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Air Blasting with Steel
Abrasives
A Practical Guide to Improving
Productivity
9/13/2012 air blasting with steel abrasives
www.satactics.com
If you can’t measure, you can’t
manage
To follow this program, you will need:
1. some simple tools
2. to measure key operational performance
factors
9/13/2012 air blasting with steel abrasives
www.satactics.com
ESSENTIAL MEASUREMENTS AND
INFORMATION
1. ABRASIVE COST PER TON
2. LABOUR COST PER NOZZLE HOUR
3. FLOW RATE OF ABRASIVE – KG per hour per nozzle – can be average or
specific
4. AIR COST PER NOZZLE HOUR
5. CYCLES ABRASIVE RE-USED
6. AIR PRESSURE AT BLAST NOZZLE – measured with hypodermic needle
pressure gauge
7. MAINTENANCE AND CONSUMABLE COST PER NOZZLE HOUR
8. PRODUCTION RATE – Square meters per hour
9/13/2012 air blasting with steel abrasives
www.satactics.com
Basic Rules and Principles
1) Site Management
2) Abrasive - use the smallest abrasive
particle size that is capable of removing
the contaminant
3) Nozzles – Correct type (Venturi) at the
correct air pressure AND monitor wear
4) Designed air pressure for blasting steel
is 7 bars or 100 psi
9/13/2012 air blasting with steel abrasives
www.satactics.com
Site Management
1. Equipment Audit and daily
check list (e.g. nozzle wear, hose wear etc)
2. Materials handling and
logistics (Removing bottle necks and
constraints)
3. Personnel management and
goal setting (Leadership and innovation at
all levels)
9/13/2012 air blasting with steel abrasives
www.satactics.com
Abrasive Particle Size, Nozzle
Design and Air Pressure
Use the smallest particle size capable of
removing the contaminant – WHY? More
impacts per second increases productivity
Steel grit >< 150 and 400 microns (GH80) will
remove any contaminant if blasted through a
venturi nozzle at 7 Bars (100 psi)
9/13/2012 air blasting with steel abrasives
www.satactics.com
Particle Velocity through a venturi nozzle
Air
500
100µ S/S M/S
400
250µ S/S
300
500µ S/S
120
0 0.1 0.2 0.3 0.4 0.5
Meters
9/13/2012 air blasting with steel abrasives
www.satactics.com
Abrasive Particle Energy = mass
(weight) X Velocity (speed) ²
Energy at 7 bars = 250 X 300² = 225 energy
units
250 micron
Energy at 7 bars = 500 X 120² = 72
energy units
500 micron
9/13/2012 air blasting with steel abrasives
www.satactics.com
Blasting Nozzles are designed to work at 7
bars (100 psi)
Bore Diameter Exit Diameter
14
10.5
Bars
7.0
3.5
0
1 1.2 1.4 1.6 1.8 2.0 2.2 2.4
Area Ratio = exit diameter/bore diameter
9/13/2012 air blasting with steel abrasives
www.satactics.com
Blasting Efficiency decreases with air pressure by
1.25% per 1 psi - 14psi = 1 bar
100%
66%
50%
@ 7 Bar @5.6 Bar @4.2 Bar
9/13/2012 air blasting with steel abrasives
www.satactics.com
Blasting Costs and Productivity - ALFACAMP
analysis
Change Change Change
Change Labour air cost cycles Change
Abrasiv cost per per of air New
e cost nozzle nozzle abrasive pressur Combine
Variables Actual per ton hour hour re-use e (psi) d Actual
R5400
R
Abrasive cost per ton 4,700 R 5,000 R 5,000 R 5,000 R 5,000 R 4,700
R
Labour cost per nozzle hour R 80 60 R 96 R 60 R 60 R 60 R 96
Flow rate of abrasive per nozzle hour (kg) 600 600 600 600 600 600 600
R
Air cost per nozzle hour R 55 55 R 55 R 60 R 55 R 55 R 60
Cycles of abrasive re-use 50 50 50 50 55 50 55
Air Pressure (psi at nozzle) 70 70 70 70 70 85 85
Maintenance and consumables % 12 12 12 12 12 12 12
Production Rate Sq Meters per nozzle
hour 10.0 10.0 10.0 10.0 10.0 13 13.0
9/13/2012 air blasting with steel abrasives
R
Cost per square meter R 22.38 www.satactics.com 20.16
19.20 R 23.63 R R 18.99 R 15.08 R 17.86
A detailed implementation
program to improve productivity
is available at no cost – simply
use abrasives from Simple Active
Tactics
Thank you for your time!
9/13/2012 air blasting with steel abrasives
www.satactics.com
