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Cutting Tool Wear Analysis

Cutting Tool Wear Analysis

The use of cutting tool under different pavement condition
and the operating style of the driver will affect the ser vice
life dramatically. For the following key analysis, please refer

(Normal used condition)

(1) Cutting tool is hat-shaped

The cutting tool wears fine, the tungsten steel tip is
almost completely gone, and the tip wears out radially.


(2) The washer is being cut

The cutting tool wears fine and radially just like figure 2-1,
but the operator needs to pay more attention as the worn
washer may not protect the tool holder enough.


(3) The cutting tool has a cylindrical shape

The cutting tool wears fine, the rotating performance is good,
but the tip become shorter, in this situation, the cutting tool
need to be replace.


(4) Cutting tool is hat-shaped

The cutting tool wears fine, washer slightly wear, tip wear out
badly, steel body is worn out 1/3. As you can see this cutting tool rotates well.


(5) Tip fracture

Scenario: After heavy work, as the below picture shown,
the carbide tip fractured.
Solution: Steel bars or large stones under the ground
                            cannot be detected in advance. It is difficult to avoid
                            cutting tool breakage due to excessive construction.


5-2 There are two factors cause the tip to break

Excessive usage of the cutting tool will cause tip fracture. The
milling pavement contains non-millable (suggestion: non-millable
to non-workable) or extremely hard objects. Ex. Steel bar, Rocks,
Gutter Cover.

Due to inefficient cooling water spray while milling process will
cause the cutting tool to generate too much heat and finally overheat.
In this situation, the fractured tip will always accompany the overheated
sign on the steel body.


To avoid too much heat, the water spray system should check regularly
or increase the among of cooling water, slowing the milling process.
Because the walking speed and the milling drum rotating speed will decide
the depth of cutting tool.
The longer the milling distance, the higher the friction, finally lead the
cutting tool overheating.

(6) Steel body partial wear

Compare to the tip, the steel body and washer are worn out badly.

Possible Cause: The paving machine walks too fast, the pavement
too soft, or the conveyor system ejects the waste material too slow.
The waste material cannot be ejected properly from the chamber
and continuing turning with the milling drum finally damage the
cutting tool. In this situation, because of too much waste material
is crushing in the milling chamber, it will finally cause the cutting
tool wear out partially.

There are 2 solutions:


1.Apply more tungsten steel in the cutting tool.

2.Slowing the paver walking and operating speed.


(7) Excessive lengthwise wear

The cutting tool has been completely worn out and its service life
has been exceeded, and the tungsten steel has been completely
worn out as well. The contact surface of the tool holder is severely
worn due to the wear of the washer and the tip of the cutting tool.

Cause: The cutting tool had already worn out and it was discovered
too late.

Solution: During construction breaks, operator should check the
cutting tool regularly to avoid the service time expiration.

(8) Badly worn

The cutting tool is in cone-shaped, and the cutting tool is worn out
badly from one side. Mainly due to poor operation performance.

Cause: Inefficient cooling water spray causing dust stuck inside the
tool holder as a result the cutting tool cannot rotate freely and increasing
the worn out speed of tool holder.

Solution: Water spray system should be checked regularly. Once
the cutting tool has been removed, one should check the tool
holder is clean without any dust or is there any partial wear on the
tool holder.


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