Derek Korn

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.

Posted by: Derek Korn 16. November 2015

Variations on the Rotary Transfer Theme

Bar-fed rotary transfer machines combine multiple cutting stations around the periphery of a round, indexing table. (These tables are commonly oriented horizontally, but “trunnion-style” versions in which the table is oriented vertically are also available.) Fixured or collet-held workpiece blanks arranged around the table are indexed from one machining station to the next until all operations are completed. (Some stations are used to invert the workpiece to enable back-side machining at subsequent stations.) A finished part(s) is ejected with every index of the table.

The Hydromat open house event I attended last month at its U.S. headquarters in St. Louis, Missouri, was timely because I was able to see a few rotary transfer machines in build that demonstrate the degree to which they can be tailored to specific high-volume applications. Although what’s shown below is a random sampling, it represents varying levels of rotary transfer sophistication engineered to meet a user’s particular production needs. For example (in the order of basic to complex):  

This Epic R/T 25-12 collet-style machine with a single bar feeder and no vertical machining stations represents a basic rotary transfer system. It’s similar to original Hydromat designs that were hydraulically driven, but it’s CNC-controlled. As for the model number identification, “25” indicates the diameter of the barstock material it is designed to accommodate (25 mm) and “12” is the number of available machining stations.​

This Epic R/T 32/45-16 machine (16 stations can be set up for 32- or 45-mm maximum barstock diameters) has two opposing bar feeders delivering stock into stations 180-degrees from each other. The operations performed are the same around each side, and two finished parts are dropped with each index. (It’s basically doing the work of two machines simultaneously.) So around each side, stock is fed into the first station, machining is performed on the next three, the part is inverted on the following one, back-side machining is performed on the next two, and the completed part is ejected on the last. Note that this setup also has four vertical machining spindles.​

This Epic R/T 25-12 machine also has two bar feeders. However, instead of opposing each other as in the previous example, they feed small-diameter barstock into adjoining stations. Plus, each has been modified to feed two bars apiece into custom workholding collets designed to hold two parts (not just one as you might expect). As a result, four parts are dropped complete with each 3.4-second table index, helping the customer to meet its very-high-production volume goal.​

This Epic HS 16 indexing chuck shows the extent to which ancillary equipment can be added to offer a complete parts manufacturing solution, including robotic part handling, part gaging and part cleaning.  ​

At the open house, Hydromat also offered a sneak peek at its Epic Gen II rotary transfer machine platform, which will be officially introduced at IMTS 2016. This next-generation version of the company’s flagship rotary transfer machine line (shown below) includes a number of advancements related to servomotor, process feedback, programming software, reporting software and other technologies.

Posted by: Derek Korn 9. November 2015

Would You Rather Have a Paper Print or a 3D-Printed Prototype?

Here are two examples of complex custom tool concepts that Quinn Saw can print and provide to customers so they can more easily comprehend the overall design concept compared to basic illustrations.

Say you need a custom cutting tool that’s likely to cost you a few grand. Would you rather the cutting tool manufacturer you’re considering provide you with a CAD model or printout of the design or, better yet, a 3D-printed prototype of it?

During a recent open house at Hydromat, I got the chance to chat with Troy Frame, product development manager at W.D. Quinn Saw Co., who talked about the value in providing customers with prototypes of custom tools printed from its Formlabs SLA desktop 3D printer.

Started in 1903, Quinn Saw is a single-family-owned business that’s now into its fifth generation. Bill and Joe Zickel are the current owner-operators (4th generation). The company’s core business has always been reconditioning saw blades and manufacturing new ones, but it has since branched out into custom tooling with Troy as the lead designer.

Troy actually worked for Hydromat from 1997 to 2007 as a tooling engineer, engaging with Quinn Saw (Hydromat’s primary blade supplier for its rotary transfer machines) on many projects to improve the barstock sawing process using HSS and carbide-tipped blades. After joining Quinn Saw in 2007, Troy started developing custom tools, such as the printed prototypes shown above, for unique customer applications.

