Refining Shopfloor Processes for Mission-Critical Parts

Even a Top Shop can benefit from process refinement, and in the four years since Pacon Mfg, Inc. (also called PACON after founders Paul and Connie) qualified as the 2020 Top Shops Honoree in Shopfloor Practices and Performance, the shop has continued thriving due to its enduring focus on the same ideas that led to it becoming a Top Shop. In addition to its automated five-axis workflow, this has involved the acquisition of a second location to offload operations better suited to other types of machining processes, as well as an increasing investment in software to meet the ever-evolving needs of its customers.

Mission-Critical Machining

Most of PACON’s parts are mission critical in one way or another. The company works with clients in the space, defense, life science, semiconductor and automation industries, all of whom require tight tolerances for their expensive parts. Many of these customers have also introduced stricter traceability requirements over the last few years, necessitating paperwork and traceability all the way from final checks to the initial production of parts’ raw materials. Many parts include features that have tolerances of 0.0002 inch — not just for location repeatability, but for perpendicularity and flatness.

Steve McClure, CEO of PACON, says that while meeting location repeatability is relatively simple, reaching the perpendicularity and flatness tolerances are more difficult. He says that the quality of the machine and workholding have a lot to do with ultimately reaching these tolerances, and that five-axis machining is well suited for machining parts where surfaces must be related to one another. As such, the shop has standardized on five-axis machines and common workholding — as was covered in the 2020 Top Shops article.

At that time, the shop was well-equipped to handle its workflow, which was about evenly distributed between its work segments. In the years since, the instability inflicted by COVID has stress-tested the shop’s systems, showing the strength in many of them while also presenting challenges that required further process refinement.

Cell Service

Walking onto the shop floor of PACON’s original location in Livermore, California, the 60-pallet Makino MMC2 flexible machining system (FMS) commands a lot of attention. The system is connected to two Makino a500Z horizontal five-axis machines, each with a 313-tool magazine and tool breakage detection systems. The different pallet slots have different vise configurations for different types of part configurations, with the FMS running “air traffic control for the machine,” as McClure puts it, by keeping track of which program goes to which pallet.

During the initial setup of the cell, PACON’s team looked at about three years’ worth of repeat parts, grouped them, and developed hypothetical pallets to machine these parts in batches. Ultimately, they found that so long as work on a pallet is running for an hour — no matter whether the pallet is dedicated to one part or multiple — it becomes profitable. The Makino a500Z machines also share about two-thirds of their tooling, so either one can tackle most of the pallets for lights-out automation.

This was especially important at the outbreak of the COVID-19 pandemic, when PACON’s life sciences customers urgently needed components to produce PCR tests. Producing these components in sufficient quantities required a massive increase in productivity, even as many of the shop’s other customers continued ordering. McClure says the cell was the key to meeting this surge. With standard pallets and tooling, the cell was able to perform work lights-out and perform a year’s worth of production in two months — without sacrificing the shop’s other customers.

Dynamic(s) Automation

PACON’s other big automation push centers on its quality department and its software. With 75% of parts requiring evidence of quality beyond a certificate of conformance and defense customers wanting full inspection reports on every unit of every part number, the shop has needed to juggle a large paper trail for every one of these parts. Accomplishing this efficiently has required the automation of front office tasks and the digitization of the material chain of custody. To do so, the shop has sought after an ERP to match the lean philosophy of its shop floor.

In 2023, this led PACON to adopt Microsoft Dynamics Business Central as its ERP system. This system has the power to capture part documentation and quality records from their point of origin, connect these documents to the correct shipments and lots, automate basic communications such as advance shipping notices and carry forward the barcode-driven production monitoring the shop began under its previous ERP. McClure also says that Windows 11 and the Microsoft 365 environment are useful for meeting CMMC requirements, with features like built-in support for document encryption and Multi-Factor Authentication access control on user devices.

Beyond ERP, PACON manages its part quality through a Hexagon CMM programmed using customer models and a repeatable program to take critical dimension inspection reports. It also relies on a combination of Mastercam for CNC programming and Vericut for NC program simulation.

With Mastercam, McClure says the shop leverages tool path generation algorithms wherever possible, with special emphasis on OptiRough. He says these algorithms cut a lot of time not just from programming, but from machining cycle times as well, and that they provide a high-quality finish. The shop then runs the part program, complete with its tooling and fixturing, in Vericut. This simulation software detects potential crashes during the program and can also compare the final simulated part to the blueprint, with highlights showing where the simulated program would cut too much or not enough.

A Tale of Two Shops

Completed programs go onto PACON’s floor day and night, with the shop’s pallet system eliminating the divide between production and prototyping. But even with lights-out pallets, the FMS is not the right machine for every job. Sometimes a feature requires turning, or could be easily completed with three-axis work.

Acquiring a second location in Morgan Hill, California, has given PACON the capacity and capability to handle these jobs. McClure says there is a lot of knowledge sharing at the shops, and the ability to access two labor pools — the eastern San Francisco Bay Area from Livermore, and the southern from Morgan Hill — has been useful for keeping machines staffed. The two facilities are only about an hour to an hour and a half drive apart, depending on traffic, so parts can be transferred between them depending on which facility’s machines and expertise better suit the part. PACON can also optimize its work mix at each facility, ensuring more consistent utilization for its FMS and five-axis mills in Livermore and its lathes and three-axis mills in Morgan Hill.

For the future, PACON is looking to further automate its inspection capabilities and potentially expand its capabilities with multi-axis moving-head mill-turns. The shop also plans to continue maturing its automation implementation with ERP so that it can dynamically respond to front office work as it now can with work for its FMS. With its core markets on an upswing, the shop only plans to get busier — but its workflow is poised to handle these upswings without trouble.