The machining industry’s demand for increased productivity and reduced costs continues to drive developments that focus on innovative, state-of-the-art tools and cutting materials as well as changes in production technologies. In addition, tailored tool coatings play a special key role in increasing cutting speeds, raising productivity, and lowering costs for demanding gear-cutting processes. Excellent performance can be achieved as demonstrated in customer tests with Oerlikon Balzers’ high-end coating Balinit Altensa.
The manufacture of durable, low-noise, and highly efficient gears, such as for transmission applications, is associated with enormous quality demands and a correspondingly high production effort. Industrial competition therefore demands both the shortest possible production times and low production costs.
Manufacturing Costs as a Major Issue
Gears transmit movement, forces, and power in a system. Thus, they must perform even at the highest of stress levels, and cutting these high-precision geometries demands the utmost in performance of machines, tools, and coatings. The industry focuses on the best quality with the lowest processing times in order to provide long-lasting products with low-noise emission and high-gear efficiency. The key to this is the manufacturing process used for the gears, including the cutting tools, their coatings, and the productivity of the production process itself.
Production costs are a major issue in the machining and cutting industry. A closer look at the influencing factors shows the savings potentials that lie within the process:
The tools themselves amount to only 8 percent of the total manufacturing costs, on average.
Depending on the cutting process, cooling costs amount to 12 percent. Dry machining operations are used in many gear cutting applications, but this is not suitable for all of them.
Setup costs (24 percent) can be lowered using coated tools that have a longer service life while maintaining the same level of operational reliability.
A minimum of 26 percent of total costs is allocated to other, restricted factors.
This leaves the actual cutting costs at about 30 percent – by far the largest single factor. The easiest way to reduce these costs is by improving the cutting speed: An increase of cutting speed from vc=180m/min to vc=350m/min makes it possible to reduce production costs by 25 percent, for example. (Figure 1)
Efficiency Through Longer Service lifetime
Modern wear protection coatings increase tool service life and, thereby, also ultimately reduce setup costs. Their strengths are, however, above all displayed in cutting applications, in which they enable significantly higher cutting speeds.
An example calculation based on test with Balinit Altensa coating demonstrates this: If the speed of gear cutting can be increased from 200 to 300 m/min, machining time (primary and secondary times) goes down from 0.56 to 0.42 minutes per gear. This reduces machining costs by about 25 percent, based on the machine-hour rate. If one considers the overall costs of producing a gear, this represents a cost saving of about 10 percent. It thus pays to invest in new substrate materials or coatings.
Confirmed Productivity Gains with Balinit Altensa
Tests conducted on the premises of an Oerlikon Balzers customer, a renowned car manufacturer, used 90mm HSS hobs with Balinit Altensa. Compared to Oerlikon Balzers’ Balinit Alcrona Pro coatings, it was shown that a significant increase of 30 percent in cutting speed — from vc=200 to 260m/min — was possible with no difficulty thanks to the innovative gear-cutting coating (Figure 2). What’s more, tool life was extended by 20 percent. A second series of tests showed that even at cutting speeds of 300m/min, which represents an increase of 50 percent, tool life was still longer than the original values obtained.
Balinit Altensa showed great results for carbide hobs as well. Under the high-speed cutting conditions of vc=480m/min, tool life was extended by more than 30 percent.
Carbide stick blades are used to produce bevel gears. Tests at an automotive supplier showed that tool life at moderate cutting speeds of vc=148m/min was increased by 70 percent with Balinit Altensa. At the same time, output rose from 1,200 to more than 2,000 parts. After this successful initial test, the customer agreed to increase the cutting speed by more than 35 percent. Even then, a 30 percent improvement in tool life was achieved. (Figure 3)
In addition to hobs and stick blades, tests with shaper cutters and power skiving tools were also carried out. Balinit Altensa delivered remarkable results here as well. HSS shaper cutters with a diameter of 130 were tested in wet operation — with the result being an increase in tool life of 140 percent. (Figure 4)
Improved Conductance and Hot Hardness
Balinit Altensa is the coating from Oerlikon Balzers’ successful AlCrN-family to excel, above all, in terms of wear resistance, thermal shock stability, and hot hardness. In essence, Balinit Altensa reduces thermal conductance and improves the hot hardness of the coating by more than 20 percent. This produced even greater crater wear resistance, which can, in particular, occur at high service temperatures and reduce tool service lifetime.
Abrasive wear resistance was, moreover, optimized by about 35 percent, as was oxidation resistance. This reduces flank wear at moderate and high cutting speeds and extends tool service life, even with dry machining. The bottom line is that the numerous improvements in layer development enable considerable productivity gains with longer tool lifetimes, significant performance boosts at the highest cutting speeds for all substrates (PM-HSS, MC90, carbide), as well as higher cutting speeds and feeds.
Balinit Altensa: More Performance, Reduced Costs
Using Oerlikon Balzers coating solutions, customers are able to increase their productivity, which results in higher total production output and lower manufacturing costs. Balinit Altensa, the innovative Oerlikon Balzers gear-cutting coating, leads to unprecedented tool service life and more reliable processes at higher cutting speeds. This not only saves money, but also sets the performance level for the ever-demanding gear cutting process.
About Oerlikon Balzers
Oerlikon Balzers is one of the world’s leading suppliers of surface technologies that significantly improve the performance and durability of precision components as well as tools for the metal and plastics processing industries. Extremely thin and exceptionally hard coatings, marketed under the Balinit and Baliq brand names, reduce friction and wear. The Balitherm brand opens up a broad range of heat-treatment services, whereas Baltone comprises coatings that are available in a full range of elegant colors, perfectly suited for decorative applications. Balimed ThinFilm coatings — with wear-resistant, biocompatible, antimicrobial, and chemically inert properties — have been developed especially for medical applications. Under the Balifor technology brand, the company has introduced technologies that provide tailor-made solutions for the automotive market, while ePD allows the metallization of plastic parts with a chrome look.
Worldwide, more than 1,100 coating systems are in operation at Oerlikon Balzers facilities and its customers. Equipment engineering and assembly of Balzers’ systems are processed in Liechtenstein, in Langenthal (Switzerland) and in Bergisch Gladbach (Germany). Oerlikon Balzers operates a dynamically growing network of more than 100 coating centers in 35 countries in Europe, the Americas, and Asia. Oerlikon Balzers is — together with Oerlikon Metco and Oerlikon AM — part of the Surface Solutions Segment of the Switzerland-based Oerlikon Group.
Oerlikon engineers materials, equipment, and surfaces and provides expert services to enable customers to have high-performance products and systems with extended lifespans. Drawing on its key technological competencies and strong financial foundation, the group is sustaining mid-term growth by executing three strategic drivers: addressing attractive growth markets, securing structural growth, and expanding through targeted mergers and acquisitions. A leading global technology and engineering group, Oerlikon operates its business in two segments — Surface Solutions and Manmade Fibers — and has a global footprint of more than 10,500 employees at 175 locations in 37 countries. In 2018, Oerlikon generated CHF 2.6 billion in sales and invested around CHF 120 million in R&D.