Just as today’s society continues to develop, the sheet metal industry has also rapidly advanced to keep up with increasing consumer demand. Common, everyday examples include chimneys, furnaces, car and other vehicle casings all require sheet metal parts.
Sheet metal is a comprehensive cold working process. It can include work by hand, die stamping, and more to form desired shapes and sizes; as well as forming more complex parts by welding, machining, cutting, punching, compounding, folding, stretching, riveting, splicing, and lots more!
In addition, materials can also be divided into mold processing and non-mold processing operations. Non-mold processing is a high-cost processing method of sheet metal using a CNC punching machine, laser, folding machine, riveting machine and other advanced tools.
Alternatively, mold processing is done through a fixed mold: the sheet metal is added to the mold and this process is mainly used in batch production to decrease the overall cost.
In addition, depending on the different functions of the final products we need to consider the best possible products and materials to use, as well as the cost of these. Generally, the surface of products processed by sheet metal is not as smooth as that milled by turning, but the processing cost will be slightly lower. Weimi has two sheet metal processing machines in total.
We generally use materials that are cold rolled sheets (SPCC), which are formed with a material thickness of ≤ 3.2mm, however as the surface is not protected, it can easily become oxidized when exposed to the air, hence we usually advise customers to use paint spraying or electroplating processes to avoid oxidization.
Hot rolled plate (SHCC): material thickness is ≥ 3.0mm. Also used with electroplating as it’s low cost but difficult to form, though is mainly used for plate parts.
Galvanized sheet (SECC, SGCC): SECC’s substrate is a general cold-rolled steel coil with superior corrosion resistance and decorative appearance. It is highly competitive in the market for electronic products, home appliances, and furniture. For example, the SECC is commonly used when making computer casing and we fulfil many orders of this nature for our customers.
Copper: It is mainly made from conductive materials and can have nickel surface plating, chrome plating, or no treatment; though please note the cost to use copper is very high compared to alternatives.
Stainless steel plate: Generally uses no surface treatment, however, there is a high cost to produce the products. We often buy the raw materials with a protective film as it prevents surface scratching and can also allow customers to purchase products that can be stored for future use, allowing our clients to enjoy discounts for bulk ordering. Below, you will see a hotel decoration accessory we made for an Australian customer – it is made from stainless steel 316.
Should the client not have specific colour requirements for any finished products, the internal sheet metal parts can be rust-proofed by electroplating to ensure any 3D products retain their appearance for longer.
If the customer has color requirements for the finished product, the inner part will usually be anodized, and the exterior will be powder coated to achieve the desired result. The below example is a case we customized for a client and the surface has a blue powder coating.
In addition to the above, general forming process, sheet metal manufacturing is usually combined with other methods of processing to create a fully assembled finished product. These methods most commonly include welding, which allows for a permanent assembly solution when there are multiple parts.
There are many ways of assembling products, including non-welding processes such as screws, rivets, bolts, and more. After assembly, the parts are polished to improve their aesthetic appearance and also remove any dust or residue formed during the manufacturing process.
The quality of sheet metal processing is not only related to the equipment and tools used, but also to the experience of operators and the production processes. Weimi has strict requirements in the production process and performs an independent quality inspection on the sheet metal parts – firstly, checking the size of the products compared to the specification, and secondly checking the appearance and visual quality. Should parts not pass our QC process, we will look to amend or repair if possible and alternatively, we will recycle that parts.
Our quality control processes extend to post-production finishing services as well – we will always check products for their colour, corrosion resistance, coating adhesion, and more. Any parts that do not pass this inspection will be repaired or remade as appropriate. Our clients’ satisfaction is our number one priority!