Big-Plus and HSK are superficially similar in some ways. Both of these machining center spindle-and-toolholder interface systems aim to provide a more stable connection than the typical machining center system employing standard conical toolholders. And both of these systems are roughly equal in price when it comes to purchasing a set of toolholders for a machine. But Cory Cetkovic, applications engineer for Big Kaiser Precision Tool, says the two interface systems actually differ fundamentally in their method of clamping the holder. That difference has important implications.

The Big-Plus system involves elastic deformation of the spindle connection, he says. During clamping, that deformation results in axial displacement of the toolholder into the spindle. Prior to clamping, the toolholder makes only taper contact within the spindle, but after clamping of the retention system, the spindle expands within an elastic limit until the toolholder achieves the second area of contact—contact at the spindle face—that is the defining feature of the Big-Plus system.

HSK, meanwhile, works by elastically deforming the toolholder. Fingers inside the hollow shank of the toolholder clamp the holder by Indexable Inserts pushing out. High spindle speed helps this interface, because the centrifugal force strengthens this clamping.

In large part because of this very different clamping, these two systems are not equivalent, says Mr. Cetkovic. Big Kaiser supplies hardware for both, including Big-Plus tooling manufactured by Big Daishowa Seiki, the originator of the concept, and HSK toolholders that are hard milled, hard turned and ground after heat treatment for precision, surpassing that of commodity holders. Thus, the company often advises shops considering new machine tools on which toolholder interface to select. The choice depends on the application, he says. It also depends partly on the wishes of the user.

For example, the notion that a set of toolholders for either system is roughly equal in price, while outwardly true, masks a source of savings with Big-Plus that might be Carbide Drilling Inserts important to a given shop. Big-Plus is the system that adds spindle face contact for heightened rigidity to a toolholder interface that otherwise uses the same 7:24 cone of CAT and BT tapers. As a result, standard CAT and BT holders can be used in a Big-Plus machining center, and Big-Plus holders can be used in standard machines. Though the face contact is not realized in either of these cases, a given shop might prefer the Big-Plus system’s freedom to use existing, standard holders in cuts for which the rigidity doesn’t matter.

Testing at Big Kaiser has measured what this rigidity means and what performance it seems to delivers within the range of applications most favorable for this system. Machining tests with a 12-mm four-flute carbide end mill were run on two identical machines (same make and model), one equipped with Big-Plus and the other with HSK. On each machine, the workpiece was milled at various tool overhang lengths to measure the maximum axial and radial depths of cut at which the tool would perform effectively. The graphs on this page show the depths of cut at which chatter set in for each set of parameters. No doubt the different natural frequencies of the different toolholder systems contributed to how deeply a given tool setup could cut without chatter, so clamping stiffness alone isn’t the whole story. Still, at nearly every test run, the Big-Plus system provided for the capacity to take a deeper cut.

But results such as these do have a speed limit, Mr. Cetkovic says. It is the shops moving into higher spindle speeds that ought to consider HSK, partly because of the toolholder’s lighter mass, and partly also because of the very fact that the toolholder in the HSK system deforms rather than the spindle. Again, high rotational speed helps the clamping of this interface.

At around 24,000 rpm, he says, the centrifugal force’s relaxation of the connection for a conical holder, combined with that same force’s strengthening of the HSK clamp, results in the rigidity advantage crossing over to favor HSK from that speed up.

The Carbide Inserts Website: https://www.estoolcarbide.com/pro_cat/parting-and-grooving-inserts/index.html

IMCO Carbide Tool Inc. has developed a new series of end mills — M936 Pow-R-Feed — designed for faster part cycles and speeds, regardless of the machining stations’ horsepower.

The M936 is designed to maximize the output of machines most customers use, according to Steve Avers, IMCO’s technical support manager. With conventional low-horsepower machines, this free cutting action means the M936 cutter can run to the machine’s upper capacity limits.Shoulder Milling Inserts

Users can reportedly make various toolpath moves without slowing down, providing faster cycle times and more production. When a five-axis machine can swing an end mill around in all directions without clogging, the machinist can complete the operation with one chucking, saving time.

Unique flute and core geometries achieve aggressive cutting parameters, and the proprietary end face enables aggressive ramping and helical entry parameters. A super-tough carbide core and an ultra-modern AlTiSN slippery-smooth coating prevent chip buildup and enable higher feeds and metal removal rates. According to the company, tool life is exceptional, due to the variable helix and variable index effects on vibration damping, as well as the specially engineered carbide grade and coating.

“This is the cutter for any programmer machining steels, stainless steels and titanium on three-axis to five-axis CNC machining centers that wants to run fast and helical enter, ramp, slot and tungsten carbide inserts peripheral mill at fantastic feed rates,” says Matt Osburn, vice president and technical director for IMCO. “The M936 is designed for very aggressive traditional tool paths, stepovers and depths beyond the reach of any of the industry’s legacy tools. It’s IMCO’s free-est cutting end mill in steels to date.”

