Precision machining of tiny parts calls for miniature tools

Today's industrial products are constantly developing in size and scale. The processing of more and more products, such as medical and dental equipment, mobile phones, notebook computers, aerospace and electronic components, requires more miniaturization and miniaturization of cutting tools and tool systems.
Peter Matysiak, president of Emuge Corp., believes that the need for microfabrication and the development of micro-tools is increasing in order to meet the needs of Swiss-style machining, high-speed milling, thread milling and tapping.
Emmo's recently launched products also clearly show that the application of the thread milling process is growing. According to Matysiak, "Advances in modern machine tool technology have made thread milling an important method of hole machining in a variety of applications, such as medical, aerospace, defense and computer industries. Today's CNC machines are small desktop machines. Or a larger machine with a precision spindle and a holder that holds these tiny tools, with a spindle speed of up to 60,000 r/min or higher."
Emerson has developed a new range of solid carbide micro-thread milling cutters for the processing of difficult-to-machine materials such as stainless steel, titanium alloys, K-Monel copper-nickel alloys, Hastelloy nickel alloys, Inconel chrome-nickel alloys, etc. The possibility of tap damage and its consequences, and the need to manually tap the thread when machining the complete hole bottom thread, can be processed into a hole bottom thread.
Miniature thread milling cutters can be used for thread milling of through and blind holes for excellent thread surface quality and dimensional accuracy. According to Matysiak, “In order to successfully tap or mill threads, all kinds of tools have to be processed together, so it is very important that the holders have a particularly high precision. Therefore, we will not produce only one type of tool. Produce the holder that holds the tool correctly."
“Because of the small size of microfabrication and the high demands of production efficiency and high return on tool investment, solid carbide is not used as the tool material,” explains Rob Keenan, president of Seco Tesco. “The geometry of the tool, the coating and the matrix material are the three elements that determine the right tool for a particular job.”
In order to optimize the machining efficiency of the tool, the machining of each workpiece material requires a change in the composition of the cemented carbide tool material. Seco Jabro Mini Series End Mills have recently expanded their coatings, carbide grades and cutting geometry design to make them more suitable for hard materials (such as hardened steel, titanium alloys) and softer materials ( Such as aluminum alloys, copper alloys) and high abrasive materials (such as graphite). These new tools can be as small as 0.1mm in diameter.
The two new Seco Jabro mini series solid carbide end mills range in diameter from 0.1 to 2.0 mm and feature a ball head structure and a bull nose structure. The JM100 series is designed for machining tool steels with a hardness of HRC65; the JM400 series is specifically designed for machining aluminum and copper alloys. The Seco Jabro Mini Series complements the full range of carbide end mills to provide higher processing efficiencies for a wide range of processes such as molds, medical parts, aerospace, and general machinery.
In small-size tooling, high-precision tools are a key factor in machining small molds with tight dimensional tolerances and good surface quality. Jay Verellen, Rotary Tool Product Manager at Seco Tools Inc., explains, “Although the tool size is small, the size ratio is exaggerated to some extent: the tool you are using may be only 2mm in diameter, but the length is It may reach 30mm and its aspect ratio is as high as 15:1. Imagine that when machining automotive parts, you may use a 50mm diameter cutter, but few people can imagine using a diameter of 50mm but up to 750mm. The tool is machined."
As more and more manufacturers recognize the versatility of Swiss-style CNC turning in the machining of precision engineered components, the importance of this process continues to increase. From all aspects, Swiss-style CNC machining is no less complex than multi-task composite machining, and may even be more complicated due to the small size of the workpiece.
When machining a part with a bar (usually up to 32 mm in diameter), the bar moves forward through the sliding tool holder and several tools are machined simultaneously on the spindle (often also on the rear axle). Programming is still complicated, but many CAD/CAM software companies (such as Partcam, a subsidiary of Delcam) have developed processing software that makes the application of Swiss-style processing easier.
According to John Dotday of Sandvik Coromant Co., “These Swiss machines have 10-15 axes that can be machined in rectangular, circular or arbitrarily shaped workpieces that you can imagine.”
