool data management, connecting and coordinating information between the tool management department, operators and machines,” said Green. “Its ability to monitor and report tool data from the machines to our tooling department enables us to know when a tool needs replacing way ahead of time. By providing operators with easy access to tool drawings, we’ve been able to perform on-the-spot troubleshooting for faster error resolution and replace the tools well before production has been impacted.”

STANDARDIZED FIXTURING FOR ON-DEMAND PRODUCTION

Adding to the uniformity of the 24/7 machining line’s tooling catalog, Micro-Mechanics’ fixture department has successfully engineered a setup solution that standardizes tombstones, clamps and fixtures. These capabilities are a key component to the company’s on-demand production requirements, ensuring that any part can be ordered at a moment’s notice with guaranteed results.

“In order to meet our goal of perfect parts made on time, every time, we knew that our setup methods had to ensure the repeatability of our machining processes, but also provide for flexibility and interchangeability,” said Troy Fisher, manufacturing engineer for Micro-Mechanics’ fixture department.

To ensure the highest level of repeatability, Micro-Mechanics’ fixture department designs its custom tombstones in-house. Each tombstone is built within a true position of less than 0.001 inches with one-time locating to pallets within 0.0005 inches. According to Fisher, fixtures can be transferred between like tombstones without any offset adjustments and still hold positioning tolerances within 0.0005 inches across all coordinate axes. Of course, this repeatability is dependent on the excellent flatness and quality of Makino’s basic pallet on the a61nx’s.

Micro-Mechanics’ fixture department applies similar principles for standardization in the design and development of its fixtures. Regardless of part applications, all fixtures are designed and machined from pre-machined, cast aluminum and are anodized to protect accuracy. Additionally, all hardware, including clamps, dowels and helicoils are standardized and purchased from approved suppliers.

“Based on the inherent accuracy we’re building into tombstone and fixture designs, we no longer need to perform test runs,” said Fisher. “And while it may seem unnecessary, we also have the capability to create offset files for the MAS-A5 control directly from our CAD software, which will only bring us closer to our perfected models. It doesn’t hurt to have a stable, rigid automated system to rely on, either.”

PROGRAMMING IN THE SAME LANGUAGE

With predictable, flexible and interchangeable tooling and fixturing methods in place, Micro-Mechanics focused its attention on the standardization of programming and design practices.

“Developing programming standards made everything come around full circle and closed the loop for our 24/7 engineering with impermeable collaboration,” said Mike Maguire, Micro-Mechanics’ manufacturing engineering section manager. “Since the tooling group already established operating parameters, we just had to normalize our coding procedures and cutter paths to ensure that the same tools were used in the same way on similar features to produce repeatable results. As such, our first article inspection is no longer an evaluation of parts, but processes.”

Micro-Mechanics has also unified all programming and design practices into identical software platforms to ensure that all designers and engineers see the same things when a file is opened. To avoid potential bugs, the company never applies new software releases until after the first update is distributed.

“The biggest benefit to our programming and design standards is that there is no more second-guessing. As long as we’ve followed the guidelines put into place, we know a program will work. That’s the difference between a skill and the science of machining,” said Maguire.

MAINTENANCE AND HOUSEKEEPING

“Where many companies would have considered our 24/7 machining line to be complete, we still had a number of fundamentals remaining relative to preventive maintenance and 7S housekeeping,” said Borch. “This is where many manufacturers would fail to achieve 24/7 machining, overlooking what they would consider to be minor supplemental activities, such as cleaning off chips from the fixtures and organizing setup tools. However, if you disregard these fundamentals, your manufacturing process will suffer in the end.”

According to Borch, there are two kinds of costs on the shop floor: one-time costs (i.e., initial automated system investments) and ongoing costs (i.e., consumable tooling, equipment downtime and repair). He explained that many manufacturers get hung up on one-time costs due to the substantial investment required, but neglect to see the totality of ongoing costs, which over the full life span of an investment can become the far larger of the two costs.

“Our mind-set is that we’d rather clean, replenish and replace and not repair. This is why we dedicate eight hours each week to basic cleaning and preventive maintenance procedures,” said Borch. “While this may reduce our number of productive hours in the short term, decreasing the likelihood of significant repairs will ultimately gain us more long-term productivity and ensure the accuracy and repeatability of our 24/7 manufacturing process.”

In addition to preventive maintenance, Micro-Mechanics follows another fundamental element of 24/7 machining, which it calls 7S housekeeping. Building on the well-known 5S methodology, 7S housekeeping factors in safety and sustainability.

“Nobody wants to deal with a cluttered and potentially hazardous workplace, especially if it can mean additional cost savings and proper stewardship to the environment,” said Borch. “One of the ways we are building this cleaner work environment is through a custom-designed draining bin, where coolant is collected from our chips before they are sent out for recycling. We save on coolant loss this way. Furthermore, we’ve also gone almost completely paperless on our shop floor, thanks to the data storage and transfer capabilities of the MAS-A5 control. These may seem like minor adjustments, but every little bit counts.”

THE JOURNEY TO PERFECTION

In June 2012, Micro-Mechanics reached a key engineering milestone with the first production order for its 24/7 machining line. In preparation for more orders, the company has already started early planning to replicate its current capabilities with the addition of a second Makino automated system. Once installed, the Makino cell is expected to help Micro-Mechanics create separate and dedicated resources for engineering and production—the final key fundamental for 24/7 machining.

“When we started our journey toward 24/7 machining, we didn’t know every step that we would have to take along the way. It was a challenging process that could have never been accomplished alone,” said Borch. “Despite not being a fundamental factor for 24/7 machining, we’ve also found that supportive and knowledgeable business partners can be a tremendous asset. Joe Clancy at Clancy Machine Tool, the distributor of our Makino flexible manufacturing system, was with us every step of the way. We collaborated and always found a way to meet our requirements.”

While Micro-Mechanics has not quite reached 168 hours of nonstop production as of yet, the pursuit of this objective is bringing tremendous benefits and value to their competitiveness and to their customers. The company is evaluating future improvements, including further optimization of fixturing methods through RFID.

According to Borch, Micro-Mechanics is going to be successful regardless of whether or not it achieves true 24/7 machining capabilities. “When I tell people that our ultimate goal is perfect parts made on time, every time, I typically receive a puzzled look questioning why we would strive for something that is unobtainable. But what they don’t understand is that in the quest for perfection, we might just catch excellence.”

Through the science of machining, Micro-Mechanics will continue to imagine what can be achieved.