The Carbide Inserts Website: https://www.cuttinginsert.com/product/16er-insert/

F. Zimmermann has released its FZ40 Compact, a powerful machine based on the company’s FZ33 Compact and offering the same space-saving dimensions. Its primary applications include efficient machining shoulder milling cutters of steel, cast iron and titanium. Like the FZ33 Compact, it has a rigid monoblock structure that allows it to be set up easily and rapidly. The new FZ40 Compact is targeted to those who do heavy-duty cutting and want to focus more on toolmaking.

Whereas the FZ33 compact was designed for fast and efficient machining of aluminum and composites, the FZ40 compact goes a step further. With the same external dimensions and a working area measuring 2,400 × 2,900 × 1,250 mm (XYZ), it is especially suitable for machining workpieces made of steel, cast iron and titanium.

The machine features the VH60 two-axis milling head with a spindle power of 63 kW, a spindle speed of 15,000 rpm and torque of 300 Nm. It is available with the HSK-A100 tool holder. Zimmermann has given the new system all the advantages of the FZ33 compact SNMG Insert but enhanced it for heavy-duty cutting, making the portal more massive and more rigid. The machine also has a larger cross slide and a vertical slide designed for machining tool steel.

The strengthened base plate can now hold workpieces weighing as much as 16 metric tons. Eight additional mounting elements are provided for greater stability. The side walls are filled with special concrete and rest on the machine bed. This makes it possible to erect the machine on a solid industrial floor, usually without special machine foundations. Users thus have greater flexibility when setting it up.

The FZ40 Compact can machine steel components quickly and economically on five axes. According to the company, it achieves short throughput times, high availability and high precision. 

The Carbide Inserts Website: https://www.estoolcarbide.com/tungsten-carbide-inserts/

When is a CNC Swiss-type lathe the most appropriate machine tool for the job? For years, these machines have been equated with high precision for efficiently machining small, complex parts. The reputation is well deserved. However, as these machines become more common, work is increasingly assigned to them erroneously. The distinction between work suited for Swiss and work suited for more straightforward turn-mill machines may not be readily apparent. In fact, Index Corporation believes the misapplication of Swiss-type technology is quite prevalent.

“Our studies have shown that between 70 to 80 percent of 1 1/4-inch work designated to Swiss machines could also be accomplished quickly and accurately on fixed-headstock machines,” says Olaf Tessarzyk, Index Corporation CEO.

Because a Swiss-type machine offers a means to quickly produce small, long and often complex parts in one handling, shops defer to this method for a broad range of small parts without fully exploring their options, he says. More important than the part’s diameter is often the part’s length-to-diameter ratio (L:D). As a general rule, a Swiss-type lathe is needed for pieces with L:D ratios of 4 to 1 or greater, he CCMT Insert advises.

The trick to accurately cutting pieces within this L:D range is maintaining enough rigidity during the cutting process to minimize workpiece deflection. The Swiss-type machine pairs a sliding headstock with a guide bushing. The sliding headstock pushes the workpiece through the bushing during the cutting process. Z-axis motion comes from this; the tool doesn’t have to move. With the intended purpose of counteracting deflection, the guide bushing ensures that the cutting tool can remain as close to the collet as possible. By providing support across the entire length of the part in this way, the bushing helps deliver tight accuracies and fine surface finishes.

That said, parts with lower L:D ratios can be machined accurately without a guide bushing.

“In some instances, a shop can easily machine a short, 1-inch part without a guide bushing more WCMT Insert economically than it would be able to with a Swiss-type,” Mr. Tessarzyk explains.

Many Swiss-type machine builders now offer an option of bushless sliding-headstock machines to accommodate lower L:D ratios. Another alternative is a fixed-headstock machine, such as a more general turn-mill. Index offers the C100 high-production turn-mill, for example. While still supplying the requisite rigidity to precisely machine small parts, this machine can address some limitations of a Swiss-type, one being its lower milling power. The turrets on a fixed-headstock design can supply more power for milling medical parts and various other jobs, Mr. Tessarzyk says.

According to Index, a machine such as this can also process certain parts more economically than can Swiss-types. Mr. Tessarzyk cites these potential areas for cost reductions:

Material Costs. To process parts in this diameter range on a Swiss-type, shops would typically need to purchase pre-ground material. The turn-mill can accept normal stock, potentially reducing material costs. In addition, the average user is actually consuming more material. There is more of a remnant because the spindle is behind the guide bushing and a certain amount of material is needed simply to reach this distance.

Maintenance Expenses. Each time that the guide bushing slides on the material, debris is created. Over time, the bushing can get dirty. Weekly maintenance is required to clean away the accumulation.

Setup Time. The vertical bed design (as opposed to slant) enhances accessibility to tools. The operator can reach the tools and change them out more quickly, thereby minimizing setup time. Meanwhile, the footprint is still as compact as a Swiss-type lathe.

