PCD Tool In Automobile Engine Production

PCD tool In Automobile Engine Production

Poly-crystalline diamond PCD blade is a complex sintered by the fine diamond particles of a certain size on the surface and the hard alloy as the matrix under high temperature and high pressure. Because it cleverly combines the high hardness and wear resistance of diamond with the high strength and toughness of hard alloy, it can obtain excellent comprehensive performance and withstand large impact. Can be used for intermittent cutting and the use of large cutting depth, and its isotropic properties, unlike natural diamond as anisotropy, so the use of the blade without adjusting the orientation, and can be repeatedly regrinding, most suitable for non-ferrous metal, non-ferrous metal processing, and can be non-ferrous metal for ultra-precision processing.

1. Application of PCD diamond cutting tools in the production of engine cylinder head and shell

Polycrystalline diamond inserts are suitable for processing high silicon aluminum alloy, quenched steel, and other high-hardness, wear-resistant materials. They can also process non-ferrous metals and alloys; their life is 50 ~ 100 times higher than carbide tools. However, under high-temperature conditions, iron group elements and carbon atoms have an affinity, resulting in cold welding and sharp tool wear, which is unsuitable for processing iron group metals.

The material grade of the cylinder head is AC4B. The strength of the aluminum alloy material is much higher than that of ordinary aluminum alloy material. Therefore, many PCD and PCBN cutting tools are very useful in cylinder head production, and people can obtain good economic benefits.

The cylinder head OP10 process in the machining center processes the top surface, the bottom surface, and the positioning pinhole. In the hinged positioning pin hole, the use of an internally cooled diamond step reamer, φ11.5-φ13.5-102L each can process more than 25000 pieces, the cutting parameters for the speed 10000r/min, cutting speed 361m/min, The feed rate is 0.18mm and the feed speed is 1800mm/min.

During the finishing milling and semi-finishing milling of the bottom and top surface, the production line uses φ100-150L face milling cutter to process, the number of teeth Z=8, each tooth is diamond cutter head, cutter number T1202, 7-02711-02, and the cutting parameters are 10000r/min, 3142m/min, 0.96mm feed. Feed speed 9600mm/min.

Cylinder head OP40 process in the machining center processing inlet, exhaust valve conduit seat bottom hole, and spark plug hole, the use of internally cooled diamond reamer, tool number T4106, specifications of φ12.8mm, φ14.5mm, φ21.2mm, φ23mm, φ26mm tools can be processed more than 3000 ~ 5000 pieces each time. The cutting parameters adopted are speed 6000r/min, cutting speed 241m/min, feed rate 0.36mm, and feed speed 2160mm/min.

The cylinder head OP80 process processes the inlet and exhaust valve guide seat bottom holes and sparks plug holes in the machining center and adopt internally cooled diamond or cubic boron nitride compound reamer during processing, as shown in Table 1.

Tool Table of Exhaust valve guide base hole and spark plug hole machining as follows,

 Figure 1 shows the insert model is APHX100304ALU, which is used in the 4G13 engine cylinder head production line.

2. When processing cylinder head and shell, the influence of the formation of chip tumor on the quality

With pcd tools cutting cylinder head and shell and other non-ferrous metals, if not cutting fluid, usually will produce a chip tumor; cutting speed change affects the height of the chip tumor; when the cutting speed is low, the size of the chip tumor is large, cutting speed is more significant than 314m/min, the chip tumor tends to be stable, the height change is not practical, indicating that low cutting speed, cutting temperature is relatively low. It is more suitable for accretion tumor growth, and the height value of accretion tumor is relatively stable at a low rate and unstable at high speed.

(1) The blade's microscopic defects directly affect the chip tumor's height. For example, under the same conditions, the size of the chip tumor of the complete blade is 5mm, while the height of the chip tumor with a slight chipping edge is 18mm. When the feed rate is minimal, the height h of the chip tumor is large, the value of h is minimum when f=5mm/r, and the importance of h slightly increase when f increases. The roughness of the machining surface should be reduced to eliminate or minimize the chip tumor, and the use of cutting fluid can achieve the above purpose.

When machining rugged aluminum, jet gasoline as cutting fluid can significantly reduce the machining surface roughness, and under low speed, the surface roughness is also minimal, then the cutting speed has nothing to do with the machining surface roughness; In the production of aluminum alloy, copper processing, using cutting fluid can eliminate the influence of chip tumor.

(2) PCD precision cutting chip tumor influence on cutting force and machining surface roughness precision cutting cylinder head and shell, low-speed cutting force, cutting force decrease sharply with the increase of cutting speed, cutting linear speed reached 200 ~ 300m/min, cutting force remains the same, chip tumor high cutting force, chip tumor hours cutting force is small, And the rule of ordinary cutting steel is just the opposite of PCD common cutting steel, chip nodules can increase the actual front Angle of the tool, so the chip nodules increase can reduce the cutting force, and the cutting force increases when the ultra-precision cutting. Ultra-precision cutting nose chip nodules instead of cutting edge, chip nodules and machining surface intense friction to increase the surface roughness, machining surface roughness is directly related to the height of chip nodules, that is, chip nodules height, surface roughness, chip nodules hours processing surface roughness is also tiny. The relationship in cutting force and cutting speed is shown in Figure 2.

3. Application of PCD diamond tool in the production of an engine housing

Polycrystalline diamond cutters have been widely used in the shell production line, and enterprises can obtain good machining quality and economic benefits.

Automobile engine transmission housing BS15-1701002 and clutch housing BS15-1701001 material for AlSi9Cu3Fe, equipment for processing center SPN50-H.O. For example, OP60 process boring φ62+0.02mm hole using a diamond boring cutter blade, blade type is TPMH110304SE, each knife can process more than 14000 pieces, the cutting parameter is 4109r/min, cutting speed 800 m/min, feed rate 0.10mm, feed speed 411mm/min.

Clutch shell T25, T26 station reamer φ6mm hole using an internal cold diamond reamer, specification is φ6-55L, in the machining center, SPN50-H.O using speed 5539r/min, cutting speed 750m/min, feed 1108mm, cutting depth 0.10mm, Each blade replacement can process 12,000 products.

Diamond blades GDCN2004ZDTR1 and GDCN2004PDFR3 are super hard tools used for shell processing. After the unique fixture design, we used a high-precision EWAG tool grinding machine to grind diamond blades in batches.

When the diamond reamer machining shell transmission R-2 process is used, it is easy to have the phenomenon of the tooth breaking at the end teeth and cause the direct scrap of the tool. Adding two R=10mm arcs on the chamfering part of its end can improve the tool life.