Numerous engineering advances mean today’s plasma consumables are capable of lasting longer than ever before. Unfortunately, many businesses are not enjoying the cost savings longer consumable life can bring. Here are six reasons why their consumables may be wearing out sooner than expected.
1. They change consumables at the wrong time. Changing out consumables too soon is a common cause of excessive consumable use. Many businesses change consumables after a set number of pierces or during a shift change. The fact is consumable wear is application specific. Generally, standard all-copper electrodes should be replaced when the hafnium pit depth reaches 0.040 of an inch. Silver / hafnium interface electrodes can safely reach a pit depth of 0.080 of an inch.
2. Their torch is too far (or too close) to the workpiece. Proper pierce height is critical to long consumable life. If the height is too low, spatter blown back during piercing can destroy the nozzle after only a few starts. Piercing too high may cause excess pilot arcing and lead to premature nozzle damage. Proper pierce height is 1.5 to 2 times the correct torch-to-work distance.
3. Their arc stops at the wrong time. Make sure your torch remains over the plate when the cut ends. If the arc terminates abruptly because it runs off the plate, an excessive amount of hafnium can be ejected, translating into a loss of 10 to 15 arc starts.
4. Their gas supply is too low. Probably the most common cause of excessive consumable wear, low flow rates can lead to catastrophic, almost immediate, nozzle destruction by causing the pilot arc to attach to the inside of the nozzle orifice.
5. There isn't enough coolant flowing to the torch. Proper coolant flow is essential to proper consumable wear. Flow restrictions reduce consumable cooling, which results in excessive heat buildup in the consumables and more rapid erosion.
6. They don't have a good work cable connection. A good electrical connection is essential. With a good connection, arc transfer occurs within 100 milliseconds. A poor connection can delay that to 1⁄2 second or more, causing excessive consumable wear and misfiring.