A Riveting machine is a type of riveting tool used to fasten materials together. They can be hand-held or automated and are electrically, pneumatically or hydraulically actuated. They are available in a variety of configurations, from simple hand-held tools to multi-head automated machines that can be integrated into robots to operate in flow-line production. There are three main types of riveting machinery: compression riveting, non-impact riveting (also known as orbital riveting) and impact riveting.
The first step in selecting a Riveting machine is to define your assembly process objectives and constraints. This helps you choose the best equipment to achieve your goals, whilst minimising risk. For example, if you need to join materials that are not compatible with traditional riveting techniques, then you may need to use a hot upset riveting machine which deforms the rivet shaft by heat rather than pressure to create strong bonds.
Riveting machines are available in a range of configurations, from simple hand-held riveting guns to complex multi-head automatic machines that can be integrated into robots to automate the operation of your assembly line. They are typically electrically, pneumatically or hydraulically driven and are designed to produce high quality, robust joints with minimum maintenance and downtime. Riveting systems are widely used to produce a wide range of applications including brake linings for commercial vehicles, aircraft and locomotives, metal brackets, window and door furniture and latches as well as sensitive electrical or electronic components. They are also highly efficient, providing a rapid joining solution that reduces processing times compared with conventional riveting and spot-welding. Self-piercing rivets are also considered to be a clean process with lower energy requirements than many other fastening methods and produce fewer fume emissions.
Unlike other fastening methods, the cycle time of a riveting machine is relatively short and does not increase for thicker materials or larger stacks. For higher productivity and throughput, the process can be automated using dedicated process monitoring systems such as those offered by Orbitform, shown in fig 8.1. These systems monitor the setting force and punch movement throughout the process to generate a graph plot called a force-displacement curve. The curve is then compared with a reference curve to determine whether the joint has been successful or not.
If a problem is detected, the system can be flagged for attention or even halted. The Orbitform ‘Watchdawg’ system, for example, uses a series of sensors to monitor the position and force applied by the rivet gun during the riveting process to provide a real-time data feed. These are then used to calculate a’smart’ control algorithm which ensures the correct force is being applied, thus optimising production efficiency and quality. Other systems are also available which use a combination of different sensors to measure the clamp and punch position, as well as up to two clamp and punch pressures. These are often electric servo-systems which allow for finer control of the process parameters than the simpler hydraulic systems.