Metal Stamping China — Top 5 Things to Consider
Metal stamping in China can be challenging but very competitive when done right. Here are 5 top things to consider when sourcing stamped parts from China.
This blog article was first published on www.sourcingallies.com
China has continued to be a preferred manufacturing location for Amazon sellers despite the trade tensions in the recent times. Among the multitude of products sourced from China are stamped metal parts that find numerous applications in different industries.
Whether you are looking to source door handles, lighting parts, metal latches or other stamped metal parts for various industries and applications, you will need to consider these top five factors:
#1: Understand the basics of metal stamping
Before you start contacting suppliers in China for sourcing stamped metal parts, it is important for you to know the basic technology and processes used in metal stamping. This will help you gauge the expertise of the manufacturer in China and the processes they follow.
Metal stamping is also described as a cold-forming process or pressing where stamping presses and dies are utilized to transform flat sheet metal into desired shapes. Flat sheet metal pieces, typically called blanks, are fed into the stamping press featuring a die and tool surface that creates a new shape out of the blanks.
Custom metal stamping is the metal forming process where custom techniques and tools are used to produce specific parts for customers.
Metal fabricators and production facilities that offer stamping services place the stamping material in between die sections. The pressure applied will shear and shape the material into the final desired shape for the component or product.
There are numerous applications of metal stamping particularly in terms of three-dimensional (3D) lettering, designs as well as other surface engraving features. These metal stamping products are typically manufactured for home appliance manufacturers, the lighting industry, automotive companies, retail products, aerospace industries, telecommunications services, electronics companies and medical equipment manufacturers.
Every household is sure to have a product where the parts have been created using metal stamping from cars to household appliances.
The specific components and parts can include simple stamping items (springs, metal clips, brackets, weights and washers) to complex designs and components such as the ones seen in friction plates or engine bases. This specialized process can produce large machinery parts as well as incredibly detailed smaller parts. Parts that have minute diameters of 0.02 inches can also be produced with micro-precision stamping.
Metal stamping is also used to make electronic components through electronic stampings such as lead frames, pins, springs, contacts and terminals. These products find application in a variety of industries right from telecommunications, home electronics, aerospace and home appliances. A number of metals can be produced with electronic stamping including aluminium, steel, copper, copper alloys and expensive metals including gold and platinum.
Metal stampings are also widely used in electronic equipment, medical devices and computers. With various stamping processes, specialized shapes can be created and the cold forming process is used for making many electronic components.
Stamping operations can be performed along with other metal forming operations and usually there are a series of specific techniques or processes involved such as:
Blanking and punching are processes where a die is used to cut the sheet material into desired specific forms. For punching, a scrap material piece is removed from the workpiece when the punch enters into the die, leaving a hole in the material. On the other hand, in blanking, the workpiece is removed from the original material and the removed component is the desired blank or workpiece.
Embossing refers to a process of creating a recessed or raised design in the flat sheet metal. This is done by passing the blank material through the roller die or pressing the blank against the die containing the desired shape.
Coining is a technique of blending wherein stamping is done on the workpiece which is placed between the punch/press and die. Because of the pressing action, the punch tip penetrates the metal and produces repeatable, accurate bends. The deep penetration also removes any internal stresses in the workpiece.
Bending is a general technique of creating desired shapes out of sheet material such as U, V or L, shaped profiles. Flanging is a process where a flange or flare is introduced into the metal workpiece by using presses, dies or specialized flanging machinery.
Metal stamping machines can go above just stamping and can punch, cut, cast as well as shape metal sheets. Machines can be numerically controlled by a computer or programmed to offer repeatability and high precision of each stamped piece.
#2: Technology and quality
Irrespective of the industry you are catering to and what component you need manufactured, your top priorities are to ensure quality and precision. The first step when shortlisting custom metal stamping manufacturers in China is to understand what type of metal stamping they can undertake, the tools and technology used as well as the quality assurance process they follow.
Precision metal stamping creates dimensionally accurate components while being manufactured according to the requirements that you or your customers specify. Some of the aspects you need to look into when sourcing stamped metal parts from China include:
Types of stamping they do
The type of stamping you require will depend on the industry or application of the product/component. For instance, deep draw stamping is a technique of a sheet metal blank is pulled through a punch into a die to form a shape. This type of metal forming is suited for creating components with a range of diameters and ideal for producing aircraft parts, automotive components, utensils/cookware and electronic relays.
Check if the manufacturer has machines and technology that can cover almost all types of metal stamping including progressive metal die, compound die stamping and single punching stamping. If you have varying needs for stamped metal parts, the manufacturer should be able to handle all of your requirements instead of referring you to different manufacturers.
Apart from deep drawing, the other common types of stamping that you may require include:
Progressive die stamping- In this technique, a series of sequential stamping stations are used where each step performs a specific punching operation, bend or cut on the metal to progressively and gradually achieve the desired shape and design or the end product.
Transfer Die Stamping- In this the part is transferred between stamping stations using a mechanical transport such as conveyor belt system.
