New technology improves the productivity of steel and cast iron drilling

It is fair to say that in small shops and large production facilities, hole processing accounts for the largest processing share. Moreover, most of the hole machining is done in steel and cast iron with a diameter of no more than 1 inch (25 mm). Promoting drilling and tapping performance are advances in substrates, coatings, three-edge designs, and combined tools. It is also important to use different sizes of holes and shapes to promote advances in coolant delivery for chip removal.
You may be able to use the latest developments presented here by some leading tool manufacturers.
Drew Strauchen, executive vice president of the GWS Tools Group in Tavares, Florida, pointed out that part of the development trend of hole making (and metal processing in general) is customized hole making solutions to more perfectly adapt to customers’ actual applications while maximizing To reduce operations. “The ability to select the best substrate, geometry, coating and tool length for a specific application in the workshop is essential for more manufacturers who want to compete in the global market. Together with customization, it combines the two Or more tools to further reduce operations and shorten the cycle, which is the definition of optimization.” He said.
In addition to realizing new advancements in technology, GWS Tool Group has also designed a combination tool that allows customers to use one tool instead of two, three or even four tools to perform multiple drilling operations. Strauchen said: “Being able to tailor tools for specific applications is essential to reduce operations and shorten cycle times.” He provided examples of combined tools developed for electric vehicle manufacturers.
“The tool is designed for high abrasiveness, high silicon and aluminum composition. The geometry of the tool combines counterbores, chamfers and drill bits, which can be completed step by step, thereby eliminating expensive cycle times.” Strauchen said. “Previously, the process required three operations, three tool changes and three inventory management of different part numbers. The three-slot high-shear design has a coolant channel behind each cutting edge to maximize intake Feeding, and through the super polished groove to further improve the emptying of chips. The feed rate in this application exceeds 300 ipm.”
The base material is ultra-fine grained carbide with reduced cobalt content to reduce the possibility of stacking edges. Tool coating is a material-specific ALU coating that can extend tool life and maintain sharpness.
Strauchen says that three-edged drills also benefit steel applications for a variety of reasons. Three-edged drills were previously only effective for aluminum applications, but they are becoming more and more popular in materials such as cast iron and steel. “The new flute form that incorporates coolant passing technology has expanded the production capacity of ferrous metal materials. The addition of the latest super smooth PVD coating and integrated reverse mesh taper further enhances our ability to produce drill bits, which can ensure Optimize productivity while stabilizing chip evacuation,” he said.
The first big challenge in drilling steel with three grooves is to make the chips evacuated through the groove volume, and with the addition of the third groove, the groove volume naturally becomes smaller. Strauchen said: “Aluminum shavings are softer and more ductile, so even longer shavings can be ejected from the hole.” “On the other hand, if not properly fractured and controlled, the tolerance of steel shavings is much lower. Many. Together with the third flute, it is crucial to produce small chips (6 and 9) to ensure stable, consistent results.”
Combination tools are versatile, as suggested by this choice of GWS. Strauchen said: “Each tool has its own story and the problem it solves.” “A drill creates three steps in a mirror-polished part. The other is a four-step high-precision reamer, each with a groove 45˚ coolant port. This design keeps the tolerance within 2μm and finishes processing at 8 RMS.”
He also described a large brazed carbide reamer with staggered coolant holes in each groove. This cemented carbide reamer has an independent rotating plunger designed to detect blind holes or small holes. When encountering obstacles, it detects these holes by compression and blocks the coolant, thereby stopping the machine before the tool breaks.
YG-1 USA, located in Mount Vernon, Illinois, is a full-line supplier that not only provides hole machining tools, but also provides carbide, round tools and blades as well as high-speed steel, powder metal and cobalt suppliers. According to Steve Pilger, National Product Manager for Hole Processing, it produces about 60 million round tools every year. “We provide customers with the latest CNC and traditional Bridgeport. The challenge for hole machining is to use tools with excellent life and application capabilities to produce higher quality products and to achieve the highest tolerances in the shortest time.” Pilger said.
According to Pilger, the main product of YG-1 is Dream Drill solid carbide drill bits. He said: “Dream Drills maximizes tool life and chip evacuation when running cast iron and steel.” “For example, for steel applications that need to be executed at the fastest feed rate and highest speed, split points may be recommended For stainless steel, you can use more aggressive four-sided drills.” Dream Drills range in diameter from 1-20 mm and lengths are 3xD, 5xD and 8xD. YG-1 also provides stocks of 10xD, 15xD, 20xD, 25xD and 30xD super long drill bits, all of which are available from stock. “Some customers are changing the way they handle steel such as 4140 alloy steel. They want to process high-quality parts with high productivity.” Pilger said. “They need higher cutting speeds, with an average cutting force of 350 to 450 sfm in order to produce the highest quality parts and obtain the longest tool life.” For these high-volume, high-volume environments, YG-1 provides Dream Drill Pro series products are used in alloy steel and cast iron auto parts.
