Factory Tour for Power Systems Vol.2

In this series, we’ll take a look at how products get made at SANYO DENKI.

Here, we’ll examine the manufacturing process for UPS (uninterruptible power supply) at a Fujiyama Works, located in Ueda, Nagano Prefecture. This second section will introduce the assembly process for printed circuit boards (PCBs).



4016, Fujiyama, Ueda-shi, Nagano

Property Area:

95,632 m2

Main Products:

Fans, UPSs (uninterruptible power supplies), PV inverters, servo amplifiers, stepping drivers, system controllers, etc.


Making an Uninterruptible Power Supply

Assembly Processes highlighted in yellow is what is covered in this page. 

1. Acceptance


2. Unloading

& Setting

3. Parts Assembly

Small Capacity UPS

A. Wire Processing


4. Final Assembly

Assembly & Wiring

5. Final Inspection



6. Shipping Preparation


B. PCB assembly

Component Mounting


Mid & Large Capacity UPS

4′. Final Assembly

Unit Assembly

Assembly & Wiring

5′. Final Inspection



6′. Shipping Preparation


3: Parts Assembly

B. PCB assembly Component Mounting


(1) Inserter Process

While maintaining high-accuracy, electronic components are automatically mounted to substrates at rates up to one per 0.12 seconds.

Inserter Line and Component Mounting



The first finished piece of a lot is compared against diagrams and checked to make sure the right component is mounted in the right orientation.


(2) Manual insertion

Electronic components that cannot be mounted automatically are mounted by hand.


Manual Insertion and a production guide system



The production guidance system and digitization of work order sheets contribute to the establishment of a work environment which limits the possibility of human error.




(3) Soldering

After flux is applied in the automatic fluxer, soldering is applied in the automatic soldering tank.


Spray Fluxer & Automatic wave soldering machine


The inverter before loaded into the soldering machine/ and after soldering



Depending on the type of PCB, a wave solder pallet may be used to protect thermally sensitive components. Temperature, speed, and nozzle height are managed in shift-start and periodic inspections to ensure solder quality.



(4) Finishing

Finishing processes include adjusting solder, mounting nonstandard parts, affixing the lot number, and applying coatings. Soldering work may only be performed by those who have passed a hand soldering certification exam.



Final Adjustment by hand/ Applying Coating




Finished PBC top



Finished PBC bottom



Treating all PCBs with a transparent coating known as HumiSeal results in improved moisture and corrosion resistance and overall-reliability. Two layers of coating can be applied to further increase reliability, especially for harsh environments.



(5) Inspection

And lastly, various inspections are performed to complete the PCB assembly process.


Left: Component mount condition inspection by an automated optical inspection

Right: Electrical characteristics and circuit check by an in-circuit tester (ICT)





Visually inspects the state of mounted components, soldering, and coating






The outflow of defective goods can be prevented through double and triple inspections. All inspections are carried out by certified workers. Visual inspectors also must have been certified for soldering work.




“To build a high-quality product, we gather and discuss ways we can make improvements.”