Rivets have long been used for attaching things together and this has continued since the Bronze age. Previously, there were two workers required for setting the rivets. One worker had to use a hammer for pounding the rivet through a hole while the other worker used a bucking bar for setting the rivet on the other side. However, during the mid 1930s, major efforts were put in by the engineers who came up with blind or pop rivets. These are rivets that allow workers to install fasteners from one section of the work piece when the other side cannot be seen or is inaccessible.
The Work Procedure of Pop Rivets
Pop Rivets are used for assembling almost everything from steel beams in bridges to electronic components found in mobile phones. These are available in different shapes, materials, sizes and styles. These types of rivets are used for joining different materials in varying thicknesses. They also have the capacity of handling demanding environments. A pop rivet features a very smooth, cylindrical and hollow body which is topped with a solid-rod mandrel and flared head extending from the unfilled rivet shaft. The rivet looks very similar to a nail. The installation procedure of a pop rivet is as follows:
• The jaw in a setting tool is used for gripping the mandrel pulling it into the rivet body by way of a punched or drilled hole in more than two material layers.
• The head of the mandrel helps in expanding the rivet walls outward and presses them strongly into the walls of the hole. This forms a load bearing region on the opposite section of the material and this region is tightly clinched.
• All the unused mandrel parts break off with an increase in tensile force.
• There are several rivet manufacturers who put in the grooves on mandrels for weakening them. There are other varieties of mandrels with mechanical locks that snap into place, plug the rivet shell opening and capture the remaining part of mandrel within the sleeve. The entire installation procedure right from the point when the trigger is pulled by the operator to setting the rivet finally, takes around a second leaving a vibration-resistant and a permanent joint.
Factors Affecting Controlled Expansion of Rivet Body
Proper material and design selection help in accomplishing controlled expansion of rivet body. Both these components together ensure uniform hole fill and compression. This allows the pop rivet to join various dissimilar materials like woods, plastics and metals. Designers make the choice of Pop Rivets depending on specific applications. The major challenge that they face in choosing the designs is combining the right rivet configuration and size to the best mandrel for rivet integrity and strong joints. Here, the main objective is having the rivet bodies distort as per specification and mandrels to set apart at specific loads for ensuring joint durability, strength and consistency.
Benefits Fetched from Pop Rivets
Pop rivets serve as the fastest methods of joining materials. These rivets can easily be set at around 150 to 500 per hour with each setting being identical. It helps in cutting assembly costs and time. Dissimilar to threaded fasteners, pop rivet users do not need to worry about rotation failures, tool clearance and various secondary parts like tapping plates and bolts. All these together add assembly cost, weight and time. A pop rivet avoids problems of under or over torquing as well as stripping. These rivets also do not tend to loosen post installation due to the fact that their body is larger in comparison to the hole they are put into. The rivets also do not break off or shake out with the tight seal helping in the prevention of seepage and leaks.
Types of Pop Fasteners
You will generally find two categories of pop fasteners and they are closed end and open end fasteners. The open-end fasteners are more common. These fasteners feature countersunk heads or flanges and they are used in low-strength materials and thin-gauge metals. The closed-end fasteners are used for sealing the components that hold liquid like hydraulic pumps.