Going through plasma tips

[Albino Rino]

Does having a wire guide standoff or wheel on the torch nozzle make a big difference?

[Gadget]

It keeps you from dipping the tip in molten metal which is very hard on consumables. It also keeps you at a good height for maximum cutting performance.

[WookieWelding]

having water or oil in your air supply will also eat thru tips fast

[tomsign]

MOISTURE is the biggest killer of any tip on any Plasma Cutter out there! (also distance and angle as mentioned)

[tigqk]

I've found that if I am not careful as to what is behind the peice that I am cutting that it will burn a tip up real quick so it stands to reason then if you startoff against the metal that it is gonna burn it.Longevity sells the standoff ring and the circle burner kit with rings, not sure what the price is belive it is $17.00 and $29.00 consectively.

[samsberr]

The excessive slag buildup is a problem sometimes. I have found that a 100grit sandpaper sponge works great to brush off and clean the slag from your tip. It's not rough enough to damage or degrade and it does a great job at knocking that crap off.

I started using a small brass brush, I found it at HF for .99...works great.

[tigqk]

Found this and had it saved;

How to avoid the top 10 problems in plasma cutting: Practical tips you can use right now

By Chuck Landry

February 19, 2001

Attention to detail at the outset can save plasma cutting operators a load of trouble during production.



The old adage "measure twice, cut once" is as important for plasma arc cutting operators as it is for carpenters. The phrase could be reworded to "inspect twice, cut once" for the plasma industry. Careful preparation, setup, and maintenance can alleviate many costly problems which operators encounter.

Strategy
The following is a list of remedies that may help operators avoid some of the most common problems encountered in plasma arc cutting.

1. Replace Consumable Parts Regularly. Think about a car—changing the oil regularly is much less costly than replacing the car's engine. In the same way, replacing consumables regularly is much more cost-effective than replacing the torch. Using severely worn consumables can lead to uncontrolled arcing in the plasma chamber, which can cause torch failure.

What are the signs of spent consumables? Often, deteriorating cut quality is the first sign of worn parts. Visual inspection is important as well. If a nozzle shows signs of oxide residue on the inside, or if signs of gouging exist on the inside or outside of the nozzle, it should be replaced.

To tell whether an electrode is spent, check the pitting of the electrode element. Depending on the gas being used, the pitting should not be deeper than 3/32 inch for oxygen or air or 1/8 inch for argon or nitrogen. If the pits are deeper than these guidelines, it is time to change the electrode.

Finally, if an examination of the gas swirlers reveals cracks, arc burns, or dirt or grease in the holes, the swirlers should be changed.

Problems 2 through 5
2. Properly Assemble the Torch. Torches should last for a long time with correct care. The torch should be assembled so that the parts are in proper alignment and fit together snugly. This ensures good electrical contact and the correct flow of gas and coolant through the torch.

In addition, the torch threads should be clean, and seating areas should not have any particulate contamination. When changing parts, consumables should be kept on a clean shop rag to prevent dirt or metal dust from contaminating the torch.

3. Use the Correct Parts for the Job. Consumable selection depends on the cutting amperage and plasma gas used for each job. The operator's manual defines which consumables are appropriate for various types of cutting. Using incorrect consumables can lead to shortened parts life and reduced cut quality.

Furthermore, parts must be run at the correct amperage. The amperage should be set to 95 percent of the nozzle's rating. If the amperage is too low, it leads to a sloppy cut. Overpowering will drastically reduce the nozzle's life.

4. Ensure Proper Gas and Coolant Flow. The flow and pressure of gas and coolant should be checked every day. If the flow is insufficient, consumables will not be cooled properly and parts life can be adversely affected. Constant gas pressure is important to maintaining the cutting arc. Excess gas pressure is a common cause of hard starting, a situation in which the torch fails to initiate an arc when all other conditions for normal operation are correct.

Likewise, plasma gas must be kept clean and dry. Premature torch failure and short consumable life are two results of contaminated gas. Compressed air systems are especially prone to contamination.

5. Avoid Excessive Application of O-ring Lubricant and Antispatter Compounds

Sometimes, it is possible to get too much of a good thing. When applying O-ring lubricant, use just enough to put a shine on the O-ring. Shields must be removed before putting antispatter compounds on them.

Too much of either material can contaminate the torch, resulting in premature torch failure. In the same vein, grease or other lubricants should not be applied to torches; torches do not need lubrication.

Furthermore, lubricants may conduct electricity, which can ruin the torch. Any excess compounds can clog swirl rings and attract metal dust, which can cause arcing problems.

Problems 6 through 10
6. Avoid Using the Torch as a Hammer. Would you pay hundreds of dollars for a hammer? Of course not. Torches were not designed as hammers and should not be used as such. Banging the torch on the workpiece to remove slag or cut pieces can damage the torch.

7. Avoid Torch Collisions. Tip-ups and crashes can irreparably damage a torch. Torch collisions with the workpiece can be prevented by programming the shape cutting system to travel around (rather than over) cut parts. Torch height sensors also offer protection from workpiece crashes by correcting for variations in workpiece height. Finally, breakaway torch mounting devices can help prevent damage to the torch if a collision does occur.

8. Avoid Arc Stretching. If the arc must stretch to reach the metal, consumable parts will prematurely fail. Whenever possible, edge starts should be used rather than pierce starts.

When doing an edge start, the plasma arc should be started with the nozzle orifice directly centered over the edge of the workpiece.

When piercing, set the standoff to twice the height used for cutting, or the maximum height that will allow arc transfer. Appropriate timing of the arc-off signal will eliminate arc stretching at the end of the cut.

9. Maintain Correct Standoff. Standoff is determined by the thickness of the material being cut. By maintaining the correct standoff, the arc is able to flow correctly; too high or too low a standoff can damage the torch or the workpiece.

For hand-held cutters, standoff devices can assist operators. Mechanized systems can be manually set or maintained by automatic height control.

10. Clean the Torch Routinely. It is important that operators watch the torch for signs of contamination. The internal and external torch threads should be kept clean and in good condition. If necessary, they should be retapped.

The nozzle and electrode seating areas should be cleaned if they become dirty or pitted. To clean the torch, use a cotton swab and electrical contact cleaner or hydrogen peroxide.

Conclusion
Proper operation of plasma arc cutting equipment can save countless hours and reduce expenses. Proper operation can also result in good cut quality and longer parts life.

In addition, less time and effort may be spent cleaning the metal before it goes on to the next step in the manufacturing process. For example, if the cut piece is to be welded, a clean, high-quality cut is important to the integrity of the weld.
"Unquote"


Knowing arc welding or mig welding we know that when we pull the arc/electrode away from the puddle the voltage increases until their is so much of an increase in voltage that amperage is lost, it may be safe to assume that this is then also true for plasma cutting and a potential source of cup wear.Something to think about.

[arandall]

Tigqk:
Thanks. I'm going to print your post, and keep it along with my reference material for plasma/TIG/Stick/MIG etc..

[tigqk]

Simon should consult the author and put into the manuals.