Riveting in Sheet Metal Using CNC Technology(rivet types Cash)

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Riveting is a crucial process in metal fabrication and manufacturing. It involves joining two or more metal sheets or plates using a metallic fastener called a rivet. The rivet is inserted into pre-drilled holes in the materials being joined and its shank is then deformed to clamp the materials together.
Riveting used to be done manually using simple hand tools. But with the advent of computer numerical control (CNC) machines, automated riveting is now possible, even for complex jobs. CNC riveting streamlines the riveting process, improves consistency and quality, and reduces labor costs.
Benefits of CNC Riveting
Here are some of the major benefits of using CNC machines for riveting tasks:
- Increased speed and efficiency. CNC riveting is much faster than manual riveting. CNC machines can install hundreds of rivets per hour versus just a few dozen with manual work. This results in faster production and reduced labor costs.
- Improved consistency and quality. CNC machines apply optimized pressure and force so that all rivets are deformed to precise specifications. This results in consistent and high-quality rivet joints.
- Reduced errors. Automated machines eliminate human errors in rivet placement and installation. The CNC program guides the machine for precise hole alignment and rivet setting.
- Flexible production. CNC machines can be programmed for different riveting patterns and sequences. This makes them ideal for high-mix, low-volume production. Switching jobs on a CNC machine takes minutes versus hours with manual setups.
- Ability to rivet complex jobs. Intricate riveting applications like contour following are very difficult and slow to do manually. But CNC machines can be programmed to handle complex riveting tasks with ease.
CNC Riveting Process
The basic process for CNC riveting involves three stages: hole drilling, rivet insertion, and rivet setting.
1. Hole Drilling
The material sheets to be riveted are loaded into the CNC machine. The machine drills holes at precise locations in the materials based on the programming. CNC machines use specialized drilling heads that allow for multiple holes to be drilled simultaneously.
High spindle speeds combined with peck drilling cycles ensure excellent hole quality and diameter accuracy. The dust produced during drilling is also effectively evacuated by the machine.
2. Rivet Insertion
After drilling, the CNC machine automatically inserts a rivet into each pre-drilled hole. For automation, the machine uses a feed system that supplies rivets from a vibratory bowl feeder or tape reel.
Sensors detect when the rivet is successfully deposited in the hole while machine vision systems help align the rivet for proper insertion.
3. Rivet Setting
In this stage, the inserted rivets are upset to deform the shank and clamp the materials together. The riveting head of the CNC machine uses a pneumatically driven rivet set to apply squeeze force and upset the rivets.
Different rivet profiles like round head, countersunk head, and flush rivets can be accommodated by changing the rivet setting tools and programs. The force applied by the machine is modulated to avoid damage while ensuring the rivets meet set specifications.
CNC Riveting Using Robotic Arms
For maximum automation and flexibility, articulated robotic arms integrated with CNC controllers can carry out drilling, riveting, and fastening tasks.
Robotic CNC riveting provides these advantages:
- Multi-axis riveting capability for complex parts and irregular surfaces like airplane wings or fuselage.
- Complete automation from loading to drilling to riveting.
- High flexibility for easy switching between different applications.
- Compact, portable robotic units take up very little floor space.
- Lower equipment investment compared to large gantry-style CNC machines.
- Ability to reach confined spaces and rivet hard to access areas.
- Safer operation with enclosed work-cell that separates robot from human workers.
The robot arm is pre-programmed to move over the workpiece surface and position the riveting end-effector accurately at each fastener location. Force feedback, motion control, and machine vision enable the robot to drill holes, insert rivets, and upset them to specification.
Multi-axis access allows riveting of parts in almost any orientation. And the robot can be quickly changed over to another application by loading the appropriate program.
Key Considerations for CNC Riveting
To implement automated CNC riveting, here are some important factors to consider:
- Part design - Optimize part geometry and hole patterns for CNC riveting during the design stage itself. Avoid awkward angles and access issues.
- Fixturing - Proper workholding fixtures that can secure parts firmly without deformation are a must for vibration-free CNC riveting.
- Hole quality - Precise hole diameter and surface finish are vital for good rivet seating when using a CNC machine.
- Rivet specs - Select optimal rivet material, diameter, and grip length to suit part thickness and required joint strength.
- Riveting heads - Tooling must be selected to suit different rivet types and materials - aluminum, steel, titanium, etc.
- Machine capacity - Look for CNC machines or robots with enough drilling spindle power, force generation, and axes range for the riveting work.
- Software - User-friendly CAM software makes programming of complex riveting patterns simpler.
With careful planning and selection of proper equipment, manufacturers can implement automated CNC riveting to boost productivity, quality, and profitability. CNC Milling CNC Machining