Dotday explained, “These multi-tasking machines use a sliding front tip that moves differently from the Z-axis of the other machine's turret. It moves from the bar in the Z-axis and feeds the turret through the bar. Inward movement combines to achieve cutting. As a result, since the cutting is performed near the guide sleeve (the tool is only 1-2 mm from the guide sleeve), the machining rigidity is excellent. Due to the high rigidity of the tool and the workpiece material, Therefore, it is possible to use a large depth of cut and to machine parts with no vibration marks and excellent surface quality."
Dotday said, “The external turning process uses positive-angle inserts. The CCET, DCET and VCET series of inserts we launched a year ago have extremely sharp cutting edge lines for large depth-cutting turning, which is what Swiss-style machining requires. The workpiece must be in the required diameter dimension in one pass and the tool should have the ability to machine a wide range of materials at large depths (2.5-5 mm) and low feed (0.02-0.08 mm)."
“About 60%-70% of Swiss-style processing is used to make parts such as bone screws and surgical implants in the medical device industry,” says Dotday. “There are many types of Swiss-made materials, such as 300 series stainless steel. , 17-4 PH, various titanium alloys, cobalt-chromium alloys, Inconel 718, and hard turning of steel."
The US industry is constantly discovering the advantages of micro-knives in medical, electronics, aerospace, and high-speed mold processing. Sherwood Bollier, president of Niagara Cutter, said, “Microtools have been used in Japan and Europe. In the United States, the use of such tools is just beginning to become popular, but its potential advantages continue to grow, using a diameter of 0.13mm. The number of precision high-speed machine tools for the above carbide end mills is increasing." Although many of the results are patented, manufacturers are increasingly interested in micro-milling and micro-machining, and also promote tool suppliers. Constantly tap its development potential.
In addition to small precision medical devices and parts, typical applications for microfabrication include electronics, aerospace, hardened die milling, and high-end applications such as precision alloys and gold jewelry. At present, the increasing performance of high-speed precision machine tools developed by leading machine tool builders such as Sodick, Makino, Roku Roku (machining machine tools), Roeders, Mikron, Datron and Kern has become a key driver of the development of micro-machining technology.
Niagara Tool Company has developed the MicroTool series of small diameter carbide tools for medical and electronic processing, including square and ball end mills in two and four groove configurations with diameters ranging from 0.13 to 3 mm. In addition to uncoated carbide standard tools, MicroTools offers TiAlN patented coatings to improve tool life and performance. The company has more than 30 standard product types (square head, ball head, truncated type, conventional type and length type). The groove type includes two slots, three slots and four slots, and the diameter ranges from 0.13 to 3.2 mm. With an increment of 0.03mm, it offers a wide selection of uncoated, PVD TiAlN coatings and CVD diamond coatings. Special micro-milling products customized according to user's processing requirements also occupy a large proportion. Milling cutters with a diameter less than 0.13mm can be ordered according to special products.
Kerry Cranford, global small tool product manager at Kennametal Inc., said, “When it comes to micromachining, I think of a drill with a needle that is thinner than a needle or an end mill with a diameter as small as 0.15mm and 0.08mm under the microscope. Drilling of computer boards. Currently in the field of micro-parts processing, Swiss-style machining, Swiss-type automatic lathes, small lathes and combination machine tools are the fastest growing applications, especially in the medical and dental parts processing sector." Kenner 2008 The new micro-part machining tools are based on small interchangeable cutter carbide tools and small indexable tools.
Kenner's Swiss-style turning tools include a complete range for machining both inside and outside diameters. The inner diameter machining tool includes a boring tool with a minimum machining hole diameter of 0.25 mm (thinner than a needle), a profile cutter that can be machined in a 1.6 mm diameter hole, a grooving knife that can be slotted in a small hole of 2.8 mm diameter, and Machining 5# thread (2.5mm aperture) taps, end grooving knives can be as small as 0.41mm or even 0.28mm.
