HOMENunobiki Manufacturing’s RootsThe Challenge of Minus Hole Screens

The Challenge of Minus Hole Screens

The simultaneous two-axis numerical control special press, which was installed on the completion of the new headquarters factory, was designed to provide higher precision than the requisite technology for production at the time. This press used to its full potential made it possible to produce a type of perforated screen referred to by Nunobiki Manufacturing as a “minus hole screen.”

Minus hole screen

Minus hole screens are special screens with holes smaller in diameter than the thickness of the metal sheet being punched. Since this type of screen is actually in little demand, this press was not often used to its true capacity until a major client placed orders for minus hole screens in 1997.


This machine may have held the ability to make minus hole- and other special screens, but the entire process, including die making and fabrication, was still beyond the company’s capability at the time. So it was a great challenge for Nunobiki Manufacturing.

Generally, 80 to 100 percent of hole diameter was the limit of sheet’s thickness. Much effort was put into punching screens thicker than the hole size (minus holes), and Nunobiki Manufacturing can today punch screens a maximum of 166 percent thicker than the hole size (thickness: 2mm, hole size: 1.2mm), an applicable hole size of 0.63φ to 2.0φ.


The topics touched on in the Nunobiki Manufacturing’s Roots series, to date, are only part of the story. Nunobiki Manufacturing receives orders, domestically and from abroad, to manufacture items that manifest its unique and completely new technology, and corporate secrets. Even though Nunobiki Manufacturing wants to further promote its technological strength, the reason it continues to thrive, today, lies in its ability to attract customers and gain their trust by protecting its know-how, which it can never divulge.

A new episode in the Nunobiki Manufacturing tale will appear in this section if we have something good to share in the future.