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6 Process Maintenance 6.3 Maintain the Print Enviroment Process Foundation DEK Micron-Series 12/2017 41 6.3 Maintain the Print Enviroment Correct Temperature Within Printer The temperature inside the printer should be st…
6 Process Maintenance
6.2 Maintain the Process in Real Time
40 Process Foundation DEK Micron-Series 12/2017
6.2 Maintain the Process in Real Time
There may be circumstances during production when small changes to the process are required in
order to compensate for variations in the hardware or environment. Examples include:
●
Variations between batches of boards
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Temperature fluctuations
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Multiple stencils with varying accuracy used on same process
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Wear and tear of process hardware
The underlying reasons for problems like these should be addressed and rectified quickly so that
they do not compromise the aim of high yield and throughput. However, in the short term there are
actions that can be taken to keep production running with minimum defects.
Actions that can be taken in "real time" i.e. without having to stop the printer include:
Recovery Actions Process Adjustments*
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Under Screen Clean
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Print Speed
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Add Paste
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Print Pressure
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Knead Paste
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Separation Speed
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Alignment Offset
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Fiducial Set-up
*Adjustment to the process should be restricted to qualified and authorised personnel as making
changes can seriously compromise the production quality.
Note: Changes made whilst running will be lost when the product file is changed or power is
removed from the printer. To make changes permanent stop the machine and save the
file in the menu.
Recording Process Adjustment
It is good practice to record any changes made to the process so that the root cause of the adjust-
ment can be investigated.
Exercise
Cycle a board from left to left with no squeegees and print pressure at 0kg:
1. Adjust the print speed and observe when the change takes effect
2. Instigate a screen clean operation and observe when it takes effect
6 Process Maintenance
6.3 Maintain the Print Enviroment
Process Foundation DEK Micron-Series 12/2017 41
6.3 Maintain the Print Enviroment
Correct Temperature Within Printer
The temperature inside the printer should be stable at the material manufacturer’s recommended
working temperature (normally around 22°C – 24°C for solder paste). Printer covers should be left
closed whenever possible to avoid fluctuations.
Correct Humidity Within Printer
The humidity inside the printer should be stable at the material manufactures recommended
working level (normally around 40% – 65% relative humidity). Printer covers should be left closed
whenever possible to avoid fluctuations.
General Factory Environment
Generally speaking, if the environment is comfortable for humans it will be suitable for the print
material. If you feel uncomfortable (too hot, too cold, too dry) then it is likely that the print
performance of the material will be compromised The factory should have a clean, stable
atmosphere. Ideally it should be air-conditioned with temperature and humidity stable throughout
the day and throughout the year.
Best Working Practices
●
Keep printer covers closed whenever possible to avoid environmental fluctuations
●
Monitor internal temperatures regularly throughout the day
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Use covers over conveyors to prevent airborne contamination
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Locate the printer in a clean area away from open windows, direct sunlight, heat sources,
draughts, sources of vibration, etc.
●
Isolate an area around the printer to prevent human traffic, trolleys, etc. coming near the
printer
●
Regularly check that the TCM is switched on, set correctly and all cables are connected
Exercise (if a TMC is present)
Using the TCM operator handbook as a guide, adjust the TCM to the mid-point of the
recommended temperature range for the material you are using.
6 Process Maintenance
6.3 Maintain the Print Enviroment
42 Process Foundation DEK Micron-Series 12/2017