So why the 3D printer for prototypes? Troy says one reason is that his tooling designs often have intricate features and details that are difficult for many people to fully understand and appreciate just looking at paper illustrations. Plus, the people making the purchasing decisions often are not as familiar with the project as their engineering staff, so the printed models enable the decision makers to have something really close to the actual tool in hand, making it easier to comprehend the overall concept.

But another reason had to do with preventing possible interferences. He points to a tool that took 8 weeks to manufacture. Although the customer was happy with how it looked, the tool ultimately didn’t fit into the required space due to an interference with another device in the tight machine environment. This required rushing the tool back and forth between parties for revisions, which was expensive, but Troy notes the biggest impact was the unexpected delay and black eye for providing a tool that was not functional upon receiving it. After resolving the issues and providing a successful tool, Quinn Saw management met to determine how to prevent this from happening again. The idea of using a 3D printer for prototypes was brought up, so Dan Zickel (of the company’s fifth generation) was tasked with sorting through all of the available 3D printer types and options to determine what model was most suitable and cost effective for its needs. After significant reviews of the vast array of machine types, sizes and cost, Dan narrowed it down to the Formlabs Form 1+, which it purchased this past February. This printer offered a suitable printing envelope with a very reasonable cost as well as high printing definition.  

Quinn Saw chose this Formlabs Form 1+ SLA 3D printer because it offered a suitable printing envelope, a very reasonable cost and high printing definition.  

The machine was purchased just before this year’s Precision Machining Technology Show (PMTS) in Columbus, Ohio. This enabled Troy to print and offer models of concepts to show attendees rather than just pictures. Plus, having high-cost actual tooling on a show display table typically isn’t practical or cost effective unless you have a guaranteed avenue in which to sell it afterwards. The 3D printer is also used to scale up small tool features (see the photo below) that would normally require viewing through a magnifying or inspection device, which sometimes isn’t practical at a trade show or in front of a customer.

The company’s 3D printer is also used to scale up small tool features that would otherwise require a magnifying or inspection device to see.

The company sees value in using its 3D printer in other ways, too. For example, Troy says coolant delivery has been a problem for one of Quinn Saw’s grinding machines that has an articulating head. The company is considering printing a new guard with internal coolant ports. Although this design would be costly and impractical to produce via conventional machining, the 3D printer could produce the complex part at little expense. Then after experimenting with the printed guard on the grinding machine, it’d be easy to tweak the design if necessary and simply print another to try.

Troy cautions that while 3D printing technology is helpful, it’s not perfect. Quinn Saw’s 3D printer uses support material during printing that basically snaps off after the part is printed, but leaves small imperfections where it was attached. Those must be removed by filing and or sanding. Plus, there is a fair amount of physical cleanup on printed components to make them all fit precisely and look more presentable—parts don’t just emerge from the resin batch complete and perfect. But in his experience, while the technology is still in its infancy, it is evolving rapidly and so are the machines that do the printing.

Posted by: Derek Korn 5. November 2015

Integrating Robot Programming into the CNC: One Example

For this demonstration, the robot performed both workpiece pallet changeout and simulated polishing operations of machined parts.

I’ve been aware of the Run MyRobot capability available with Siemens Sinumerik controls for a little while, but I believe the cell below that was in Handtmann’s EMO Milan booth represents the first time I’ve seen a demonstration of the concept using an actual machine tool.

The idea is to provide intuitive robot programming capability at a machine’s CNC via the Sinumerik Operate GUI. In the case of this cell, the execution of the movements of the six-axis Kuka KR 600 Fortec robot (with 600-kg load capacity), provision of robot safety functions and other robot-specific functions are performed by the Kuka KR C4 robot control. However, that control is connected to the Handtmann five-axis HBZ Trunnion 80 machine’s Sinumerik 840D sl  CNC. Therefore, the machine tool operations and robot program can be tracked and controlled on one screen via parallel channels.

The machine tool operations and robot program can be tracked and controlled on one CNC screen via parallel channels (the robot channel is shown here).

For this demonstration, the robot performed both workpiece pallet changeout (using Schunk clamping systems) and simulated polishing operations of machined parts. Of course, the robot can be used to perform a range of secondary operations, including drilling, brushing and deburring, depending on a manufacturer’s needs.

