Latest Developments Cutting tools make the machining world go round
Cutting tools are the be-all and end-all of tool and mould making. Since efficiency and quality requirements in this industry are constantly increasing, suppliers respond with tools that are highly specialised to meet the demands of diverse customer applications.
Speed and fast cycle times are becoming increasingly important in tool and mould making. Modern cutting and milling solutions offer great potential to accelerate production times and are even able to fully replace entire processing steps. Nevertheless, accuracy and surface quality are also crucial. Especially when narrow and deep contours and cavities have to be cut, the demands on the milling tool are high.
The special and often ultra-hard materials to be machined in tool and mould making call for equally specialised and hard cutting tools. Companies that make tools and moulds therefore expect high-quality tools that ensure complete process reliability. They need their tools to offer the highest levels of precision, a long tool life, minimal setup times, and of course to be available at cost-efficient prices. This is because modern mould making is under relentless pressure to become even more productive. Constant progress in automation has helped a lot in achieving this goal. The cutting tools used in automated process have to keep up with these developments to meet the high demands of customers in terms of speed, stability, flexibility and production reliability.
Anyone who wants to optimise the cost-effectiveness of their machining processes should pay attention to productivity in the overall process.
Accelerating the cutting speed has a direct effect on the machining time
and thus enables cost savings, argues tool manufacturer LMT Tools. High-performance cutting tools that guarantee high metal removal rates and maximum process reliability are therefore essential. With the Multiedge T90 PRO8, the company provides an efficient solution for shoulder milling operations.
Efficient milling operations
The Multiedge T90 PRO8 is a tangential insert milling system with a total of eight effectively usable cutting edges per insert. The cutting material, geometry and coating have been specially adapted for machining steel (ISO-P), cast iron (ISO-K) and stainless steels (ISO-M) and are designed for roughing and semi-finishing applications. The tangential mounting position of the inserts ensures a favourable ratio of contact area and clamping force, which guarantees maximum stability. Process reliability is ensured even at high metal removal rates. The ratio of tool diameter to number of teeth, in combination with the high feed rates that can be realised, enables these high metal removal rates. As a result, shorter cycle times are achieved, which reduces the total process costs or cost per part. The high number of cutting edges per insert also contributes to the efficiency of the milling system. The system includes carrier bodies in the range of 50 to 160 mm and directly pressed inserts with cutting depths of up to 10 mm. The press-to-size process eliminates the need for grinding during production, thus reducing manual rework to a minimum.
Reducing cycle times has a direct impact on productivity and therefore on the profitability of a company. Now that CAM vendors are developing cycles for circle segment milling cutters, Walter has introduced the new MD838 Supreme and MD839 Supreme series of end mills that deliver cycle time reductions of up to 90 percent, the company claims. In finish machining, the new circle segment tools can reduce cycle times by increasing the tool step-over significantly. In comparison to ball-nosed end mills that typically step down at a rate of 0.1 mm to 0.2 mm when applied to profile milling, the circle segment milling cutters can achieve a step-down rate of 2 mm or even more, depending on the chosen tool diameter and tool flank radius. This solution reduces tool path movements to slash cycle times. With the facility to engage the entire flute length, the new MD838 Supreme and MD839 Supreme series improve material removal rates, enhance surface finishes and extend the tool life. The two-circle segment milling cutters are available in the WJ30RD grade for machining steel and cast iron materials. The tools are also offered with Walter’s WJ30RA grade for highly productive machining of stainless steel, titanium and heat-resistant alloy grade materials. Thanks to their specially developed geometries, both milling cutters are ideal for semi-finish and finish machining of components with steep walls, deep cavities, prismatic surfaces and transition radii. This range of applications and materials makes the MD838 Supreme and MD839 Supreme ideal for productive finish machining in the mould and die making segment, Walter says.
Difficult-to-machine materials such as stainless steels and super-alloys are frequently used in mould making and pose special challenges. Dormer Pramet has also added some new products to its range that are geared to handle these tasks. Its new generation of solid carbide five-flute end mills has been specifically designed for dynamic milling in general machining and die and mould applications. The S7 assortment of solid carbide mills offered by Dormer Pramet covers a wide range of operations in a variety of steels, cast irons and difficult-to-machine materials, including stainless steels and super-alloys. The latest additions, S770HB, S771HB, S772HB and S773HB, offer feed rates up to 25 percent higher compared with four-flute cutters, the company claims. All models feature a positive rake angle for smooth cutting action and to reduce the risk of work-hardening. An AlCrN coating provides thermal stability, reduced friction, excellent wear resistance and prolonged durability, while a small corner radius and cutting-edge design gives stable performance and prolonged tool life.
For five-axis machining centres, the same manufacturer has developed an advanced barrel-shaped end mill. According to the company, the new S791 cutter provides excellent surface quality and is suitable for semi-finishing and finishing in steel, stainless steel, cast iron and super-alloys. It is the first design of its type within the company’s Dormer range and includes a nose radius for fillet milling, plus a larger tangential form for curved and deep wall surface machining.
Providing more overlap compared with conventional ball nose end mills, the barrel-shaped cutter achieves a greater area of contact with the workpiece, increasing tool life and lowering cycle time. According to the manufacturer, the fewer passes needed help reduce machine time by half, while continuing to achieve all the usual benefits associated with a robust ball nose end mill. In a recent example, the barrel end mill required just 18 passes, compared to 36 with a ball nose version, when machining with the same parameters.
