This blog shows how to pick one reflow oven for both leaded and lead-free soldering. Learn key specs, profiles and checks to keep your SMT line stable and safe.
You stand in front of two spec sheets.
One job is still leaded solder.
The next big customer wants RoHS lead-free.
And you only want one reflow oven, not two monsters eating floor space and power.
Let’s walk through how to pick a reflow oven that can run both leaded and lead-free, without turning your SMT line into a daily fire-fighting show.
First thing, forget the brand names for a moment. Think about the metal and the heat.
To get good wetting, your peak temperature must sit above the melting point:
| Item | Leaded Solder (SnPb) | Lead-Free Solder (SAC305) | Comment |
|---|---|---|---|
| Melting point (approx.) | ~183 °C | ~217–219 °C | Lead-free needs higher heat |
| Typical peak temp range | 210–220 °C | 240–250 °C | 20–30 °C higher for lead-free |
| Time above liquidus (TAL) | 30–60 s | 30–60 s | Window is similar |
| Preheat range | ~120–150 °C | ~150–190 °C | Lead-free wants a warmer start |
| Thermal stress on parts | Lower | Higher | PCB and plastic feel more pain |
You can see the pattern:
If the oven can’t comfortably run a clean lead-free profile, it will always feel weak, even for leaded.
So you choose the reflow oven by the harder job: lead-free.
For mixed production, the oven should:
If your oven barely hits 245 °C when it’s new, in one year with dust, filters, half-blocked fans, it may not reach enough heat for tight lead-free work. Then operators start “tuning by feeling” and line quality go down.
You want the oven that still feel relaxed at lead-free peak.
More zones = more control.
For serious lead-free:
With too few zones, you are always making compromise:
In real life, your NPI engineer don’t have time to fight the oven every time a new project comes.
Lead-free solder oxidizes more. That’s why many factories talk a lot about nitrogen reflow:
But nitrogen is not free. Gas cost + maintenance are real. Many plants use a simple strategy:
So when you look at a reflow oven, ask:
For lead-free, peak is high. Cooling matters a lot:
Look for:
If you build electronics that work together with refrigeration units components and metal frames, you often mount heavy relays, big terminals, and connectors on your PCB. Those guys love to twist the board if cooling is crazy. A decent cooling section will save you many mystery failures later.
This is common:
What you need from the oven:
Your SMT line looks stable, and quality guys stop shouting.
Let’s say your factory also builds fan grill guard and other metal parts for cold rooms, and you integrate control PCBs for those systems.
Now:
Here the reflow oven plays a “silent” but very important role:
In this kind of project, many buyers talk with phrases like:
So they ask your team about:
If your oven supports easy data logging and traceability, your sales team can show them real curves instead of just saying “our quality is very good la”.
When you sit with the oven supplier, keep this small list next to you. If most answers are “yes”, you are on the right track.
If the answer is “no” many times, don’t expect the line to magically run smooth when you mix leaded, lead-free, samples, rush orders… life will be more hard.
For a company like yours, offering custom wire shelving manufacturing services and building parts like freezer racks, refrigeration units components, and cold storage room hardware, the PCB is just one piece of the system.
But:
