The project and technology of Halnn superhard cbn inserts turning Gear

With the rapid development of the auto industry, it also lead the rapid rise of the auto downstream industry, such as auto parts and other industries. And with the mass production of cars, a lot of manufacturers which processing auto parts belong to mass production, such as automotive gear, gear shaft and other components. This article describes the selection about process technology and materials of auto parts, and how to process auto gear.

Part 1 The material and performance of the auto gears

Currently, there are 18-30 pieces gears per auto usually, the gear is the main basal transmission parts in the car industry, its quality directly affects the noise, stability and service life of the car. And choose different gear material, the gear will play a different role, such as automotive transmission gears, drive axle pinion gear, driver different gear and others often used 20CrMoTi,20CrMo as materials; automotive crankshaft gear often used 40,45 or 40Cr as Material. In order to make the car gear have a higher hardness, strength and flexural fatigue strength and contact fatigue strength (resistance to fatigue pitting)when running, usually use heat treatment process to improve the hardness, wear resistance and fatigue strength of the gear .

Part 2 The heat treatment process for Automobile Gears

The Heat Treatment for Automotive gear usually include: normalizing, quenching, carburizing and other processes, normalizing happened before process the parts for removing the internal stress and increase the hardness of the material; quenching and carburizing generally happened after rough processing the gear, in order to obtain a high surface hardness, high wear resistance and fatigue strength, and the unit has a strong heart and toughness to keep low-carbon steel after quenching, the work piece can withstand shock loads, for extending the life of the parts. You need choose the different heat treatment process according to the different materials. The important gear (such as transmission wheel 20CrMoTi material) required carburizing after heat treatment, for improving the wear resistance and fatigue resistance. In order to ensure the core part has enough strength and toughness, the material harden ability need a high requirements, the core parts hardness should be 35 ~ 45HRC, hardness of surface was 58-64HRC.

Part 3 The machinery processing technology and Inserts selection for auto gear

We had introduced the auto gearbox wheel(20CrMoTi materials) heat treatment process above , Now here is the brief processing line: Turning-Forged-normalizing-roughing-carburizing- quenching and tempering-finishing process-shot-grinding-Assembly. The hardness of 20CrMnTi material gear after heat treatment is HRC 58-64.While the hardness of other material’s gear was generally HRC45 or more after heat treatment, and there will inevitably be some distortion problems during the heat treatment ,will make trouble for finishing, so it is so important to choose the right inserts material when finishing process, as the car gear requires high accuracy, high quality, and the need to ensure the efficiency when mass production machining. There are three types materials for inserts on the market currently, which are coated carbide tools, ceramic cutting tools and cubic boron nitride(CBN) cutting tools, although the hardness and strength of coated carbide insert is better than uncoated carbide insert, the performance was the same as the surface wear-resistant layer is thin. So we did not suggest you choose the coated carbide tools when large volume processing. Of course the Ceramic inserts was brittle, and only was suitable for finish process the material which hardness was between HRC45 to 55. 

However Cubic boron nitride(CBN) cutting tools, has a higher hardness, higher strength and better wear resistance than the other two kind cutting tools we mentioned. Especially the non-metallic adhesive cbn insert researched by Halnn superhard. The development of non-metallic adhesive cbn inserts which was researched by Halnn superhard, which is a CBN insert company solving the problem of finishing processes.

The CBN inserts from Halnn Superhard can be used for turning the hard material all around and efficient. Halnn superhard cbn insert company was the first one to put forward to the conception of solid cbn inserts.

Now we will introduce how to choose the Halnn cbn inserts to process the gear.

Part 4 Halnn super-hard CBN inserts finishing process the gear

The working allowance is generally less than 0.3mm when finish turning gear, Halnn super-hard cbn inserts research BN-H10 and BN-H20 Non-metallic adhesive cbn inserts for finish turning gear. The two grade inserts both belong to the welded cbn inserts.

Following we will introduce how to choose the right grade inserts according to the different condition.