Four-Slide Stamping- Also called four-way stamping, four-slide stamping is used typically for complex components with multiple bends or twists. Two slides horizontally strike the workpiece to shape the material.
Fine Blanking- Fine blanking produces smooth edges and high accuracy finishes and is usually done on a mechanical or hydraulic press.
The stamping process and certification
Check how many metal stamping machines the manufacturer has and whether they use hydraulic or mechanical presses.
Mechanical presses utilize a motor connected to a flywheel for transfer and storage of energy. The size of the punches in mechanical presses can range 5 to 500mm while the speed of the presses also varies and the per minute value can typically be within the bracket of 20 to 1,500 strokes. If your requirement is for simpler and shallower parts from sheet metal, the mechanical presses may be the ideal choice. These presses are used for progressive as well as transfer stamping for large production runs.
Hydraulic presses feature pressurized hydraulic fluid for force application on the material. Hydraulic pistons allow consistent pressure to be applied as well as provide an advanced level of control on the extent of pressure exerted. The size of the presses can be from 20 to 10,000 tons where stroke sizes can vary from 10 to 800mm. These presses are more suited for smaller production runs and can create deeper and more complicated stamping as compared to mechanical presses.
Ask if the manufacturer has ISO 9001: 2008 certification and state-of-the-art technology. The other desirable technology features include the use of CAD (computer aided design) packages such as Cadkey and AutoCAD and 3D packages including SolidWorks and Creo. These advanced systems can ensure precision design and manufacturing of custom metal stamping products.
The other factors involved in custom metal stamping is the choice of metal which varies depending on the finished product’s attributes. The customary metals fabricated with stamping include:
- Precious metals including platinum, gold and silver
- Ferrous metals such as stainless steel
- Non-ferrous metals including zinc, brass and bronze
- Beryllium nickel or beryllium copper and other non-standard alloys
Also check the manufacturer’s website to know the kind of technology and quality measures the manufacturer employes for different processes of metal stamping such as:
Stamping process: Blanking
Metal: Black sheet
Technology and quality standard: CNC measuring technology
Stamping process: Punching
Technology and quality standard: Own measuring rooms
Stamping process: Embossing
Metal: Carbon Steel
Technology and quality standard: SPC documentation
Stamping process: Flanging
Metal: Stainless steel
Technology and quality standard: Creation of logs
Stamping process: Stretching and bending
Metal: Brass and copper
Technology and quality standard: ISO 9001:2008 /ISO/TS16949
#3: Ask for samples
One of the best ways to ensure the supplier adheres to your quality specifications for custom stamped metal parts from China is to ask for samples. Before placing your order make sure to request samples.
If the first sample that the manufacturer sends does not meet your specifications, write down the issues that you have observed and communicate the same to the custom stamped metal product manufacturer. Ensure that the China supplier has understood the changes you require and can provide you with a sample of the modified version.
The supplier will be interested in meeting your exact standards when they know that the volume of the order is high. This is why it is recommended that you give the supplier an idea of how many stamped metal parts you need.
#4: Inspect the factory and the process
A crucial part of the process of sourcing from China is the factory inspection process. To ensure the custom metal stamping manufacturer has the necessary technology, machines and quality processes, the best way is for you to personally visit the factory. For most business owners in the U.S. or EU, this can be very difficult and expensive.
While you can check the manufacturer’s website, licenses, ISO certification and evaluate the sample, there is no way to make sure the factory has state-of-the-art metal stamping technology unless you visit it. Partnering with a China sourcing agent can solve this problem as the agent has an office in China and can visit and conduct an audit on the factory on your behalf.
#5: Work with a sourcing agent specializing in custom metal stamping
One of the top reasons why Amazon sellers and other businesses in Europe and the U.S. look to source from China is the cost advantage. While China can fulfill your requirements of low cost metal stamping manufacturing, working with a China sourcing agent who specializes in custom metal stamping can give you distinct advantages.
Cost, while being important, is only one of the aspects to look at when sourcing from China. The other crucial aspects that can influence the success of your business include quality, reliability, turnaround time and communication.
One of the first hassles that many sellers face when sourcing from China is the difficulty of finding the right manufacturer or factories for custom metal stamping manufacturing. A specialized sourcing agent can step in here and help you in zeroing in on the right factory equipped with the range of tools, techniques and technology for custom metal stamping.
The second most common challenge that you will face comes while negotiating the prices, evaluating different quotes and ensuring the manufacturer understands your stringent technical specifications.
The sourcing agent, who has an office in China, can negotiate on your behalf in the local dialect ensuring the manufacturer and the factory workers understand your expectations while getting you the best quotes and deals. The sourcing agent’s support is invaluable in terms of conducting factory inspection, verification of the supplier’s authenticity and in ensuring the parts reach you on time.
Your sourcing agent helps you find reliable custom stamped metal parts manufacturers who are detail oriented and who are willing to provide you with a sample for your evaluation even before you book the order.