Choosing Mass Finishing Media for Better Process Efficiency

Choosing the Right Mass Finishing Media Matters

Selecting the correct mass finishing media is one of the most important decisions in any surface finishing process. The wrong media can increase cycle times, damage components, reduce finish quality, and create inconsistent results across batches.

At ActOn Finishing, we help manufacturers select the most effective finishing media based on:

• Part material
• Component geometry.
• Required surface finish.
• Process type.
• Production throughput.

Whether you are using ceramic media, plastic media, or walnut shell polishing media, the correct selection improves process efficiency, finish consistency, and operational reliability.

Ceramic vs Plastic Media

1. Ceramic Media

Ceramic media is commonly used for:

• Faster material removal.
• Deburring metal components.
• Edge radiusing.
• Surface smoothing.
• Pre-polishing operations.
• Finishing hard materials.
• Burnish or highly polish finish.

Ceramic media is:

• Dense
• Aggressive
• Long-lasting

It is often selected for:

• Hardened materials.

Because it is aggressive it is important to not use it to process components made out of soft materials, as it will damage the shape easily.

Choosing the right shape and size

Size:
The component finish is also subject to the size of media chosen. A larger media will generate higher energy; hence it will cut and finish faster with higher wear rates. This is also recommended for processing larger parts.

A smaller media can hold more water and compound resulting in less part-on-part damage. Also, a smaller media has a gentler impact on part, which results in longer processing times, better finishes and less media wear.

Generally, media size has to be of a different size to the part to allow complete separation at the end of the finishing process. If media is larger than parts, then an inverse separation system can be used. For ferrous components, magnetic separation is also available.

Shape:
When choosing the shape of the media it is important to consider the geometry of the part – hence any lodgement of media can be avoided and the part finish will be consistent.

A flat sided media, such as triangles, tri-stars, wedges and the end side of cones, can generate longer surface contact time on edges for deburring and radiusing. However, round shaped media, such as balls, cylinders and cones generate a single point contact concentrating energy in one small point, therefore producing more work in that area.

For components which have corners, holes and slots both TriStar media and wedge media are recommended, minimising the possibility of media lodgement.

For surface improvement of hard to reach areas, an ellipse or cylinder shape can be considered.

2. Plastic Media

Plastic media provides a lighter and less aggressive finishing action.

Typical uses include:

• Softer metals like Aluminium, Copper, Brass, Gold and Silver.
• Delicate finishing operations.
• Cosmetic surface preparation.
• Applications requiring lower material removal.
• Smooth finishing.

Plastic media is commonly used where preserving dimensional accuracy or reducing surface damage is critical.

Compared with ceramic media, plastic media generally:

• Produces smoother finishing action.
• Generates less aggressive cutting.
• Reduces part impingement risk.
• Works well with softer materials.

3. Agro Media

The maizorb grains have high abrasion resistance, good moisture absorption and low specific gravity. This agro product is best suited for drying, cleaning and polishing components.

Walnut shells are hard and fibrous, and are known as ‘soft abrasive’. Being extremely durable, walnut shells are used for the cleaning and polishing of heat-treated components, jewellery, surgical components, watches, etc.

Then you have the pre-treated maizorb: developed to produce a bright mirror finish. This can be used both in vibratory and high energy machines.

The pre-treated walnut shell imparts high lustre on components. It has been proven that on certain materials, pre-treated walnut produces a much brighter finish than pre-treated maizorb.

FAQs

1. What is ceramic media used for in mass finishing?

Ceramic media is commonly used for deburring, edge radiusing, surface smoothing, and faster material removal on hard metal components.

2. When should plastic media be used?

Plastic media is typically used for softer materials, delicate components, and applications where lower aggression and improved cosmetic finishing are required.

3. How do I choose media for my part?

Media selection depends on part material, geometry, finish requirements, machine type, and the amount of material removal needed.

4. Why does media cost vary by quantity and process?

Media pricing depends on specification, purchase quantity, process intensity, application requirements, and expected media lifespan.