The cordless suction tweezers “HAKKO 394” makes mounting the board easier than normal tweezers.

I bought HAKKO 394, which is an adsorption type tweezers with a built-in vacuum pump.


 The cordless suction tweezers

HAKKO 394 is an electric cordless suction tweezers.

It has a built-in pump to suck in air. When you press the button, the pump operates and the part is sucked to the tip of the nozzle. When you release the button, the pump stops and the part is released.

To date, surface mount chip components, such as the 1608, have been mounted using inverse tweezers.

ICs and microcomputers with large areas have been mounted using manual suction tweezers.

The merit of the cordless tweezers I bought this time is that it can absorb not only IC but also chip parts.

In the case of tweezers, a space of about 2 mm is required between the parts because space is required to open the tweezers after placing the parts.
Therefore, parts cannot be mounted in high density with tweezers.
In the case of the adsorption type, since it is sucked from the top of the parts, the space between the parts is not so necessary.
If you pay attention only to the trembling of your hands, you can mount it more densely than with tweezers.
However, the standard nozzle is too thick to absorb the chip parts.
In order to absorb chip components such as JIS 1608 (0603) and JIS 1005 (0402), it is necessary to purchase an optional 0.26 mm nozzle (vent nozzle A1198) separately.

When the vent nozzle A1198 is installed ↓

Try to suck the parts

I tried to absorb the chip resistance of JIS 1608 (0603 size).
The adhesion force was very weak and it was difficult to adsorb, but once it was attached, it could move to the substrate.

Use to mount components on a board

Print the solder paste with a stencil.

Secure the target board by placing an unnecessary board of the same thickness around the target board.

Align the stencil and use the squeegee to print the solder paste.
More information on stencils and reflow can be found here.

The solder paste is placed nicely.

Pick and place

SOT 323 package

The suction force is weak and it doesn’t stick easily, but it can absorb SOT 323 package.

By sucking the part directly from the tape, the direction of the part is always the same, so there is no need to check the location of the pin 1, and it can be picked and placed quickly.

In addition, when using suction tweezers, the parts are mounted on the board as if they were pressed against the board from above.
There will be less solder defects such as lead sticking into solder paste and lead floating.


The absorption power was weak and it was difficult to absorb it, but we also made a chip diode SOD – 323 package.
Chip diodes are difficult to visualize because they tend to be upside down if they are taken out of the tape and torn apart. Moreover, it is very difficult to see the line that shows the polarity.
So it is very troublesome to pick in the right direction.
When I peeled the tape cover and sucked it directly from the tape, the parts in the tape were facing the front and the polarity was also facing a certain direction, so it was very easy.


It worked from the first time I tried.

The adhesive force is weak, so if you touch the solder paste, it will leave even if the pump is running.
This is useful.


The chip capacitor of JIS 2016 (0806) size was also able to be adsorbed somehow.

Larger components

Parts larger than JIS 2016 (0806) cannot be attracted.
Therefore, a suction cup (pad A1166) with a diameter of 3 mm is used.

This suction cup is attached to HAKKO suction tweezers if you have one.

This suction cup is attached to the original bent nozzle to absorb the parts.

Implementation complete

I have tried to mount a large amount of parts, but I think that using the cordless suction tweezers of the HAKKO 394 can shorten the mounting time to about 1/2 compared to mounting with the reverse action tweezers.
It is so efficient.

Reflow to complete the substrate

Reflow with a hot plate.
If you use a thermocouple thermometer, you can monitor the temperature of the board, so it is very convenient to know if it is not heated enough or heated too much.
I only need to know the approximate temperature, so a cheap one is enough.
It’s convenient if you have it.

After reflow, inspection is done and the substrate is completed.
Thanks to the use of HAKKO 394 cordless suction tweezers, it was completed in a relatively short time.

Advantages and Disadvantages of Using HAKKO 394

Here is a summary of the advantages of the HAKKO 394 cordless suction tweezers that I learned using it.

Benefits : Shorter mounting time

After all, using the HAKKO reduces the time it takes to mount the electronic components, rather than using tweezers. By sticking the part in the tape to the HAKKO, the part is always facing the front and the orientation is constant.

You don’t have to tap the parts to face the front or check the direction to arrange them.

Also, in the case of tweezers, the solder paste may stick to the tip of the tweezers when placing the parts. Then the part may stick to the tweezers in the next time. Even if you open the tweezers, the part may not come off. To avoid that, you need to wipe the tip of the tweezers with alcohol. In the case of an adsorption tweezers, that doesn’t happen. I’m very happy about that.

Benefits : High density mounting

This board was designed on the assumption that it is mounted with tweezers.
As a result, there is no high-density component spacing.With HAKKO, parts can be placed on the board from the top and separated.
Therefore, it can be mounted even if parts are close to each other.


Disadvantage : Weak adsorption force

In any case, the absorption power is very weak. The parts don’t absorb easily. This is quite a stress.Much of the time it takes to pick and place is spent on this trial and error. It is weak even when picking up JIS 1608 (0603) chip resistance. If the pump is a little stronger, the HAKKO 394 should be a fairly useful tool.
2019.9.17  Postscript :
The suction force was weak because the nozzle was clogged. Once the clogging is cleared, the nozzle can be easily sucked. See ↓ ↓

The advantages outweigh the disadvantages.

However, even if you include this drawback, the merit is better.

It is so convenient that I can’t go back to the tweezers.

Combination that you should buy

In addition to the HAKKO 394 cordless suction tweezers that we have found through actual mounting, we will summarize the optional parts necessary for mounting the chip parts.

Required Options

The bent nozzle A1198 is required to pick parts smaller than 2 mm, such as chip resistors, chip capacitors, chip diodes, and SOT 323.

Better option

A suction cup (pad A1166) with a diameter of 3 mm is required for parts that are larger than 3 mm and up to 5 mm, such as chip coils and SOP ICs.

The QFP package does not require any options.

For parts larger than 5 mm, such as the QFP package, a combination of the bent nozzle provided with the HAKKO 394 and a 5 mm diameter pad can be used.

I’m glad I bought HAKKO 394.

The suction force is weak, but the cordless suction tweezers was a very convenient tool because it shortened the mounting time. I’m really glad I bought it.


I thought I could adjust the suction force if there was a circuit to keep the suction force constant, so I disassembled it.

You can take it apart by removing 3 screws.

The mechanism is very simple : it consists of batteries, switches, pumps and hoses.

There was no mechanism to adjust it, but because of its simple structure, if you simply increase the voltage, you may be able to increase the suction force. I will try it later.