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‘Profile the easy way..’
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
The need for continuous monitoring
•The classical way to obtain a temperature profile is to attach thermocouple sensors to the
PCB and record the temperature profile using a heat protected data logger which travels
through the process behind a test PCB.
•This method works very well for initial machine setup it does not lend itself to ongoing
process monitoring in high production rate environments as it can only be deployed
periodically.
•Manufacturers are therefore faced with the less than ideal situation of having to manually
‘snapshot’ the process every few hours and assume that in between the process remains
‘good’.
•Each time a process ‘snapshot’ is taken, production must be stopped to allow the test
board and profiler to pass through. If a problem does occur, it will only be discovered the
next time a process ‘snapshot’ is taken, and under the worst case this could involve
several hours of production.
What is required is a simple automatic system which can remove the need to profile
with test boards during production.
SOLDERSTAR APS – Virtual PCB Profiling
www.solderstar.com
What is ‘Virtual PCB’ Profiling ?
Traditionally a profiling instrument is used to establish the correct thermal profiling for
the soldering process. Thermocouples are attached to a real PCB, and the component
level temperatures are captured by the measurement datalogger.
Verification profiles are then captured on the SMT line by periodically passing the test
PCB and instrument through the process.
If we wish to ensure that the thermal profile is correct for 100% of all PCB’s
manufactured the APS 2000 system is employed.
The APS 2000 continuously tracks PCB movements through the machine and also
monitors process fluctuations at products level. These changes are then used by a
mathematical model to calculate what the resulting PCB profile would be, this is known
as the virtual profile. Process parameters can then be calculated and tested within limits
SOLDERSTAR APS – Virtual PCB Profiling
www.solderstar.com
Virtual PCB Profiling ( continued )
Step 1: We capture the actual profile from a PCB using a Solderstar Profiler
(This gives the software the thermal model of the oven & the
components/PCB)
The following steps are performed to all the APS 2000 to calculate profiles in real-time.
Step 2: The APS 2000 analyses and records the ‘good’ state of the reflow oven
Step 3: The APS 2000 now measures in real-time any fluctuations in the process, the
information from Steps 1&2 is used to calculate the resulting profile. Process
parameters are calculated and tested against defined limits.
SOLDERSTAR APS – Virtual PCB Profiling
www.solderstar.com
Virtual PCB Profiling ( continued )
Capture the actual profile from
a PCB using a Solderstar
Profiler
The APS 2000 analyses and records the
‘good’ state of the reflow oven
Product level
temperatures are
measure along
with conveyor
speed
Real-time
profile
Original PCB Profile
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
How the system works
The SolderStar APS is a full time reflow process monitoring system designed for
convection reflow ovens. The system works by continuously measuring product level zone
temperatures and conveyor speed and comparing these measurements to a captured
process reference which the system has previously learned.
The system continuously compares each new set of measurements with the reference and
evaluates any differences.
Should the difference between the current process and the reference exceed user defined
limits, then further boards are prevented from entering the oven by way of the oven
SMEMA interface.
The user is then alerted in order for corrective action to be taken
Full live statistics and process Cpk are produced automatically.
Speed and temperature measurements are stored in a database for each PCB
travelling through the soldering process for full product traceability.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Why measure independently of the oven ?
The APS system measures the product level zone temperatures and conveyor speed
independently of the oven. This is important for two reasons:-
Firstly the machine may malfunction for example a heater or fan may give trouble.
Secondly, an operator may load the wrong recipe for the board being produced.
Why measure temperature at Product Level?
The oven itself monitors and maintains the temperature of each zone. This measurement
is made near to the heaters and does not closely reflect the temperature seen at product
level which is a function of the machine convection.
The APS system adds independent temperature sensors mounted at product level close
to the conveyor rails. These sensors are designed to closely measure the heating levels
impinging on passing circuit boards whilst at the same time minimizing shadowing caused
by the sensor itself.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone N
Probe A
Probe B
The APS system is configured as follows:-
Dual Rail Monitoring System
The Dual Rail Monitoring configuration uses temperature probes to measure at product
level on both the left and right side of the conveyor. Probes are custom made for each oven
with sensors positioned centrally within each zone.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Process Reference
The process reference is captured prior to production starting and when the process has
already been setup and confirmed to be correct using classical profiling techniques and a
test board.
During this phase the oven SMEMA interface is asserted which prevents loading of boards
into the oven.
As part of the Reference Teach, the user must set process WARN and STOP limits that
are to be enforced by the APS system during production.
These limits allow upper and lower thresholds for each of the product level temperatures
and the conveyor speed to be specified.
They dictate how far away from the reference the process will be allowed to drift before
production is stopped.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Process Monitoring
Once the Reference has been learned and limits set for the process, the APS system can
start monitor the process.
As a PCB enterer the reflow oven, its progress is tracked through and temperatures
recorded at product level sensor as the PCB goes through the zone.
When the PCB exits the oven, the profile is mathematically calculated using the live
measurements, and the PCB reference profile, it is then evaluated PASS/FAIL and
recorded.
For each PCB we have a record of the process speed, and each zone temperature and
the mathematical profile.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Software Overview: APS Central, intuitive and simple to use.
Navigator Bar
Active Profile
Process History
The navigator
bar provides
instant shortcuts
to each feature of
the software.
Process Window
Checkers
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Software Overview : Process History
A complete record of the activity per PCB within your reflow process
Process List Process Result
History
Production
Batches
Process Events
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Software Overview : Zone Checker window
The zone checker window is a live update window when the APS is running which
shows measured oven parameters plotted against the process user limits for the
Process.
Process OK Process Warn Process Stop
Parameter Value
at Reference
Parameter Limit Bands
The green area represents a
parameter which is inside the WARN
limits and represents a normal
process.
The amber area represents a
parameter which is within the STOP
limits but outside the WARN limits.
The red area represents a parameter
outside the process STOP limits.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Software Overview : Process Checker window
The process checker window is a live update window which shows the live process
parameters calculated from the current calculated ‘virtual profile’. Warning and Stop
levels can be configured for Peak Temperature, Time above and soak time.
Process Limits
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
Software Overview : Oven Data Window
The oven performance data window shows live readings from the APS system along
with reference and set-point values when the APS system is running.
Measured Values
Left & Right
Reference Values
Left & Right
Heater set points Conveyor Speed
Values
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
The APS System Advantages …
• Easy to understand system concept
• ‘PROCESS TEACH then TEST’
• Simple to fit and operate
• Full time monitoring of reflow soldering process which does not rely on
repeated profiling.
• User Process limits allow the machine to be automatically stopped if the
process drifts too far away from the reference.
• Automatic process tracking and traceability for all products produced.
SOLDERSTAR APS – Continuous Reflow Monitoring Solutions
www.solderstar.com
About SolderStar
SolderStar is a specialist in the design, development and manufacture of specialist
thermal profiling equipment for the lead-free electronics industry.
Incorporating state-of-the-art technology and full lead-free compliance, SolderStar’s
range of instruments and software tools offers leading-edge performance, functionality,
heat-resistance and miniaturization.
SolderStar satisfies all of today’s thermal process control needs, from full-feature high
performance product profiling for reflow and wave solder processes, to fully integrated
SPC capabilities for continuous quality and process control.
Products are available individually or in packages that are tailor-made to suit the
technical and budgetary requirements of all electronics manufacturers, whatever their
size and needs and wherever they are in the world. For more information about
SolderStar, visit the company’s website at www.solderstar.com.
