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Grinding• stock removal• dimensional control
Microfinishing • uniform,
Superfinishing • down to sub-1 micron Ra.
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• Stock removal • Dimensional accuracy• Uniform surface for further polishing.
Roll Grinding Diagram
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Belt Grinder
Materials Commonly Ground with Man-Made Diamond and
CBN
CBN Man-MadeDiamond
Tools SteelsHardened Alloy Steels
Bearing SteelsSuperalloys
Tungsten CarbideTitanium Alloys
GlassCeramicsCermets
CompositesDie SteelCast Iron
KGS Telum CH – Flexible Resin Diamond Tools
Product description: • Hard resin bonded belt• open structured surface • many leading edges allow good cut rate• with coolant & swarf channels. • colour coded for easy identification.• 60 Mesh; 120 Mesh; 200 Mesh; • 400 Mesh; 800 Mesh; 1500 Mesh • 3000 Mesh.
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KGS Telum CH – Flexible Resin Diamond Tools
A consistent, predictable process. Makes achieving finish specs easy. Delivers required geometry tolerances. An easy-to-use, adaptable solution. Faster dimension & finish attainment. Less operator skills required.
KGS Product Data Sheet
Process Parameters - Surface Finish – Ra Values
Roll grinding with KGS Telum CH Diamond Belts – Tungsten Carbide - HVOF Spray Coating
2.50 2.10 1.60
0.60
0.20
0.10
0.05
0.02
0.01
0.10
1.00
10.00
GY - 50 GN -60
BK - 120 RD - 200 YE - 400 WH -800
BL -1500
OR -3000
Finish Achieved with KGS TELUM CH Belts onHVOF Tungsten Carbide Cylindrical Parts
Ra: µm
SURFACE FINISH RESULTS - per Grit Mesh
Thickness of WC material removed per pass
Colour-Mesh Ra: µm Ra: µin Pulley Micron Thou
GY - 50 2.50 100.00 Fixed 72.0 2.83
GN - 60 2.10 84.00 Fixed 65.0 2.56
BK - 120 1.60 64.00 Fixed 41.0 1.61
RD - 200 0.60 24.00 Fixed 23.0 0.91
YE - 400 0.20 8.00 Floating 3.5 0.14
WH - 800 0.10 4.00 Floating 1.5 0.06
BL - 1500 0.05 2.00 Floating 0.6 0.02
OR - 3000 0.02 0.80 Floating 0.2 0.01
Roll grinding with KGS Telum CH Diamond Belts – Tool Post Grinder Settings - Belt Grinding Machinery
KGS Engineers’ Notes
Process Parameters – Belt Grinding Machinery
KGS Engineers’ Notes
Process Parameters – Floating or Fixed Head
Floating or Fixed Head
Depending on machinery set-up options available for the TPG
FIXED HEAD (Totally Rigid – controlled In-feed)) FLOATING HEAD (Variable Pressure & In-feed) FREE RUNNING (Not grinding on the Pulley)
Each setting affects the grind stock removal and finish.For accurate calibration of 2.5D rolls use Fixed Head.
For slightly conical or curved rolls a Floating Head is generally required.
Floating
Free
PULLEYSHardness and type of Pulley will impact on Ra and stock removal –General purpose serrated rubber rolls with hardness around 60 Shoreare fine for exactly that - general purpose grinding.
For accurate calibration of 2.5D rolls an incompressible non-serrated type is preferable.
This is not so important for the 400 grit down polishing stages.
KGS Engineers’ Notes
Process Parameters – Pulleys
KGS Engineers’ Notes
Process Parameters – Different Materials
Roll grinding with KGS Telum CH Diamond Belts – Surface Finish - HVOF Spray Coating
As a guide – Remember that the previous results are on Tungsten Carbide –Higher stock removal is expected for softer materials such as Chrome Carbide –And a higher Ra and coarser finish for the same parameters.
MICRO-INCHES
TUNGSTEN CARBIDE
CHROME CARBIDE
Colour Grit
Ra: µm Ra: µm
GN - 60 2.42
BK - 120 1.82
RD - 200 0.65 1.30
YE - 400 0.16 0.55
WH - 800 0.09 0.38
BL - 1500 0.05 0.13
OR - 3000 0.02 0.07
TUNGSTEN CARBIDE
CHROME CARBIDE
Colour Grit
Ra: µ"Micro-Inch
Ra: µ"Micro-Inch
GN - 60 96.8 -
BK - 120 72.8 -
RD - 200 26.0 52.0
YE - 400 6.4 22.0
WH - 800 3.6 15.2
BL - 1500 2.0 5.2
OR - 3000 0.8 2.8
KGS Engineers’ Notes
Process Parameters – Pressure
Pressure
• The rigidity and pulley hardness limit the grinding pressure available –
• As will the power rating deliverable from the motor.
