1. Visual Inspection of Self-Pierce Riveting Systems for the Automotive Industry
By Paul Johnson
Supervisors: Dr Francis Lilley, Professor David Burton.

2. Overview Self-Pierce Riveting Why SPR? SPR Problems Current Technology
Technology Problems
Project Objectives
Project Status
Conclusions & Future Work
A problem to solve… (this means you!)

3. Joint creation process.
Self-Pierce Riveting
Mechanical joining process / aluminium
Handheld, pedestal or automated
High speed, single operation, no prep
Fully pierce top materials & partially pierce bottom material
Joint creation process.

4. Self-Pierce Riveting
A cross section of a successful SPR joint. A semi-tubular rivet joining three sheets of aluminium.
Animated Joint creation process.
C-frame which accommodates the tooling.

5. Doidge Type 120 Riveting Machine
Self-Pierce Riveting
Doidge Type 120 Riveting Machine
impact riveting machine
semi-tubular, tubular, bifurcated
steel, brass, copper, aluminium and light alloy
semi-tubular steel rivets
3.1mm diameter / 7.4mm length
aluminium grade 1200 (BS1470:1987)
Doidge Type 120 Riveting Machine

6. EU Emissions Directive 70/220/EEC.
Why SPR?
reduce emissions
lighter vehicles
smaller engines
EU emissions regs
directive 70/220/EEC
category M1
passenger vehicles
8 seat max
EU Emissions Directive 70/220/EEC.

7. Why SPR? Traditional joining / steel body
new light weight vehicles (ally)
RSW is impractical for aluminium
lower resistance than steel
consumes more energy due to heat loss
SPR is a viable solution
lower power consumption
creates an air/water tight joint
high speed
no insertion hole and material alignment
pierce and fasten in one operation
Spot weld machine.
Sample spot weld.

8. SPR Problems Poor joint access / dual access
C-frame, die, punch
Quality control of the joint
Predominantly destructive (chiselling, pulling)
Handheld ultrasonic probe
Physical Teardown
One car, ~5000 joints, two men, 30 days
Time, money, delayed quality control

9. Current Technology Driven by… HENROB Ltd increased automation
dissimilar materials
Decline of skilled/cheap labour force
HENROB Ltd
Industry leader for SPR systems
BMW, Audi, Jaguar, Volvo, Chrysler, Mercedes, Freightliner and Hyundai.

10. SLIDES REMOVED FOR CONFIDENTIALITY

11. Project Status (Rivet Status)
Applying camera to
nose for rivet status:
bespoke software
identifies light intensity
requires calibration to ambient lighting
pre-process
inspection point
intensity values
decision
Intensity profile of a missing rivet.
Intensity profile of a single rivet.
Intensity profile of a double rivet.

12. Project Status (Mat. Depth)
Applying camera and laser to
identify material depth
physical filters
image processing
identifies laser stripe
thickness in mm and px
pre-process
requires joint calibration
lens
distance from material
ambient lighting / threshold
A 6mm stack of sheet aluminium.
As above, with neutral density and red filters.
Screenshot of the process monitoring software.
As above, with threshold and laser line identification.

13. SLIDES REMOVED FOR CONFIDENTIALITY

14. Thank You!