Hakko FX-100 Curie Point Induction Soldering
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Hakko FX-100 Curie Point Induction Soldering

A Review of the Technology

A Little History

For 60 years, Hakko has been making soldering irons based on ceramic heating technology. This year they have entered into the domain of Curie point induction heating technology with the FX-100 soldering station. Induction heating technology has been around for over 100 years and Metcal started using this technology in the early 1980s for soldering.

In the mid 1990s there was a need for more power in soldering irons due to the increased use of SMT components and thicker, heavily-grounded PCBs. Metcal was able to gain market share during this time and through the advent of lead-free solder alloys. Since then Hakko has made great improvements with ceramic heating and their T15 series of composite tips are able to handle the vast majority of such applications. However, there are still power requirements that only induction heating can meet. After over five years of research, Hakko has designed the way to make the technology meet their strict requirements for quality, performance, and control as well as improve upon it so that it’s not just another soldering iron, but arguably the best induction heating soldering iron available today.

Basic Difference in Heating Technologies


Ceramic heating technology uses a microprocessor and thermocouple to control the temperature of a soldering tip. As the temperature drops, a signal is sent to the microprocessor, which in turns sends more current to increase temperature. This allows the tip temperature to be set at the station, but has a little latency as the signal travels back to the station and increased current is sent back to the heater.

Induction heating technology traditionally does not have this feedback loop. Here's a somewhat simplified explanation, as I understand it. An AC signal is sent down the handle through a coil, which induces an eddy current in a ferromagnetic heater causing temperature to increase. Once this heater hits its Curie point, the magnetic properties of the heater change and the eddy currents are no longer induced, so heat is no longer produced. As soon as the temperature drops below that Curie point, current is once again induced and the temperature is increased until the material once again reaches its Curie point. This happens dynamically and maintains the tip basically at its Curie point, with the unique feature of never going above it. This technology does not traditionally allow for any variations in peak tip temperature, as the Curie point is determined by the alloy of the heater in the manufacturing process. This is where the range of tip temperatures come from within the same series and why Metcal does not seem to like to talk about temperature.

The Hakko FX-100

Hakko’s power supply improvements

2 Modes Available

1) Two modes (Normal / Boost)
Hakko’s FX-100 power supply offers two different modes: normal and boost. The common understanding in the industry is that the temperature of the tip is determined solely by the particular alloy of the heater, but actually there are several other factors at play. The impedance of the inductor coil, frequency of the AC signal, and voltage of the signal can also affect the final temperature. The impedance of the inductor coil is determined by the material used as well as the number of turns; both of these are set at the manufacturing of the tip. The frequency and voltage of the signal are determined by the power supply. This requires proper tuning of a power supply. If these two variables are permanently set within the station, then the same tip plugged into the same station will always have the same peak temperature, but if either of these variables are different in another station, then the same tip will produce a different temperature in the second station. Metcal has done a good job of being consistent with their power supplies so that this potential hazard is not seen nearly at all in the field. They have also designed the station well so that the frequency and voltage of the signal do not drift, yielding consistent results. Hakko's high quality standards have led them to these results as well. However, given this understanding, Hakko has added the Boost Mode. In Boost Mode, the FX-100 increases the voltage slightly to increase the temperature by about 9F and improve power output through the tip.

2) Auto Power Assist
The FX-100 has an added microprocessor that monitors the current draw down the cord to the heater. When it detects that the temperature has dropped and an increased current is being drawn, the FX-100 will automatically up the voltage to assist the heater in getting back up to temperature. This is basically using the same method as Boost mode to get an increase in thermal performance, but not employing it long enough to get an increased temperature.

3) Interface
While not necessary to the use of the station and possible to completely lockout with a password, the FX-100 offers a few settings besides the two modes for you to adjust. The tips series in use can be displayed as well as different profiles set up for different users. Other settings include auto sleep, auto shutoff, and alert time.

4) Size/Shape
The unit is approximately 5”W x 6”H x 6.6”D and weighs in at 6.6lb. Although it is slightly larger than the MX-5000, this compact design still doesn’t take up a lot of bench space and if you require two, you can stack them.

Hakko’s solder tip improvements

1) Tip life
Hakko’s renowned tip plating extends to the new T31 series of tips for the FX-100. The average plating thickness is about 200 um, compared to Metcal’s average of 120um. The thicker the “armor” plating, the longer it will last.
Typically, the thicker the plating, the lower thermal performance, but Hakko makes up for this with the improvements below.

