Riveting in Sheet Metal Using CNC Technology(press fit tolerancing Lee)

  • Time:
  • Click:5
Riveting is a crucial process in manufacturing and construction that involves joining two or more metal parts together using a rivet. In sheet metal applications, riveting offers several benefits over other joining methods like welding or bolting. The rise of computer numerical control (CNC) machines has transformed how riveting is performed on sheet metal, enabling faster, more consistent, and higher quality results.
What is Riveting?
A rivet is a mechanical fastener that consists of two main parts - a smooth cylindrical shaft and a head. To rivet, the parts to be joined are clamped together and a hole is drilled through the materials where the rivet will be placed. The rivet is inserted into the hole and the protruding end is then upset, or buckled to form the second head. This creates a permanent joint.
Rivets come in many styles, materials, and sizes but three of the most common types used in sheet metalwork are:
- Solid/Round Head Rivets: Have a dome-shaped pre-formed head on one end. Used in applications where appearance matters.
- Blind Rivets: Have collapsible mandrels that are inserted into pre-drilled holes. Pulling on the shank then forms the second head. Allow riveting without access to both sides.
- Self-Piercing Rivets: Designed to pierce and clinch in a single operation without pre-drilling holes. Common in auto manufacturing.
Benefits of Riveting Sheet Metal
Compared to welding, soldering, or using adhesives, riveting sheet metal offers several advantages:
- Speed: Fast installation as it requires less preparation and avoids heating/curing time.
- Strength: Forms a reliable, permanent, and vibration-resistant joint.
- Appearance: Provides a smooth finish with no blemishes.
- No Heat: Avoids potential warping or damage to protective coatings.
- Disassembly: Rivets can be drilled out if needed to separate parts.
- Material Versatility: Joins dissimilar metals or combines metal and composites.
- Lower Cost: Riveting equipment is affordable for most fabrication shops.
Automated Riveting Processes with CNC
The integration of computer numerical control into riveting systems for sheet metal has brought higher speed, precision, consistency, and efficiency to the process compared to manual riveting. This makes CNC riveting ideal for mass production environments.
Some advantages of CNC riveting machines include:
- Automated Hole Punching: CNC systems can be programmed to drill perfectly aligned rivet holes. This avoids inconsistencies of manual hole punching.
- Precise Rivet Placement: Rivets are fed and installed in the pre-drilled holes by the CNC machine in the programmed locations to tight tolerances.
- Consistent Quality: Rivet setting force, diameter, grip length, and flushness is the same for every rivet, ensuring uniform high quality.
- Faster Cycle Times: CNC systems rivet much faster than manual fabrication, speeding up production.
- Safer Operation: Automating the riveting with CNC reduces the risks associated with repetitive tasks.
- Reduced Secondary Processing: Automated precision riveting minimizes the need for filing, grinding or other post-production work.
- Lower Labor Requirements: CNC riveting reduces labor demands and cost. One machine can do the work of many manual riveters.
- Flexible Manufacturing: CNC machines allow quick changeovers between rivet sizes and materials with no downtime.
- Reduced Material Waste: Optimized hole punching and precisely placed rivets minimize wasted material.
- Improved Inspection Capability: Inspection cameras can be integrated into the CNC riveting system.
- Tolerance Checking: Probes check for any riveting errors in real time during the CNC program cycle.
Leading CNC Riveting Machines
Major machine tool manufacturers offer advanced CNC riveting solutions for high productivity sheet metal fabrication. Some of the top models include:
- Trumpf TruPunch 5000 Series: Offers punching, forming, and riveting in one flexible CNC machine. Equipped with Smart Riveting to monitor and document each rivet joint.
- Amada Astro 100NT & Astro 100NTH: Programmable auto-feed riveting machines with brushless DC motors and servo control for smooth, quiet operation.
- Bystronic Xpert 40 & Bysoft 6: Powerful 40-ton CNC press brake with intuitive software optimized for flexible riveting in short runs.
- LVD Strippit S32X: Built-in servo-electric riveting axis and Smart Rivet Monitoring for consistent quality and zero-defect production.
- Mazak Variaxis C-600: Done-in-one 5-axis riveting/joining cell with multi-tasking capabilities.
The possibilities for computer-controlled riveting in sheet metal fabrication continue to expand. CNC technology enables manufacturers to implement lean, agile, flexible and automated riveting processes that maximize quality and throughput. Riveting remains a fast, strong, and cost-effective method for assembling sheet metal components. CNC Milling