• Results are EXTREMELY variable by PRESSURE –
• increasing the grinding pressure stock removal can go up by 50% - And Ra can vary by 25% !
Free Running Belt Grinding
KGS Technical Application Overview
INTRODUCTION - Roll Grinding
Surface Conditioning – Yankee Rollers
The large “Yankee Roller” used by the Pulp Industry is often as large as 18 feet diameter by 21 feet long. This roller can get damaged or lose it’s surface condition. The maintenance of the surface for this & other large rolls can be done by a light grind utilizing the “Doctor Blades”.
This is done In Situ by attaching diamond strips along the Doctor Blade by QRS (Velcro) and turning the roll. By positioning the blade at a suitable angle to get a reasonable pressure – this light maintenance can save substantial downtime that would be incurred during a total re-grind.
KGS supplies QRS strips 2”x48” with a 15 degree angle for this operation – usually in Flexis or Telum Pattern and grits 120, 200, 400, 800.
KGS Technical Product Overview
Introduction - GLAZING
GLAZING –
Insufficient pressure/speed or “Firing” can lead to rounding of the sharp cutting edges of the diamond.
Glazing results in a rounded diamond like a glass bead. This CANNOT be re-sharpened like a wheel which can be dressed to expose fresh diamond
Because this KGS Nickel product is a single layer of diamond.
NICKEL
KGS Metallised
Fabric
Belt Backer
KGS Telum CH – CBN version
To avoid the GLAZING issues found with Diamond Belts
Customers can now benefit from using CBN versions.
CBN belts are suitable for either –
Removing existing Hard Coatings and calibrating the metal surface below the coating.
Or –
Removing existing Chrome plated coatings as preparation for replacement HVOF coating.
KGS Business Unit Precision Tools
Existing Patterns
Colour mesh sizeGreen 60 301µm
Black 120 126µm
Red 200 76µm
Yellow 400 40µm
White 800 20µm
Blue 1500 9µm
Orange 3000 4µm
KGS Technical Application Overview
INTRODUCTION - Roll Grinding
Surface Conditioning - Long Strips
Although some rolls require a high reflective finish and low Ra values – other require a specific surface roughness for friction grip &/or ink or water retention.
During the constant use of these rolls, they tend to lose this surface roughness and become “Polished” during use.
Depending on the coating thickness, some rolls can be “Re-furbished” many times before needing stripping and re-coating.
This can be done by diamond belts or long strips on a “Super-Finishing” machine.
KGS now supplies these long strips with circa 3 feet “TAILS” on a BYW3 (Similar to a conventional SiC belt backer) backer on a 3” keyed plastic tube.
KGS Telum CH
Large rolls for Steel Mills Customers often require coarse Ra values as rough as 3.0 or even 4.2 Ra.
This roll, which is slightly tapered normally takes over 8 hours to finish with a diamond wheel.
KGS Telum CH Diamond Belt System took less than one hour, including set-up, to achieve the required finish.
KEY POINT – KGS can massively shorten cycle times compared to diamond wheel grinding.
HVOF WC Coated Roll for Sheet Metal
KGS Telum CH - Retro fitted belt system !
Customers with large diamond wheel grinders can normally benefit from the belt system at a very low capital investment cost, without the investment in a Tool Post Grinder.
Retro-Fit Belt on Diamond Wheel Grinder
Just fit an extra pulley !
By replacing the diamond wheel with an incompressible pulley – and adding an EXTRA smaller pulley - as shown to the back of this picture. With sufficient tension KGS can manufacture to the customer’s required size.
KEY POINT – This set up gave the same Ra values as the KGS R&D team, and took a fraction of the time to both grind and polish both WC & CrC sprayed coatings..
KGS Telum CH – Caterpillar Hydraulic Rams
Caterpillar is supporting a worldwide program to replace the existing Chrome Coating with a suitable new HVOF Coating such as Chrome Carbide.
Caterpillar Hydraulic Rams – Chrome replaced by HVOF CrC
KEY POINT – Picture shows the first grinding pass with KGS Telum CH red 200 grit Belt running on a Dynabrade Tool Post Grinder (48” x 2” Belt).
KGS Telum CH – Dynabrade Belt Finishing Machine
Caterpillar Hydraulic Rams – Free Running Belt Polishing
KEY POINT – Grinding and calibration is done with the coarse belts on an incompressible pulley, as per the previous slide.