(1)Continuous turning conditions: Select BN-H10 cbn inserts,BN-H10 welded cbn insert has a high hardness, wear resistance and good resistance to chipping damage,suit for high-speed and continuous finishing cutting conditions,cuttingparameters:ap≤1mm,Fr=0.05-0.35mm/r, Vc= 60~250m /min.                                                                       

Application Case: Turning the gear which hardness was between HRC58 to 63.

Cbn inserts grades: BN-H10;

Cutting parameters: ap=0.2mm,Fr=0.1mm/r,Vc=180m/min.

Processing steps: Dry cutting.

Processing effect: life is 4 times longer and only cost 40% than ceramic tools.

                                                                                        

(2)Interrupted turning conditions: Interrupted turning was named that there is groove in the gear end’s hole.This operating mode should select Halnn superhard cbn inserts BN-H20 grade, this grade not only has a higher hardness, excellent wear resistance and impact resistance ,but also has a multi-blade numbers, reduce the tool costs.

                                                      Application Case: Turning the end surface of the gear which hardness is between HRC58 to 63

Cbn inserts grade :BN-H20 grade;

Cutting parameters: ap=0.25mm,Fr=0.1mm/r,Vc=120m/min.

Processing methods: Dry cutting.

Processing effect: Compared with European brand PCBN inserts, Halnn BN-H20 tool has a longer life, and only cost 1/2 price than European brand PCBN inserts .

                                                    

So Halnn superhard tools will be your best selection for turning the Gear. If you would like to know more about cbn insert turning gear, please check the following link http://www.halnntools.com/news/case/126.html,or send us email halnntools@gmail.com,Or contact with me directly:whatsapp:+8618695866134.

Compared Ceramic insert and Halnn CBN insert

When process the machinery,inserts has been always referred to as "industrial manufacturing teeth," while cut performance of the cutting tool material determine the efficiency of its production,and the tools material also play an important role in production costs and processing quality, therefore, the proper selection of cutting tools material is so crucial, ceramic tool has a good advantage in excellent heat resistance, wear resistance and chemical stability,  the main raw material of the ceramic tools are Si and Al ,and there are a lots the two elements in the crust, it is said that they are inexhaustible. Therefore the new type ceramic tool has a good prospects.

Part 1 The types of ceramic tool
The development of ceramic tool materials focused on improving the ceramic materials of the traditional tools performance, grain refinement,composite components,the use of  coatings,improve the sintering process and development of new products, etc.

In order to obtain high temperature resistance, abrasion resistance and anti-excellent chipping performance which can match the needs
of highspeed precision machining. Halnn superhard Institute divide the material of ceramic tools into three categories:alumina, 

Cubicboron nitride (CBN tools) .In metal field, alumina ceramic inserts and silicon nitride ceramic tools are both called ceramic tools; while in inorganic non-metallic materials science, cubic boron nitride material attributed to the ceramic ma-terial categories. 

The following are the characters of the three types of ceramics.

(1) Alumina (Al₂O₃) based ceramics: carbide ceramics add Ni, Co, W, etc. as a binder metal, can increase the bonding strengthof aluminum and carbide. With good wear resistance, heat resistance, and good high temperature on chemical stability,hardly occur mutual diffusion or chemical reaction with iron element , so alumina ceramics was used most widely, it suitable for steel, cast iron and highspeed machining alloys;as the improvement of the thermalshock performance it can also be used for milling or planing under intermittent cutting conditions, but it should not be used for machining aluminum, titanium and tantalum alloys, otherwise prone to chemical wear.

(2) Silicon nitride (Si₃N₄) based ceramic tool: adding an appropriate amount of metal carbide , metal and composite enh-ancer base on the silicon nitride matrix, and use the composite strengthening effect (also known as the dispersion strengthening effect) produced. Characters include: good high hardness, wear resistance, heat resistance, oxidation resistance. silicon nitride
will has a smaller chemical reaction with carbon and metal element, friction factor is also little. Suitable for fine cutting, semi-cutting , fine milling or semi-intensive milling.