Check out this video that shows the cell at the show.

Posted by: Derek Korn 27. October 2015

Getting to Know Glebar

Glebar’s new 44,560-square-foot facility represents a consolidation of three other locations and features an eco-friendly design and improved workflow for the production of its range of grinding machines.

I must admit, until recently, I didn’t know Glebar as well as I would have liked to. That’s why I was glad to attend the grinding machine manufacturer’s open house last week to celebrate the opening of its new headquarters in Ramsey, New Jersey.

Glebar was founded in 1952 by Miner Gleason (the “gle”) and Robert Barhorst (the “bar”) as a manufacturer of centerless plunge-grinding machines. In the 1960s, it adapted its plunge grinding technology to form billiard balls and golf ball cores. (To this day, 90 percent of all golf ball cores are produced on Glebar equipment.) The company’s product portfolio has since expanded to include OD grinders, double-disc grinders, CNC roll rubber grinders with SCARA-robot feeding systems, CNC serrated-steel rule grinders, CAM grinding systems, dressing machines and Ferris wheel grinders. (Here’s what a Ferris wheel grinder is if you’re not familiar with them.) Glebar serves many markets, including medical, metals, automotive and aerospace, and all of its equipment is made here in the States.

Adam Cook, CEO, says that after operating for more than 60 years in Franklin Lakes, New Jersey, Glebar consolidated its three locations and moved to its larger facility in Ramsey to accommodate the company’s recent growth and international expansion. Its new 44,560-square-foot headquarters features LED lighting, updated power systems and eco-friendly features to reduce energy consumption, as well as new manufacturing and inspection equipment, including HMC, VMC, EDM and turning center equipment. The new facility with open layout also enables the company to facilitate workflow through the shop and more effectively implement a lean manufacturing mindset.

Glebar has invested in a number of new machining centers for its shop area, including HMC, VMC, EDM and turning center equipment. At some point, a pallet-pool system will be added to the new Mazak Nexus 6800-II HMC.

Glebar designs its grinding equipment to be modular so it can tailor systems per customers’ applications to enable automation, in-process feedback and intuitive programming and operating. One good example is its CAM2 micro-grinding machine for medical guidewire and other small components. This machine, which can accommodate workpiece stock as small as 0.005 inch in diameter and offers a minimal grinding diameter of 0.0005 inch, can be configured with an in-line gage, wire cutter and wire extractor, spool feeder and cutting system, vacuum feeding system, programmable part extractor and so on.

The company’s CAM2 micro-grinding machines are commonly used to grind medical guidewires for minimally invasive surgical procedures as well as small parts for dental and other applications. The machines accommodate workpiece stock as small as 0.005 inch in diameter and offers a minimal grinding diameter of 0.0005 inch.

It can also be used in conjunction with the company’s new P4K gaging system, a profile metrology device that uses high-speed optical micrometer technology whereby a part is pulled through a laser gage via a precision linear stage while matching diameter and length readings in real time at a rate of 10,000 readings per second (these readings are taken every 30 millionths of an inch). The P4K can scan and feed back diameter measurements to the grinding machine, including taper and radii, to automatically correct wheel dress shape. 

Posted by: Derek Korn 15. October 2015

High-Production CMM Inspection

The shopfloor CMM inspection system shown above caught my eye at this year's EMO show in Milan, Italy, largely because it resembled a pallet-pool HMC. The difference is that this system is designed to perform long stretches of unattended measurement of various parts, not machining them.

The heart of this system is a four-axis Leitz Serio XI CMM from Hexagon Metrology, with the fourth axis provided by a rotary table. Instead of having an automatic toolchanger, it has an automatic probe changer that can accommodate 24 probes. It also features multiple pallets that can be pre-loaded with parts requiring inspection. Semi- or fully automatic pallet loading versions are available.

This concept reminded me of this article I wrote earlier this year, in which a shop was developing a process to enable lights-out inspection of its parts, leveraging CMM and quick-change fixturing technologies to enable unattended measurement of multiple workpieces.

Implementing strategies like these can minimize the impact that part measurement has on a shop’s bottom line.

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