Since its invention in Pennsylvania in 1870, abrasive blasting has made its way in industrial manufacturing as a method of choice for surface preparation and finishing. There are now countless ways to blast a surface due to the variety of abrasive materials that can be used such as stainless-steel shots and dry ice blasting.
But abrasive blasting systems come with important downsides, the most important ones being that they generate substantial waste, can damage surfaces, and often require manual masking. Most manufacturers are used to manage these downsides, but others are turning to alternatives like laser texturing which can drastically improve how surface preparation is performed—especially when precision is needed or when processing a large number of parts.
What is Abrasive Grit Blasting and How Does It Work?
Grit blasting, also known as sandblasting and abrasive blasting, is a surface treatment for metal surfaces. The process shoots abrasive media at high speed to remove surface contaminants or modify the texture. There are countless ways to do grit blasting, with different types of blasting media, particle sizes, and blasting methods.
Harder abrasives are used to process surfaces more efficiently while softer ones are used to avoid damaging the surface. Examples of abrasive materials include minerals (silica sand, garnet sand), organic materials (walnut shells, corn cobs), metals (steel grits, stainless steel shots), and synthetic materials (baking soda, dry ice, aluminum oxide, silicon carbide, glass beads).
Several methods can be used to propel the blasting material through the blast nozzle. Wet abrasive blasting uses liquids under high pressure (such as water) to help trap dust and lubricate the surface. Other methods use vapor streams, compressed air, or a spinning wheel (wheel blasting).
Benefits of Abrasive Blasting Methods
Abrasive media blasting is a versatile process used for metal parts (and sometimes plastic parts) in a wide variety of applications, including in the automotive and aerospace industries. Here are some of the key benefits:
- Abrasive blasting is fast and ideal to process large surfaces.
- The variety of blasting methods offers a wide range of surface finishes. Bead blasting, for example, can create a smooth surface finish and remove burrs on machined parts. Other processes can create a matte finish.
- Abrasive blasting can remove most surface contaminants, including corrosion, paint, mill-scale, and rust.
- Blasting can be used for surface preparation. For example, it can prepare surfaces for welding by removing contaminants, or improve surface adhesion for coatings by creating a rough surface.
- Shot peening can harden surfaces to improve durability and longevity.
- Blasting processes are well-known by manufacturers, who are used to manage their downsides.
Grit Blasting Safety Drawbacks
When it comes to abrasive blasting, most drawbacks are related to safety. This is because sandblasting generates large amounts of dust originating from the abrasive particles, the surface contaminants, and the substrate itself. Noise generated by the blasting equipment can also be harmful.
- Workers who inhale abrasive dusts are exposed to serious health issues. One well-known example is from silica sand, which causes several diseases, including silicosis, an incurable lung disease that can lead to disability and death.
- PPE is needed to protect workers from several hazards. An abrasive blasting respirator must cover the worker’s head, neck, and shoulders. Other PPE includes hearing protection, eye and face protection, a helmet, gloves, and safety boots.
- All PPE should be inspected daily to ensure it is not broken or worn down.
- The blasting operation needs to be contained to protect other workers. This can be done by performing the operation in blast rooms or blast cabinets, by using barriers and curtain walls, or by creating a restricted area if the operation is not enclosed.
- An exhaust ventilation system is needed to capture dust generated by the process.
If you need guidance to manage safety, you can use the OSHA’s factsheet on how to protect workers from abrasive media blasting.
Grit Blasting Quality Drawbacks
Grit blasting can cause important quality issues in part manufacturing. This is especially true when preparing surfaces for other operations like thermal spray coating.
- Blast cleaning leaves residual dust that needs to be removed to get a clean surface, which is often needed for subsequent operations.
- The process cannot be used to remove all types of surface contaminants. Grease and oil need to be removed before blasting.
- The operating life of blast machines and blasting equipment is relatively low due to the abrasive nature of the process. Equipment that is worn down can hinder the quality and consistency of the process. This also means that maintenance costs are huge.
- The substrate (especially if it’s a soft material like aluminum) can be damaged by the blasting material, causing defects such as microcracks.
- Blasting is unprecise and hard to control. It cannot be used to treat specific areas.
- Over time the blasting media degrade, resulting in texturing quality variations.
- Manual masking is often needed to protect certain areas from blasting. This process is slow and prone to error.
Laser Texturing; An Alternative to Grit Blasting
Lasers have long been used for material processing in industrial manufacturing to replace slow, polluting, or inconsistent technologies. They are widely used for welding, marking, cleaning, cutting, and so on.
Laser texturing is a lesser-known laser application that can replace other texturing methods like shotblasting and grit blasting. It can modify the surface texture as needed and remove all types of contaminants at the same time.
What Are the Benefits of Laser Texturing?
With its high precision, laser texturing can process localized areas—without the need for manual masking—and generate consistent results. It can be used to prepare surfaces for thermal spray coating, adhesive bonding, laser cladding, as well as several types of coatings. In addition, it provides other important benefits:
- No consumables
- No waste
- Low operating costs
- Low maintenance
- Easy to automate
- No PPE required (when equipped with a laser enclosure and a fume extraction unit)
- Green technology
- Non-contact process
When Is Laser Texturing a Better Option?
Knowing which texturing method is best for an application is not always clearcut. As a general rule, laser texturing is a better alternative when:
- Precision is needed, such as when localized areas need to be treated
- The texturing process needs to be automated
- A large volume of parts needs to be treated daily (which is when it provides a high return on investment)
- The number of part models is limited to a few (as the process needs to be programmed for each part type)
If you have an application you think could benefit from laser texturing, contact our laser experts today. They will review your application and tell you if it is a good option for you.