In the same way, chatter in machining is not a result of "plucking" from the cutting edges, but is instead a result of the continuous interaction between these impacts and the surface that has already been machined. That previously machined surface has waviness in it resulting from the previous pass. Even if the surface looks mirror smooth, the waviness is there. Vibration from cutting edges hitting the workpiece is one component of chatter, and this waviness is the other.

The cutter or cutters are held in place by keys which fit in the keyways and by the spacers which pinch in on the sides of the cutter and position the cutter in the desired place along the arbor. The key prevents the cutter from turning on the arbor.

2.)  Fixtures: Another frequently used work-holding device is the fixture; fixtures are usesful for repetitive work when a large number of identical parts are being made or when there is an irrregularly-shaped part that will not fit easily into a vise.

How can shops can make informed decisions using data-driven feedback to improve shopfloor efficiency and profitability? And how will these technologies differ between high- and low-volume production?

This graph illustrates a portion of the vibration signature of an actual milling spindle. The graph is like a topographical map, where each line denotes a constant depth of cut. These depth lines range from 2 mm to 9 mm. The graph shows how at some speeds the cut is stable and cutting force is low, while at other speeds chatter dominates and the peak cutting force is high.

4.)  Arbors:  An arbor is needed for the horizontal milling machine. It is a strong, solid steel cylinder onto which a milling cutter or milling cutters are placed.

Job shops are implementing automation and digitalization into workflows to eliminate set up time and increase repeatability in production.

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Lee:  I know you’re using the cutters described in the blueprint and the production notes, but sometimes the engineers make mistakes. If it keeps happening and it’s slowing you down, you might tell the supervisor and have a conference with one of the engineers.

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The first step, says Dr. Badrawy, is to understand something about the nature of this optimum spindle speed you're after.

The first two cases have already been alluded to. One is when spindle rpm is very low. Exactly how low will differ from process to process, but at the early end of the speed range, natural process damping will be strong enough to smother chatter before it starts.

In this lesson we will study some accessories that help the milling machine to do more jobs: Some of these accessories are for holding the workpiece (e.g., a vise which is bolted to the table) and others are for holding and driving the milling cutters (e.g. an arbor or an adapter)

Your own testing should record this same information. Record the spindle used, for example. Shops with redundant machines get a break here because identical machines with identical spindles can be expected to have identical (or at least similar enough) harmonic characteristics.

Another toolholder choice that is not recommended is the hydraulic toolholder, he says. This design's clamping mechanism and hydraulic bladder make for a heavier toolholder body, potentially making vibration more difficult to control.

The L.S. Starrett Co. has been manufacturing precision measurement tools in Athol, Massachusetts, since 1880. Attention to U.S. manufacturing often focuses on reshoring manufacturing from other countries, but Starrett never left. The facility in Athol employs hundreds and produces thousands of tools that remain vital for measurement in machining and other fields.

Pacon Mfg, Inc. has not rested on its laurels as the 2020 Top Shop Honoree for Shopfloor Practices and Performance. In the years since, it has refined its processes to continue excelling in a volatile market.

In this episode of the AM Radio podcast, Robots & Autonomy Editor Julia Hider joins Additive Manufacturing’s Executive Editor Stephanie Hendrixson and Editor-in-Chief Peter Zelinski to discuss how robots and 3D printing enable each other.

The latest episode “Made in the USA” podcast explores a company that uses collaborative robots, one of the key tools helping US machine shops and other manufacturers compete with lower cost countries by automating production.

Faster spindle speeds affect all metal cutting applications, but speed changes the rules for aluminum more than it does for other metals. In steels and harder alloys, the higher speed is combined with a light depth of cut, leaving the fundamental limits on the process unchanged. Maximum metal removal rate is still set by the performance limits of the tooling and the machine.

The sweet spot is a speed at which these two components harmonize. Chatter is at its worst when the opposite is true—when vibration from the cutting edges moves as the mirror image of surface waviness. (See the diagram) In the language of vibration analysis, this condition is "180 degrees out of phase." The ideal condition (also shown in the diagram) is when the waviness and cutting vibration are perfectly in phase. At this speed, the load is constant, the cut is smooth, and the tool can take a much deeper cut without adverse effects. Truly, this is a sweet spot at which to mill.

Facing increasing competition from lower-cost imports, Suburban Tool made a move toward large-scale, in-house machining. By identifying a niche in large, precision angle plates and tombstones, the company has strengthened its ability to control quality and protect its reputation.

A software tool or analyzer that can zero in on the right spindle speed can save the time and material necessary to hunt for this speed by counting down to it from the top of the speed range. However, even with the analyzer, it's still necessary to perform test cuts at various depths to determine how deep the machine can cut at this speed.

You may think chatter in milling is entirely the product of cutting edges hitting the workpiece—in other words, bang bang bang, and chatter comes from this.

Now, reduce spindle speed by 1,000 rpm and follow the same procedure again. The machine may perform better at this speed, or it may perform worse. In either case, at the maximum chatter-free axial depth, record MRR and spindle load again.

Lee Wimmer invited us to tour his second-generation family-owned machine shop in Perkasie, PA. This video explores the production processes behind precision-machined parts for both Wimmer Custom Cycle and LS Wimmer Machine Co., and shows how ingenuity and determination are still at the heart of American manufacturing. Today, both companies are now managed by Wimmer’s three sons.

By equipping MassRobotics with its advanced cobots, ABB aims to facilitate the creation of new and impactful solutions that address real-world challenges across various industries.

In other words, when sweet spot machining moves the chatter barrier out of the way, the barriers that remain are the machine and tool limits that shops working at lower speeds have faced all along.

Not only can Gelsight’s tactile sensor detect and evaluate defects, but it can also measure part features, surface roughness and even contamination.

For radial depth of cut, pick an arbitrary value that will remain constant until the sweet spot is found—50 percent of cutter diameter, for example.

1.)  Vises:  Any table vise will have U-shaped spaces cut on the sides for the T-bolt ends to fit. When bolted to the table, a vise has a pair of jaws for holding the workpiece; the jaws are tightened or loosened by turning the screw or crank at the end of the vise. There are several kinds of vises:

Entrepreneur Scott Colosimo found early success in China producing parts for his Cleveland-based motorcycle company in the mid-2000s. This is the story of how IP theft issues overwhelmed the business, prompting Colosimo and his team to start over from scratch — and move production back to the United States.

Looking to automate your shop floor? The Automated Shop Conference (TASC) will connect shops with experts who can advise them through this transition.

Even before inspection, Datanomix and Caron Engineering’s TMAC AI can extrapolate part quality from cut information. This information also helps shops push their tool life to its limits.

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It may also be useful to note the spindle load. MRR and spindle load will help you compare the best the machine was able to do at this speed with the best it can do at other speeds.

The MFG Meeting brings together manufacturing technology industry leaders to address key business challenges and provide actionable solutions. Sessions cover a wide range of topics, including workforce, economics, supply chain, leadership, politics, and more. This unique meeting experience provides unparalleled opportunities to network with executives from companies that make, sell, service, and support MT. These peers and competitors will learn from each other, build long-lasting connections, and share insights that will benefit their business.

The Automated Shop Conference (TASC) will give shops of all sizes and production volumes key insights and practical guidance on how to implement automation.

CCAI is offering a comprehensive Industrial Finishing Safety Seminar developed by industry experts well-versed in safety for finishing operations.  This day-and-a-half seminar focuses on NFPA 33, the Standard for Spray Application Using Flammable or Combustible Materials and will deliver important and critical information on how to safely operate an industrial finishing line. Topics Covered: An introduction to safety Overview and definitions General requirements and electrostatic spray equipment Ventilation Storage handling and distribution Fire protection Operations, maintenance and training Drying and curing Liquid and powder coatings Authority Having Jurisdiction panel discussion Who Should Attend? Manufacturing, staff and environmental engineers (industrial health & safety) Lead painters Maintenance leads and personnel Finishing equipment designers System controls and project engineers Facility managers Finishing industry distributors Date: Tuesday, March 11 and Wednesday, March 12 Time:  Tuesday - 9:00 AM - 4:00 PM and Wednesday 8:00 AM - Noon Location: Sames 45001 5 Mile Road Plymouth, MI 48170 Registration Fee: CCAI Members: $599  /  Non-Members: $750 Registration Fee Includes: Classroom instruction; lunch on day one; a certificate of completion; and a printed copy of the NFPA 33 Standard for Spray Application Using Flammable or Combustible Materials. Registration: CLICK HERE to register. Space is limited.

Among the Cincinnati Machine employees who assist customers with this work is principal engineer Sinan Badrawy, source for much of this article. Dr. Badrawy is one of a group he calls the "dynamic mafia," a small number of metalworking industry researchers (most affiliated with the University of Florida at one time or another) who study dynamic vibration analysis specifically as it applies to machining. Tools commonly employed in this research include a sensitive hammer for "ringing" the spindle like a bell, coupled with electronic sensors for mapping the vibrations that result. Mathematical tools for analyzing these vibrations include numbers so far removed from the numbers you and I count with that they are called—literally—imaginary numbers.

A fair amount of cutting may be required, however. The following point can't be overstressed: Harmonic characteristics are not inherent to the spindle and not inherent to the machine . . . but instead are characteristic of the entire system of spindle + toolholder + tool + tool gage length. Change any one of these components, and you have a different system for which different optimum cutting parameters will have to be found.

Now it's time to vary the radial depth of cut. At the chosen speed, run at a variety of radial depths to simulate the different types of cuts this tool might take. A good mix might be to run at 25, 50 and 100 percent of cutter diameter—representing finishing, roughing and slotting cuts, respectively. Every radial depth will permit a different axial depth. Perform test cutting to determine the maximum stable axial depth for each one.

In addition to favoring a three-flute tool (see picture), here are other cutting tool considerations for high speed milling in aluminum:

Each year Products Finishing partners with thousands of finishing operations in the U.S. to celebrate National Surface Finishing Day (NSFD) on the first Wednesday in March. NSFD is designed to celebrate and showcase the industry to trade schools, businesses, officials and media, as well as to celebrate employees and staff. The overarching goal of NSFD is to bring further awareness to the important roles plating and coating facilities play in their communities. Facilities are encouraged to host events and work with local media to build awareness about the contributions made by the surface finishing industry. For a helpful guide to reaching out to media outlets, download the NSFD toolkit here. How can you celebrate? Share your company’s story Hold an open house where the public can check out your facility –— either in person or virtual Offer student shop tours to local trade schools Invite local elected officials to visit and get to know your staff Celebrate your employees Share news about what you’re doing on social media and use the hashtag #NationalSurfaceFinishingDay or #NSFD

When Puneet and Neelam Neotia moved from India to the United States several years ago, they brought with them a family background in manufacturing and CNC machining. Now the couple is working to get their startup machine shop off the ground, sourcing new customers and getting the word out about their shop in Clarksville, Indiana. The couple — proud to publicize their "Made in the USA" parts — is leveraging family connections and manufacturing capabilities back in India, but not in the way that some people assume.

Coordinate systems tell a CNC machine where to position the cutting tool during the program’s execution for any purpose that requires the cutting tool to move.

How can shops can make informed decisions using data-driven feedback to improve shopfloor efficiency and profitability? And how will these technologies differ between high- and low-volume production?

The problem is, large aircraft structural components often don't offer the luxury of using the shortest available tooling. A deep pocket may demand a longer reach, and a tool tip that extends farther from the spindle will whip farther if chatter sets in. Perhaps the main reason why finding the sweet spot permits such large process improvements in aircraft machining work is that these parts typically call for tooling that is less than ideally rigid.

His rule of thumb is to run at a chip load of 1 percent of cutter diameter or 0.015 inch per tooth, whichever is less. He sometimes runs as high as 0.020 ipt. Compared to a typical metal removal rate in aluminum of 3 cubic inches per minute per hp, this approach to chip load lets him achieve MRR up to 5 cubic inches per minute per hp.

The tapered end of the arbor is pulled into the tapered spindle by the use of a draw-in bar which is run through the back of the mill into the spindle. The draw-in bar is screwed into the arbor about one inch. The arbor is secured with a nut at the other end of the arbor beyond the draw-in bar last arbor support.

The testing is now finished for this system. Armed with these data, programmers can know exactly what speed and exactly what depths of cut to specify whenever they call for this combination of machine, toolholder and cutting tool.

What's the difference? The same as the difference between a guitar and a violin. A guitar's sound comes directly from a single impulse, that of a finger plucking the string. But a violin's sound is a continuous tone that feeds on friction. A bow passes over the string, and the sound grows out of the harmonic resonance that results.

This cutter design slightly staggers the positions of the cutting edges so they don't strike at steady intervals. The resulting irregularity can be enough to break up harmonic effects.

Another case is when depth of cut is light—say, 0.050 inch and below. Chatter isn't significant where cutting forces are low.

At Carnegie Mellon University’s Manufacturing Futures Institute, researchers use a robotic test bed where AMRs deliver Lego bricks to robot arms for assembly to study AI, multirobot collaboration, assembly, safety and more.

As the demand for faster production cycles continues to grow, the ability to produce high-quality parts quickly and efficiently has become increasingly important. High-speed 3D printing has emerged as a key solution to reduce lead times and increase productivity across industries. However, like any advanced technology, it comes with its own set of challenges. In this webinar, Forward AM will explore both the opportunities and hurdles of adopting high-speed printing with a particular focus on overcoming those challenges. It’ll start by discussing the fundamentals of high-speed 3D printing and how it differs from conventional 3D printing methods. It’ll then move on to the key factors that influence successful implementation, including the impact of materials, equipment and design considerations. One of the main hurdles in high-speed 3D printing is ensuring the right balance between speed and part quality. Different materials behave differently under high-speed conditions — and not all equipment is optimized for this process. Forward AM will showcase some validated materials and equipment that are proven to perform well under these conditions. In addition, the presenters will look at real-world examples and applications where high-speed 3D printing has been successfully implemented, highlighting the collaboration between designers, engineers and manufacturers. By the end of this webinar, you'll not only have a clearer understanding of high-speed 3D printing with FFF but also the practical steps and considerations needed to make the most of this cutting-edge technology. Agenda:  Introduction The power of high-speed printing Know the process The practical side

Pacon Mfg, Inc. has not rested on its laurels as the 2020 Top Shop Honoree for Shopfloor Practices and Performance. In the years since, it has refined its processes to continue excelling in a volatile market.

ModuleWorks and Toolpath announce a technology partnership that intends to utilize intelligent cloud-based manufacturing solutions for machining estimation and CAM automation.

In this webinar, director of manufacturing Phil Linscheid will discuss how Hamilton Company has transformed its manufacturing operations with real-time production data. Learn how Phil and his team have increased throughput five times since 2017, while simultaneously improving production efficiency. Phil will share his journey over the past few years making strategic decisions to grow the machine shop’s impact as well as how his team uses MachineMetrics to improve production visibility, automate cycle time tracking, increase machine uptime and enable accurate quoting and planning. Agenda: Enabling production visibility in Nevada’s largest machine shop Improving quoting, planning and scheduling with accurate cycle times The importance of integrating shop floor data with operational systems

Speed changes the rules. To maximize metal removal rate with a high speed spindle, follow some fundamental tooling considerations and mill at just the right rpm.

Kennametal (Latrobe, Pennsylvania) is one company supplying these differential pitch cutters. And to reduce chatter in end milling applications, the company extends the same design principle to a line of helical cutters that feature flutes with differing axial rakes.

Lee:  To cut down on heat, you need to use the correct speed and feed rates. You have to check if you’re using the right coolant and that the cutting area is getting plenty of coolant on it.

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When milling out a pocket at a "sweet spot" spindle speed, take all cuts at a radial depth equal to 100 percent of the cutter diameter.

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Achieve higher metal removal rates and enhanced predictability with ISCAR’s advanced high-feed milling tools — optimized for today’s competitive global market.

Adding pallet systems brought Mach Machine success and additional productivity. The shop has since furthered its automation goals while adding new capabilities.

Any attachment which holds the workpiece in place on the table is very important. All such attachments depend on the T-slots cut along the length of the table. Into these slots, T-bolts can be inserted:  they will project their threaded ends up above the surface of the table and can be used to attach a variety of work-holding devices.

In fact, the difference in spindle life between high-chatter and low-chatter cutting can be striking. He once deliberately ran a high speed spindle in high-chatter conditions just to see how long it would hold up. He got it to fail in only three hours. By contrast, in processes run at harmonically optimized conditions, he has seen little enough effect on the spindle that he questions the very notion that high speed machining has to turn the spindle into a disposable commodity. Running at high rpm does accelerate the life cycle, but not as much as the replacement frequency in some shops would suggest. With chatter under control, he says, a quality spindle used in production high speed milling can last 3 to 5 years.

No matter what your workholding application, automation always makes sense. Kurt Workholding helps you pick the right tool for the automation job — whether it be a single-vise setup or multiple vises holding large work pieces. This webinar will cover automation solutions using pneumatic, hydraulic and electronic actuation. Agenda:  Most common types of vise automation solutions How to pick the right type of automation for an application Key differences between custom workholding and off-the-shelf automation solutions

As you keep testing, likely you will find some spindle speed at which it's possible to take much deeper cuts without chatter. You know you have found a sweet spot if performance is significantly better at this speed than the performance at speeds both 1,000 rpm faster and 1,000 rpm slower. This sweet spot is probably—but not certainly—the speed at which you want to machine.

Avoid sharp corner radii. Some cuts do demand sharp corners on the tool, so it's not always possible to follow this advice. For other cuts, however, use a tool with more rounded cutting edges. In heavy use, a sharp corner will wear away, leaving a cutting edge that may just smear the material instead of cutting it.

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A better choice is simply to avoid this transition. Run at conditions appropriate to 100 percent of the diameter for 100 percent of the time the tool is in the pocket.

Chip load doesn't matter. For actual production machining, the choice of chip load is very significant (see Chip Load, below), but because chip load doesn't influence harmonic effects, any reasonable value will do during testing so long as the same chip load is used for every cut.

However, just test cutting alone can also be enough. A shop can find optimum spindle speeds and depths of cut using resources it already has available. Probably the most expensive investment will be time on the machine.

In this episode of Made in the USA, several executives and senior staff at Hardinge give their first-person account of how they formulated the plan to shift the manufacturing of its milling and turning product lines from its Taiwan plant to its plant in Elmira, New York, the major challenges they encountered and the rewards that made it worth the effort.

Take a look inside James Engineering, a high-end CNC Deburring OEM that became a job shop when they decided to produce their own parts in-house.

Adding pallet systems brought Mach Machine success and additional productivity. The shop has since furthered its automation goals while adding new capabilities.

For the maximum depth achieved prior to chatter, compute the metal removal rate. MRR equals feed rate × axial depth of cut × radial depth of cut.

Roberto:  Lee, I had a problem this morning while milling some parts. I had to stop twice and change cutters, because they were getting dull.

Not every aluminum milling process, even at high speeds and even at high depths of cut, will feature a sweet spot that is so strikingly superior. There are at least three cases in which the search for a sweet spot may not be necessary.

Ever wonder what sets Top Shops apart from the competition? Dive into their award-winning practices and explore behind-the-scenes strategies for operational excellence.

FANUC’s IMTS 2024 booth includes real-time demonstrations that show the abilities of its equipment, including robots, controllers and machine tools.

Machine Shop VESL Copyright © by Lisa Hillyard is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

The primary result of these harmonic effects is that the top speed is no longer the best speed as far as metal removal rate is concerned. Instead, any milling process run at around 15,000 rpm or higher is likely to offer some optimum spindle speed, a "sweet spot," where the cut is significantly more stable than it is at both higher and lower speed settings. This sweet spot rpm value may permit double the depth of cut compared to other speeds. It may permit triple the depth of cut. That's why effective high speed machining of aluminum calls for a type of knowledge—basic vibration analysis—the shop may never have needed before.

