diamond teeth vs carbide impact to cutterheads...
TRANSCRIPT
Diamond Teeth vs CarbideImpact to Cutterheads,
Influencing the Paving Operation
Randy DobsonDavid PetersonCaterpillar Paving
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
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: 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
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