How to Make a Metal Prototype in the Best Way?

At present, metal prototypes have been closely related to many important industries in life, such as automotive, medical, aviation, architecture, aerospace, technical design and other industries.

We will various effective prototyping methods in this article, such as CNC machining, 3D printing (additive manufacturing), sheet metal forming, casting, etc.  Heju Stamping is able to combine multiple processes and provide the best solution for your metal prototyping needs.

What is Metal Prototype?

A metal prototype is a sketch or model of a product in production. Its main purpose is to make it more convenient for designers to verify the feasibility of the method, and to constantly develop and update the required prototype parts. Depending on the prototype manufacturing process, designer can often make different rapid prototypings from a variety of materials. A sheet metal prototype is made by using metal prototype fabrication techniques such as CNC machining, casting or sheet metal forming. They can be made of aluminium, steel or any other materials.

Material Selection for Prototyping? Metal or Plastic?

Generally speaking, engineers can choose a plastic for testing during the early prototyping. Because the early prototype have no functional or mechanical role, it does not matter whether they have certain properties such as strength, ductility, and electrical conductivity. Besides, the cost of plastic is far cheaper than metal. It makes sense to make fast prototyping by using cheap and readily available plastic materials.

But in terms of functional testing, if the part is also going to be produced in metal, then we would have to choose a rapid sheet metal prototype.

Advantages of Metal Prototypes

High-strength metals, especially stainless steel, are characterized by being strong, hard and very durable. This material is often the best choice for rapid prototyping metal. Even during fabrication, metal can withstand almost any external factors and maintain the design perfectly. The main advantages of metal rapid prototypes are as follows:

• Higher heat resistance – Metals have a much higher melting point than plastics. This makes it less likely to be degraded at high temperatures.
• Abrasion resistance – The abrasion resistance of metal is obvious better compared with plastic. This makes metal prototypes last longer and less prone to damage.
• Cost savings – Metal is more cost-effective than plastic in some applications. Because the performance of the metal reduces the frequency of replacement and thus greatly reduces the cost.
• Better visual effects – Metal products tend to be superior and more attractive than plastic products.
• Rapid production – Metal rapid prototyping are easier and more convenient to go into rapid volume production than products that require tooling.

How to Get a Prototype in Metal?

There are many techniques for making rapid metal prototypings. Some prototype sheet metal may be only suitable for one manufacturing process due to their geometry, tolerances or quantities. However, most prototyping parts can be manufactured using a range of different methods. Therefore, we need to find out which method is the best from the point of view of how to achieve the best mechanical effect and keep the cost and manufacturing time to a minimum. Below are some of the most common metal prototype fabrications.

Metal Machining Prototypes

CNC machining is a fairly inexpensive option at the prototyping stage.

CNC machines use computer instructions to guide a metal cutting tool that precisely removes material parts from metal blocks. Custom prototyping require no tooling or MOQ and are relatively affordable. However, due to the subtractive nature of this process, there is some material waste.

The CNC process is available in a variety of metal materials such as aluminum, steel, titanium, zinc, magnesium, etc. In addition, 3–axis, 4–axis, and 5-axis CNC machines provide extraordinary flexibility for manufacturing complex and feature-rich parts.

Advantages

• Low cost
• Design freedom
• Material diversity

Disadvantages

• Some material waste

Metal 3D Printing Prototypes

Metal 3D printing, also known as Direct Metal Laser Sintering (DMLS) and Direct Metal Laser Melting (DMLM). It is another fairly affordable way to manufacture prototype. Like CNC machining, 3D printing uses digital designs as input, making it possible to change designs quickly.

The biggest advantage of metal 3D printing is the flexibility of geometry.

Metal-printed prototypes can be used for very complex features, including complex internal structures, because they are made layer by layer rather than cut from solid blocks.

Several metals are available in AM powder form, which means there are fewer materials to choose from.

In addition, for other forms of custom prototypes, the surface finish of the printed metal prototypes is not high.

Advantages

• Low cost
• Design freedom

Disadvantages

• Parts surface finish is not high
• Material selection is less

Metal Casting Prototypes

Metal casting is the injection of hot liquid metal into a mold that contains hollow grooves or cavities to achieve the desired shape of the finished product. The liquid metal is then removed from the mold and allowed to solidify.

To use die casting, you need to make a mold or tool. The tool can sometimes be recycled thousands of times until it wears out and then replaced with a new one. Casting metal models is more expensive, and while it may ultimately save the customer money in the long run, it is not a one-off appropriate prototype metal method.

Therefore, metal casting is often not considered a more convenient way of prototype manufacturing.

Advantages

• Extremely strong parts;
• production quality.

Disadvantages

• Need expensive tools
• Specialized equipment

Sheet Metal Prototypes

Sheet metal forming processes include laser cutting, stamping, bending, spinning and welding. Prototypes are best suited for stamping and forming sheet metal rather than pure casting or CNC fabrication. Once the cutting has been done, various machines will fold, bend, stamp or otherwise shape the sheet metal to your design specifications. Sheet metal is very solid. Sheet metal prototyping works best with stamping and forming sheet metal instead of purely casting or CNC fabrication. Stamping, cutting, folding, and other processes create complex and beautiful geometries.

Sheet metal is often cold-rolled, giving it superior strength characteristics than cutting across the metals’ grain themselves.

Advantages

• High Quality
• Flexibility
• Range of sheet metal selection
• Inexpensive and fast prototyping

Industries that commonly benefit from prototyping using sheet metal prototype fabrication are medical, communication, and low volume part fabrication.

Metal extrusion prototype

Metal extrusion is another metalworking technique that is not usually considered a prototyping process.

During extrusion, the material is forced through shaped openings in the die, resulting in an elongated part with a uniform cross-section.

The process is suitable for testing and pre-production prototypes, where the extruded metal prototype is  very similar to the final part. It is not recommended for parts that will be produced using any other technology.

Advantages:

Production quality

Disadvantages

Limited range of materials

Conclusion

As an ISO9001 certified metal stamping company with over 30 years of experience, our experienced project managers will help you understand your sheet metal production needs and We will guide you through the materials and processes available so that we can provide you with parts on time and to specifications every time.  If you are looking for a prototyping company to complete your design, please feel free to contact us.