What Are The Advantages Flange Head SEMS Screws? Part One — Gorun Screw

What Are the Advantages Flange head SEMS Screws? — Gorun Screw

You may have already noticed that flange head SEMS screws are among the core products in Gorun Screw’s main product lineup.

So, let’s take a closer look at how flange head screws differ from conventional screws used with separate washers.

When installing screws, placing a washer under the screw head serves several important functions:

1.

Increase Bearing Area
Prevents the screw head from deforming soft substrates (e.g., plastics, wood) by distributing pressure over a larger contact area.

2.

Protect Component Surfaces
Avoids scratches or damage caused by direct contact between the fastener and sensitive surfaces—especially critical for precision components. Smooth, transparent PVC washers are often used for this purpose.

3.

Enhance Joint Reliability
Washers help evenly distribute clamping force, reduce contact stress, improve joint durability, extend service life, and can also cover oversized or irregular clearance holes.

4.

Prevent Loosening
Increases friction to resist loosening in vibratory environments. Specially designed spring washers, for example, apply counterforce to maintain tension—particularly useful in heavy machinery subject to constant vibration.

5.

Conform to Irregular Surfaces
For instance, when fastening COLORBOND steel corrugated roof sheeting, large-diameter EPDM rubber washers not only conform to the curved wave profile for stable seating but also provide a watertight seal around the screw hole, preventing leaks.

To achieve superior performance and higher assembly efficiency,flange head screws integrate the washer function directly into the screw head via a one-piece flange design. This eliminates the need for separate washer installation, boosting assembly speed by over 40%.

The annular flange is precision-stamped with thickness and diameter carefully engineered to match load requirements. 

This ensures more uniform pressure distribution on soft materials, reducing deformation risk by up to 65%.

Moreover, because the flange is part of the screw body, it receives the same high-quality corrosion-resistant surface treatment (e.g., zinc plating, Dacromet, or Zn-Ni), ensuring consistent long-term protection.

To Be Continued