Statistical Process Control for
Aerospace Manufacturing
Presented by: Ben Allister (Infodream Ltd)
Introduction To Infodream
Software Developer and Continuous Improvement (CI)
competence centre
 Real Time QC Software
Real Time Data
Collection and Process
Control
 Cont Imp. Services
 Strategy and implementation
 Training
Integrated
Advanced Quality
Toolbox
• Bespoke industrial software solutions
 On-site Mentoring & Services
Some of Our Clients
Aerospace
Marignane (FR)
La Courneuve (FR)
Nantes (FR)
Saint Nazaire (FR)
Toulouse (FR)
Filton (UK)
Stade (GE)
Illescas (SP)
Liège
Filton
(UK)
Fareham
(BE)
Méru (FR)
Conflans Ste
(UK)
Méaulte (FR)
Saint Nazaire
Genève
(FR)
Montrichard(FR)
Toulouse
(FR)
Valenciennes
(FR)
Modane
(CH)
Niort (79)
Roche la Molière
Le Havre (FR)
Toulouse (FR)
Genevilliers
Evry - Corbeil
Le Creusot
H.
Issoire
(73)
(42)
(63)
What is SPC
Statistical Process Control (SPC) is a continuous
improvement tool
Reduce waste
 Improve quality
 Increase productivity
 Tells us whether our processes can consistently meet the
customer requirements
 Identifies sources of unwanted variability in the process and helps
us understand the relationship between product & process
 Pro-actively monitors &controls the process to avoid defects and
failures
What is SPC
- Using meaningful data
- To understand a process
- To make it behave the way we want
Understanding Variation
Limit
Limit
Understanding Variation
Limit
Limit
Understanding Variation
Limit
Limit
Understanding Variation
(The Enemy)
Limit
Target
Limit
- Material Waste
- Scrap
- Repair
- Ass’y Problems
- Tight tolerances
- Additional operations
- Increased Inspection
Understanding Variation
USL
LSL
Too Much!
_
X
Understanding Variation
USL
LSL
Better.....
_
X
Understanding Variation
USL
LSL
Best?
_
X
Process Control
May
April
March
Feb
Jan
Process Control
May
April
March
Feb
Jan
Inspection
Product validation - Traditional Inspection
Lower Limit
 Is the part good or bad ?
 Is a concession needed ?
 Is further work needed ?
What about….
 Will the next part be good?
 Does the process need adjusting
Upper Limit
Data Approach
 Quantify how good or bad process is.
 Can tolerances be met?
 How often is inspection needed?
 Is something wrong with the process?
 Should I adjust the process?
 Is ‘Tool A’ better than ‘Tool B’?
Summary
SPC Approach
Traditional Approach
Inspection
Action on the
product
Product
Man
Method
Machine
Product
 Product Inspection
 Rectification
Information on
the process
Action on the
process
Material
Measurement
Environment
 Process control
Key Benefits
- Reduce waste due to Scrap & Repair
- Reduce NVA such as Inspection and unnecessary
process steps
- Provide objective data for continuous improvement
and new product development
- Create a LEAN environment by ensuring a stable
and consistent process
Have confidence your process will achieve
customer requirements – First Time & Every Time
Aerospace
Aerospace invests large sums of money on metrology systems
 CMM’s
 Laser Trackers
 Measurement arms
 Machine probes
 ……..
Is the data being put to good use?
Or
Misconceptions
“ SPC is only for automotive”
“ You can’t pull into the hard
shoulder at 40,000 feet”
“ SPC is can’t be used for low
volume production”
“ Aerospace tolerances are too
tight for SPC”
“ CAA doesn’t allow SPC”
Aerospace SPC
Some products are low volume......................but
 There are lots of repeated features
on a large component
 Many parts are very similar and
made using the same process
Rib 1
Rib 2
Rib 3
Rib 4
The solution is to carefully group characteristics, products &
processes and use the correct SPC Tools.
Aerospace SPC
But, long runs and high volume do exist!
Some elementary parts are produced in high quantities
 Blades
 Stringers
 Ribs
 Fastenings…
Lots of Key manufacturing processes are long run or continuous
 Drilling
 Bath treatments
 Painting
Aerospace SPC
DFM
- Knowledge transfer
- Tolerance validation
- Statistical Tolerancing!
Process
Qualification
- New Processes
- High Risk
Equipment
Selection
- New Machines
- Metrology systems
SPC Tools &
Techniques
Process
Improvement
- Waste Reduction
- Cost Reduction
- Process Optimisation
Process Control
- Identification of critical
process parameters
- Preventative/early
warning control
Example Project
Presented by: Eric Leblais
Assembly Structures
SPC Integration Leader
Process Overview
Contact zone
Contact zone
joggling
Process Overview
Contact zone
Contact zone
Wedges are inserted between
the Keel beam, front lower and
rear lower fuselage sections.
Wedges
Wedges
Process Overview
BEFORE
Measurement of
the referential
system
A0
Assembly of
each work
package
A1
Positioning of the
Keel beam
A2
Gauging of the
joggling
A3
Machining of the
wedges
A4
Drilling and
adjusting of the
wedges
A5
Assembly of the
angles
A6
Improvement Opportunity
Measurement of
the referential
system
A0
Assembly of
each work
package
A1
Positioning of the
Keel beam
A2
Gauging of the
joggling
A3
Machining of the
wedges
A4
 Non-Value Adding process steps
 Additional cost & assembly time
Drilling and
adjusting of the
wedges
A5
Assembly of the
angles
A6
SPC Analysis
USL
LSL
Cp = 2.7
Cpk = 2.3
 Proved Straightness and Joggling Process
was Capable & Consistent.
 Proved that Wedges & Shimming process
were not needed.
Action Implemented
AFTER
Measurement of
the referential
system
A0
Assembly of
each work
package
A1
Positioning of the
Keel beam
A2
Gauging of the
joggling
A3
Machining of the
wedges
A4
Drilling and
adjusting of the
wedges
A5
Assembly time reduction
Assembly of the
angles
A6
~ 10h !
Action Implemented
Measurement of
referential
system
A0
assembly of
each work
package
Lower fuselage of
15/21 section
A1
Positioning of the
Keel beam
A2
Assembly of the
Bond angle
A6
Design Change
 A new definition of the angles was required because of the removal
of the joggling process.
Process Control
 SPC Implemented for Lower fusalage section to monitor & control
process
AFTER
Results & Savings
 Cancellation of the realization of joggling on the 8 angles.
 Cancellation of wedges machining. (32 per Aircraft)
 No more Gauging time. (~1h)
 No more drilling and adjusting of the wedges. (~ 7h)
 No more painting protection of wedges surfaces. (~1.5h)
 No more fettling corrosion on the critical zones.
 New feedback from the assembly to the design office.
Money Gain 8 K€/MSN
8 MSN/month => 64 K€/month
ROI = 3 MSN
Q&A
Ben Allister
ben.allister@infodream.co.uk
Web: www.infodream.co.uk
Questions ?