Table of Contents
How do you set a reflow oven profile?
A solder reflow oven is profiled by attaching thermocouples (TC’s) to the board that is being processed. These thermocouples are attached using solder or epoxy. Aluminum or Kapton tape can be used to attach thermocouples, but is not suggested due to trapped air and loosening of the tape’s adhesive.
What is reflow temperature profile?
Profile recommendations
| Zone | Lead (Sn63 Pb37) | Lead-free (SAC305) |
|---|---|---|
| Soak | from 150 °C to 165 °C in 120 s | from 150 °C to 180 °C in 120 s |
| Reflow | Peak temperature 225 °C to 235 °C, hold for 20 s | Peak temperature 245 °C to 255 °C, hold for 15 s |
| Cooling | -4 °C/s or free-air cooling | -4 °C/s or free-air cooling |
What is reflow profiling?
Profiling is the process by which we determine the proper time-temperature durations a PCB assembly should sustain throughout the reflow cycle. These are dictated by such paste characteristics as alloy type, sphere size, metal content and the chemistry.
What is soak time in reflow profile?
The results indicate a soak time of 60 seconds and time above liquidus of 60 seconds is preferred to achieve a thin IMC layer. The recommended time to peak temperature is 240 seconds and the soak temperature is 150°C.
How many zones are in reflow?
four stages
In the conventional reflow soldering process, there are usually four stages, called “zones”, each having a distinct thermal profile: preheat, thermal soak (often shortened to just soak), reflow, and cooling.
How many types of reflow profile are there?
two
The two most common types of reflow profiles are the ramp-to-peak profile, also called ramp-to-spike or tent profile (see Figure 1) and the soak profile, or ramp/soak/spike profile (see Figure 2). A ramp-to-peak profile is a linear ramp to the peak (max) temperature.
What is Delta in reflow?
Delta-T in reflow generally means 2 things – difference in temperature on a product or difference in temperature of your oven. Delta-T on a product is what are your hottest and coolest areas on the board. Larger parts toward the middle of the board with higher mass heat slower than smaller parts on the edges.
What is RTS profile?
As seen in Figure 2, the RTS profile is simply a gradual linear ramp from ambient to peak temperature. The RTS profile ramp zone serves as the preheat zone for the assembly, wherein the flux is activated, the volatiles are driven off, the assembly is prepared for reflow and thermal shock is prevented.
What temperature does solder paste melt?
A manufacturer can solder a component or components using, for example a high Lead (Pb) solder alloy. These alloys melt in the 300° range. He can then do a secondary solder using a Tin Silver solder (SnAg), which melts in the 220° range.
At what temp does solder reflow?
The typical reflow temperature range for Pb-Free (Sn/Ag) solder is 240-250°C with 40-80 seconds over 220°C.
What is dwell time in reflow profile?
The elevated temperature reduces surface tension and promotes wetting. The time above melting temperature, or dwell time, should be 20 to 70 seconds. When the time limits for these various factors are added up, the minimum and maximum time that an assembly should be exposed to reflow soldering can be determined.
What is solder reflow temperature?
The typical reflow temperature range for Pb-Free (Sn/Ag) solder is 240-250°C with 40-80 seconds over 220°C. It should be noted that the recommended Sn/Pb reflow temperature range are less critical, and that minor deviations in temperature of equipment and components generally do not create soldering problems.
What is Profile temperature?
Temperature profiling is the term used to describe the process of recording and interpreting the temperatures of products and/or air through a conveyorized heat-treating process.
What causes tombstoning?
Tombstoning occurs when one end of a component (like a resistor) completes the Wetting process before the other. This end then pulls and tilts the component to create the Tombstone effect. The PCB Layout can influence the Wetting process.
What causes tombstoning PCB?
Some of the most common causes of a tombstoning issue on a PCB can include: The temperature of the reflow oven being uneven, which can cause the solder to begin and finalize its wetting process at different times on your PCB layout.