Visual Inspection of Self-Pierce Riveting Systems for the Automotive Industry By Paul Johnson (p.johnson1@ljmu.ac.uk) Supervisors: Dr Francis Lilley, Professor David Burton.

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!)

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.

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.

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

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.

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.

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

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.

SLIDES REMOVED FOR CONFIDENTIALITY

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.

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.

SLIDES REMOVED FOR CONFIDENTIALITY

Thank You!