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Case Study

Challenges of the Production Engineering Dept. to achieve "half the production man-hours" and "quarter the lead time"

SANYO DENKI CO., LTD Kangawa Works (3,900 Employees)
  • Decided to manufacture in-house equipment to automate the assembly process, but the challenge was to achieve high positioning accuracy.
Solution and Results
  • In-house production by using SANMOTION G servo motor. High-precision positioning enables automatic adhesive application and shorter cycle time.
In this case study, we would like to introduce a challenge of production innovation through automation by the members of the Production Engineering Dept. at SANYO DENKI. To achieve our goals of "half the production man-hours" and "quarter the lead time," we introduced a new servo motor SANMOTION G and produced the assembly equipment in-house.
SANYO DENKI CO., LTD Kangawa Works

SANYO DENKI CO., LTD Kangawa Works

Total area: 67,140 m2

Number of employees: 648

Certifications: ISO 9001, ISO14001

This factory has large-scale automated production lines for producing servo motors.


Urgent need for automation of production lines. Decided to manufacture in-house equipment to automate the assembly process, but the challenge was to achieve high positioning accuracy

Disc module for encoder
▲Disc module for encoder (Figure)

SANYO DENKI has been making efforts to build a production innovation line to strengthen the automation of our factories in accordance with the Mid-Term Management Plan.
Kangawa Works (Nagano Prefecture) utilizes an integrated manufacturing system to produce motors for our Servo Systems Division. There, we were working on automating the assembly process of disc modules for encoders. Mr. Suzuki of the Production Engineering Dept., shared his story:

"The goals of the production innovation line were extremely demanding: to achieve the target performance as designed, to stabilize the quality, and to reduce the production man-hours by half and the lead time to a quarter. As part of achieving these goals, we focused on the time-consuming and labor-intensive task of assembling disc modules for encoders, and studied how to automate this process. Our challenge began, as this required accomplished skills."

"While there were opinions that it would be more efficient to outsource the process to an external equipment manufacturer, we decided to manufacture the assembly equipment in-house, determining that commercial equipment would not be able to handle the assembly of discs with higher precision. The benefits of in-house production were significant in terms of reduced production costs and stable supply, and above all, the enthusiasm within the company to take on the challenge for future development encouraged us to develop the equipment in-house."

Soon after, the Production Engineering Dept. started developing the disc module assembling equipment for encoders. However, problems remained in how to reproduce the high-precision positioning made by skilled workers with a motor.

Disc module for encoder
▲Disc module for encoder (Figure)

Solution and Results

Realized in-house production by installing SANMOTION G servo motor

Development of the disc module assembly equipment for encoders by the Production Engineering Dept. involved a number of processes that required high-precision positioning.
"One of the processes was to align the center axis of the hub exactly with the center axis of the disc. The camera recognizes minute errors in the pattern printed on the disc and corrects the detected misalignment while assembling the disc. This process used to be done visually with a microscope, and requires a micron-order level of skill. A high-resolution motor was essential for positioning this compensated position, and high-precision motor control was also required to ensure that the dispenser applied the adhesive at the targeted position," said Mr. Suzuki.

▼Component structure of disc module
Component structure of disc module

In response, we incorporated the AC servo motor SANMOTION G to complete the disc module assembly equipment for encoders.

▼Completed disc module assembly equipment for encoders
Completed disc module assembly equipment for encoders

Overview of equipment:
Automated the process of disc module assembly to inspection.

  • ・ The disc and hub are positioned with high precision using image processing, and two types of adhesives are automatically applied.
  • ・The ring magnet is precisely inserted into the hub, and the adhesive is cured in an automatic rotary heating furnace.
  • ・Performs automatic inspection of disc surface blur and magnet flux density after magnetization of the ring magnet.

Servo axis configuration:

  • ・ Transfer axes: 30
  • ・ Rotary axes: 5
  • ・ Total axes: 35

Realized high-precision positioning, adhesive application, and reduced cycle time

The High-Resolution Encoder

SANMOTION G servo motor comes with a 23-bit*1encoder as standard, which enables 64 times finer positioning than our conventional model.

*1: 23-bit is an accuracy that enables positioning at an angle of approximately 8.3 millionths of a revolution.

The High-Resolution Encoder

Speed Frequency Response

In addition, the newly developed current control improves the speed frequency response from 2.2 kHz to 3.5 kHz. It responds and operates more agilely than the conventional model, thereby improving the processing quality.

"By using this motor, positioning with higher precision is possible. This, in combination with image processing, enables the dispenser to apply adhesives with high precision by correcting minute misalignments," said Mr. Suzuki.

The assembly equipment significantly reduced the cycle time and realized a stable supply of discs. The Production Engineering Dept. which has successfully realized the production innovation line, will continue to take on further challenges in the next phase of manufacturing automated assembly equipment.

Speed Frequency Response

Date of publication: July 15, 2022

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