When aluminium is the material of choice, on the other hand, the Aluflash series from ITC promises high performance. The new series of end mills is an all-rounder that is ideal for slotting, ramping, side milling, plunging, interpolating, dynamic and helical milling. Capable of eradicating vibration and running at accelerated speeds and feeds, this series comprises two- and three-flute solid carbide end mills that are available in diameters from 1 to 25 mm. To accelerate perform
ance and permit steeper ramping angles, the new Aluflash incorporates a host of new technologies that combine to meet high demands in high-performance milling. The Aluflash introduces a W-shaped flute that improves chip formation and evacuation to enhance process stability and reduce the cutting forces. Complementing this is a parabolic core that increases tool stability, reduces deflection and the potential for breakage whilst enhancing surface finishes. The Aluflash also has double or triple rake gashing depending upon whether the customer selects the two- or three-flute variant. The rake gashing further improves chip evacuation to improve ramping capabilities and Z-axis machining.
When it comes to the machining of aluminium, Lach Diamant looks back on 40 years of experience. It all started in 1978 with the production of the world’s first PCD milling cutters — straight cutting, with axial angle or profile — for customers in the wood, furniture, plastics and composites industries. Over time, with the increasing development of CNC machines, the company’s polycrystalline diamond (PCD) cutting material became the state of the art in the automotive and accessories industries for machining aluminium and composite components in series production.
Keeping heat under control
High-performance milling of aluminium requires special protection of the diamond cutting edge against unwanted heat generation. To address this issue, Lach Diamant in cooperation with Audi has developed the “cool-injection” system. In this new technology, the cooling jet coming out of the carrier tool is conducted through the diamond cutting edge directly to the chip being generated. This eliminates the production of damaging heat. Several patents have been granted for this innovation, which has already won the Hessian Innovation Prize. The “cool-injection” system is key to the PCD-Monoblock, a high-performance milling tool that enables series manufacturers to gain the best possible advantages from HSC/HPC aluminium machining. The solution allows the maximum width of the available PCD cutting edge to be used for the infeed.
With expansions to its range of tools for slot milling and slot cutting, Paul Horn is responding to the requirements of users for better control of the heat developed during machining. The company now offers its M310 milling system with a cutter body that has an internal coolant supply. The expansion of the company’s range for slot milling and slot cutting tools with a new cutter body increases the service life of the indexable inserts and therefore reduces tool costs. The internal coolant supply also allows a higher level of precision for slot milling, since no heat is transferred from the cutting zone into the component. What’s more, the flushing action of the coolant, combined with the geometry of the cutting edges, reduces any tendency of chips to jam in deep grooves.
Horn offers two types of milling and slotting cutters. The screw-in milling cutter is available in diameters from 50 mm to 63 mm with widths from 3 mm to 5 mm. As an arbour milling cutter, the main bodies are available with diameters from 63 mm to 160 mm, also with widths between 3 mm and 5 mm. The three-edged S310 carbide inserts are bolted on the left and right of the main body and so ensure good distribution of the cutting forces. In addition to further geometries for processing different materials, Horn has developed inserts with a geometry for milling aluminium alloys.
The 3+2 or 5-axis pre-finishing and finishing of tough ISO-M as well as ISO-S materials such as titanium, precipitation-hardened steel or stainless materials can require low cutting speeds and the use of a wide variety of tools. In addition to long cycle times when using conventional ball nose end mills, the use of new, technically demanding machining strategies in metal cutting often poses a challenge. The new barrel machining tools from Seco Tools shorten time-consuming finishing processes by up to 80 percent compared to conventional ball end cutters. The tool geometries and shapes enable fast machining with large stepover, without increasing the cutting speed. Users benefit from shorter cycle times, fewer tool changes, high reliability and consistent surface quality, the company says.
Combining several machining steps in one tool makes manufacturing as economical as possible. For example, bores can be drilled and reamed simultaneously with the Drill-Reamer from Mapal. This tool with internal cooling for tapping, drilling and reaming is available in 3xD and 5xD lengths. With six guiding chamfers for excellent guiding properties, precision-ground chip flutes with matching groove shape for good chip removal and a self-centring chisel edge, the new Tritan Drill Reamer is convincing all around. The self-centring chisel edge ensures good positioning accuracy and improved tapping behaviour. Three cutting edges guarantee optimal roundness of the bore and highest performance. The reaming cutting edge produces high-quality surfaces.
Every company has different cutting requirements. That is why in its new catalogue, Inovatools presents a range of tool solutions divided into their respective area of application, such as tool and mould construction. Whether mills, drills, reamers and counterbores, the modular cutting system Inoscrew or saw blades of all different kinds — from mini, diamond- coated and XL through to special versions, users can always find the tools they need for their specific operations.
One example is the Curve Max curve segment mill, which is deployed primarily in tool and mould construction. Thanks to their special geometry, the new Curve Max mills permit bigger path distances and line jumps during pre-finishing and finishing. Although the working radius is larger than that of a traditional full-radius mill, the tool still has the same diameter.
Just like all of the solutions presented here, this new process promises to increase surface quality and shorten processing times. These aspects are at the centre of any purchasing decision for new cutting tools made by tool and mould makers to help achieve the targets of speed, efficiency, and ultimately the profitability of the company.