In recent years, as the automobile manufacturing industry has entered a stage of rapid development, diversified personalization has become a major feature of its development. At the same time, automobile and gearbox manufacturers such as engines and gearboxes have also placed more urgent demands on efficient processing.
As a major factor affecting the processing efficiency, the tool has received more and more attention, and the tool supplier has continuously optimized the tool material and structure.
Metal processing for efficient machining All manufacturing companies, including tool makers, are eternal. In recent years, as the automobile manufacturing industry has entered a stage of rapid development, diversified personalization has become a major feature of its development, and it has become an important means to improve the ability of automobile manufacturers to respond quickly to changes in market demand. At the same time, auto parts manufacturers such as engines and gearboxes have also placed more pressing demands on efficient machining.
Machine tools, tooling, crafts and even programming software, cutting fluids, etc. all affect machining efficiency, but constitute the most important elements of machining: machine tools, tooling tools. Therefore, the tool acts as the final cutting material, and whether it can achieve important factors for efficient machining. In particular, the tool has the option of using the limits of existing production equipment and shortening the machining time by means of tools, which directly promotes efficient machining. The old saying goes, "When a worker wants to do something good, he must first sharpen his tools." Today, modern manufacturing has been given a broader connotation. To improve the processing efficiency, and constantly optimize the "tool" - the tool is very important, the following briefly introduces several optimized tool methods.
"Lee" its material, changing the cutting speed
Tool suppliers have been continuously developing and introducing tools with longer service life and faster cutting speeds to achieve higher feed rates and improved machining efficiency. To change the cutting speed, it is important to change the surface coating of the base material of the cutting material. At present, the tool supplier's choice of tool materials is mainly concentrated in cemented carbide and some CBN, and the research and development efforts are continuously increased, and new products are introduced. For example, the tool material produced by Sumitomo Corporation of Japan is taken as an example:
For general carbon steel and alloy steel cutting, the cutting speed of early cemented carbide coating material is V=100～250m/min, and Sumitomo's new material AC700G/AC820P has been processed by the technical innovation of SCM420 on the base material coating. The cutting speed is increased to V=390m/min. At the same time, it has excellent resistance to breakage. When machining SCM425 gears, it can achieve a cutting depth of 5mm, the feed rate is 0.5mm/rev, and the service life of the original material is 1.5~2.7 times.
For hardened steel (HRC58~62) material products, such as bearings and shaft key gears, most of them are grounded after heat treatment and then ground. The efficiency is low and the size is not easy to guarantee. Some users also use CBN (cubic boron nitride) material processing, but the cutting speed is low (80 ~ 150m / min), the processing efficiency surface quality is not high. Sumitomo introduced a new material BNC100 cutting speed of 100 ~ 300m / min, and maintain high line speed while the feed value of 0.1 ~ 0.35mm / rev. Similarly, for automotive mold milling, Sumitomo developed BN700 material round-blade milling inserts with BRC arbor. When SKD is quenched to HRC47-52 material NAK pre-hardened steel HRC40～45 material, it can realize 150-400m/min and 200-800m respectively. /min ultra-high speed finishing, processing time is shortened by 3 to 5 times, and surface finish is excellent.
"profit" its structure, changing the tool cutting allowance feed
The structure of “Li” mainly refers to the continuous optimization of the geometric design of the blade structure, and the new breakthrough in processing efficiency from the aspects of improving the cutting force and the strength of the cutting edge. Take the Japanese BIG Sumitomo product as an example:
1.FCM fast peak milling cutter
The BIG milling cutter has a 20° axial rake angle and a large radial rake angle double rake angle design, which not only cuts lightly, but also has extremely low resistance. At the same time, the eccentric relief technology is applied to the machine-type end mill for the first time. Therefore, the back angle is not too large, which does not affect the sharpness of the blade edge, and can improve the blade edge strength and is not easy to chip.
For example, on the BT40 spindle machine, the S50C material is cut, the φ32mm milling cutter has a cutting depth of 9mm, the speed is 1500r/min, and the feed can reach 550mm/min. Due to the brisk cutting, the product has a good right angle and good wall surface after processing, the straight angle can be 0.01mm, and the roughness Ra is 0.51mm. This product not only achieves the efficiency breakthrough in conventional slot milling and square shoulder milling, but also makes the spindle power insufficient, the clamping rigidity is not good, and the efficient machining is possible in the case of long suspension.
