Advanced Manufacturing: 24-7 CNC Machining

As the manufacturing industry continues to move towards leaner factory models, so does the demand for a higher level of technology and the corresponding skillsets of our modern labor force. At PBC Linear, we are continuing to build upon previous successes in lean manufacturing, keeping in stride with new automation technologies and advancements in our workforce. Our automated devices and machines are now doing tasks that were considered monotonous, labor-intensive, and posed a higher risk of injury for personnel. The results are advancements in the form of transferred and elevated skillsets that focus more energy on the inspection process and the quality of parts. For PBC Linear, that means a factory that is leaner, smarter, safer, and capable of greater output.

This article and the video below are part of a longer series that details how PBC Linear is incorporating technological enhancements into its production systems. The following examines the lights-out reliability of our Hitachi Flexible Manufacturing System, along with its benefits to our workers, our business, and most importantly our customers.

Advancing CNC machining

Computer Numerical Control milling, commonly referred to as CNC milling, is a computerized manufacturing process where pre-programmed software and code controls the production operations. This type of code instructs machine tools to cut and shape materials using precise production measurements such as feed rate, speed, location, and coordination. Typical tolerances range between 0.001 to 0.005 inches, with some milling machines achieving tolerances of up to 0.0005 inches.

The versatility of the milling process allows for its use in a wide range of industries, and for a variety of part features and designs including slots, chamfers, threads, and pockets. Four common CNC milling operations include:

  • Face milling: cutting tool has an axis of rotation perpendicular to the surface.
  • Plain milling: cutting tool has an axis of rotation parallel to the surface.
  • Angular milling: cutting tool has an axis of rotation at an angle relative to the surface.
  • Form milling: involves irregular surfaces, contours, and outlines, such as parts with curved and flat surfaces.

CNC milling cutting processes are either aligned horizontally or vertically. As their name’s suggest, each type has its unique orientation of the spindle that holds the rotary cutting tool. While they have similar functions, horizontal mills are better suited for more complicated and larger volume projects as they will complete tasks much quicker than their vertical cousins. For the Hitachi FMS, PBC Linear utilizes a horizontal spindle type for greater machining flexibility and output. The machine’s orientation also allows for easier metallic chip evacuation that translates into cleaner surface finishes and less need for post processing fabrication.

Image showing the Hitachi flexible manufacturing process-

Advancing productivity

PBC Linear utilizes many CNC type processes in its shop. Among the most reliable and productive is the Hitachi Seiki Flexible Manufacturing System (FMS). The horizontal machining system consists of four machining stations along with a seventy-two-palette interchange system. Each palette or “tombstone” has the capability of running anywhere from five to two hundred pieces at once. Typical cycle times range from fifteen minutes up to seven or eight hours.

Head Shot for Bob Gronewold , General Manager

Bob Gronewold, General Manager

We have 4 machines in a cell, and each machine can handle ten different programs at a time, which means we can have as many as forty jobs lined up. The operator can load up the tombstones and literally walk away, leaving those machines to run 24-7 until their programs are completed.

I love the Hitachi FMS machines. It’s one of our key core product machining centers. Between the FMS, the bar loaders, and lathes, they allow us to continue our 24-7 operation. It’s a lights-out product production system.

Advancing our product lines

The FMS machines are critical in meeting product delivery times. For comparison, they have the same amount of output of roughly three fully staffed shifts of eight to ten people. Often, we use them on high-volume orders, such as restocking many of our over four-hundred standard core products including Simplicity round bearings, flange mounts, pillow blocks, and more. The FMS machines can also be critical for emergency customer orders that need to be expedited quickly. In other words, if a customer surprises us with a crunch time deadline, or has a specific product request, this is the ideal machine to facilitate a quicker delivery time on that request.

PBC Linear cuts tens of thousands of pounds of steel, stainless steel, and aluminum in a single year. The four CNC horizontal mills from Hitachi represent a substantial part of that workload. Along with their high quantity output, they also offer a high quality of production. When we need to do an AQL (Acceptable Quality Limit) on our production parts, the FMS makes this an easy process. For instance, if we run 200 pieces at a time, and after every 330 pieces we are checking them, then our quality is going to be excellent on those machines, and this entire process can be easily replicated.

Aerial View of the Hitachi Flexible Manufacturing System

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See other related information in this series that showcases how PBC Linear is advancing manufacturing: