An exclusive Key Grip locking mechanism provides anti-pullout protection. It is placed into the Weldon flat of the end mill shank, which is then inserted into one of the three Key Grip grooves inside the chuck. A spring functions to remove the gap between the Key Grip and the wall of the groove. Tightening a clamping nut secures the Key Grip in place, achieving dual contact between the nut and chuck body for rigidity close to that of an integral cutter.

Indexable inserts are interchangeable cutting tools that are indispensable for various industrial applications, especially in metalworking. They are used as cutting material carriers for machining metals, plastics or wood. Their manufacture requires high-precision production processes to ensure an exact geometry and perfect surface finish. Even minimal deviations affect not only the service life but also the performance of the cutting insert. The smallest defects that are invisible to the human eye can cause immense damage, for example when milling or cutting high-quality components – including consequential costs. Careful quality control is essential to ensure that only flawless indexable inserts leave the production process and meet the high requirements in terms of durability and reliability.

“We work with DENKnet for a good reason. The performance is not comparable with that of other providers, it is truly excellent,” emphasizes Marvin Krebs. “Using artificial intelligence in the most diverse variants on this scale has never been done before.” Further variations are currently being tested, for example to further simplify hole detection.

”After more than four years, there have been no documented cases of a tool pullout with a secuRgrip holder,” said Chris Herdman, technical field support engineer for Rego-Fix. “The only mode of failure is that of the cutting tool itself.” Unlike other systems, secuRgrip does not require purchase of specially modified end mills, but rather can accept standard 0.5–1″ (12.7–25.4-mm) carbide or HSS end mills. The system maintains 0.0001″ runout and allows users to preset tool heights.

Hydraulic expansion toolholders were developed by Schunk more than 35 years ago and have been continually improved to keep pace with advancements in machine technology and carbide tooling, Krolak said. The Tendo line features a high concentric clamping force, excellent vibration dampening and runout of less than 3 µm @ 2.5×D. All commercially available tools, with Weldon, Whistle notch or cylindrical shanks, can be clamped. Micron-accurate tool changes can be made in seconds.

“The first challenge results from the numerous color variations within the powder per pressing process,” explains Marvin Krebs. “If certain parameters such as time, pressure or positioning vary, this leads to color or gloss level deviations or to a different distribution of speckles on the surface, but this is not a defect.” The AI-based image evaluation software used had to be trained to correctly recognize the numerous possible color deviations of the surfaces and rate them as ‘OK’. On the other hand, the smallest irregularities such as cracks, scratches, inclusions or other anomalies must be recognized as such and classified as ‘NOK’. The inspection of metal surfaces is considered one of the highest skills of surface inspection, as their texture can be matt, shiny or even reflective. “The AI had to be extremely trained to variations and lighting conditions for this application,” emphasizes Marvin Krebs.

But in addition to the visual appearance, it is also about the insert geometry. Categories such as triangle, rectangle, rhombus or square can be found in countless variations due to the smallest deviations and are therefore divided into manageable subcategories, so-called geometry families. Xactools made the pre-selection for the training of the meshes; almost one hundred geometry families were defined and then taught in by the manufacturer itself. What sounds like a laborious undertaking was done surprisingly quickly. “No more than 20 to 30 images were needed to teach each geometry family,” recalls Marvin Krebs. The DENKnet palletizing AI used for this purpose uses the DENKnet segmentation and classification network. The customer himself trained the customized image analysis solution with the DENK VISION AI Hub. The AI was integrated into the production line in just a few months and achieved almost perfectly reliable AI results for the metal components to be tested right from the start. “Indexable inserts identified as defective are sorted out and grouped according to the size and position of the defect. The AI image analysis detects more than 99 percent of production errors,” adds Daniel Routschka, Sales Manager Artificial Intelligence at IDS Imaging Development Systems GmbH.

Rego-Fix Tool Corp. (Indianapolis) markets both a friction fit and a tool locking system. The powRgrip series includes holders, collets, and automatic or manual pressing systems. The collet is pressed into the holder with up to 9 tons (8.16 t) of pressure, which Rego-Fix claims to be the highest clamping force in the industry. The compression contacts the nose of the holder and not the taper.

For maximum tool security, the Pin-Lock Collet system is available as an option. This feature works with any Weldon shank tool and guarantees pullout protection.

One of BIG Kaiser’s newest products, the Mega Perfect Grip milling chuck, is designed specifically to prevent cutter failure. The high-accuracy milling chuck has fully concentric clamping and runout of less than 0.0004″ (0.0102 mm) @ 4×D. It accepts standard Weldon flat end mills and requires no special grinding of the milling cutter.

In addition to the characteristics inherent the hydraulic expansion design, the Aviation toolholder employs a locking mechanism. A cutting tool with a standard Weldon shank is inserted into a special sleeve with a ball lock. The tool/sleeve assembly is then locked into place via set screws in the base of the toolholder. Finally, the holder is hydraulically actuated. As with other Tendo models, this process can be accomplished in seconds.