T31 vs STTC tip construction 2) Tip performance
Hakko has made a heater cap that fits over the copper core of the tip and is brazed together. This allows the coil to be closer to the action than Metcal’s coil, which is wrapped around a heater opposite the tip and pressed into the solder tip. The closer the inductor coil, the closer the source of heat is to the tip and the quicker the response time, increasing thermal performance. The brazing ensures that the heat is transferred to the end of the tip without any gaps that may be seen in a press-fitted assembly.

3) Tip temperature
Hakko also talks about their tips’ fixed temperature. The two currently available series are either 840F or 750F (update: 660F now available) and all the tips of these series will be a fixed temperature within the IPC J-STD-001 recommendation of +/-27F. Similarly, Metcal sells 800-series and 700-series tips, but do not tell you what temperature these are. The closest thing I could find is a maximum temperature, which is 905F+ (does that count as a max?) and 775F, respectively. I have no idea what they use as the minimum. Many people I talk to think their 700-series tips are 700F, but that simply isn’t the case. Hakko's method for getting this tighter range of temperatures in a series is the brazed cap heater. They are able to make a large sheet of this alloy, cut and shape it, then braze it onto the copper tip. Metcal's strategy is to anneal the heater alloy around a copper slug, which allows for more variations in the alloy from tip to tip.

4) Power efficiency
Hakko’s heater cap also increases the efficiency of the tip. The power coming from the station down to the coil creates a magnetic field. With Metcal’s design, only one side of the field is being used. With Hakko’s brazed cap design, two sides of the field are being used to create eddy currents and heat. Initial studies by Hakko have shown the 50W FX-100 outperforming the 80W MX-5000.

Cost savings

5 tip geometries

Hakko’s T31 tips cost approximately $18, with a few exceptions. This is about $4-5 lower than Metcal’s STTC list price (which vary widely depending on tip geometry and temperature series). This, coupled with the expected increased tip life due to thicker plating, should decrease a user’s tip costs by around 50%. As this is a new product and data is still being collected, this is still an estimate.

Hakko’s FX-1001 soldering iron handle uses a standard RF connector to attach to the power supply and runs at 13.56 MHz, the same frequency that Metcal uses in their older MX-500 and newer MX-5000 series (it also fits into their stand). It will not work in the formerly branded OKi products as these use a lower frequency of 450 KHz. This means that with the purchase of the FX1001-51 for about $85, a user can switch over to the superior, affordable Hakko T31 tips and start saving money right away. Once the competitor’s power supply dies out, the Hakko FX100-04 power supply can be purchased to give a further performance improvement, including the Boost Mode.

Shared features of note

  • Graphical display of dynamic power usage
  • ESD-safe
  • Tip sleep function to reduce tip temperature when handle is in stand
  • Simple, plug and play operation
  • Heat-resistant iron cords
  • Ergonomic handle


  • Only soldering - This is a brand new product, so there is not a full-scale release of every possible handpiece everyone could want. Hakko has started with the standard soldering iron, which is what probably over 95% of people are looking for anyway.
  • Tip geometries - As of this writing there are 15 different tip geometries available. These options cover the vast majority of work, but more are needed. UPDATE-Mar 15, 2015-Hakko continues to release new geometries and requests are being taken.
  • Tip temperature ranges - As of this writing there are 2 different temperature options (840F and 750F), which are the most common. Hakko is currently working on a ~650F tip series for sensitive, tin-lead soldering applications. UPDATE-Jan 27, 2015-Hakko has released 660F tips.
  • The FX100-04 package does not come with a specific tip holder - tips can be placed in the back of the stand or a B2756 tip holder can be purchased for about $17.
  • FX-100 station only has one port. My experience in the field has shown me that very, very few people use the two ports available on Metcal stations prior to the MX5200 series. Manually switching back and forth is not the friend of the production line operator. The MX5200 does address this by moving that switch for you very quickly using software.
  • Distinction between tip series - Like Metcal, Hakko does not have a clear way to tell which tip temperature is in use. However, Hakko has provided two indicators. Firstly, the lengths of the two series are different by about 3mm. Secondly, the 840F tips have a P on them. This P is visible while in the handle, so an operator can quickly reference what temperature they are using, but it’s not bold enough that someone walking by would necessarily notice. Some have proposed a painted color to indicate the different series, but Hakko has some customers that are extremely sensitive to FOD and this paint does come off with each insertion and removal of the tip.

Thank you for reading. If you'd like to schedule an in-house evaluation, please contact your local rep.

If you have any comments or suggested changes, please email me.

Hakko's official videos released thus far:
How to use the menu

Please note that this writing expresses the understanding and opinions of the author and not necessarily the companies mentioned within.

If you appreciated this review, you can also read my review of Hakko's FR-810 Convection Rework Station

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