Chatter is a self-excited vibration. It results from the interaction between the oscillation of the tool and the waviness in the surface. When the oscillation and waviness are in harmony (far left), cutting force is constant. This is a sweet spot. The worst case (far right) is when oscillation and waviness move precisely opposite to one another.

The image is partly correct, but it misses something fundamental. The "bang bang bang" describes a forced vibration. Chatter, on the other hand, is a self-excited vibration.

Learn more about the variety of technology and machinery Hwacheon Machinery America, Inc. is featuring at its IMTS 2024 booth.

Founded in 2001, PMTS reconvenes in April 2025 to celebrate its 13th biennial event for precision machining pros. Mark your calendar now and plan to join the precision machined parts community when we once again gather in person to share challenges and insights, see new technology solutions and learn about process innovations you can take back and immediately put into use in your own shop. The Precision Machining Technology Show is centered at the intersection of the industry's newest and most advanced product technologies, process innovations, business development prospects and personal career growth opportunities.

The payback—a higher metal removal rate in aluminum—has never been more valuable. Speed doesn't just change the rules for effective milling, it also increases the very demand for this milling work. Today's freedom to machine aluminum faster has allowed many costly assemblies in aircraft frames to be replaced economically with sophisticated structures machined in one piece out of aluminum billet. In many cases, better than 90 percent of the original stock gets turned into chips to make these parts. That's why a high metal removal rate is so beneficial.

But Dr. Badrawy insists that diagnosing a machining center's sweet spots can be done without any of these tools, and without a degree in dynamics.

Each tool setting technique has merit, and it depends on where you are as a shop and the type of work you do, as cost and efficiency all come into play.

Q-Mark has built its metrology business by providing what customers need, when they want it. This goes for its IMTS booth, too, with free drinks alongside custom technology.

AI technology isn’t just a concept for the future—it’s here now, ready to transform your estimating process with the new AI BOM builder in JobBOSS². In this first-launch webinar, discover how AI can revolutionize bill of materials (BOM) entry in your shop, saving time, reducing errors and boosting efficiency. In this session, ECI will review how to use AI to build BOMs through a powerful feature that automates the extraction and input of BOM data from PDFs, Excel spreadsheets and images, all within JobBOSS². You'll have the opportunity to watch a live demonstration of the AI BOM builder in action — showcasing its ability to reduce BOM entry time from hours to mere minutes — thereby allowing you to focus on more strategic tasks. Additionally, you will learn about the real-world benefits of AI-driven BOM entry, including the minimization of manual errors, enhanced accuracy, and streamlined estimating processes — all of which can provide your shop with an immediate competitive edge. Finally, there will be a Q&A session with experts, giving you the chance to ask questions and find out how to integrate AI effectively. Agenda:  Experience AI in action in a real-world manufacturing setting Discover how the AI BOM builder can immediately impact your shop’s efficiency and productivity Get hands-on insights on implementing AI to streamline your operations

The new space includes a showroom, office spaces and an auditorium that will enhance its work with its technical partners.

The tool crib is the backbone of any machine shop — without the right tools, nothing moves forward. While most ERP systems overlook the tool crib, ProShop integrates it seamlessly with CNC programming, job planning, scheduling and more. Join this webinar for an exclusive look at how Roush Yates Manufacturing Solutions leverages ProShop to document tool requirements, sync tool demand from CAM software and efficiently manage the tool crib and work instructions. Discover how ProShop transforms the tooling workflow to maximize efficiency and precision.

More flutes than that can be too many because a tool with four or more flutes may not leave enough room for the chip to escape. At high cutting speeds, aluminum may adhere between closely spaced flutes, potentially leaving the cutter looking like an aluminum lollipop.

Choose a steep helix. The helix angle is measured from the tool centerline. This angle should be no more than about 35 degrees. A larger value than this will tend to increase the pull force the tool sees while cutting. When striving for optimum harmonic conditions, this is bad. The pull may relax some of the preload force on a spring-loaded spindle bearing. This change in the system would change the sweet spot, potentially invalidating the testing that had been done to find the optimum speed.

This presentation focuses on the vital role that linear and angular encoders play in ensuring precision in machine tools. Attendees will learn about the common challenges compromising accuracy, such as thermal expansion, mechanical misalignments and vibration. Whether you're an OEM, integrator, or machine operator, this webinar will offer valuable insights into optimizing CNC performance. Agenda: Challenges to CNC machine accuracy Understanding encoder technology How encoders address accuracy challenges

When the tool enters a corner, it may cut on 100 percent of its diameter no matter what the radial depth was beforehand.

JD Machine, 2024’s Top Shops Honoree in Human Resources, embodies its “Education for Life” core value with a robust apprenticeship program and significant continuous improvement efforts.

Downtime is the enemy of efficient manufacturing — a problem FIBA Technologies has addressed through purchasing a Soraluce FLP 14000.

Determining whether to use high-density fixtures or to simplify workholding requires a deeper look into the details of your parts and processes.