It can see exactly where and in which rotational position the indexable insert is positioned so that the magnetic gripper can finally place it on pin pallets. To ensure this, the gripper, to which the indexable insert is attached, moves over a camera that detects the exact position of the hole from below. At the same time, the contour of the insert and the outer edge of the gripper are detected in order to correct the position of the indexable insert and hit the pin if necessary. In addition, each individual pin position is detected in order to recognize bent and broken pins so that they are not palletized in the first place.

However, the performance of the solution is almost unique. The entire inspection process takes place in a cycle time of four seconds, with almost 100% picking efficiency. The image analysis of live images from eight cameras via a DLL (Dynamic Link Library) requires enormous computing power.

TIR is less than 0.0001″ (0.0025 mm) even after thousands of tool changes, and powRgrip’s rigidity and high mass minimizes harmonics, extending tool life and reducing consumable costs, according to the company. The system has five sizes, resulting in only five machine inserts the operator would ever need to use every holder, and eliminating the need to purchase machine taper mounts.

The aerospace industry in particular has a big stake in secure toolholding, notes Jack Burley, vice president, sales and engineering for BIG Kaiser Precision Tooling Inc. (Hoffman Estates, IL). “A number of critical components are made from titanium, which is expensive and difficult to machine. If a cutting tool slips or pulls out, the results are extremely costly, in terms of both downtime and material loss,” Burley said.

For high production tapping, the Speedsynchro tap holder features a programmable integrated transmission of 1:4.412 to optimize thread production on CNC machines with synchronous spindles. Combined with Softsynchro’s minimum length compensation, this allows high cutting speeds at a relatively low synchronous machine tool speed, compensating for synchronization errors during the threading process. Thread production cycle time is reduced by up to 40%, and the lower spindle speed can result in significant savings in energy costs.

A flagship project by automation and measurement technology specialist Xactools from Germany demonstrates how artificial intelligence can help visual inspection make quantum leaps. The medium-sized company has developed a fully automated handling and inspection system for a global manufacturer of indexable inserts based in Scandinavia, in which the DENKnet solution for AI-based image evaluation plays a decisive role and sets new standards in terms of performance, zero-defect production and speed.

Engineers at Rego-Fix agree that even with the highest clamping forces available, there are applications that require additional cutter retention measures. At IMTS 2012, Rego-Fix introduced the secuRgrip anti-pullout system, available for powRgrip, ER collet holders and milling chucks. A small, profiled steel locking key insert is installed in the ground flat of standard Weldon-shank cutting tools, locking the tool to the collet. A threaded friction bearing cap secures the collet in the holder and provides increased clamping force to prevent the collet from spinning.

Toolholder manufacturers have responded with a variety of rigid, highly secure systems offering anti-pullout protection. These include shrink-fit, hydraulic expansion and locking toolholders. Each features high gripping torque (clamping force) for a tight friction fit on the tool shank. Many offer proprietary locking mechanisms that can guarantee up to 100% tool retention.

As machining speeds increase and more difficult-to-machines alloys are introduced, machine shops need to continually re-evaluate their toolholding options. While highly secure toolholders typically cost more than their standard counterparts, the payback—in terms of the ability to machine at higher speeds and fewer scrapped parts and tools—can be substantial.

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Several years ago, Haimer developed and patented an anti-pullout system, Safe-Lock, as an optional feature on its shrink-fit holders and power collet chucks. Safe-Lock employs special drive keys in the holder and mating grooves in the tool shank, ensuring positive locking in place of the cutter and preventing spinning and pullout. Unlike Weldon flats, the mating ground grooves are perfectly symmetrical, thus eliminating issues associated with unbalance and uneven side loads. The system also provides users with the ability to adjust the axial position of the cutting tool in the holder. With 14 of the largest round tool companies as official licensed partners, tools from any number of global suppliers are readily available.

A total of eight cameras with resolutions between 5 and 30 megapixels provide live images of the indexable inserts, which are positioned by magnetic or interchangeable grippers. For example, a camera records the individual indexable inserts from below and from above in order to check them for surface defects. Two other cameras check their cutting edge. A lighting screen measuring 1 x 1 meter provides extremely high illumination at the palletizing stations. “The system detects defects in the thousandth of a millimeter range,” emphasizes Marvin Krebs. This ensures that no damage is caused to the high-end surfaces to be processed later. This is because “uneven and faulty milling processes can potentially impair profitability and competitiveness”, as the manufacturer also knows.

There are secure toolholders for a variety of cutting operations, including milling, drilling and tapping. For example, Emuge Corp. (West Boylston, MA) offers its highly rigid FPC Mill/Drill Chuck with three tons of traction force to hold a tool securely. This is the world’s only chuck with a 1:16 wormgear, according to Emuge. The collet-cone assembly absorbs virtually all vibration, for maximum vibration dampening. With a 3×D tool length, variation in concentricity is less than 3 µm, which extends tool life and substantially improves workpiece surface finishes. All models are balanced to G2.5, 20,000 rpm. In a speed comparison with four competing chuck designs, the FPC chuck enabled the feed rate to be increased by 30% with no loss in performance.