The Carbide Inserts Website: https://www.cuttinginsert.com/product/seer-insert/

Whether on Swiss and other turn/mill centers, drilling and tapping machines, or with milling attachments, shops are doing more milling with small spindles than ever before. That’s partly due to the growing adoption of multitasking equipment, but also the increasing prevalence of near net shape machining particularly on parts generated with metal additive manufacturing.

Because available space and spindle HP are often limited with this equipment, shops have had little choice but to stick to solid tools for milling operations. Now the tooling is catching up with the need with indexable and modular tools available in surprisingly small sizes. This provides shops with much more flexibility to get the best combination of tool substrate, coating and configuration for your part features and materials. Plus, the modular approach can reduce required tooling inventory – or machining compromises – and reduce cost by getting much better utilization of carbide cutting edges.

That’s not to say that solid tools don’t still have their place; it really all depends on the application. Cutting tool manufacturer ISCAR makes both types of tooling, and so has a balanced view on where modular tooling fits in these types of applications.  Here’s how ISCAR addresses milling with smaller spindles.

Much has been said about high feed and high efficiency milling in recent years because these processes can dramatically increase metal removal rates while consuming less spindle power. In comparison to traditional milling, high feed milling (HFM) uses similar stepovers but shallower depths of cut at higher feed rates. Tools designed for HFM must be very efficient at cutting near the tip of the tool. High efficiency milling (HEM) uses a much deeper depth of cut, but smaller stepover, also at higher feeds and speeds. Solid tools are frequently used for HEM because cutting with the side of the tool is what matters, and you get much better edge utilization because a larger portion of the flute length is used in the cut.

What doesn’t make sense for HFM, or any other shallow DOC cutting, is extensive use VNMG Insert of solid tools where you are using a small percentage of the cutting edge. Tools wear out with as little as 10% of the carbide flutes having cut anything at all.
 

High feed milling is but one area where indexable and modular tools come into play. But there are many others. For example, ISCAR’s Multi-Master line is a completely modular solution based on standard head-to-body and body-to-toolholder connections. It supports all types of rotating tools, offering 61 different types of solid carbide heads and 25 indexable body types with a wide variety of inserts from which to choose.

The tools with replaceable heads include families for milling (square shoulder, plane surfaces, slots and grooves, splines etc.) and hole-making (drilling, countersinking). Based on the original design principles of ISCAR’s CCMT Insert Multi-Master and Chamdrill lines, the tools feature the “no setup time” principle, that is, replacing a worn head typically does not require additional setup operations.

The Multi-Master concept features centering by a short precise taper, face contact and a unique thread profile. This enables a highly accurate and rigid connection that provides significant possibilities for modular tooling with a wide range of shanks, extensions, adapters, and reducers.

The shanks are made of steel, cemented carbide with considerable stiffness, and heavy metal, all with good vibration-resistant properties. ISCAR also recently introduced two new lines designed to leverage the Multi-Master system. With an exact 90 degree insert profile, the LogIQ and NeoLogIQ lines are designed for square shoulder and face milling. Multi-Master and FlexFit mutual connections substantially expand the application range for both families.

ISCAR also has a range of tools designed specifically for high feed milling, a process that is based on the axial “chip thinning” principle. Tools with a shallow lead/entry angle enable high feed cutting. The geometry of these tools is designed precisely for this application with care taken to ensure correct distribution of the cutting force components. The NanMill, NanFeed, MicroFeed, and HeliMill products are particularly appropriate for small spindle applications with the smaller modular tools lines ranging from 8 to 25.4 mm (0.315” – 1.000”) in diameter.

The Multi-Master line also includes a range of solid carbide heads designed for different cutting conditions and materials. In all, there are more than 48,000 possible combinations of cutting heads, bodies and toolholders to fit small milling machines, turn/mill and Swiss turning center driven tools, and milling attachments.  And the accuracy of the head and body combinations helps reduce downtime. Replacing a solid head typically keeps tool length within ±4 “tenths” which means you can generally index to a redundant tool without need to reestablish tool tip location. Multi-Master heads with indexable inserts repeat to about ±5 “thousandths” which is sufficient for many roughing applications.

For additional efficiency in a modular system, a single ER32 to M12 collet (FLEXFIT) can handle multiple SUMOCHAM drill bodies covering a range from .236” to .823”. 
 

The main benefits of modularity are versatility and time-savings. A modular concept facilitates the quick and easy building of an optimally customized cutting tool using an assembly of standardized elements. You don't have to order costly, specialized tools and wait months for delivery. If a tool is urgently needed for immediate production, a suitable solution is close at hand.

When deciding on a particular tool, both advantages and disadvantages of the modular concept need to be considered. The key to deciding which tool is the best for an application should be based on production strategy, current production demands, or an immediate need of a tool. The cutting tool manufacturer should provide the means to make the correct choice and at the same time continue to develop modular products that achieve greater adaptability, rigidity, and accuracy.

Please visit the ISCAR website for information on ISCAR milling tools.

The Carbide Inserts Website: https://www.cuttinginsert.com/product/snmx-insert/