2009 CAFA Convention February 13 – 16, 2009 Indian Wells, CA CAFA 2009 Coated Abrasive Components Coated Abrasive Components and Their Effect on Performance February 14, 2006 Presented by Mark Boudreau
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
CAFA 2009
Coated Abrasive Components Coated Abrasive Components
and Their Effect on
Performance
February 14, 2006
Presented by Mark Boudreau
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Top Size/Stearate
Size Coat
Typical Coated Abrasives Construction
Top Size/Grinding Aid – Third layer grinding aid to reduce friction and heat.
Stearates help prevent loading on soft materials.
Size Coat
Size Coat – Hide glue, Urea resin, or Phenolic resins.
Grain
Backing
Base Coat
Base Coat – Hide glue, Urea resin, or Phenolic resins
Backing – Cotton, Polyester, Poly-Cotton, or Paper
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Cloth Manufacturing
• Produced by spinning of fibers into a filament that is 20 – 30 mm long.
• Filaments are spun into yarns.• Filaments are spun into yarns.
• Yarn is woven into raw cloth.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Cloth Manufacturing
• Warp is the yarn running the length of the material.
• Weft is the yarn running the width of the material.
• Weft yarn is weaved over and under the Warp yarn in ratios of 1:1, as high as 1:4, with 1:2 the most common.
• Typically the Warp (length) yarn is larger, and therefore stronger, then the Weft (width) yarn.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Backing Types
Cotton:
– Lower tensile strength due to the non-elastic (low stretch) characteristic of cotton.
– Low tear resistance in both Warp and Weft.
– Cotton must be treated to prevent migration of the base coat resins into the cloth which creates brittleness.
– The treatment of the cotton is detrimental to creating a mechanical bond that optimizes grain retention.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Backing Types
Polyester:
– Excellent strength and durability due to the elasticity.
– Tear resistance of the width due to the larger threads – Tear resistance of the width due to the larger threads of the Warp.
– Polyester does not require treatment to prevent brittleness.
– The untreated cloth provides a mechanical bond for optimal grain retention.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Backing Types
Poly-Cotton:
– Mixture of polyester and cotton fibers to create filament which is spun into yarn.
– Typical ratio of polyester to cotton is 65% to 35%.
– Hybrid backing has benefits of both polyester and cotton with good base adhesion and low stretch.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
60
80
100
120
0
20
40
Y X T J F E
Cloth backing type
Cloth backing type and stiffness
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
200
250
300
350
400Weight of paper g/m
2
0
50
100
150
200
A B C D E F G
Paper type
Weight of paper g/m
Paper type and weight
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Summary of Grain Characteristics
CeramicZirconia AluminaA/O & S/C
• Single crystal
• Cut rate decays at
start of grinding
• Fracturing - Dulling
• Brittle
• Billions of crystals
• Cut rate remains constant
for 75% of grinding life
• Self-sharpening grain
provides more aggressive
cut
• Tough
• Multi-crystal
• Cut rate decays at
start of grinding
• Self-sharpening
• Tough
CeramicZirconia AluminaA/O & S/C
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Grain Sizing
• The ANSI, FEPA & JIS scales
have grain size differences at
the fine and coarse ends of the
scales
FEPA P
(European Std.)
ANSI
(U.S. Std.)
JIS
(Japanese Std.)
AVG. GRAIN
DIAMETER (µµµµm)
P16 1616
1292
P20 2020
973
P24 2424
743
P3030 30
626
P3636 36
523
P4040
40 412
P5050
50 328
P6060 60
262scales
– JIS separates from ANSI
and FEPA coarser than 36
grit
– ANSI separates from FEPA
& JIS finer than 240 grit
• Micron grading is based on the
average size of the grain
diameter
P80 80 80 196
P100 100 100 157
P120 120 120 122
P150 150 150 98
P180 180 180 76
P220 220 220 66
P240 240 58
P280 240280
52
P320320
46
P360 280360
40
P400 400 35
P500 320 500 30
P600 600 26
P800 400 22
P1000 500800
18
P1200 600 1000 15
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Evolution of Bonding Systems
Hide Glue:
– Water soluble (non-waterproof).
– Elastic characteristics creates a passive grain presentation resulting in uniform finishes.presentation resulting in uniform finishes.
Urea Resin:
– Cheaper than hide glue.
– Water resistant characteristics.
Phenolic Resin:
– Most durable waterproof bond.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Grinding Aids
Cryolite:
– Sodium Hexafluoroaluminate, Na3AlF6.
– Added into size coat for heat dispersment on metal enhancing performance 10% - 20% as a lubricant enhancing performance 10% - 20% as a lubricant reducing friction.
Top Size:
– KBF4 also known as Potassium Fluoroborate.
– Typically used as a third layer resin to reduce heat in grinding high alloy steels such as stainless steels, titanium, and inconel.
– Adds no benefit to mild steels.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
BackingElectrode
Electrostatic Coating of
Coated Abrasives (schematic)
Grain Conveyor Belt
Electrostatic FieldAbrasive Grain
Electrode
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Conventional
Abrasive
Coating Technologies
Close Coat
100% Grain Coverage
Open CoatAbrasive
Split Coated
Abrasive
-Higher grinding forces per grain
-Enhanced grain regeneration
-Designed for light to moderate
pressure applications
Open Coat
25% - 80% Grain Coverage
Split Coat
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
10 lbs Force
2 lbs Force per Grain
100% Coverage
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
10 lbs Force
2.5 lbs Force per Grain
75% Coverage
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
10 lbs Force
3.33 lbs Force per Grain
50% Coverage
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Coated Abrasive
Product TypesProduct Types
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Product Types - Supported
• Flap Discs
• Spiral Bands• Spiral Bands
• Discs
• Belts
• QTD
• Body Cones
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Product Types - Unsupported
• Flap Wheels
• Sanding Stars• Sanding Stars
• Overlap Discs
• Slotted Discs
• Rotofinishers
• Slashed Loadings
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Product Types - Wrapped
• Cartridge Rolls
• Cone Points• Cone Points
• Square Pads
• Cross Pads
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Common
Coated Abrasive Coated Abrasive
Problems
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Loading• A loaded abrasive shows
metal packed in between
the abrasive grains
• Most commonly • Most commonly
encountered with non-
ferrous metals
• Can be inhibited by use
of Grease, Calcium
stearate or open-coated
abrasive.
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Stripping - Shedding• When an abrasive
material strips or sheds,
the grain is pulled away
from the backing
• Most often encountered
during high pressure on
the individual grain points
• Consider using 100%
coating on polyester
backing
2009 CAFA ConventionFebruary 13 – 16, 2009
Indian Wells, CA
Glazing • Glazing is caused by heat
build up due to friction
created by the dulling of the
abrasive grain.
• Most commonly encountered • Most commonly encountered
with harder alloy metals such
as titanium, inconel, and
harder stainless.
• Reduce cutting speeds, top-
size, ceramic grain, open or
split coat abrasive.