YG-1 provides the I-Dream Drill General series of products, which can be used for multi-functional drilling of steel, carbon, alloy and cast iron. It can be used for drilling with high flexibility and does not require the highest speed and feed. The amount of steel and cast iron.
The newest member of YG-1′s drill bit series is the I-ONE modular interchangeable bit drill with lengths of 3xD, 5xD and 8xD. The steel body is flexible and can accommodate five or six blades of different sizes cut from the same flexible steel body. I-One has the advantages of cemented carbide drills.
For coating, YG-1 has developed a post-coating treatment for its proprietary H-coating, which can help in the evacuation of chips in deep hole drilling. “This treatment can smooth the peaks and valleys that lead to the coating. We have found that by polishing the blade, the tip of the blade and the normal size drill bit, the tool life can be increased by about 20%.” Pilger said. “For deep hole drilling, the delivery of high-pressure coolant on the machining center forced the workshop 15 years ago to spray parts on a special spray gun machine at a speed of 1-2 ipm. Now, they can work at 20 to 30 ipm. The same deep hole is machined on the CNC machining center.”
The two-blade SUMOCHAM interchangeable-bit drill production line of Iscar America adopts advanced technology, which forms the basis for the design of the three-blade LOGIQ3CHAM interchangeable-bit drill production line. “When you think of a hole, it seems very simple-just project the radius to the third dimension. But this is a common function used to produce products in workshops and high-production environments (such as automobiles). [In molding, medical It is also common in high-precision applications such as the off-road industry," said Craig Ewing, a national product expert at Iscar USA in Arlington, Texas.
The diameter of SUMOCHAM ranges from 4 to 32.9 mm (0.157 to 1.295 inches) in increments of 0.1 mm (0.004 inches). It can be a variety of carbon steel and alloy steel, as well as high temperature steel alloys and anti-rust. SUMOCHAM's clamping system can increase productivity while adding more blade indexes. The handle itself is designed with a twisted nozzle and has a strong, durable and structurally stable body. According to the company, the indexable head comes in ten different standard geometries and is designed for drilling steel, special materials, cast iron or aluminum.
The unique cavity design of the SUMOCHAM drill bit utilizes the cutting force of the machine acting on the tool. These forces are converted into clamping forces used to tighten the blade towards the back of the bag-the greater the cutting force applied, the better the clamping force obtained.
Ewing said the SUMOCHAM interchangeable bit drill offers a variety of styles for common alloy steel applications. He said: "They have 1.5D, 3xD, 5xD, 8xD and 12xD depths and are suitable for typical machining center applications with CAT 40 and 50 tool holders, HSK, CAPTO, live tools in lathes, and for Mazak Integrex, etc. Functional machine tool.".
LOGIQ3CHAM is a three-blade interchangeable head drill production line with a diameter range of 12 to 25.9 mm (0.472-1.020 inches). The drill body size is 1.5xD, 3xD, 5xD, and some sizes are 8xD. Additional chip flutes allow for higher feed rates, Ewing said: "We found that the third flute is more beneficial in high-volume applications, and it also increases tool life."
LOGIQ3CHAM is designed for carbon steel materials ISO P and ISO K cast iron and ductile iron. According to Iscar, it can increase productivity by up to 50% compared to ordinary two-edged drills with interchangeable heads. The concave cutting edge can smoothly penetrate into the working material, and has excellent centering and stable drilling effect. Features include a durable drill body made of hard high-strength steel with better wear resistance. According to the company, the polished groove surface ensures smooth and easy chip evacuation, and dovetail clamping prevents the drill bit from being pulled out of the drill cavity during retraction.
Mark Hatch, product director of Emuge in West Boylston, Massachusetts, said that drilling holes is one of the last critical production steps. Correct tapping is essential to avoid rework and even scrapped parts. As steel alloys and irons, it is necessary to choose the right taps, and there is a wide range of solutions," he said. "When tapping alloy steel, due to changes in chemical properties and heat treatment, [shape] chip shape, size and length are all changed. . The type and percentage of each chemical element, coupled with heat treatment, together produce different mechanical properties that affect cutting performance. When selecting a tap for the application at hand, consider the base material of the tap, coating and geometry are key. ”
When selecting a substrate, several processing factors are critical, such as torque, thermal stability, and wear factors. For example, the powdered metal HSSE-PM substrate can provide higher wear resistance, thereby improving the quality of the edge of the tool.
In the past five years, Hatch pointed out that due to improved tool coating, it can improve the life of tap tools and process consistency. “Emuge has developed optimized coatings designed with excellent thermal stability, wear resistance and low coefficient of friction. Due to the peak and valley values ​​of the tool, the adhesion of the coating on the tap can be challenging, so The coating designed by Emuge can be accurately distributed on the entire surface and will remain intact.