Finishing with the finer belts can be supported by the “Free Running” attachment from Dynabrade.
This system gives great flexibility for the operators to both grind and polish much more rapidly than by using a Diamond Wheel followed by an expensive Super-Finishing Machine
KGS Telum CH – Free running dry
KEY POINT –
Telum CH belts are used dry on special hard coatings with a free running set-up.
The advantage from Telum CH to SiC belts is huge.
Not only has the grinding time been decreased from 6 hours to less than 1 hour, there has also been a high cost saving in Silicon Carbide abrasive belts.
- Coating: SiCAlOx 700Hv and TiOx 900Hv- Finish to achieve: Ra: 1 µm Rt: < 15 µm- Cutting speed: 14 m/sec- Traverse rate: 160mm/min- Roll rotation: 400 rpm
Silicon Aluminium Oxide coating – Free Running Belt Grinding
KGS Telum CH – Dynabrade Tool Post Grinder
KEY POINT –
Customer has not been able to achieve a good result with old type belts used.Telum CH belts gave instantly a good result on HVOF coated parts.Both WC and AlTiO coatings were ground and finished within specification.Customer now uses the set-up on a daily base.
Machine: Dynabrade 64991Coatings: WCCo 1200Hv and AlTiOx 700HvFinish to Achieve: Ra 0.15Cutting Speed: 20m/sTraverse Rate: 95mm/minRoll rotation: 500rpmCoolant: Water and 5% oil
Various HVOF coatings – Belt Grinding
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Seal Manufacturers Specification for Off Road Machinery Hydraulics
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How big is a Micron ?2,000 times size
..0001 Inch.00254 mm
Micron.000039 Inch
.001 mm.001 Inch.0254 mm
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Human Hair.0035 Inch.0889 mm
Micro-finishing & Belt Grinding
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3M film-backed abrasives • Uniform, consistently even finishes • Sub-1 micro inch Ra.
Microfinishing Diagram
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Microfinisher
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GEM Microfinisher System
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Supply
Take Up
New Abrasive
Used Abrasive
Variable Infeed Pressure
Platen
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Microfinishing Application
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Ra Rq
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These three surfaces all have same Ra values
Ra Surface value
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Rp: is the maximum height of the Roughness profile above the mean lineWithin the evaluation length (5 cutoffs)
Rpm: is the mean of the 5 Rp values in The successive cutoff lengths
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Sk: is the measure of the symmetry of theADF curve about the mean line. Negative Skewness indicates a plateau - dominatedSurface, and a positive skewness indicates
a peak – dominated surface.
ADF Curve
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Comparison of Good and Bad Bearing Area
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Flex backing
Nickel pellet
Diamonds
Flexible Diamond Construction
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Lapping FilmAluminum Oxide & Diamond
3M Imperial Lapping Film-polyester film backing-slurry coated- produce consistent Ra finishes.- available in 0.3 - 60 micron grades.
3M Imperial Diamond Lapping Film- to use on hard material: tungsten carbide, thermal or plasma sprayed ceramic.- micron graded diamond particles- polyester film backing- available in 0.1 - 45 micron grades.
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- produce consistent, predictable and repeatable finish- precision micron graded- electrostatically oriented- polyester film backing- resin bonded
3M Microfinishing Film
Properties of Superabrasives and Conventional Abrasives
Thermal Relative
Knoop Compressive Conductivity Abrasion
Material Hardness Strength (psi) Cal/C*cm*s) Resistance
Diamonds 7000-9000 1,260,000 5.0 43
Borazon CBN 4700 945,000 3.3 37
Silicon Carbide 2400 210,000 0.10 14
Aluminum Oxide 2100 500,000 0.08 9
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3M Flexible Diamond Belt- flexible backing- durable and longer life- aggressive cutting action- reduce grinding loads- use on rolls harder than 55-60 Rockwell C
3M Imperial Microfinishing Film- produce consistent, predictable and repeatable finish- precision micron graded- electrostatically oriented- polyester film backing- resin bonded
3M Imperial Lapping Film-polyester film backing-slurry coated- produce consistent Ra finishes.- available in 0.3 - 60 micron grades.
3M Imperial Diamond Lapping Film- to use on hard material: tungsten carbide, thermal or plasma sprayed ceramic.- micron graded diamond particles- polyester film backing- available in 0.1 - 45 micron grades.
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Superfinisher Application
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Microfinisher
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Grades 0.3 to 150 MicronAluminum OxideSilicon Carbide
Diamond
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