Bulge Control Fastener Technology

It can be difficult to decide which bulge control technology (BCT®*) is right for each particular application. There are many different mechanics that can be considered for use. Evaluating important factors like materials involved, size and tensile forces will help you select the best bulge control fastener for your product.

Brittle Material
This particular technology is perfect for carbon fiber, fiber glass or ceramic sheet material where it is vital to ensure there is no radial expansion in the sheet. Radial expansion must be controlled in order to avoid excessive compression that could lead to cracking or delamination of the sheet metal. This BCT® option is often used by leading automotive manufacturers.

Composite Sandwich
Composite Sandwich technology is used when sheet material provides no support to the rivet nut. This type of bulge is controlled and ensures that the rivet nut can form a bulge within the sandwich or on the back side of the sandwich.

Solid Material
Designed for solid material applications, this bulge control technology requires no through-hole in the application material. In this BCT®, the rivet nut forms a bulge deep inside the hole, compressing material between the bulge and the head of the rivet nut. This method offers enhanced performance compared to existing solid fastening methods due to the volume of material that is under compression.

Irregular Hole Formation
This BCT® method may be used in slotted or oversized holes to aid in alignment. Irregular Hole Formation can also be used in oversized holes to assist with alignment of the rivet nut into the application hole. This method can be used as a repair option when a material hole is poorly finished or is made oversized.

Clamp
If a bulge forms behind the rear sheet first, a Clamp BCT® would work best. The stroke of the installation tool is used to create pre-tension within the joint to ensure panels are drawn together during the rivet nut installation.

Multigrip
With the same grip range capability matching three standard rivet nuts, this BCT® fastener offers a flexible and versatile solution and also works to enhance error proofing. This fastener solution benefits the end user by reducing inventory costs and bill of material.

Micro
When minimal rear sheet space is available either before or after installation, it is often impossible to use rivet nuts. When this occurs, BCT® Micros can be installed with minimal clearance on the back side while still meeting the thread performance standards.

Lateral Space Restriction
Lateral Space Restriction BCT® is perfect for channels or edges of panels where there is limited space for the bulge to spread. This fastener technology allows for the product to be installed flush against obstructing surfaces which also acts as an anti-rotational feature.

Tubes
Perfect for when it is impossible to use a standard rivet or nut, this BCT® is blind and often used with limited rear sheet space and a curved sheet surface. Working by forming its bulge in the uniform plane of the tube, this fastener technology uses a combination of BCT® Micro and BCT® AR2.

High Strength
This BCT® can be used to replace weld nuts in cases requiring 12.9 property class thread performance. This technology allows the user to install before or after painting and deters issues surrounding welding splashes and fumes.

Restricted Space High Strength
Available for use in spaces with only a 2mm clearance, this fastener has superior thread and pull out / push out performance.

To determine what bulge control technology works best for your application, consider the materials being used and visit the Bossard North America website to get connected with an engineer.

TO learn more about Bulge Control Fastener Technology, contact us at ProvenProductivity@bossard.com.