Removing oxide from aluminum usually comes as a necessary evil to ensure that high-quality parts are manufactured. If you’ve manually cleaned oxides before, you’ve probably spent a lot on manual labor and had a hard time ensuring consistent results.
Laser cleaning, mechanical cleaning and electrochemical cleaning have all proven to effectively remove oxides and other contaminants from aluminum surfaces. All these methods can either be automated or performed manually. Let’s see how they work and what their benefits and drawbacks are.
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Cleaning Aluminum Oxides with Laser Technology
Fiber lasers remove oxides by pulsing a laser beam onto the part’s surface. The beam heats oxides and surface contaminants to the point where they are vaporized into fumes.
Automated Laser Oxide Removal
Laser oxide removal is easier to automate than other technologies. In fact, many inline solutions already exist. Since laser systems have no moving parts, they require very low maintenance. And unlike mechanical and electrochemical cleaning, lasers function without consumables. As a result, they are very well suited for automation and can operate 24/7, all year long, with minimal downtime.
Automated laser cleaning is perfect for applications where oxides and contaminants need to be removed from specific areas, such as before and after welding. It’s also proven to work extremely well as a pretreatment for adhesive bonding.
Manual Laser Oxide Removal
You can remove oxides manually with a handheld laser. Since this type of laser is easy to adapt for complex geometries and different parts, it is best suited for maintenance and refurbishing applications. Manufacturers use them to remove oxides before/after welding as well as to improve the electrical conductivity of aluminum.
Because they are not in a laser enclosure, handheld lasers require additional safety measures. For example, the operator needs to wear laser safety goggles. Anyone who doesn’t wear laser goggles must be outside the safety perimeter to prevent eye exposure to the laser beam. Ideally, handheld lasers are used indoor in a controlled environment, but they can also be used outdoor with proper safety measures.
Drawbacks of Laser Technology
One of the drawbacks of laser cleaning is that it may be slow if you need to remove a thick layer of aluminum oxide or if you are cleaning a large aluminum surface. Other methods like mechanical brushes may be better adapted for these types of applications.
Mechanical Cleaning of Aluminum
You can clean aluminum oxide by scrubbing the surface with rotating brushes. These brushes work great even with thick oxide layers, transforming them into dust. Brushes can also remove burrs at the same time, making them a great choice to clean aluminum after cutting applications.
But be warned: before scrubbing the metal surface, you may need to remove oil, grease and other contaminants with acetone. You need to do this, for example, for welding applications. With laser cleaning, all types of surface contaminants can be removed at the same time.
Automated brushes require frequent monitoring and maintenance. Since the brushes use up quickly, the quality of the results diminishes over time. Without close monitoring, this leads to inconsistent results and defective pieces. Hence, the aluminum cleaning process needs to be stopped often to replace the brushes.
If you have a low production volume, you can remove oxide films by manually scrubbing with a stainless-steel wire brush or a steel wool, but be prepared for some elbow grease.
Removing Oxides with Chemicals
Electrochemical cleaning uses acids to remove oxides from the surface of aluminum. Once acids are applied with a heated carbon brush, the ensuing chemical reaction removes oxides at a rate that varies according to the temperature and concentration level of the acid.
You then need to remove and neutralize the cleaning agent. This is done by first wiping the surface with a dampened clean cloth, then by applying a neutralizing agent, and finally by rinsing off with water. With stainless steel welds, you might need to apply a passivation agent afterward.
Electrochemical cleaning is typically performed manually with a specialized aluminum cleaner, but it can also be automated. For example, robots can be used to automatically apply acids onto welding joints using a brush or spray.
Drawbacks of Chemicals
Electrochemical cleaning provides amazing results whose quality cannot always be replicated with other technologies, but it is expensive, complicated to manage, and potentially dangerous. If you want to adopt this technology, you need to be prepared to work with its constraints.
Managing chemicals can be a real headache. To follow environmental and safety regulations, you need to make sure that you retrieve all the chemicals used in the cleaning process. For example, you need to store and dispose of rinse water properly.
Chemicals can also severely harm your employees if not handled properly. To prevent this, the list of PPE is quite long. Employees need to wear chemical resistant gloves, overalls, shoes, and goggles for body protection as well as a respirator for respiratory protection. You may also need an enclosed room for the cleaning process to manage toxic fumes properly.
How to Choose the Best Method for Oxide Removal
Now that you have a good understanding of the three most common methods for aluminum oxide removal, you should have a good idea of which method is right for you. For laser oxide removal, contact our experts to discuss your manufacturing process and find out which products best meet your needs.