1. Air Blasting with Steel Abrasives
A Practical Guide to Improving Productivity
11/26/2018
air blasting with steel abrasives

2. If you can’t measure, you can’t manage
To follow this program, you will need:
some simple tools
to measure key operational performance factors
11/26/2018
air blasting with steel abrasives

3. air blasting with steel abrasives www.satactics.com
ESSENTIAL MEASUREMENTS AND INFORMATION
ABRASIVE COST PER TON
LABOUR COST PER NOZZLE HOUR
FLOW RATE OF ABRASIVE – KG per hour per nozzle – can be average or specific
AIR COST PER NOZZLE HOUR
CYCLES ABRASIVE RE-USED
AIR PRESSURE AT BLAST NOZZLE – measured with hypodermic needle pressure gauge
MAINTENANCE AND CONSUMABLE COST PER NOZZLE HOUR
PRODUCTION RATE – Square meters per hour
11/26/2018
air blasting with steel abrasives

4. Basic Rules and Principles
Site Management
Abrasive - use the smallest abrasive particle size that is capable of removing the contaminant
Nozzles – Correct type (Venturi) at the correct air pressure AND monitor wear
Designed air pressure for blasting steel is 7 bars or 100 psi
11/26/2018
air blasting with steel abrasives

5. air blasting with steel abrasives www.satactics.com
Site Management
Equipment Audit and daily check list (e.g. nozzle wear, hose wear etc)
Materials handling and logistics (Removing bottle necks and constraints)
Personnel management and goal setting (Leadership and innovation at all levels)
11/26/2018
air blasting with steel abrasives

6. 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)
11/26/2018
air blasting with steel abrasives

7. air blasting with steel abrasives www.satactics.com
Particle Velocity through a venturi nozzle
Air
500
M/S
100µ S/S
400
250µ S/S
300
500µ S/S
120
0.1
0.2
0.3
0.4
0.5
Meters
11/26/2018
air blasting with steel abrasives

8. 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
11/26/2018
air blasting with steel abrasives

9. 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 1
1.2
1.4
1.6
1.8
2.0
2.2
2.4
Area Ratio = exit diameter/bore diameter
11/26/2018
air blasting with steel abrasives

10. 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
11/26/2018
air blasting with steel abrasives

11. Operating costs per nozzle hour Square meters cleaned per hour
Blasting Costs and Productivity - ALFACAMP analysis
Variables
Actual
Change Abrasive cost per ton
Change Labour cost per nozzle hour
Change air cost per nozzle hour
Change cycles of abrasive re-use
Change air pressure (psi)
New Combined Actual
Abrasive cost per ton
R5400
R 4,700
R 5,000
R 4,700
Labour cost per nozzle hour R R R R
Flow rate of abrasive per nozzle hour (kg)
600
Air cost per nozzle hour R R R
Cycles of abrasive re-use 50 55
Air Pressure (psi at nozzle) 70 85
Maintenance and consumables % 12
Production Rate Sq Meters per nozzle hour
10.0 13
13.0
Cost per square meter
R 22.38 R R R R R R
Instructions
1) You will need to measure the variables of your existing operation and record them in the "Actual" Column
2) Enter a new cost for abrasive, labour and air cost and see what effect it will have on overall cost per square meter
3) Look at improving abrasive recovery systems to increase the number of cycles of abrasive use and enter this number
4) Investigate ways to improve nozzle operating air pressure and enter the new operating pressure
5) Refine the operating system targeting the largest savings first (usually air pressure)
6) Target new combined costs after adjusting variables through preformance management systems
Cost calculations are derived by:
Operating costs per nozzle hour
Square meters cleaned per hour
11/26/2018
air blasting with steel abrasives

12. air blasting with steel abrasives www.satactics.com
A detailed implementation program to improve productivity is available at no cost – simply use abrasives from Simple Active Tactics
Thank you for your time!
11/26/2018
air blasting with steel abrasives