One interesting trait of chatter is that the sound of a single cut taken at some speed where chatter occurs can contain enough mathematical information to determine what the stable cutting speed would be. Accordingly, there are software tools and analyzers that use a microphone to listen to the cut, then calculate optimum spindle speeds based on this input. (For information on two such products, refer to the “Learn More” near the top of this page.)

The diagram here is a simplified schematic that shows a typical pattern of stable spindle speeds. At higher speeds, damping effects fall away, and the potential for higher depths of cut becomes pronounced.

Determining whether to use high-density fixtures or to simplify workholding requires a deeper look into the details of your parts and processes.

Whatever the choice, balance must be respected at high speeds. The centrifugal force from an unbalanced toolholder is a function of the spindle speed squared, so vibrations resulting from unbalance can grow very strong at higher speeds. Investing in a toolholder balancing machine is probably not necessary, Dr. Badrawy says. However—particularly where collet toolholders are concerned—it is worth the extra expense to buy quality toolholders that have been prebalanced to a strict requirement.

Though curled chips like the ones at the top may be typical in aluminum milling, the chips at the bottom—resulting from a higher inch-per-tooth feed rate—suggest that a heavier chip load may provide the more power-efficient way to mill.

AccuRounds has created synergy between culture and technology, driving a commitment to customer satisfaction and continuous improvement.

One machine tool builder that has a vested interest in helping shops achieve these high metal removal rates is Cincinnati Machine. The Cincinnati, Ohio, builder offers a range of high speed machine tools for aluminum milling. At the far end of this range is the company's newly introduced "Hypermach" line of high speed horizontal machines for large aircraft parts. Linear motors give Hypermach models high feed rate and high linear acceleration. Spindle options include a model offering 100 hp and 24,000 rpm. To win the most effectiveness from this and other higher-end machines, finding the right speed for each application is key.

TWO-FLUTED END MILL FORMED CUTTER METAL SLITTING SAW WOODRUFF KEYSEAT CUTTER DOVETAIL CUTTER T-SLOT CUTTER SIDE-MILLING CUTTER WITH STAGGERED TEETH

New U.S.-based event announced in 2021 finally debuts next year: focuses on complete additive manufacturing value chain. More at formnextchicago.com.

Across a range of technical presentations aimed at small and mid-sized job shops, the first-ever Automated Shop Conference (TASC) offered insights into several automated technologies, implementation strategies, shopfloor training tips, and even the untapped power of automated coolant delivery.

AccuRounds has created synergy between culture and technology, driving a commitment to customer satisfaction and continuous improvement.

The final case where the search for a sweet spot may not be necessary is when everything about the process is very stiff. That is, the workholding is rigid, the spindle has a high dynamic stiffness and a secure hold on the toolholder, the toolholder itself is compact, and the cutting tool is very short. When all of these conditions are met, chatter may not play a major role, and the top speed may indeed be the best speed.

Here are data from actual cutting tests used to find the optimum speed for a spindle equipped with relatively long tooling (L/D = 5). The sweet spot occurs at 17,000 rpm. Once this stable speed was found, test cuts were taken at a variety of radial depths.

Facing increasing competition from lower-cost imports, Suburban Tool made a move toward large-scale, in-house machining. By identifying a niche in large, precision angle plates and tombstones, the company has strengthened its ability to control quality and protect its reputation.

Aluminum, however, is unique among the most commonly machined metals in that the high spindle speed is often combined with heavy cuts. This combination—speed plus depth—makes chatter a far more significant concern. As a result, the shop hogging aluminum at high spindle speed faces not two process limits, but three. There are the machine and tool limitations just like always, and now there is also the limiting effect imposed by the harmonic characteristics of the spindle and tooling system overall.

Indeed, the tightly curled aluminum chips typical of many aerospace shops reveal where this energy is lost. The spindle is spending some of its precious output on the unnecessary task of working the chips into these curls. To avoid some of this waste, Dr. Badrawy prefers to hit the material fast enough and at a heavy enough feed rate that the chip breaks away without deforming.

Soraluce’s wide range of machine heads and the ability to have multiple heads on a single machine (with automatic changing stations) provides flexibility and reduced setups for large-format machining.

The better choices are collet holders and shrink fit holders. Both do clamp the tool from all directions around the shank. Shrink fit is preferred, but the need for a heater may make shrink fit the more expensive option.

Lee:  Well, Roberto, many times the quick dulling of a cutter is due to excessive heat. When the steel of the cutter heats up it loses some of its hardness, the wear is greater, the cutting is less efficient, and then even more heat builds up.

"The most important thing to say about toolholders in high speed milling of aluminum," says Dr. Badrawy, "is not to use a set-screw holder." A set-screw holder doesn't clamp the tool from all directions, but instead it pinches the tool shank between two points of support. "At high speeds, a set-screw holder will chatter no matter what," he says.

Verisurf’s Machine Tool Probing (MTP) suite is an in-process automated inspection solution for CNC machine tools, offering inspection and reporting capabilities.