(3) Boron nitride ceramics (cubic boron nitride cutting tool): High hardness, wear resistance, heat resistance, good thermal stability, and also have good thermal conductivity, lower coefficient of friction, small linear expansion coefficient.Such as cubic boron nitride BN-S20 grade tool for roughing hardened steel which from Halnn superhard company, BN-H10 Grade for high speed finishing the hardened steel, BN-K1 grade processing the high hardness cast iron, BN-S30 grade high-speed cutting the gray cast iron ,they are all can get a better economic returns than ceramic inserts.

Part 2 the characteristics of ceramic cutting tools

Characteristics: 

(1) good wear resistance;

(2) high temperature resistance, good red hardness; 

(3) the tools life was several times higher than traditional tools, reducing the tools changes times when Processing, guarantee the machined workpiece small taper and high-precision; 

(4) not only can roughing and finishing the high hardness material , but also for milling, planing, intermittent cutting and rough pulling force shortage roughing impact such a large processing; 

(5) the friction is small when cutting metal with ceramic inserts,not easily adhered to the cutting blade, not easy BUE, and also can perform high-speed cutting.

Ceramic inserts compared with the carbide inserts: ceramic blade can stand high temperature about 2000 ℃, but cemented carbide will be soften   at 800 ℃; ceramic tool was more hightemperature chemical stability, high speed cutting, but its disadvantantage is that the ceramic blade strength and toughness is very low, easily broken. Then we research the boron nitride ceramic (also known as cubic boron nitride(CBN) cutting tools), mainly used for turning, milling, boring superhard materials. Cubic boron nitride cutting tool is much higher than the hardness of the ceramic tools, due to the high hardness, we call that superhard material with diamond together, often used to process a material which hardness harder than HRC48, it has excellent high-temperature hardness - up to 2000 ℃, though it was brittle than carbide inserts, impact strength and resistance to crushing performance has improved significantly compared with alumina ceramic inserts. Moreover, some special cubic boron nitride cutting tools (for example: BN-K1 grades and BN S20 grade from Halnn superhard company)  canstand a large  margin roughing chip load, also can stand the impact of interrupted during cutting and finishing time wear and cutting heat, these features says we can roughing har-dened  tool steel  and high hardness cast iron with CBN inserts.

We will introduce the application scope of Halnn superhard material companies CBN inserts .

Part 3 Halnn superhard cubic boron nitride cutting tools applications

Halnn superhard company was called Henan Institute of superhard materials before,was professional for manufacturing cubic boron nitride cutting tools and other superhard materials products.Being the first one research inserts production match gray cast iron, all kinds of cast iron / steel, hardened steel tools and other materials. Especially was perfect in intermittent cutting hardened steel, high chromium cast iron processing and many other areas, leading the worldclass level, in academia Halnn superhard tools enjoyed a high reputation as a pioneer in the localization of superhard cutting tool, hard materials processing and high-speed machining the most well-known tool brands.Halnn brand CBN tool used the non-metallic ceramic as a adhesive successfully, and further balance the CBN tool brittle and ductile, is one of the advantagesof this tool brand. 

As a machine folder indexable CNC blade structure, as shown in the table blade style, cubicboron nitride inserts divide into welded CBN inserts and solid PCBN inserts, welded insertsCBN usually apply for finishing , cut at about 0.3mm and less, while the overall sintered CBN inserts can cutting difficult materials in large margin , particularly was perfect in strong interrupted cutting machining in tool industry,Halnn superhard material as a national brand was known all over the world. The following is welded CBN inserts and integral CBN inserts
application table:

The grade and application of Halnn’s welded CBN inserts

 The grade and application of Halnn’s integral CBN inserts

Part 4 Conclusion

At present, the ceramic cutting tools developed rapidly, the level of research and development equal the international.Through the study of ceramic tool ceramic tool material components, manufacturing process and materials design can improve the toughness and impact resistance greatly based on high hardness, high wear resistance and red hardness, prepared in line with modern cutting techniques using suitable materials requirements. It is the realization of an efficient turn instead of grinding "hard processing technology" and "dry cutting technology", improve part surface quality. Achieve dry cutting, the control of environmental pollution and reduce manufacturing costs have broad application prospects.

More information ,please check http://www.halnntools.com/news/focus/128.html,Or contact with us halnntools@gmail.com,skype:cbn_inserts_angels,whatsapp:+8618695866134