7.3 Process steps in the production p‌hase

Specific quality assurance measures in the production p‌hase

1. Logistics (transport, goods receipt, storage, availability of special materials, disposal)

Dispatch tests and test certificate of the manufacturer
Monitor transport
Check and test materials (identity, appearance, rheology, composition, usability, expiry date)
Labelling of containers (date of receipt)
Samples
Monitor storage conditions (temperature, humidity, time, light intensity/ radiation)
Availability of special materials (e.g. tape for marking areas off, warning signs, “wet adhesive” stickers, silicone-free skin-cleaning and skin-care products)
Ban sources of contamination (e.g. silicones; also from gloves, cleaning cloths, lubricants, cleaning and impregnating agents, etc.)
Optimise organisational systems (e.g. for storage)
Heed specifications
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2. Ensure optimum ambient conditions

Mark off the area where work is to be carried out and ensure unauthorised persons do not enter the work area
Protect the work area from contamination via the air
Take measurements in the work area (temperature, humidity, dust, aerosols, gases, light intensity)
Avoid draughts
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3. Acclimatise the substrates, primer and adhesives

4. Test the accuracy of fit

Check the accuracy of fit and tolerances using suitable test and measurement methods (e.g. templates)
Check substrates for other damage and abnormalities
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5. Cleaning

Thoroughly rinse off aggressive cleaning agents
Avoid recontamination (e.g. via contaminated cleaning agents, cloths, gloves)
Prepare a summary of the dependence of the evaporation time on temperature and humidity
When using adhesive tape for masking purposes bear in mind that residues may remain after removing the tape
Measurements (time, pressure, temperature, composition, surface contamination)
Monitor (settings, appearance)
Associated tests (e.g. wetting tests with test inks, contact angle method))
Labelling of containers
Minimise storage and transport times after cleaning
Monitor storage and transport conditions after cleaning
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6. Pretreat surfaces

Never pretreat contaminated surfaces without cleaning them adequately
Only use contamination-free materials (e.g. etching agents, grit for blasting, sandpaper)
Thoroughly rinse off any aggressive pretreatment agents (e.g. etchingagent)
Measurements (time, pressure, temperature, stress, composition, layer thickness, degree of coverage)
Monitor (settings, appearance)
Associated tests (e.g. wetting tests with test inks, contact anglemethod)
Labelling of containers
Minimise storage and transport times after pretreatment
Monitor storage and transport conditions
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7. Primers (also applies for activators, pre-applied activators, etc.)

Strict protection of primers from contamination and moisture, reseal containers immediately
Use coloured materials
Apply the correct layer thickness, avoid applying excess
Prepare a summary of the dependence of the drying time on temperature and humidity
Measurements (layer thickness, degree of coverage)
Monitor (appearance, rhelogy)
Labelling of containers (e.g. date of first opening, shelf-life after first opening)
Minimise storage and transport times after priming
Monitor storage and transport conditions
Monitor storage and transport times
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8. Adhesive stocks

Protect adhesive from contamination and moisture, reseal containersimmediately
Use coloured adhesives
Measurements (temperature, pressure, time, contamination, thorough mixing, rheology, usability)
Monitor (settings, appearance, air contact)
Labelling of containers (e.g. date of first opening, shelf-life after first opening)
Monitor storage and transport conditions
Monitor storage and transport times
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9. Feeding

10. Dosing

Twin cartridge for manual processing; for automatic processing use 2-C dosing and mixing unit
Automatic control circuit sensor-machine
Measurements (pressure, volume, weight, time)
Monitor (settings)
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11. Mixing

- Use coloured components
- For small quantities, twin-cartridge with static mixer or use 2-C adhesives premixed by the manufacturer and stored under cool conditions

m‌ixing ratio

Check the quality of mixing
Stipulate the rinsing interval, maintenance interval, change interval for dynamic mixers
Measurements (progress of the curing, usability, rheology, time)
Monitor (settings, appearance)
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12. Application

Definition of quantity to be applied, application pattern and geometry of the bonding area
Ensure the correct film thickness is applied, especially for solvent-containing contact adhesives
Avoid closed voids which could cause condensation of moisture
Stipulate the maximum processing time
Stipulate the minimumbcuring time
Use coloured / fluorescing adhesives
Automatic control circuit sensor-machine
Measurements (quantity, position, shape, contamination)
Monitor (position, shape)
Associated tests (e.g. wetting tests, bead peel test)
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13. Joining the substrates

14. Fixing

15. Curing

Protect from unpermitted loads/stresses during the curing process
Prepare summary of the dependence of the curing process on humidity, temperature, pressure and dose
Avoid build up of high stress in the bonded joint by optimising the curing parameters
Stipulate the strength required for handling
For hot-curing adhesives ensure the curing temperature in the joint is reached for the necessary time
Automatic control circuit sensor-machine
Measurements (temperature, humidity, dose, time, pressure)
Monitor (settings)
Associated tests (e.g. bead peel test)
Samples
Final checks:
- Work samples or random samples: destructive tests to demonstrate that the required and geometry have been achieved strength Random samples or 100%-test: non-destructive tests to demonstrate that the required geometry has been achieved
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