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Electronics Manufacturing: Process Automation
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The Client:
Circuit board manufacturers. HP, DEC,
Raytheon, Honeywell, Data General, Kollsman, and others.
System installed in 30 sites in the US and Puerto Rico.
The Requirement:
Automate the setup of existing wave
solder manufacturing equipment, and instrument the machines
to provide automated data collection of process conditions
and historical reports. Remove variables associated
with operator setup and assure process consistency for
quality control. Collect historical batch data as a
basis for process and quality engineers to track, refine
the process and improve yields.
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The Design Solution:
A control system was designed as a prefabricated
panel that could be rolled up to a machine and installed during
a scheduled maintenance time. The system has a local operator
display, a PLC with interface components and data collection
capabilities at each machine. A single PC based SCADA system
in the engineering office is networked to the plant level
machines. There is also a modem provided for remote monitoring
and diagnostics. The complete installation, tuning and operator
training could be performed in three days. Provided full turnkey
solution.
Sensors are installed to monitor critical
process parameters that previously had no tracking at all.
All manual adjustments to the process were replaced with devices
that could be wired to the PLC for automatic setup and close
loop control. The systems were first run in a monitor only
mode to track the existing operation, then a switch engaged
the automatic PLC control.
The monitoring system showed that process
variances came from a combination of control, mechanical and
operational issues that previously could not be seen. The
speed controls on the conveyor were replaced, and the relay
controls on the heaters replaced with faster solid state devices.
Mechanical changes included modifications to the heater chambers
and the addition of a flux mixing system. Automating the setup
eliminated the variance between different operators and highlighted
reasons why they were changing machine setups.
All runtime conditions are recorded for
the process engineer to monitor. The data collection helps
engage the engineer in a dialog with the operators in the
plant or satellite plants, about how the machines are run,
while letting the operators get on with the daily production.
Systems were first installed at a pilot plant, then rolled
out to all other remote manufacturing plants.
The yield improvements were outstanding.
The lot tracking and improved QC was the key for some customers
to win contracts. DEC reported a reduction on defects from
parts per thousand to 2 parts per million, and completely
eliminated the rework department.
Major Automation Equipment
- PLC - Andover Controls AC8, AC256
- Network - Andover Controls C-Net, Telephone
- Computers - PC Compatible
- Software - CENPLEX, DOS
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