2.EWB-UP high speed super precision hoe
The primary feature of the fine boring head is to achieve the precision of the adjustment precision. Because the fine boring head is a single-edged cutting, it is inseparable from the dynamic balance to achieve high speed and high efficiency machining. BIG combines the dimensional accuracy adjustment with the offset equal-balance dynamic balance adjustment into one boring part. The adjustment accuracy is 0.001mm and the dynamic balance factor G6.3 is required at the highest speed through two dial rotations. With diamond and CBN materials, aluminum alloy parts (such as gearbox housing) and cast iron cylinder bore products can be processed at high speed and high efficiency of 200-2000m/min, and good processing results are obtained.
3. Non-standard composite structure tool
For a large number of complex structures, numerous processes and difficult to machine products, standard tools can no longer meet the requirements of efficient machining. This requires a more targeted design of the tool structure based on the specific part, which effectively reduces the tool change time. Sumitomo Corporation develops special tools for the crankshaft and camshaft hole machining of automobile engines, including broaches, valve seat milling cutters, automatic guide boring tools, etc., all of which are non-standard tools to promote efficient processing and development of typical products.
"Li" clamping, achieving high cutting speed and high feed rate
The tool holder clamping system transmits and connects the tool spindle tool. It carries the spindle precision, rigidity and the rigidity of the tool holder itself, and the dynamic balance, clamping force and clamping precision are required to realize high-speed and high-efficiency machining. Take BIG products as an example:
1. High speed and high precision clamping shank
For cutting tools with a diameter of φ20mm or less, especially for small-diameter cutting tools with a diameter of φ0.25~12mm, high-efficiency and high-precision machining is required, and excellent surface finish is required, which needs to be realized by high-speed machining, which puts forward the dynamic balance performance index of the shank clamping accuracy. More stringent level requirements. The BIG beauty clamp handle series has a clamping port runout accuracy of 0.001mm, a 4x diameter front runout accuracy of 0.003mm, and a jacket accuracy grade of AA. The handles are processed by dynamic balance test, and the maximum speed can reach 40000r/min. And the standard configuration of the water, fully meet the requirements of high-speed high-precision drilling, reaming and milling. The φ8.5×5D drilling of the aluminum alloy cylinder product is processed, and the OSG carbide coated drill bit FTO-GDS is used after the US shank is used. The processing parameters are n=6000r/min, f=0.45mm/rev, The efficiency is increased by 3 to 4 times. At the same time, the aperture accuracy is effectively guaranteed.
2. Heavy-cut strong grip holder
This type of shank is mainly for φ20～50mm large diameter cutting tools. Since this diameter range belongs to the rough machining category, it has higher requirements for the rigid clamping force of the shank. The BIGHMC powerful shank series has a unique slit mechanism, the grip is thickened, the rigidity is good, and the 300Nm super torque is provided. BIG's other BBT beauty clip high-speed double-handle series can meet the needs of high-speed and powerful cutting, and the clamping precision is between 0.005 and 0.01mm. If it is matched with the BBT main shaft, the taper surface of the shank and the end surface of the flange can be closely matched, and the rigidity can be enhanced by 3 to 4 times, achieving strong and efficient re-cutting, and obtaining a good deep hole processing effect.
Conclusion
In the field of automotive processing, especially in the mass production process, tool accuracy and cutting speed life directly affect the production line start rate, processing cycle, and even final production efficiency. According to the survey, nearly 70% of China's tool cost costs account for 2% to 3% of total production costs. Although the ratio is not high, choosing reliable, applicable and efficient tool products can significantly reduce the total production cost of the enterprise.
It is worth noting that the tool product is constantly updated. Although the tool supplier constantly changes the tool material, the original tool body has not changed, and the tool price has not been adjusted after the change. For the whole vehicle and parts manufacturing enterprises, when they feel that the processing efficiency of a certain process is lacking or dissatisfied, try to choose a new tool product or change the original structure of the tool body product, which may increase the cost and increase the efficiency. Unexpected promotion. At the same time, it is equipped with serious and responsible tool management personnel, and believes that effective processing efficiency can simultaneously improve production capacity.
