How to Stay Clear of Vibratory Tumbling Damage
Though a popular form of surface finishing, vibratory tumbling can raise concerns about its potential for damaging the surface of parts. That’s because vibratory tumbling relies on the abrasion of various medias against a product. This rotation and spinning technique– when conducted improperly – can leave room for unwanted dents, inaccurate surface roughness, or other damage to the integrity of a part’s surface.
However, when you make strategic choices about how to conduct vibratory tumbling, it’s easy to avoid the potential for damage.
First, know that vibratory tumbling is actually often a less risky option than barrel finishing, because it doesn’t put delicate parts at as much of a risk for damage. Part of the reason for this is that there’s less movement involved. A vibratory tumbler’s part only moves a fraction of an inch per stroke, rather than moving a full diameter as with a barrel tumbler.
Avoiding Vibratory Tumbling Damage
1. Choose the Appropriate Media
Media selection is a huge factor in reducing the risk of damage from vibratory tumbling. The lighter and smaller the media used in tumbling, the softer its touch and the less likely that media is to cause unwanted dents, damage, or surface roughness.
There are three main groups of tumbling medias: plastics, ceramics, and hardwoods. Plastics are often the best choice for those concerned about the risk for damage, because plastic medias result in the smoothest finished surfaces when used in a vibratory tumbler. Plastics are lightweight (30% lighter than ceramic tumbling media, in fact), so their impact against parts in a tumbler is more minimal. Plastics are a great choice for products made of softer metals like brass or aluminum.
Ceramic finishing media is a dense, heavy media option that’s best suited for hard metals or products that need areas to be worn down. In other words, it’s often not the best choice for delicate products. Hardwood media is the lightest option that, when used in smaller pieces, is well-suited for parts of light durability or very mild abrasiveness is required.
2. Choose the Right Media-to-Part Ratio
Delicate parts call for a higher media-to-part ratio in a vibratory tumbling system. Applying a little napkin physics knowledge, we know that the less space something has to travel, the less force it has to apply upon impact. The more media there is in a vibratory tumbler, the less space it has to hit up against parts. Generally, a 3 to 1 ratio (by volume) of media to parts is good for deburring or deflashing. A 4 to 1 ratio or higher is better for burnishing an polishing.
3. Fast Speeds, Low Amplitude
In addition to selecting the right media-to-part ratio, be intentional about the speed at which you set your vibratory tumbling system. Despite what you might think, parts that are fragile should actually run at faster speeds. Faster speed settings in combination with low amplitude settings minimize the part’s risk for high media impact. Again, the same physics logic from earlier applies here: there’s less space for media to hit against a part’s surface, thereby lessening impact.
For more on how to stay clear of vibratory tumbling damage, contact us at 1-888-515-9443 or reach out to us online. Kramer Industries is a long-time expert in finishing systems. We’ll help keep you, and your projects safe.