Polishing Cast Aluminum - Finishing For Aluminum Casting - Sunrise Metal


Aluminum looks beautiful, but its surface gets discolored and fades with time. Due to its nature, it is prone to corrosion, which makes it appear dull as the aluminum oxide layer builds up.  The truth is that proper care and upkeep are required to enhance any metal’s appearance and extend lifespan. Proper polishing is needed to keep the metal in pristine condition. Polishing cast aluminum helps the metal to keep its visual appeal.

Various aluminum surfaces can be covered. In this case, different tools are required depending on the surface to be polished. No matter the tools required, the process is nearly the same.

Different industries, such as aerospace, agriculture, healthcare, electronics, and automotive, need cast aluminum parts. In this guide, you will learn the process of polishing cast aluminum and the various machine options available.

1. Which Situations Do You Need Polishing Cast Aluminum Parts?

There are different benefits and reasons for polishing cast aluminum. These are some of the advantages you should know:

Excellent Finish Quality

 Polishing cast aluminum

It does not matter the business you are engaged in; you have to pay attention to the quality of the manufactured parts you use. Thus, you should ensure the cast aluminum parts you use have superior finish quality. You can only achieve this through polishing.

Since cast aluminum is used in different industries, its finish requirement varies from one industry to another. As a result, there are various finish grades, such as functional grade, consumer-grade, utility-grade, superior grade, and commercial grade.

You have to ensure polishing cast aluminum is done according to each industry’s standards to get the required finish.

Strengthening Aluminum Parts

Cast aluminum can have a few burrs and pits, which can compromise different aspects of the product. Therefore, you need to eliminate these imperfections. Polishing can be used to get rid of such weak spots and strengthen your product.

Prevent the Formation of Aluminum Oxide

You should note that aluminum can react with oxygen to produce aluminum oxide. Therefore, when the surface of an aluminum cast part is not protected, it can result in oxidation. By polishing cast aluminum, you improve its resistance and prevent corrosion.

2. How to Polish Cast Aluminum Products?

 Polished cast aluminum parts

You can use the cast aluminum polishing machine to clean, remove burrs, and polish the part. The part must be fed into the machine with polishing media. In this case, the output is the polished aluminum part. The time it takes to polish the part depends on the type of machine you use and the level of polishing desired.

Media that you feed to the polishing machine with cast aluminum parts is known as vibratory tumbling media. It is available in varying abrasive strengths. You should choose tumbling media that suits your desired polishing needs.

For example, smaller tumbling media is perfect for tiny and small parts. Nowadays, you can get tumbling media in customized sizes and shapes. Different materials are used to make tumbling media.

3. What are the Advantages of Using Machines for Polishing Cast Aluminum?

Traditional methods of polishing cast aluminum are tedious and time-consuming. Moreover, they are not suitable for mass polishing. These are some of the benefits you can enjoy when you use cast aluminum polishing machines.

Save Time

In your business, the output is an important factor. The process of manual polishing is labor-intensive and time-consuming. As a result, the output is low. When you use machine polishing, you can polish many parts at the same time.


In the aluminum polishing process, you have to meet two types of costs. These are labor costs and equipment costs. For the traditional polishing process, you may need to employ more workers. Fortunately, for machine polishing, you need to make a one-time investment.

Few skilled workers can operate most cast aluminum polishing machines. Thus, it becomes cost-effective in the long term.

Batch Polishing Capability

With polishing machines, you can polish several parts at the same time. Although machines support batch polishing, it all depends on part size. If you have small pieces, then you can polish different components together.

High-Quality Finish

As you know, customers consider the cast aluminum quality before buying. With traditional polishing techniques, it is difficult to achieve a high-quality finish. Fortunately, machine polishing delivers an excellent, consistent finish. Thus, your parts can always match the expectations of your customers.

Less Damage

Machine polishing is less prone to causing surface damage. That is because the chance for error is minimal. However, you have to ensure you use appropriate cleaning media. Thus, you can be guaranteed damage-free polishing.

Lower Maintenance Cost

The truth is that the use of machines involves maintenance. Fortunately, the modern machines used in polishing cast aluminum require minimal maintenance.

4. What Types of Machines are Used for Polishing Cast Aluminum?

When choosing machines for polishing cast aluminum, you should consider your desired finish quality and the size and shape of parts you want to polish. These are the main types of machines you should use:

Vibratory Finishing Machine

This machine is suitable for polishing small and medium-sized parts. The machine is capable of cleaning, deburring, and polishing cast aluminum parts. You should use it with the right tumbling media.

vibratory finishing machine

The good thing about this machine is that it is easy to maintain and operate. It can consistently deliver an excellent finishes at a lower price. Also, it improves the surface of the part with the tumbler media.

You should note that the vibratory finishing machine is widely used in the industry. The compact design of these machines makes them suitable for most workshops. Depending on the size of the parts, you can put several parts in the chamber at the same time.

Most vibratory finishing machines have soundproof covers to protect workers. Other features you may like about these machines are automatic feeding and control. Unlike the centrifugal finishing machine, these machines provide gentle movement force, which improves the surface smoothness.

Tub Vibratory MachineTub Vibratory Machine

This type of machine is designed for polishing large cast aluminum parts. Ideally, the machine has different separators that allow you to load parts with the tumbling media.