The geometry of the tool is a key factor for effective alloy steel thread machining. The choice of straight groove or spiral groove, such as low helix angle (slow helix groove) or high helix angle (fast helix groove) will depend on the machinability of the material, that is, the hardness and heat treatment of the material. Whether the choice directly affects the chips produced and the taps selected. If the material is annealed, long chips will be produced, and a high tap may be a good choice. However, as the steel hardens, this type of tap may break.
Manufacturers have good choices in roll forming (chip-free internal thread production) and cutting taps. For example, Emuge offers Innoform-Steel-M, a series of HSSE-PM taps used to form threads with improved surface quality in medium-strength steels up to 44 HRC, while increasing static and dynamic thread strength.
Innoform-Steel-M taps have a polygonal geometry to reduce torque and extend tool life. Special powder metal substrate and higher hardness TiN-66 coating can reduce friction and extend tool life. It is recommended to use Innoform-Steel-M taps to form cold-formed steels, cemented steels, castings, heat-treatable nitrided and cold-worked steels, and high-alloy and hot-worked steels.
When long chips become a challenge, taps can provide taps with cutting surface geometry and spiral grooves, which together affect chip flow, chip curling and chip length. According to the company, Emuge chip breaking technology (Emuge CBTz) produces short, broken, controllable chips, thereby eliminating the potential for clogging of grooves and machine tapping caused by clogged cutting teeth or broken teeth.
CBTz taps have undergone TiN surface treatment to reduce the friction between the tap and the workpiece, thereby improving the thread finish of carbon steel and alloy steel, casting and forging steel, tool and die steel, and 300 stainless steel below 300 HRC and extending the tool life.
For short-cut hardened steel and cast iron, Emuge AH ​​taps are a new generation of Premium HSS-E and HSSE-PM taps, especially suitable for tapping common abrasives and high-hardness materials in heavy metals, such as cast iron equipment and agricultural vehicle markets. Emuge AH ​​taps are available with or without coolant through holes and TiCN coating or NT nitride surface treatment to extend tool life.
Successful tapping applications depend on several important factors. According to Mark Johnson, President of Tapmatic, Pat Falls, Idaho, these may include axial compensation on CNC machine tools, internal coolant supply, and special advantages associated with self-reversing tapping attachments. . He said: “Rigid or synchronous tapping on CNC machine tools has become an industry standard.” “Even if the synchronization of machine tool feed and spindle rotation is accurate, there will always be a lot of difference between the actual pitch of a specific tap and the machine’s synchronous motion. Small difference.”
The use of a completely strong bracket means that even small differences can cause high axial forces on the threaded flanks. Johnson said: “This has a negative impact on the life of the tap and the quality of the thread.” “Using a tap holder with a small amount of axial compensation can make the tap better conform to its pitch, thereby reducing the axial force, thereby significantly Improved tap life and thread quality.”
Tapmatic’s SynchroFlex tap holder includes a machined flexible part that provides a small amount of axial compensation. He said: “The SynchroFlex flexure has a high spring rate, which is important to avoid axial cuts.” “If the spring force is too soft, just like the traditional tension compression tap holder with a large amount of axial compensation, Axial misalignment may occur. This is especially true when using free-cutting high-speed tapping, which is usually recommended for synchronous or rigid tapping cycles. SynchroFlex aims to provide just the right compensation for synchronous tapping.”
Generally speaking, lubrication is very important for tapping, especially for roll tapping. Johnson said: “Using a faucet holder with internal coolant capability, you can use the axial coolant holes of the faucet for blind holes, or use radial coolant holes for through-hole applications.” To the position required to cut or form the thread. When using a cutting tap, it also greatly helps to remove the chips from the hole.”
Tapmatic’s SynchroFlex faucet brackets all include a balanced high-pressure internal coolant system. Pressures up to 80 bar or 1200 psi can be used, and because the system is balanced, the coolant pressure does not affect the axial compensation of the tap holder.
Compared with synchronous tapping, self-reversing tapping accessories have special advantages. “Using synchronous tapping, because the machine tool spindle needs to stop and reverse within a very limited number of revolutions, the machine tool cannot maintain the programmed spindle speed. Using the self-reverse tapping accessory can make the machine tool spindle move in one direction at the actual program speed Continuous rotation. The result is a shortened cycle time.” Johnson said.
For example, in a test that uses rigid tapping to tap 10 M8 holes at 2500 rpm, the cycle time is 18 seconds. Repeating the same test at 4,000 rpm saves only one second. It takes only 11 seconds to tap the same 10 M8 holes at a speed of 2500 rpm using the self-reversing tapping attachment. Johnson said: “In addition to shortening the cycle time, the use of a self-reversing tapping accessory can also make the tap run at the recommended speed, which can also extend the life of the tap.”


Post time: May-10-2021
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