But two flutes may be too few because of the harmonic effects. When you mill at the harmonic "sweet spot" of a particular system, what you are actually doing is matching the frequency of cutter strikes to what is called the "natural frequency" of that system. And for a metalcutting process, that natural frequency commonly falls in the range of 500 to 800 hertz—or 500 to 800 cutter strikes per second. A little math will show that a spindle running at 20,000 rpm, for example, is not capable of spinning a two-flute tool fast enough for cutting edges to hit the work at a frequency at the high end of this range. However, a 20,000-rpm spindle turning a three-flute tool can theoretically match any natural frequency below 1,000 hertz.

a.)  Pictured here is a plain vise; it is mounted on the table with jaws either parallel or perpen­dicular to the length of the table. b.)  The swivel base vise is a second kind of vise; it has a round base which  will rotate the vise jaws through a complete 360° tum in the horizontal plane only.

That means you may be using too many tools. If you intend to take full advantage of harmonic sweet spots in your own aluminum milling process, it may be necessary to cut back on the range of tools available, just to limit the amount of testing required.

5.)  Collets: These tools will hold tapered-shank cutting tools of various sizes. Drills and end mills can be held in a collet. The collet will fit in the milling machine’s spindle or in the vertical milling attachment.

The MPMC features a wide base, optimized guide ratio and configuration of the guideways to provide stability and prevent vibration during operation, even under extreme cutting conditions.

Different machine tool users have different opinions as to what spindle load the process should be allowed to see. In a stable process, Dr. Badrawy believes the spindle can be allowed to run continuously at a load as high as 80 percent. He knows shops, however, that prefer to run no higher than 50 percent out of consideration for the spindle life. This may be too conservative, he says. Chatter and other sources of rapidly varying load are what cause spindles to fail prematurely. A steady load—even if the load is heavy—shouldn't impair the spindle's life, he says.

In lower-speed processes machining materials other than aluminum, chatter is less likely to impair the process. However, even in these other applications, harmonic chatter sometimes does occur. One tooling solution designed for more general chatter problems at lower speeds is the differential pitch cutter.

Pacon Mfg, Inc. has not rested on its laurels as the 2020 Top Shop Honoree for Shopfloor Practices and Performance. In the years since, it has refined its processes to continue excelling in a volatile market.

Working closely with customers and making careful investments has enabled this Wisconsin machine shop to tackle difficult jobs with tight deadlines as a core part of its business.

Legacy Precision Molds takes us on a tour of their moldbuilding facility. They've recently implemented two automated 5-axis cells for metal and graphite machining that run lights out during nights and weekends.

The collets are of two kinds: either the solid collet or the split collet. In both kinds, the shank of the cutter is held in place by fitting into the tapered hole of the collet.

Take a look inside James Engineering, a high-end CNC Deburring OEM that became a job shop when they decided to produce their own parts in-house.

Chiron Group combines the best of both worlds at IMTS 2024, featuring live demonstrations of their Micro5 and Mill 2000 machines, alongside a cutting-edge virtual showroom. This innovative approach allows visitors to explore Chiron’s full product lineup without the logistical challenges of transporting large equipment.

So far, Made in the USA has looked into system-wide effects of broken supply chains, automation, skilled workforce issues and our perception of manufacturing jobs — examining each topic through a prism of individual experiences. For this final episode for Season 1, let’s look at one more system-wide question and bring it back to personal perspectives: Is there today a new dawn, a new moment for American manufacturing?

Heidenhain and Acu-Rite Solutions are offering several hands-on experiences at their booth this year, as well as internal components that reduce energy use.

There is a price to be paid in surface finish, however. That's why this approach may only be suitable to roughing. During finish milling to achieve a smoother surface, feed rates producing the curled chips may become the better choice.

Even after the ideal speed has been found, another cutting parameter remains to be optimized. Chip load does not affect chatter frequencies, so this parameter can be adjusted without affecting the harmonic testing. And it probably should be adjusted, Dr. Badrawy says. He recommends a different level of chip load than the level at which many shops run. At least during roughing, chip load should be set high enough that the tool doesn't cut the chip but instead breaks it loose through shearing. To do otherwise, he says, is to spend too much energy making chips.

Flex Machine Tools’ Open House event will take place Thursday, December 5 at the company’s headquarters in Wapakoneta, Ohio. It will feature a facility tour and live machining demonstrations.

The Detroit Auto Show, formerly known as the North American International Auto Show (NAIAS), is located squarely at the intersection of technology and mobility. It’s a global event filled with tangible advances ready to hit the pavement today. Here, the software is as revolutionary as anything out there, and the hardware always looks better with a good polish. You won’t find any devices that will fit in your pocket, but you will discover machines that will move you in the most literal sense. You’ll also connect with thought leaders from around the world, both in and outside the automotive industry, whose collective visions for the future of mobility will shape the way we move for years to come.

Why? Because if the tool is already cutting at 50 percent of diameter or more, then it will cut at 100 percent anyway every time it enters a corner. And if the tool is cutting at some heavy axial depth corresponding to the lighter radial depth, then the axial depth will be too high for the sweet spot as soon as the corner is reached. The tool will chatter in the corner.

c.)  A third type of vise is the universal vise; it rotates 360° in the horizontal plane; it also rotates 90° in the vertical plane, so a wide variety of angles are possible.

