Derek Korn joined Modern Machine Shop in 2004, but has been writing about manufacturing since 1997. His mechanical engineering degree from the University of Cincinnati’s College of Applied Science provides a solid foundation for understanding and explaining how innovative shops apply advanced machining technologies. As you might gather from this photo, he’s the car guy of the MMS bunch. But his ’55 Chevy isn’t as nice as the hotrod he’s standing next to. In fact, his car needs a right-front fender spear if you know anybody willing to part with one.
The vast majority of mass finishing processes I’ve encountered in shops use a large vibratory tumbler inside of which a mishmash of workpieces and finishing media swirl around in contact with one another, serving to smooth, deburr, radius or polish the workpieces.
While this might be perfectly fine for some applications, what about parts that have complex shapes or delicate features that could become damaged if they were to bump into each other during such a frenetic finishing process? For these, an alternate method of introducing parts to finishing media might be required to prevent potential damage from occurring.
In fact, Rösler Metal Finishing suggests three automated options to completely finish workpieces such as these or to perform targeted finishing of specific surfaces in a high-production environment, leveraging the advantages of robotic handling.
The first is shown above. Called Surf Finisher, it uses one or two robots with custom grippers to pick workpieces from a conveyor, immerse them into a rotating work bowl filled with the appropriate grinding or polishing media, then return them to an outbound conveyor. The work bowl is available in different sizes to enable the finishing of a single, large parts or the simultaneous finishing of multiple smaller parts. The robot can guide the workpieces through the processing media in pre-programmed movements including defined treatment angles, different immersion depths and rotary motion to enable the targeted finishing of specific surface areas.
The work bowl with processing media is also rotating at a speed of up to 80 rpm (actual speed is determined by the types of workpieces and finish requirements). The robotic movement combined with the work bowl rotation creates a “surfing” effect with very high pressure between workpiece and media. This concurrent, intensive pressure is said to create a surface smoothing effect in a relatively short amount of time, achieving Ra finishes to 0.04 micron.
The second, shown above, also uses one or more robots that perform two functions: material handling and programmed movement of workpieces through the processing media. For this system, which is called High-Frequency-Finisher (HFF), the media for wet or dry processing within the work bowl are agitated by vibration with a speed as high as 3,000 rpm. The robot with custom gripper immerses the workpieces into the agitated media, and the dual movement of the robot and media results in a high-pressure, highly intensive treatment of the parts completed in fast cycle times.
The third, shown above, is a new version of Rösler’s Drag Finishing system that includes automatic workpiece loading/unloading. In fact, this automated system was developed for Walter AG, multinational cutting tool manufacturer, to enable the company to automatically deburr a variety of different sized tool bodies instead of having its employees do that manually.
The system uses two interlinked drag finishing machines each having six working spindles served by a robot that automatically installs and removes tool bodies in and out of the spindles. The finishing process for these tools requires a safety load system that combines workpiece surface modeling and load pattern simulation. To ensure that handling errors do not occur, electronic sensors continuously monitor the pneumatic coupling system to ensure tool bodies remain safely fixtured in the spindles.
Once loaded, the tool bodies are then “dragged” through the stationary wet or dry processing media. Process parameters such as carousel and spindle speeds, immersion depth and treatment times are stored in pre-set programs in the system’s PLC. After completion of the finishing cycle, the robot removes the tool bodies, moves them to a rinse and cleaning station, and then places them onto a tray.
The company says this system can also be used to perform effective, repeatable surface finishing for items such as orthopedic implants, geared components, and aerospace and automotive components.
The Industrial Internet of Things (IIoT), additive manufacturing and collaborative robotics are emerging technologies that will change the nature of how manufacturers make parts. In a growing number of instances, they already are changing the nature of how manufacturers make parts. That’s why it is important that we cover these topics in our magazine, this blog, our various social media channels and so on.
That said, the concept of lean manufacturing should remain at top of mind for all parts producers out there. In fact, I plan to revisit this topic in a story for our July issue, describing how a shop’s efforts in cultivating a lean culture is enabling it to grow and win a greater amount of aerospace work.
The title of this article might be something like “What Comes After 5S?” Many shops start their lean journey by implementing 5S workplace organization tactics, as did the shop I’m hoping to profile. However, I’d like this article to describe the next steps after 5S as it worked to establish its lean-manufacturing mindset and culture of continuous improvement.
In addition to appearing in our magazine, the story will be added to our website’s Lean Manufacturing Zone, which contains stories about other machining facilities that have made a lean transformation. For example:
This one explains how a contract shop leveraged lean as a means to help it manageably control growth.
This one describes how a job shop can integrate lean manufacturing into its DNA.
This one describes what an A3 problem-solving process is all about and how an industrial equipment manufacturer uses it.
And this one offers an overview of what 5S is all about.
In “Working Toward Lights-Out Inspection,” I explain how contract shop PDQ Corp. had been developing a process to enable its new CMM to inspect multiple parts unattended. A key element of this strategy is a modular, quick-change CMM fixture system developed by Phillips Precision called Inspection Arsenal. This system uses standard plates that magnetically interlock like puzzle pieces to enable parts fixtured on the plates to be easily removed and replaced to speed change-overs for new inspection jobs.
Recently, air-assist fixture plates have been developed for this system to enable a CMM operator to easily maneuver heavy workpieces across the CMM table as necessary. The plate glides over the CMM bed with minimal effort even for workpieces weighing as much as an anvil. See how in the video above.
Ogden, Utah’s LeanWerks practices open-book management (OBM), a management style in which a business’ financial information is regularly shared with all employees. In fact, Reid Leland, who started the company in 2003, says it represents the cornerstone of his company’s culture.
OBM as it is applied at LeanWerks has three primary elements: financial training, feedback and profit sharing. That said, Reid says this management style is not a panacea. Learn more.
Reid Leland’s LeanWerks offers financial training to new employees as part of its OBM approach, covering topics such as the gross profit to operating expenses (GPOE) ratio. GPOE is calculated each day and presented to employees on a large monitor inside the entrance to the shop area. This simple metric shows if the shop is profitable on any given day. Simply put, the company makes money on days in which the ratio is higher than 1, loses money when the ratio is less than 1, and breaks even when the ratio is precisely 1. Profits are shared with employees when total GPOE for a month is 1.2 or higher.
Flat-bottom drills are nifty tools. Those that have true 180-degree flat cutting edges can create holes on inclined or curved surfaces without a preliminary center drilling operation to create a start hole. And unlike conventional drills, flat-bottom drills tend to shear material as it exists the back side of a workpiece instead of pushing through, leaving behind a minimal burr.
The video above demonstrates this. Produced by Nachi, it shows a slow-motion comparison of a conventional drill and the company’s Aqua Drill Ex Flat completing a through-hole. You can see the tip of the conventional drill pushing through the material, whereas the flat-bottom drill performs more of a shearing operation. The video also shows the flat-bottom drill creating holes in inclined and contoured surfaces without requiring a starter hole.