
精密金型の匠
Japan Quality
Specialists in internal threads, undercuts, and complex molds.
Sekiguchi Seiko Co., Ltd.
About Us
Sekiguchi Seiko Co., Ltd. has consistently handled everything from 3D design support for plastic products to mold manufacturing and molding processes.
At our headquarters factory in Goka, Ibaraki, we operate with a small team of experts dedicated to producing high-hardness and high-precision molds.
We value the “human senses that machines alone cannot achieve” and deliver smooth and stable molds with meticulous attention to surface roughness and clearance accuracy of sliding parts.

Do you have any troubles like these?
✓ Do you experience significant cavity-to-cavity variation in multi-cavity molds?
✓ Are frequent mold failures or repairs causing you trouble?
Let us handle it!
Our Strength
Our molds never use parts outside of drawing tolerances.
This ensures high compatibility, repeatability, and durability during part replacement, while maintaining excellent maintainability even at remote production sites.
We are highly regarded for our strict focus on parallelism and squareness in component production, delivering ultra-precise parts.


Only a handful of companies in Japan are capable of this technology, and we excel at producing highly complex and precise molds such as internal thread molds, internal undercut molds, and insert molding.
We are one of the few “technology-driven” mold manufacturers capable of handling extremely fine and complex shapes.






Promotion Video
Service
Providing comprehensive services from 3D design support of plastic products to mold manufacturing and molding processes.
Main Products
■Manufacturing of high-hardness, precision molds for super engineering plastics
■Production of insert molding molds and molds for internal threads and internal undercuts
■High-precision machining of components with strict parallelism and squareness



Company
Sekiguchi Seiko Co., Ltd.
134-6 Kotesashi, Goka-machi, Sashima-gun, Ibaraki 306-0315, Japan
Phone +81-280-84-2541
Corporate Website
https://www.sekiguchi-seiko.com/Manufacturing Environment & Quality Control

Our headquarters factory is capable of manufacturing molds up to 100 tons.
We also specialize in precision molds for very small products, flexibly supporting everything from prototypes and one-off items to mass production.
By combining advanced equipment—including state-of-the-art machining centers—with the skills of our craftsmen, we build quality into every mold.
With CAD/CAM/CAE and design support, we meet dimensional tolerances as precise as ±2µm, delivering reliable solutions for even the most challenging projects.
Main Equipment
・Machining Center / Makino (IQ300)
・Die-Sinking EDM Machine / Mitsubishi Electric (SV-12PM)
・Forming Surface Grinder / Okamoto Machine Tool Works (HPG500NC SL)



If you have any questions or concerns about our products, please feel free to contact us.
Contact usSekiguchi Seiko Co., Ltd.
134-6 Kotesashi, Goka-machi, Sashima-gun, Ibaraki 306-0315, Japan
Phone +81-280-84-2541