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sheet metal parts Common connection methods

Sheet metal parts are very common in our daily work and life. For example, car bodies, equipment shells, safes, furniture supports, electrical accessories and chassis, computer component cabinets, and now new energy battery boxes, etc. Due to different manufacturing processes and usage requirements, engineers have developed various connection methods. These processes not only solve the connection problems quickly and economically, but also bring great convenience to our lives.

The common connection methods for sheet metal parts include 

flanging riveting, 

Definition:

This is a fastening process where the protrusions of a metal part are pre-joined with the through holes or slots of another workpiece. Then, using a round punch, the peripheral walls of the protrusions are flipped and tightly pressed onto the surface of the slot or plate of the other workpiece, thereby connecting the two workpieces.

2. Flanging Riveting Elements:

1) Bud Formation: A type of stamping process where the iron piece is stretched outward to form a cylindrical shape.

A. Process Steps: Pre-stamping - Stretching (multiple stages of stretching).

B. Pre-stamping: It affects the shape and height of the bud.

Without pre-stamping, the front end of the bud becomes a lotus shape, resulting in cracking.

C. Control Parameters: Bud height / Outer tightness / Wall

2) Salad: When connecting thicker workpieces, the connection surface often needs to be pre-stamped. The main purpose is to facilitate the flanging adhesion and also has the function of automatic alignment during riveting.

3) Riveting: A. Head Shape: Conical

B. Fit Tolerance (Outer Diameter of Bud / Hole): Single side 0.05 - 0.1mm

3. Common Failure Modes and Prevention

1) Riveting Loosening: Rivets come loose under tension, shear force, or other cyclic loads. Cause: The flange did not fully expand, the flange pressing area was too narrow, and the flange broke. Prevention: A. Ensure the protrusion height is appropriate, avoiding a continuous or conical shape. B. Increase uniform sanding, apply pre-pressure during riveting to avoid assembly misalignment before riveting.

2) Excessive Riveting: The protrusion of the rivet after passing through the flange exceeds the allowable height. Cause: The flange did not fully expand, the wall thickness of the rivet was too thick. Prevention: Reduce the wall thickness, increase the riveting force, increase the cone angle of the riveting punch, etc.

3) Workpiece Deformation in Riveting Area: Distorted protrusions and depressions around. Cause: Riveting is too rigid, the template deforms. Prevention: Set limits for the mold or machine, perform regular maintenance on the mold.

Tox riveting, 

Definition:

A type of stamping process that connects two sheet metal parts by forcefully stretching or compressing the materials, causing plastic deformation of the materials and allowing one part to be embedded into the other.

2. Toxing connection devices

All are: Tox integrated special machines

3. Tox bonding performance

4. Tox riveting quality control

Riveting Wall Thickness - Equipment Monitoring System/Wall Thickness Gauge

Rivet shape - upper and lower mold shape, fit tolerance/visually complete dovetail

5. Application examples

1) D/T chassis self riveting/riveting; 2) Multiple connectivity of server chassis

stud riveting,

1. stud riveting, are divided into two types: flat headed and round headed (also known as umbrella shaped). The riveting of flat head rivets must have a salad hole on the side in contact with the rivet head. The riveting of round headed rivets has a flat contact surface.

   
   

2. Definition: Two parts with through holes are connected by pulling the pull rod with a nail gun until it breaks, causing the outer nail sleeve to expand and become a non removable connector.

3. Working principle and comparison of equipment used

1) Hollow quick riveting: compression rivet, hydraulic nail gun

2) Core pulling riveting: Pull type rivets, pneumatic rivet gun

4. Application examples

A、 Quick rivets: commonly used for servers

B、 Blind rivets: mostly used for PC

 resistance spot welding

1. Definition and working principle

Electrowelding is a welding method that connects metal workpieces together. By applying, controlling, and maintaining a certain pressure between the welded workpieces, a stable contact resistance is formed between the workpieces. Then, the control current output by the welding power controller flows through the contact surface between the welded workpieces, generating heat, increasing the temperature, locally melting the contact points, and controlling the amount of heat and the process. Thus achieving the goal of welding metal workpieces together.

2. Heat distribution and weld core shape

3. Common Methods

 screw connection. 

1. A detachable connection method.

2. Common methods: A. White tapping bud screw

B、 Attacking buds+screw connection

C、 Rivet stud/nut+screw

3. Common tools: pneumatic screwdriver/electric screwdriver, etc. Control parameter: Torque (KG. CM/LBS. INCH)