1. What is meant by the surface treatment of metal?
When a workpiece made of stainless steel or another metal is cast, forged or formed, it is still in its raw state. Further processing is necessary so that it can fulfill its final purpose and, for example, glide seamlessly as a ball bearing, drive a motor as a piston or shine as a door handle on a cabinet. There are very different types of surface treatment. In most cases, larger or smaller layers are removed. Sanding can give a workpiece the right surface finish: It loses burrs, unevenness and impurities such as rust or scale. It is then prepared for use: either by polishing or matting. Blasting technology also has an abrasive effect in most cases. A distinction is made between compressed air blasting systems, which are usually operated manually, and automatic wheel blasting systems. The blasting medium, consisting mainly of many millimeter-sized metal balls, is accelerated and propelled against the surface to be treated to create a uniform surface.
2. What are the most important reasons for polishing or matting metal?
3. What are the benefits of polishing and matting metal?
The aim of metal polishing is to create the lowest possible surface roughness with the least possible material removal. This results in numerous advantages:
- Less friction & wear
- Smooth surfaces ensure that mechanical components interlock better.
- The result: longer service life and reliable function.
- Optimum adhesion for coatings
- Uniform surfaces improve the adhesion of electroplating, painting and other coatings.
- Basis for corrosion protection, e.g. for aluminum components in vehicle construction.
- Security & Performance
- High-quality surface finishing is crucial for the required performance and safety of many components.
- Even the smallest irregularities can impair the function.
- High-gloss polish as the basis for further processes
- Creates a surface that meets the highest requirements.
- Often serves as preparation for subsequent processing steps.
- Decorative use
- Polishing and matting are not just for technical reasons, but also for visual reasons:
- Trims, handles, decorative elements
- Emphasis on the design of furniture and vehicles
- Traditionally used in the jewelry industry for precious metals.
- Polishing and matting are not just for technical reasons, but also for visual reasons:
- Use in mass production
- Polishing and matting processes are usually carried out by specialized machines and systems.
4. What methods are used for polishing matting?
Manual polishing
Small metal parts can usually be polished by hand, for example with attachments for hand drills. This method is particularly suitable for individual pieces or small workpiece supports.
Machine polishing
If larger components are to be polished or matted, small and medium-sized companies use special machines. On an industrial scale, processing is sometimes also carried out using blasting technology on larger systems. In mechanical polishing, a loose abrasive is pulled over the surface with pressure, which removes any unevenness. At the same time, the polishing paste used bonds with the workpiece surface due to the high energy application, resulting in a particularly smooth structure. In this way, exactly the roughness that is specified for the respective application can be achieved.
Stationary machines for larger quantities
Various stationary machines such as CNC polishing machines, contact polishing machines or high-gloss polishing machines are available for processing larger quantities. These enable a uniform and reproducible surface quality.
Various finishes
Different finishes are used depending on the desired result. With the so-called line finish, fine-grained sanding belts always move in one direction. This creates fine, parallel lines, which are particularly popular for decorative metal sheets, such as for veneers.
If, on the other hand, the surface is to appear particularly glossy without a recognizable alignment, a non-directional finish is used. This can be achieved by eccentric or orbital grinding.
If a matt surface is required, satin finishing, also known as brushing, is used. Special rotary brushes ensure a matt to matt-gloss finish, the fineness of which is determined by the grit of the abrasive. Brushed surfaces usually have a decorative function.
Finish blasting in the industry
In industrial series production, finish blasting is often used to process large quantities economically and precisely. Different blast machines are used depending on the workpiece: screws and rivets are usually processed in barrel or troughed belt blast machines, while overhead conveyor or roller conveyor blast machines are used for large parts such as welded constructions or profiles.
The quality of the result depends on the composition and type of abrasive – round, angular or granular, as well as its grain size. Particularly fine abrasives of less than 0.4 millimeters are ideal for polishing blasting. Which process is used always depends on the shape, size and material of the workpiece.
Conclusion: Why the right surface finish is crucial for metal
Components always fulfill a specific purpose, which is often linked to safety requirements. Whether blasting, grinding or polishing metal: The surface finish is an essential step on the way to the best possible quality and service life. But the perfect surface treatment of the metal is also important when it comes to visual effects for a successful design. The choice of the right tool or system depends on the respective requirements and the workpiece itself. Finish blasting with suitable blasting systems leads to optimum results when large quantities are to be produced in high quality.
FAQ - Frequently asked questions about metal polishing & matting
What is the difference between polishing and matting metal?
The aim of polishing metal is to create a particularly smooth and shiny surface. Matting, on the other hand, involves deliberately roughening the surface to achieve a matt or semi-gloss finish – often for decorative purposes such as furniture, decorative strips or stainless steel fronts.
What methods are there for polishing or matting metal?
Metal can be processed manually with polishing paste and tool attachments, for example for individual pieces. CNC polishing machines, contact polishing machines or high-gloss polishing machines are used for larger quantities. Processes such as line finishing, non-directional finishing or satin finishing (brushing) are also common methods, depending on the desired surface result.
When are blasting systems used for polishing or matting metal?
Blast cleaning systems are used in particular in industrial series production when large quantities need to be processed efficiently. Screws and rivets are usually processed in barrel or troughed belt blast machines, while large components such as welded constructions or profiles are treated in overhead conveyor or roller conveyor blast machines.
For which applications is a line finish, satin finish or high-gloss polishing suitable?
- Line finish: popular for decorative metal sheets, e.g. for cladding or façade elements.
- Satin finishing/brushing: produces matt to matt-glossy surfaces, often for stainless steel in kitchens or furniture construction.
- High-gloss polish: ideal for components that require the highest precision, as well as for jewelry or design objects.
