3 Types of Impact Riveting
3 Different Types of Impact Applications
Impact riveting can be a cost effective and time saving solution over non-permanent assembly methods such as bolts and nuts, studs and nuts, retaining rings, or cotter pins, to create a strong joint with a low profile and aesthetically pleasing finish. Impact riveting is a cold forming assembly process using pneumatic, electro-mechanical, hydra-pneumatic, or hydraulic force to install a rivet. Joint characteristics vary greatly depending on the rivet type: solid, semi-tubular, or self-piercing, each with its own advantages potentially saving time and money.
Impact rivets install quickly and in most cases are auto-fed for a fast cycle time, making impact excellent for high volume production. Many times, the operator handles the part, so there is no cost for part fixturing or part loading. In multiple rivet applications up to four rivets can be installed on a single machine simultaneously. Other multi riveting options are dual head and multi-head machines. When assembling brittle materials or delicate parts that may be damaged by higher forces, a load deflection option is available.
Solid Impact Rivets
Riveting with solid rivets requires more force than with semi-tubular or self-piercing rivets to drive the rivet through a pre-drilled hole onto an anvil to form the rivet head. In solid rivets the shank must swell sufficiently to fill the hole before the head collapses creating a joint suitable for heavy duty applications, in some cases, locking the joint to resist torque. Multiple rivets are recommended for high torque joints. Higher forming force can potentially distort finished parts. Thorough testing is advised.
Semi-tubular impact riveting uses a semi-hollow rivet with thin shank walls. The rivet passes through a pre-drilled clearance hole and the tubular portion of the shank rolls out on impact, drawing the parts together with minimal shank swell. This allows for the creation of articulating joints with some precision, though testing is recommended to ensure proper function. Semi-tubular rivets typically require around 40% less force to form than solid impact rivets. This may cause less distortion to parts during forming.
Self-piercing rivets are used to permanently fasten two thin sheets of material together. A driver is used to punch the self-piercing rivet along with the sheet metal into a die, causing the rivet to pierce the top layer and drive the bottom layer into a pocket. An advantage of self-piercing rivets is they do not require a pre-drilled clearance hole, saving time and a process.
In addition, self-piercing riveting can offer the flexibility of shifting the rivet location during assembly. Without a pilot hole, part-fixturing may be required to align the parts being assembled. Self-piercing riveting is not recommended for harder or thicker metals; testing may be required.
Impact Riveting, especially in high volume production, can be the right solution for permanent part assembly, potentially saving both time and money. Orbitform is an expert in assembly solutions, and has over 25 years of experience in riveting, forming, conveyors, welding, and integrated assembly systems. If you would like more information on impact riveting, or any other Orbitform products or services, visit our website at www.orbitform.com, or call (800) 957-4838 to speak to an applications engineer today. Orbitform…solutions delivered.