As the main components of the large automobile industry, the brake drum determines its driving safety, so the quality
of the brake drum is particularly important. As the friction coupler of the drum brake, the brake drum should have the
highest and stable friction coefficient as well as the appropriate wear resistance, heat resistance and heat dissipation
in addition to the strength and rigidity required as the member. As the main application materials, gray cast iron is often
used as the heat capacity.
Relevant information indicates that the parameters of the brake drum of the car are as follows:
1 ,Roundness and coaxiality tolerance ≤0.03mm,
2, Radial runout ≤0.05mm,
3,Static unbalance ≤1.5N•cm,
4, surface roughness≥Ra3.2
Conventional tools are difficult to meet the market's demand for shape tolerances. In this case, Halnn superhard CBN
tools can be used to not only easily meet the shape tolerance and surface roughness requirements of the brake drum,
but also to efficiently process and improve production efficiency.
With the increasingly fierce competition in the brake drum industry, tool materials in the process of rough brake drums
must not only ensure high surface quality, but also achieve high-speed cutting, improve production efficiency, reduce
production costs, and improve the company's Self-competitive. At this time, the CBN inserts BN-S300 grade is selected,
which can easily realize high-speed cutting, and ensure product quality and reduce production cost.
BN-S300 grade belongs to the solid CBN insert, which has excellent wear resistance, heat resistance and fracture resistance,
making it widely used in the field of rough brake drums.
Take the BN-S300 grade rough brake drum as an example:
Workpiece material: gray cast iron,
Workpiece hardness: HB180-241,
Surface finish: Ra3.2,
Inserts Grade: BN-S300 CNMN120716,
Cutting parameters:
Cutting Speed (Vc)=280m/min,
Feed Rate(Fr)=0.9mm/r,
Cutting Depth(ap)=2.5mm.
Compared to coated carbide inserts: the cutting speed of the Halnn superhard BN-S300 grade CBN insert is 2.8 times
that of the coated tool, and the feed rate is 2 times, the tool life is 15 times for the coated tool.
Tool material
|
Feed Rate
Fr (mm / r)
|
Cutting Speed (Vc)
（m/min） |
Tool life
|
|
Halnn superhard BN-S300 grade
|
0.9 |
280 |
75 pieces / edge
|
|
Coated carbide insert |
0.45 |
100 |
5pieces / edge
|
Remarks:
(1) When using the BN-S300 brand rough car brake drum, it is necessary to equip with the professional machine clamp
indexable tool holder application;
(2) BN-S300 grades should be processed by dry cutting as much as possible, and vice versa.