Sofa legs are crafted from aluminum alloy stamping materials, which are relatively softer compared to iron, more expensive, and prone to breaking. Some aluminum alloy products require subsequent processing such as brushing, powder coating, bright chrome plating, and anodizing. During the stamping production, it is particularly easy to produce top injuries and scratches.

 

Attention Points for Hardware Accessory Manufacturers in Die Manufacturing:

1. Hole Punching Process: Manufacturers will arrange the hole punching process for sofa legs to be the last procedure when it does not affect the normal production process. For sofa legs with a large number of holes, an additional process may be considered to ensure hole punching is done last.

 

2. Material Softness and Die Clogging: If aluminum material is used for furniture accessories, the aluminum is relatively soft, and the die is more prone to clogging. Therefore, when designing the die clearance, it is appropriate to set the clearance at 10% of the material thickness on both sides. The blade depth should be about 2mm, and a taper of 0.8-1° is suitable.

 

3. Bending and Forming: Since aluminum is prone to producing burrs during bending, which can cause indentations, production technicians will apply a PE film to the aluminum blank. For forming blocks under rolling and electroplating conditions, it is best to polish and hard-chrome plate.

 

4. Post-Surface Treatment Processing: For sofa leg stamping parts that require post-surface treatment processing, such as 180° flattening or pushing, the product should not be completely pressed together. Complete pressing can cause acid spitting. A gap of 0.2-0.3mm should be left to allow the acid liquid to flow out smoothly and in a timely manner. Therefore, in the process, a positioning block will be made, and the die will be set higher than the mold.

 

5. Fragility and Cracking: Aluminum material is brittle and prone to cracking, especially when bending the edge in reverse. Therefore, production technicians generally avoid making score lines. If necessary, the score lines should be made wider and shallower.

 

6. Wire Cutting for Aluminum Parts: All aluminum part blades must be wire cut using slow wire electrical discharge machining to prevent burrs and ensure smooth material ejection. Aluminum parts are prone to high temperatures, so the hardness of the stamping punch should be above 60°, at least made of SKD11 material or above, and should not have inferior quality punches such as D2.

 

As mentioned above, aluminum material is soft during processing, making it very susceptible to top injuries, press injuries, scratches, and deformation during stamping production. In addition to the requirements summarized above for the mold, there are also points to note and process requirements during the stamping production.

 

Process Requirements for Sofa Leg Stamping Production:

1. 5S Management: To ensure good aluminum part stamping and reduce the defect rate, the first step is to implement 5S management (originating from Japan, referring to the effective management of production elements such as personnel, machinery, materials, methods, etc., at the production site), especially cleanliness. This includes keeping molds, press machine tables, assembly lines, and packaging materials free from sharp objects and dirt, regularly cleaning up, and keeping the molds clean and free from debris.

 

2. Burr Management: If there is a significant burr on the sofa leg products, accessory manufacturers need to promptly send molds for repair and follow up on the results.

 

3. Heat Generation: Aluminum parts are prone to heat up and harden when piled together, so production technicians need to apply pressure plate oil (which helps with heat dissipation and smooth material ejection) to the material before stamping when punching.

 

4. Cleaning After Punching: For sofa leg products with many holes, it is necessary to clean the mold surface after each punch to keep the mold and product clean and free from debris, reducing top injuries. If top-injured products are found, the mold injury points need to be identified and resolved before continuing production.

 

5. Cleaning of Pushing Blocks: Pushing blocks in the leveling mold will produce aluminum shavings, so it is necessary to clean the aluminum shavings under the pushing blocks every day after production.

 

Cold Stamping Production Process for Sofa Legs:

I. Process Flow in Stamping Workshop:

- Raw materials (sheets and coils) are stored → Uncoiling line → Large parts are cleaned and oiled, small parts are uncoiled and sheared → Stamping production line → Mold installation and first piece adjustment is qualified → Mass production → Qualified parts are rust-proofed → Packaging and storage.

 

II. Concept and Features of Cold Stamping:

1. Cold stamping refers to a pressure processing method that uses a stamping die installed on a press to apply pressure to the material at room temperature, causing it to separate or plastically deform, thereby obtaining the required parts.

 

2. Features of cold stamping: The product size is stable, the precision is high, the weight is light, the rigidity is good, the interchangeability is good, it is efficient and low in consumption, easy to operate, and easy to automate.

 

III. Classification of Basic Cold Stamping Processes:

Cold stamping can be summarized into two major categories: forming processes and separation processes.

 

1. Forming Processes involve the plastic deformation of the blank without rupture to obtain a stamping with a certain shape and size.

 

Forming processes include: drawing, bending, flanging, and trimming.

- Drawing: A stamping process that uses a drawing die to turn a flat blank (workpiece) into an open hollow part.

 

- Bending: A stamping method that bends sheet material, profiles, tubes, or bars to a certain angle or curvature to form a certain shape.

 

- Flanging: A stamping forming method that turns the material along a certain curvature into an upright edge on the flat or curved part of the blank.

 

2. Separation Processes involve separating the sheet material along a certain contour to obtain a stamping with a certain shape, size, and cutting surface quality.

 

Separation processes include: blanking, punching, notching, and trimming.

- Blanking: Separating the material along a closed curve, where the part inside the closed curve is the blanked piece.

 

- Punching: Separating the material along a closed curve, where the part outside the closed curve is the punched piece.a