Sheet Metal Process Optimization (Production Practice)

Sheet metal is a comprehensive cold working process for sheet metal (usually less than 6mm), including a series of processes such as shearing, punching/cutting/composite, folding, riveting, welding, plastic spraying, foaming and assembly, so as to finally meet the needs of users.

As we all know, optimizing the process can not only control the processing cost, and improve the profit margin of products, but also save costs for customers.

Broadly speaking, process optimization is an important means to promote the technological progress of the industry.

However, how to optimize the process is not a small challenge and test for every sheet metal person.

In fact, it is not easy for enterprises.

Bending process improvement cases

Bending refers to the process of changing the angle of plates or plates, such as bending plates into V-shape and U-shape.

It is the most important link in sheet metal processing.

A good bending process can not only ensure the product’s accuracy and surface quality but also quickly flow into the subsequent process, so that the production line can run quickly and efficiently.

As a classic workpiece in sheet metal processing, “Square to Round” (Fig. 1) has been widely used.

In traditional manufacturing, this product is often formed by multiple bending or butt welding, but the forming effect of these two processes is not ideal.

Square to Round workpiece

Fig. 1 “Square to Round” workpiece

If the method of multiple bending is adopted, because the product can not realize the accurate positioning of bending, it is easy to lead to the unqualified appearance and low efficiency of the product;

If butt welding is adopted, the product size will not meet the standard due to the inability of accurate positioning.

Due to a large number of orders, in order to solve these two problems, our company decided to use a special bending die for bending.

Through communication with the supplier, we purchased a set of special dies specially supplied for “Square to Round” production, which were formed at one time through four knife bending, and finally the product quality met the customer’s requirements.

In the case that other large batches of ordinary bending dies are difficult to ensure the product forming quality, our company will actively use special bending dies for production after comprehensively considering the die cost, which not only ensures the product quality but also promotes the reduction of production cost.

Welding process improvement cases

Welding is a very important part of the sheet metal process, which plays a connecting role.

Especially for some workpieces that are not easy to be processed by bending, stamping and other processes, can only be completed by welding.

However, in the welding process, the welded joints often have various problems, such as bubbles, weld beading, shrinkage cavities, cracks, incomplete penetration, weld black ash and serious oxidation.

A good welding process can often get twice the result with half the effort. Taking a dishwasher (Fig. 2) as an example, the plates used in this product are basically 0.8mm thick stainless steel plates.

Due to the thin thickness of the steel plate, it is easy to deform during welding.


Fig. 2 Dishwasher

When there is a certain water pressure inside the dishwasher, the weld should be waterproof, which requires a full welding process.

Full welding is prone to deformation, which deviates from the product requirements of a flat surface and a beautiful appearance.

As all wire drawing plates are used for this product, in terms of appearance protection, only the protective film with a width of about 20mm around the weld shall be removed before welding, and then all the protective film of the wire drawing plate shall be removed after welding, so as to ensure the beauty of the external surface of welding.

In terms of welding deformation control, first fix the corners of the product symmetrically, use small current pull welding and full welding on the periphery and spot welding on the inner side, and constantly debug the welding current of the argon arc welding machine until the welding parameters meet the needs of customers, which not only solves the problem of welding deformation but also makes the welding appearance flat, firm and beautiful.

Welding and post-treatment cases

Spraying, assembly, packaging and other later processes have a vital impact on product quality.

Common problems include metal spraying, unqualified surface rating of paint coating, unqualified protection grade, unqualified overall corrosion rating, etc.

If these problems cannot be effectively solved, they will bury major hidden dangers for product quality, which will not only have an extremely bad impact on the company’s reputation but also cause incalculable losses to customers.

Taking a photovoltaic combiner box (Figure 3) produced by our company as an example, the protection grade of the product should meet the IP67 standard, that is, completely preventing the invasion of foreign objects and dust.

Combiner box

Fig. 3 Combiner box

Prevent the influence of immersion for 30 minutes in water up to 1m deep, which requires the welding process to effectively control the flatness of the product within 0.5mm.

After continuously adjusting the welding current, our company has solved the problem of flatness from the root.

At the same time, the anti-corrosion ability of the product shall meet the C5 standard.

In this regard, our company adopts spraying, electroplating, hot plating and other methods to form a protective layer on the product surface and enhance the anti-corrosion ability of the product.

The whole process of sheet metal processing has a great impact on the product quality level, service life and aesthetics.

Only by continuously optimizing the existing process can the manufacturing level of the enterprise be further improved.

After years of technical accumulation and progress, our company has formed a set of process standards and optimization systems suitable for its own development.


With the continuous expansion of the development scale of the sheet metal industry and the continuous improvement of manufacturing standards, the requirements for the level of sheet metal processing technology are becoming higher and higher.

At present, there is still a certain gap between the traditional sheet metal processing technology and the actual needs of the industry, which determines that the sheet metal process must be continuously improved, and the optimization of the sheet metal process will also promote the continuous development of the sheet metal industry.

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