Kennametal's small interchangeable cutter head solid carbide tooling system and tool holder are the most distinctive features of the KM micro-system, which allows the user to change the tool's interchangeable tool head on the machine tool, thus completing the entire tool with one installation. , outer diameter processing. In the indexable tool part of the KM microsystem, the minimum hole diameter that can be machined by the indexable tool is 4.8 mm. For example, an 80° diamond chip with a chip breaker uses all of the coating grades currently in use and special grades for machining titanium and stainless steel. Kenner also offers indexable threaded inserts and grooving inserts that can be mounted on the same shank to machine small holes 6.9 mm in diameter. In addition, there are indexable end face contouring blades and contouring blades.
Currently, Mikron Corp. Monroe has developed small to medium sized series of tools for the processing of high-end precision micro-parts for medical, dental, high-speed communications, nanotechnology, fuel nozzles, micro hydraulic systems and pneumatics. Processing of components. Its standard range of drills includes the CrazyDrill high-speed drill series for longer process lines and the MiquDrill drill series recently developed for short-lived (JIT) machining.
The three drill bits in the MiquDrill range are unique: the center drill has a diameter range of 0.5-6 mm and a minimum drilling aperture of 0.5 mm, providing a 90° or 120° drill angle. The MiquDrill 200 has a short drill length with a drilling depth of approximately 2-3 times the diameter and a working aperture of 1.5 mm. The MiquDrill 210 is a universal drill with a diameter range of 0.1-3mm. The latter two drills are designed for microfabrication. The unmachined drill has a machined diameter as small as 0.1 mm, the coated drill has a minimum machined diameter of 0.3 mm, and the diameter is from 0.3 mm to 2 mm. 0.01 mm, the dimension increment from 2 mm to a maximum diameter of 3 mm is 0.05 mm.
According to Robert Couture, tool sales technology manager at Mikron, "MiquDrill is a two-slot solid carbide drill bit. Like the Crazy Drill, it is also made of high quality micro-grained base material, but the geometry of the insert is Unlike the Crazy Drill, the manufacturer offers a single-piece, lower-cost option for short-flow, immediate machining. MiquDrill is ideal for medium-volume machining and micro-hole drilling of individual workpieces."
According to Andy Kelling, US thread processing manager at Iscar Metals Inc., Iskar continues to improve machining methods to address the heat and abrasion problems associated with machining small parts made of special metals. The challenge is mainly due to the failure of cemented carbide tools under high pressure and high heat. The hardness of traditional carbide grades is often difficult to handle these special metals.
"Synthetic crystal superhard tool material (PCD/PCBN), in some cases also cermet, as well as new carbide grades, new coatings and surface treatment methods (such as Iskar's new Sumo brand) ) is very effective for processing special metal materials," Kelling said. "We also used a mature chip-and-groove design and cutting edge preparation technology to effectively strengthen the fragile cutting edge. Various coatings (such as TiAlN coating) Layer) is also very effective."
Picco MF (Multi-Functional Compound Tool) and Picco MFT (Multi-Function Thread Machining Tool) are designed for machining small workpieces on Swiss-style machines and can be used for other processes. Picco MF tools can be used for drilling, face turning, internal hole chamfering, bore turning/boring, bore contouring, external chamfering and external turning. In addition to the above machining, the Picco MFT tool can also be used to turn 60° internal and external threads. Both series of tools are available for left-hand and right-hand double-sided machining with diameters of 4, 5, 6, 7, 8 mm and a depth-to-cut ratio of 2-3 times the diameter. In addition, each tool surface is grooved to allow coolant to flow directly to the cutting edge.
In order to process hardened steel with hardness HRC48-65, NS Tool's micro-grain carbide double-groove ball end mills use Mugen coatings and new geometric designs to improve chip evacuation and reduction Processing flutter. Doug Kline of Single Source Technologies said, “In North America, hard milling of various molds, dies and parts has become more common.” The new milling cutter has a radius of 0.05- 3mm, divided into standard and long neck.