Riveting in Sheet Metal using CNC Technology(overlapping welding Kyle)

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Riveting is a crucial process in sheet metal fabrication that joins two or more metal sheets together using rivets. With the advancements in automation and computer numeric control (CNC) technology, riveting metal sheets can now be performed with precision and efficiency.
In this article, we will explore how CNC riveting works for sheet metal applications and the benefits it provides over traditional manual riveting.
What is CNC Riveting?
CNC riveting utilizes computer numeric control to automate the riveting process for sheet metals. It involves using a CNC riveting machine that can be pre-programmed to precisely drive rivet pins into the metal sheets to bind them together.
The main components of CNC riveting technology include:
- CNC riveting machine - generally a 3-5 axis riveting machine that can be programmed with riveting instructions. It consists of riveting heads, pressure foot, clincher, and other parts to install rivets.
- Rivet setting tools - consists of punch tools with unique profiles to flare, form and insert the rivet tail into the materials. The tools come in sets for different rivet sizes and types.
- Automated rivet feeding system - vibratory bowl feeders that orient and feed rivets into the machine for automated fastening.
- Software - CAD/CAM programs are used to design the riveting sequence and program the positioning and riveting instructions.
- Computer and controller - the machine is controlled by a computer which executes the programmed riveting sequence.
The CNC machine, tools, and controller work together to accurately drive and set the rivets into the materials based on the programming instructions. Multiple rivets can be installed in a precise sequence within seconds.
Benefits of CNC Riveting
Automated CNC riveting offers immense benefits over traditional manual riveting for sheet metal fabrication:
1. Increased Accuracy and Consistency
The programmable nature of CNC allows for precise control over the riveting process. The force, alignment and location of every rivet can be calibrated to a high degree of accuracy and repeated consistently over hundreds of rivets. This leads to robust and durable rivet joints.
2. Higher Productivity and Efficiency
CNC riveting is extremely fast compared to manual operations. A CNC machine can install hundreds of rivets per hour versus a few dozen by hand. Automated feeding of rivets also minimizes production time. Overall, CNC riveting drastically increases throughput and reduces labor costs.
3. Ability to Rivet Complex Parts
One of the biggest advantages of CNC is the ability to rivet complex and curved geometries that would be impossible or unreliable by manual methods. The programmable axes of motion can access hard-to-reach angles and joints with precision.
4. Flexible and Adaptable Process
The programmable nature of CNC machines allows fast changeovers between different riveting applications. Operators only need to load the CAD file, tools, and rivets to switch the machine over to new parts programming. Easy modifications to the sequence can also be made.
5. Improved Operator Ergonomics and Safety
CNC riveting minimizes the need for the operator to perform tough physical installation of rivets manually. This improves workplace ergonomics and reduces fatigue and repetitive stress injuries. The automated process is also safer compared to using hand tools for manual riveting.
6. Minimal Secondary Finishing
The precision of CNC allows for flush riveting with minimal excess material or deformation. This reduces the need for secondary finishing operations like grinding or filing.
Applications of CNC Riveting in Sheet Metal
Here are some of the common applications where CNC automated riveting delivers benefits for sheet metal fabrication:
- Aircraft and aerospace - fuselages, wings, tail sections using standard or specialty rivets
- Automotive - doors, panels, frames that require a mix of stainless steel, aluminum and steel rivets
- Electronics enclosures - server racks, machine casings using small aluminum rivets
- HVAC ducting and piping - stainless steel sheet metal connections
- Medical equipment - MRI, CT scan, surgical tool housings requiring sturdy rivet bonds
- Furniture and displays - kiosks, sign boards, shelving using aluminum and steel rivets
- Appliances - washing machines, ovens, grill housings benefit from fast CNC riveting
For most sheet metal products, CNC offers reliable and efficient riveting. The automated installation of hundreds of rivets in a matter of minutes results in robust final assemblies.
CNC Riveting Process for Sheet Metal
The typical automated CNC riveting sequence involves the following steps:
1. Design and Programming
The sheet metal components are modeled in CAD software. The riveting locations, patterns, rivet length, and other parameters are defined in the model. This data is converted into machine programming code like G-code which provides instructions for the CNC riveting heads.
2. Fixturing and Setup
The metal sheets are properly aligned and clamped into fixtures or workholding devices. This keeps the parts steady so rivets can be driven perpendicular to the surface. The programmed code is input into the CNC controller.
3. Machine Initialization
The operator loads the rivets into the feeder, positions the pressure foot, checks tools, and initializes the machine. A test cycle may be run to check for errors.
4. Automated Riveting Begins
The operator starts the program cycle. The CNC machine precisely positions the sheet metal workpieces and triggers the riveting head to drive the rivet pin into the materials. This is repeated at lightning speeds to install hundreds of rivets.
5. Rivet Forming
The punch tool forms and compresses the protruding rivet tail to spread it into a formed head seamlessly flush with the metal surface. This tightly clamps the sheets together.
6. Completion
The CNC machine completes all pre-programmed rivet positions. The operator unloads the assembly from the fixture and inspects the quality of connections. The cycle then repeats for the next components.
With CNC riveting, sheet metal of any thickness, hardness and stack-up can be permanently fastened together with efficiency and repeatability for industrial production. The automated integration of CAM programming, precision machine servos, and specialized tooling enable quality and reliable mass riveting. CNC Milling