Afternoon Agenda Deciding on your soldering equipment and important factors to consider on configuration for a robust process Reflow
Transcript
Slide 1
Afternoon Agenda Deciding on your soldering equipment and
important factors to consider on configuration for a robust process
Reflow
Slide 2
In general machine created process defects are more to do with
original configuration decisions and daily set up understanding
rather than actual machine faults
Slide 3
One equipment contributor to reflow defects is the wrong oven
size or the wrong number of zones
Slide 4
The wrong size oven leads to incorrect profile for the paste
and the product and will lead to defects
Slide 5
Reflow The basic requirement of any Reflow oven is to be able
to consistently reflow your product at the required speed to meet
production needs Calculation is Process speed = Heated Length
(inches) Paste Dwell (minutes)
Slide 6
Example Reflow system needs to process at 30/minute with 4
minute paste dwell profile Heated Length = 30 x 4 = 120(3M) Not all
ovens have same heated length per zone Note this is NOT total oven
length More zones will allow for greater process controls and zone
definitions which allows for tighter profile control
Slide 7
Important factors for consideration Air or Nitrogen Flux
maintenance Thermal performance Power consumption Cooling
capability active or passive Other factors
Slide 8
Air or Nitrogen Air systems run invariably cleaner N2 will
widen the process window Pin in paste type applications may
influence need for secondary flux management systems due to flux
amounts (GRS)
Slide 9
Global costs Nitrogen added expense
Slide 10
Flux management Typical GRS System Flux laden gas passes
through condensation system and removable filters out side of the
tunnel for ease of maintenance
Slide 11
Affect of heater cell design on power consumption and T
Efficient design of heater cell increases thermal transfer rates
and decreases T Lowers overall cost for energy Can allow for
shorter total oven heated length resulting in lower overall cost of
ownership
Slide 12
Heater cell design affect on power usage and costs Poor heater
cell design results in much higher KW usage and slow reaction to
loading which results in slower throughput ability or increased
T
Slide 13
Cooling Cooling rate is a key component on joint integrity and
strength Product density, size and complexity will determine your
need Cooling affects the time above liquidious Active cooling needs
to be considered
Slide 14
Active cooling Passive cooling involves using make up fresh air
only and will heat up during the day causing TAL issues Active
cooling involves using recirculated liquid and heat exchangers and
will maintain down to 50 F Below this temperature an external
chiller is needed
Slide 15
Other automatic options assisting process Automated recipe
generation based on PCB type saving multiple profiling time
Slide 16
To ensure you have a robust process pay attention to the
machine configuration and daily set up Dont ignore the cooling
section Have the machine automate decisions based on certain
criteria