A tumbling barrel deburring machine might be more accurately described as a "sliding" barrel deburring machine.  This quibble has to do with the way the media and the parts to be deburred act in the barrel. 

When we think of tumbling, we see those amazing athletes who fly through the air, doing back flips and other astonishing acts on a big mat.  That’s not what happens in a tumbling barrel.  Instead the parts and the media interact by sliding together down the sides of the barrel as the barrel turns, carrying them from bottom to top.

The sliding is actually a good thing.  If the parts and media fell through emptiness, the tumbling barrel would be much less effective as a deburring solution.  In fact, the longer the sliding, the better.  The sliding motion also helps prevent parts from knocking into each other and so, potentially, causing damage.

What matters most is the ratio of parts to media.  Normally, the ratio is about one part components to be deburred to three parts media.  But the ratio of parts to media can be much higher, depending on the component.  Delicate parts generally require a higher ratio of media to part.

If there is great concern about the parts striking each other during deburring, the barrel might be equipped with fixtures on which the parts are mounted so they don’t move around in the barrel.  These fixtures are designed to prevent a number of problems caused when parts "impinge" on each other.  For example, some more complex parts might get tangled up with each other.  Others are too delicate to withstand part-to-part contact.

Barrel deburring has been around for centuries.  Over the years, the technique has developed a number of variations and refinements.  Today, this type of deburring equipment includes horizontal varieties that can continually process batches of parts efficiently as long as variables such as media, cycle time and others are carefully controlled.  Open-end tilting and bottlenecked tilting barrels allow for parts inspection during the tumbling cycle, along with addition of media and other additives. 

Tumbling barrels are less effective as deburring solutions for many of today’s complex parts.  Components with cavities and internal surfaces that are hard to reach don’t benefit as much from this kind of deburring machine. 

For other deburring applications, different technologies are available.  For example, deburring components for the automotive and aerospace industries might be more effectively accomplished with abrasive flow machining (AFM) or electrochemical deburring (ECD).  Other approaches are the thermal energy method, rotary tools and wet deburring, including CNC-controlled high-pressure water jets.  Sometimes, when deburring and chamfering are both required, for example, more than one deburring solution might be required for a single part.