Mike Bussard General Superintendent PR Systems inc The Heart Of Cold Milling Machines A cold milling machines most important tool is the milling drum Rotating pointattack cutting ID: 537481
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Slide1
Milling & Micro Milling
Mike Bussard
General Superintendent,
P.R. Systems,
inc.
Slide2
The Heart Of Cold Milling Machines
A cold milling machine's most important tool is the milling
drum.
Rotating point-attack cutting
bits
are inserted in
toolholders
that are fastened onto the drum body
.
The texture of the milled surface is determined by the
bit
spacing, which is the distance between one cutting
bit to
the next.Slide3
The Milling Drum:
Standard Drum
Standard milling drums with a tool spacing of
5/8”.
Ideally
suited for the removal of individual layers or complete pavement structures
.This drum is used 99% of the time
Micro DrumMicro fine milling drums with tool spacing's of up to 1/4”. Ideally suited to remove a very thin layer of the surface to restore the pavement`s evenness for thin lift overlays. Skid ResistanceSlide4
Surface Comparison
Standard Milled Surface
Micro Milled SurfaceSlide5
Standard Drum Pattern
5/8” Bit spacing
Can be used for complete removal up to 14”
Most common practice in todays mill & fillSlide6
Traditional Mill ProcessSlide7
What is Micro Milling?
Roughly 3 times the cutting bits of a standard drum
Best if used from 0”-2” milling depths
Used when surface texture matters the mostSlide8
Micro Mill ProcessSlide9
Ridge To Valley Depth (RVD)
Traditional Drum RVD 5/16” or 8mm deep
Micro Drum RVD 3/32”- 1/8” or 3 – 4mm deepSlide10
Micro Milling Results
Up Close Micro Milled Surface
RAP From Micro MillingSlide11
Micro Mill Advantages
Shallow grooves and small vertical edges allows you to open to traffic
Can grind entire job complete before paving
Creates a smaller RAP size
Bump Repairs
Research shows better adhesion for asphalt
When applied correctly micro milling can put IRI values in bonus $$$ RangeSlide12
Determining Factors For Surface Texture/Surface Pattern
Bit Spacing (From 1/4” to 5/8”)
Wrap Configuration
Forward Speed
RPM
Diameter of Drum, (Typically set by manufacturer)
Drum Maintenance (Very Important)Slide13
Cutter Drum Maintenance
Keep from hitting structures!!
Do not use to remove boulders (3” or Larger)
Don’t Replace used holders with new holdersSlide14
Maintaining Cutter Drums
New
Toolholder
vs Used
ToolholderSlide15
Micro Mill With Multi Plex Sensing
Multiplex systems are used to measure sustained, stretched-out unevenness and combine multiple sensors on one or both machine sides (e. g. cable, ultrasonic, cylinder sensor). Using the average value of the connected sensors, the current milling depth is calculated with high precision. Longitudinal waves can thus be highly compensated for. The system is especially suited towards fine milling work
.
With the Multiplex levelling system, sensor signals are calculated to arrive at an average differential value. This enables unevenness to be smoothed out considerably
. Slide16
Questions?