Separators are quite important as they ensure parts do not get into contact. In this way, damages resulting from the collision are minimized. If you want to polish large parts, then this is the perfect machine.

VA Centrifugal Machine

VA Centrifugal machine

This type of machine is suitable for polishing tiny and small cast aluminum parts. Another thing you may like about this machine is its ability to support batch processing. With this machine, you can polish several parts at the same time. Also, it provides smoothing and fine polishing.

Industrial Barrel Tumble

Industrial Barrel Tumble

This is a large machine for polishing aluminum cast parts. Ideally, you can use this machine for material removal from the parts. You will find it to be an economical solution for mass polishing. Thus, if you have large parts that you need to polish, this is the perfect machine.

5. What Types of vibratory Media for Polishing Cast Aluminum Parts are Used?

Porcelain Tumbling Media

Porcelain Tumbling Media

If you need non-abrasive media, then you should consider porcelain tumbling media. This media does the work of polishing and burnishing. The media contains white clay plus other components, such as kaolin and alumina.

Porcelain tumbling media is suited for the final polishing stages. If you want a better shine, you should use wet tumbling. Ideally, you can use the media with any shining solutions and water.

The good thing about porcelain tumbling media is that it has a longer lifespan than other deburring media.

Plastic Tumbling Media

Plastic Tumbling Media

This media consists of polyester resins and abrasives. You will find it suitable for getting rid of marks due to machining on the cast aluminum.

You will find plastic tumbling media available in different shapes, such as the pyramid, cone, triangle, and tristar shape. The shapes are available in different sizes.

Plastic tumbling media offers multiple cutting grades. These are medium cutting, fast cutting, light cutting, and ultra-fine cutting. If you aim to get rid of more material from your aluminum cast parts, it is recommended to use a higher cutting grade media.

Stainless Steel Media

Stainless Steel Media

Stainless steel media is perfect for aggressive polishing to minimize the polishing time. Another thing you will like about this media is its longer lifespan. In fact, it can be used for over a decade, and it is perfect for aluminum die-cast parts.

It is also available in different grades and different shapes, such as diagonal, magnetic pins, balls, and more.


6. What Are the Different Types of Aluminum Cast Parts Suitable for Polishing?

Motorcycle Parts

Aluminum motorcycle parts are big and long. In this case, you can use the vibratory machine with a separate chamber to polish different motorcycle parts simultaneously. Common cast aluminum parts used in motorcycles are wheels and frame.

Automotive Parts

polished aluminum piston engine

There are many cast aluminum parts used in vehicles. Such parts need an excellent surface finish. Thus, professional polishing is necessary. If the parts require additional processes such as electroplating or anodizing, polishing is necessary.

You can use a tub vibratory or vibratory finishing machine to polish automotive aluminum die-cast parts. For a better shine, you should use less abrasive media.

Some automotive parts that need to be polished are pistons, enclosures, wheels, pistons, and other aluminum cast parts.

Cookware Parts

polished cast aluminum cookware

You have probably noticed that most of your kitchen cookware pieces are made of cast aluminum. After years of use, the discoloring and corrosion do not do them any good. Hence, there is a need to polish them.

Most customers prefer cast aluminum because of its excellent heat retention. Some examples of cast aluminum cast cookware are frying pan, frying pot, and dishwashers.

Mechanical Components

polished cast aluminum bearing housing

You can find cast aluminum parts used in different mechanical systems and equipment. Cast aluminum parts boost mechanical properties.

However, their performance becomes compromised due to the formation of the aluminum oxide layer and scratches. Hence there is a need to polish them.  A good example is cast aluminum bearing.

Marine Parts

Cast aluminum has many properties that make it suitable for making marine and boat parts. For instance, it is strong, robust, durable, and easy to repair. Boats made of aluminum are safer.

Some of the cast aluminum parts that can be polished are cabins and decks.

Electronic Parts

polished cast aluminum closure

Cast aluminum has excellent electrical performance and can be used in high-temperature environments. For instance, it is used to make electronic enclosures that require regular polishing.

Most of the cast aluminum parts used in electronics are small in size. Therefore, you should do polishing in the right machine and use appropriate media. You can use a centrifugal disc finishing machine or a barrel tumbler.

Healthcare Parts

 polished stethoscope housing

If you look around in any given hospital, you will discover many fittings and equipment made of cast aluminum. That is because cast aluminum can easily meet the stringent safety standards and requirements of the medical sector.

Some of the parts you can polish are the surgery table, stethoscope housing, and surgical instruments.

7. How to Check the Quality of the Polishing Casting Parts?

You should note that polishing requirements vary depending on the production needs and applications. It is advisable to work with a company that is well-versed in the polishing requirements of your given industry.

Sunrise Metal provides excellent quality verification services, such as non-destructive testing and static balancing. Thus, you can be assured your finished part is ready for use. Also, all the components undergo extensive quality checks at different stages.

Sunrise Metal eliminates all defects and ensures all controls and processes are improved per international standards. The product quality is improved by constantly reviewing the polishing cast aluminum process.

Sunrise Metal has also invested in high-end machines to guarantee the quality of polished cast aluminum parts. Some of the top machines for quality assurance you will find in Sunrise Metal are X-ray detectors and Zeiss CMM. The company is also ISO 9001 and IATF 16949 certified as a demonstration of its commitment to quality.

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