That was yesterday. Today, the productivity needed to be globally competitive requires ever increasing metal-removal rates during operations such as roughing and high-speed slotting. Process reliability is paramount, especially when working with difficult-to-machine materials. Conventional toolholders typically do not cope well with the high axial forces generated by aggressive machining, and cutter pullout can occur.

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Drew Strauchen, vice president, marketing and business development, Haimer USA LLC (Villa Park, IL), cautioned against total reliance on the ability of friction-fit holders to provide maximum tool security. “High gripping torque by itself does not equal guaranteed pullout protection,” he said. “The incredible cutting forces generated by faster machine spindles and more aggressive toolpath strategies [like full radial engagement trochoidal milling] have exposed the limitations of even the best friction-fit clamping systems.”

“Over 95 percent of our measuring and testing systems have at least one AI object class integrated. The potential areas of application are getting bigger and bigger for us, the market is growing,” confirms Marvin Krebs. Promising prospects for this exemplary automated AI training for the highest demands.

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The Tendo holder contains an internal clamping piston that compresses hydraulic fluid into the oil chamber. The piston is manually actuated by an external clamping screw turned to a dead stop by an Allen key. A flexible sleeve immediately expands evenly against the tool shank, first centering the tool, then powerfully gripping it on the full surface. A length-setting screw can be actuated radially or axially for tool presetting.

Krolak agreed that machining aerospace parts is particularly challenging. “Aircraft manufacturers have many applications with materials costing thousands of dollars and individual part cycle times exceeding 12 hours,” he said. “With this much invested in each machined component, tool failure is absolutely not an option.” To meet this need, Schunk recently introduced the Tendo Aviation toolholder for applications that require a secure tool that will not pull out.

For many generations, machining was a largely manual process with relatively slow speeds and shallow cutting depths. The most common toolholders were Weldon/sidelock chucks and ER collets, and, under these comparatively benign machining conditions, cutting tool slippage or pullout was not a serious issue.

Emuge also produces an extensive line of tapping toolholders. The Softsynchro rigid tap holder, with minimal length compensation, is said to reduce axial force to a fraction of that required in typical tapping applications, improving thread quality and extending tool life by up to 300%. Patented elastomer springs separate the spindle from the tap, absorbing excessive axial forces and providing the tap with a significant boost in tool life and performance. Torque from the spindle is transferred to the tap via ball bearings in precision-ground grooves, promoting precision micro-correction of lead errors in a rigid tapping cycle. The modular system is adaptable to any application requiring a length adjustment screw and interchangeability for different size taps.

Haimer is best known for its extensive line of shrink-fit toolholding. This system is a simple one-piece, highly rigid design with no moving or wearable parts. Benefits include runout accuracy up to 0.00012″ (0.00305 mm), superior repeatability, minimum vibration and chatter and excellent balance, according to the company.

For Marvin Krebs, the added value of the DENKnet system compared to conventional image processing is obvious: “Without AI, the creation of part families and defect detection would be completely unthinkable. With rule-based image processing, the robot would also recognize parts within the standard range as NOK and sort them out.” In addition, thanks to the Vision AI Hub, no hard coding is necessary, and the flexibility of the networks was another selection criterion for the intelligent DENKnet software. “We were able to easily embed the DENKnet palletizing AI and several object classes for defects into our own Xactools image processing software via an API,” says Marvin Krebs.

Shops should be aware that heavy-duty machining is not the only cause of tool pullout, said Ryan Krolak, technical sales specialist for Schunk Inc. (Morrisville, NC): “It can also be the result of toolholders that do not offer concentric clamping,” Krolak said. “This often causes excessive runout, creating an uneven chip load on the cutter and premature tool failure. This shouldn’t have to be said, but it is important to make sure that all the running parameters are within the range of the material and the cutting tool being used.”'

Shrink-fit is based on the thermal expansion and contraction of metal, and uses an induction heating unit for assembly. The bore of the holder is initially slightly smaller than the outside diameter of the tool shank. When heated, the holder expands sufficiently to allow tool insertion. After cooling, contraction of the holder grips the cutting tool with up to 10,000 lb (4536 kg) of force. Tools can be changed in seconds, and operator training is minimal. As noted above, the Safe-Lock feature can be incorporated into Haimer shrink-fit toolholders.

As versatile as the areas of application of the small tool parts are, so varied are their properties and geometries. This manufacturer alone has around 2,800 products in its portfolio, which can be divided into almost one hundred geometry families. The aim was to automate handling and defect inspection for all of these.

The extremely varied surfaces and geometries as well as intolerances in the thousandths of a millimeter range make the visual inspection of indexable inserts a supreme discipline that can be transferred to many other demanding applications. The self-explanatory training environment DENKnet serves as an incomparably simple and at the same time high-performance tool, because it can be operated without programming knowledge and enables the automated training of AI with just a few clicks. A wide range of Vision AI technologies are available for this purpose. ‘This solution can be customized to any use case and there are no limits – no matter how many classes, which camera technology, how large or small the images or even how mixed the data sets are in terms of resolution and type, for example,” adds Daniel Routschka, Sales Manager Artificial Intelligence from IDS.

To prevent this from happening during the production process and to exercise the greatest possible caution, the system also records images of the contour and position of the panels after inspecting the surfaces and edges.