Diamond Teeth vs CarbideImpact to Cutterheads,

Influencing the Paving Operation

Randy DobsonDavid PetersonCaterpillar Paving

Topic• Diamonds vs Carbide

Evolution of Cutting Tools

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Cat® Diamond Bits: Anatomy

• Polycrystalline Diamond Powder• Tungsten Carbide Substrate• Sinter the two elements together using a

proprietary high pressure/high temperature press process to form the StingerTM tip

• Braze together the tip, carbide bolster, and hardened steel body

Each phase of this design acts as building block to provide

longer wear through improved thermal characteristics.

Worn Drum Cutting a Crown

• Worn carbide tool holders can also create another issue• Typically, the rotating tools in the center of the drum will

see more material flow• This can create a crown in the milled surface• This issue is somewhat corrected by the mold board, but

the mold board can then wear to the crowned shape

Worn Carbide HoldersImage of a “crown” situation

Cat® Diamond Bits: Features• Asphalt Milling Applications• Proprietary One-Piece Design

− Replaces the need for a tool holder• Non-Rotating Bit

− Because the StingerTM tip is wear resistant there is no need for the bit to rotate and more uniform wear provides a better cut

• Bits available to fit most drumtypes:− Cat− Wirtgen HT11− Kennametal− Sollami− NovaPick

Cat® Diamond Bits: Benefits

Cat® Diamond Bits: Additional Benefits

Diamond Teeth Stay Sharp• Reduced fuel consumption• Reduced rotor drivetrain

loads• Less vibration• Longer structural life• Component life• Improved operator comfort

Smoother roads, better fuel economy, lower vibration

FUEL DATA RESULTS

14.9% Fuel Savings

Want Smoothness? Let the Paver Do It

• Old School –the paver can fix anything

• How much can the paver fix?

Current road milling specs

Specs of most Road Agencies for road resurfacing is fixed depth milling− Road contractors gets paid by the SY and have no incentive to improve the

road profile

Current milling operations do NOT improve the longitudinal road profile

Averaging Systems for Smoothness

• SAS Systems average the grade being milled

• Different lengths of averaging skis – 9 m to 12 m (30 – 40’)

• Limit milling speed to 20 m/min (60 ft/min)

Plan Work To Meet Job Requirements

Restoring Elevations• Smoothness specification

usually tied to bump detection

• Cold planer should do the bulk of the smoothness improvement

• While also providing good texture

Plan Work To Meet Job Requirements

Creating Profile (Slope)• Cold planer has same

slope capability as a paver

• Whenever possible, cold planer should use automatic slope control to create specified profile

Condition of Milled Surface

• Properly milled surface simplifies the paving process

• Improper milling creates problems for the paving process

• What problems do you see?

Best Practice – Drum SpeedDrum speed vs. Travel speed

•Consider a reasonable ratio of drum rpm to travel speed to maintain quality•Most drums turn about 100 rpm•When the machine moves forward, a tool striation mark is created approx- 3.5” to 4” long (10 cm)•When the travel speed exceeds the drum rpm, the machine outruns the drum

Future for Paving Contractors

• More fine and micro milling requirements on horizon• Growth for asphalt recycling and related savings• Improved wear course life as technology improves• Better roads for less dollars• Better roads are safer, more fuel efficient, and will

provide growth opportunities and income for our industries for generations.

Thank You….

Copied from a California D.O.T. bid requestAdd between the 5th and 6th paragraphs of section 15-5.01C(1):

Micro milling equipment must:1. Have a minimum concrete removal depth of 0.04 inch2. Provide a surface relief of at most 0.045 inch3. Provide a 5/32-inch grade tolerance4. Produce consistent depth of texture in the finished surface

Micro milling equipment must have:1. 3 or 4 riding tracks2. Automatic grade control system with electronic averaging having 3

sensors on each side3. Conveyer system that leaves no debris on the bridge4. Drum that operates in an up-milling direction5. Bullet tooth tools with polycrystalline diamond enhanced cutting tips