Machining gray cast iron CBN insert for CNC Lathe
Part 1 The characters of gray cast iron
(1) Poor strength;
(2) Hardness: a range in tensile strength.
(3)Low notch sensitivity;
(4) Good reduction shock;
(5) Good anti-friction properties.
As its low cost, the production process is simple, so it also was widely used in auto parts, such as brakes, brake drums, flywheels. Some gray cast iron parts belong consumables, manufacturers will have large demands. Improving the processing efficiency and the costs become very important. So it is very important to choose the most suitable inserts material to machine the gray cast iron parts.
Part 2 How to choose inserts machining gray cast iron for CNC Lathe
Currently, there are 3 kinds cutting tools can be used for machining gray cast iron for CNC Lathe:carbide insert, ceramic insert and CBN insert.
(1) Carbide insert: Carbide insert was sensitive to the linear velocity.when machining gray cast iron with high speed, the tools lifetime will be low, which will result a higher frequency for change the insert, and ultimately affect the
processing efficiency and increase the insert costs (choose carbide tools for small quantities machine the gray cast ironwaseconomical choice).
(2) Ceramic insert: the hardness of ceramic insert is higher than carbide insert, but as its brittle, white tissue easily chipping when meet hard spots,It is well for ceramic tools for finish machining or large allowance process.
(3) CBN insert : CBN insert has a higherhardness than carbide insert and ceramic insert, traditional CBN insert has bugs in brittleness. But Non-metallic binder BN-S30 CBN insert has a better toughness, higher hardness, better wear resistance, strong impact toughness, and can ensure part accuracy requirements while enabling high-speed cutting,can machine the parts when meet hard spots and white tissue without annealing directly.
The Cutting parameters of CBN insert machining gray cast iron
|
The material of machined parts |
CBN inserts cutting parameters and grade |
|
Cutting speed（m/min） |
Cut depth
(mm) |
Feed rate
（mm/r) |
Insert grade |
|
Gray cast iron |
200-500(rough machining) |
1-10 |
0.2-1 |
BN-S30 |
|
500~1500（finish machining） |
≤1 |
0.05-0.3 |
BN-S30,BN-K20 or BN-S300 |
The characteristics of BN-S30 Solid CBN insert
(1) High hardness;
(2) Better impact toughness and wear resistance
(3) High-speed cutting.
(4) Both roughing and finishing, Dry cutting and Wet Cutting
BN-K20 and BN-S300 also can be used for finish machining gray cast iron.
BN-K20 CBN insert belongs to welded CBN insert, its advantage is more flexible,
more cutting edge number; excellent wear resistance;
BN-S300 CBN insert belongs to the Solid CBN insert, advantages as follows: excellent sharp type, suit for gray cast iron work pieces finishing and semi-finishing.
Part 3 Application Case: Machining gray cast iron parts with BN-S30 CBN insert
Rough and finish machining Cylindrical and end face on CNC lathe as the out diameter was different (300-419mm),the cutting time was different
One Japan carbide coated inserts: Depth of cut ap = 2.5mm (roughing), ap= 0.3mm (finishing), linear speed 270-330m/min;
roughing and finishing spend respectively 5 minutes and 4.5 minutes.
Non-metallic binder BN-S30 CBN insert: Depth of cut ap = 2.5mm (roughing), ap=0.3mm (finishing),
linear speed 650-720m/min;spend separately 1.5 minutes and 75 seconds.
Part 4 Five Summary
With the development of the technology ,manufacturers will required more on the insert lifetime and the product quality. They would like to improve the processing efficiency and obtain the excellent performance. And it also a big chance for insert manufacturers. Halnn is a professional manufacturer of cbn insert and always devote to researching new cbn insert materials to satisfy the customers’ requirements.And Halnn already become the most famous cbn insert brand in China .
Any question on cbn insert or hard materials machining,please contact with us info@halnntools.com.skype:info@halnntools.com