For axial depth of cut, start light and keep increasing until chatter sets in. For example, start at 0.10 inch, and if there is no chatter at this axial depth, take passes at 0.15, 0.20, and so on until chatter occurs.

Also record the specific tool and toolholder style, as well as the length to which the tool is clamped if it's possible for this length to vary.

In Module 7, Lesson 5 we studied the accessories used in a lathe to do more jobs. We saw that some of the accessories are for holding the workpiece (e.g., a lathe chuck) and others are for rotating the parts (e.g., a lathe dog).

Decker Machine Works recently adopted Rego-Fix’s reCool through-coolant system for ER collets, reducing the cycle times on a nickel alloy job by 70%.

Use carbide tools. This is a basic rule for many shops, but it bears repeating. A carbide tool provides more stiffness than high speed steel, and it likely will pay for itself in longer tool life.

That was certainly the case within a Boeing facility that committed to running at harmonically optimized speeds. Programmers sending work to this shop once chose tools according to their individual preferences. Taking advantage of the sweet spots required them instead to choose tools from a common list. This was the list of all combinations of tool, toolholder and spindle for which the sweet spot had been found.

Determining whether to use high-density fixtures or to simplify workholding requires a deeper look into the details of your parts and processes.

When it comes to utilizing the spindle’s power, there is a lot of headroom at the upper limits, provided it’s in short bursts. Be mindful of your time at these loads so you don’t stall out.

Determining the shape of a workpiece is required in many manufacturing processes. Keep in mind these important points to ensure that you master the process.

How can shops can make informed decisions using data-driven feedback to improve shopfloor efficiency and profitability? And how will these technologies differ between high- and low-volume production?

Lee Wimmer invited us to tour his second-generation family-owned machine shop in Perkasie, PA. This video explores the production processes behind precision-machined parts for both Wimmer Custom Cycle and LS Wimmer Machine Co., and shows how ingenuity and determination are still at the heart of American manufacturing. Today, both companies are now managed by Wimmer’s three sons.

How many flutes does it take to mill a large volume of aluminum at high speeds? As it turns out, there is a clear and precise answer to that question. An end mill with three flutes is probably ideal.

Though most frequently used for diameter measurements, an air plug and platen can be readily configured to measure perpendicularity.

Cutting tests, on the other hand, rely on knowledge that any shop hogging aluminum already possesses—how to take a milling pass, and what chatter looks and sounds like.

Automation is no longer a luxury in manufacturing today – it’s a necessity. The Automated Shop Conference (TASC) will connect job shops with experts who offer advice and considerations for this process.

Part of Major Tool’s 52,000 square-foot building expansion includes the installation of this new Waldrich Coburg Taurus 30 vertical machining center.

For example, there is software available today that can calculate the optimum spindle speed for a process just by listening to chatter across a microphone linked to the PC. This software, combined with some test cutting, can uncover the ideal machining parameters.

Moving from an aging set of five-axis mills to more advanced machines enabled Hendrick Motorsports to dramatically improve its engine production.

In the latest episode of our View From My Shop series, MMS Editor-in-Chief Brent Donaldson visited the JN Shapiro Watches headquarters and production facility where Founder Joshua Shapiro—a history teacher turned watchmaker—realized his dream of "making a watch from scratch and everything in it."

Determining the shape of a workpiece is required in many manufacturing processes. Keep in mind these important points to ensure that you master the process.

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This part of the testing—taking deeper and deeper cuts—is where keeping an eye on spindle load may be important. Within a harmonic sweet spot, the cut may be stable enough to mill chatter-free even to a depth where the spindle can no longer handle the load.

Differential gaging measures using two devices, which has advantages over standard, comparative measurements using a single sensing head. These include the ability to measure size without regard to position.

Another way to "predict" the optimum speed is through the hammer test that specialists such as Dr. Badrawy perform. This test requires no cutting at all. However, it does require an understanding of vibration analysis unavailable in most shops.

Horizontal four-axis machining enabled McKenzie CNC to cut operations and cycle times for its high-mix, high-repeat work — more than doubling its throughput.

In the latest episode of our View From My Shop series, MMS Editor-in-Chief Brent Donaldson visited the JN Shapiro Watches headquarters and production facility where Founder Joshua Shapiro—a history teacher turned watchmaker—realized his dream of "making a watch from scratch and everything in it."

Legacy Precision Molds takes us on a tour of their moldbuilding facility. They've recently implemented two automated 5-axis cells for metal and graphite machining that run lights out during nights and weekends.

In the picture, an irregularly-shaped work­ piece is held in position by four pins and two clamps. The clamps can be quickly removed and an identical new workpiece can be placed in posi­tion and securely held. The major precaution is to clear the chips away from the fixture before a new workpiece is put in place.

An adapter. as we have seen, is made to hold a variety of cutting tools, such as the shell end mill or the flycutter. The adapter is then fitted into the Morse taper of the mill’s spindle. Adapters can be used on either horizontal or vertical mills.