Clogged powder ports on a 9MP ( New picture added)
02-17-2010, 03:57 AM, (This post was last modified: 02-18-2010, 01:34 AM by garyt32.)
#1
Clogged powder ports on a 9MP ( New picture added)
I am spraying the same powder on 3 production lines, all using the same equipment. A 9mc controller, 9mb gun with a G nozzle, # 2 powder ports (2 of them) and using a 9MP feeder. One of the stations keeps fouling the powder ports, plugging it over. it is like a cap forms over it. Operators tell me it is always the same one that fouls and the other is clean. we have already taken .100 off of the length as recommended by metco on all of these stations.

Help me Please, as the time I left I swapped out the 9MP with a different unit to eliminate it from being the cause of the problem.

I am getting desperate, any thoughts would be appreciated.
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02-17-2010, 06:34 AM, (This post was last modified: 02-17-2010, 08:19 PM by LEN WOOD.)
#2
RE: Clogged powder ports on a 9MP
There aren’t too many things it can be and since you have other PS Systems for comparison then that's good. You didn’t say what powder(s) you were using is it 601NS?
Some powders do build up in time and have to be periodically cleaned to prevent splatter. Periodically glass bead burnishing injectors/powder ports inside and out does minimise problems

The injection of the powder into the plasma may not be sufficient and powder is ‘hazing’ around the powder port and melting in the vicinity causing an ‘icicle’ or cap.

I would look along the following lines:

Carrier Gas.
• Leak(s) in the carrier gas lines, go through and check the complete line from source.
• Insufficient Carrier gas flow or pressure
• Is there any chance that this gas line is contamainated by another gas (through shared piping/manifolfing) or moisture?

Plasma plume dynamics/characteristics.
There is amongst many TS Systems variation in the actual power output and subsequent delivered plasma (or arc) at the gun. Also as you know gas delivery affects the size and dynamics of the plasma plume. If this is not correct then powder injection and desired flame stream can be compromised.
• Does this problem system have the correct voltage and amperage? Is the Plasma stable?
• Check that the Gas flows and pressures are correct. Check the gas lines for leaks
• Has the system been calibrated recently (I gave you a link) and therefore readings indicate actual parameters?

Condensation
Is there any evidence of condensation? If this particular gun has being spraying down vertically then the powder ports get damp if some condensation is occurring?
• If so, is this particular PS System set at different chiller temperature set points to the others. Does it have a superior cooling system?
• The booth that this system is in - is it hotter or more humid than the others. Check the booth air flow/flow through if so.
• Is this system in a hotter location?

Metallurgical examination and comparison to the other system deposits will also give you some tell tales.
As with most TS testers it could be a combination of a few little things.

If everything checks out OK then see if something is different with this system to the others. Start the process of elimination!

Let me know how you get on ;D
Cheers
Len
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02-18-2010, 01:32 AM,
#3
RE: Clogged powder ports on a 9MP
(links dead)

Here is a picture of the nozzle and powder ports, still the same problem with a different 9MP feeder, It is like the powder is bouncing back off of the rotating part being sprayed, It is always the same port being capped over. looks like in the morning I get to start looking closer.
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02-18-2010, 08:35 AM, (This post was last modified: 02-18-2010, 01:21 PM by LEN WOOD.)
#4
RE: Clogged powder ports on a 9MP ( New picture added)
I find that when running 2 powder ports that everything goes a little better when they are positioned top at the 10-11 o’clock and 1-2 o'clock positions or opposed (10-11 o'clock & 4-5 o'clock OR 1-2 o'clock & 7-8 o'clock positions).

If the gun/feeder hardware is correct and in good condition, the feed rate & carrier gas settings are correct and the gun/siphon cooling air isn't too high or directed/deflected to the gun then the evidence points to a carrier line issue or leak. Try changing the powder hoses over to see if the 'capping' shifts to the other port. Check from the 9MP feeder to the powder port for obstructions - I have seen desiccant bead and Aluminium Oxide grit blockages in the powder shafts and ports!

How long does it take for this to occur?
Have you sprayed these same rotating parts on the other systems?

Good luck!
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02-19-2010, 07:11 PM,
#5
RE: Clogged powder ports on a 9MP ( New picture added)
Any luck fixing your Clogged Powder Port Problem?

I have used particle imaging instruments to help diagnose problems like this in the past. They can give a very useful picture as to where to look for the problem for example:
1. Determining if the carrier gas flow rate is sufficient.
2. Determining if the powder is penetrating the plasma.
3. Determining the stability of the plasma and injector orientation to the plasma.
4. Determining if powder is bouncing back from the part being sprayed.
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02-20-2010, 03:19 AM,
#6
RE: Clogged powder ports on a 9MP ( New picture added)
I have changed the feeder, lines and ports. Gas flows and pressures are correct, It is always the same powder port from the back it is the one on the right side towards the top on a quad port holder. I swapped the lines on the port holder and still it is the one on the right. I changed everything except the color of the machine.Then I thought of something one of my aftermarket suppliers told me a long time ago (I am getting desperate now) that one of his customers was going through a lot of water channeling heads because the cathode holder on his gun was bent causing the arc not to be centered and was taking out the nozzle and then of course the water channeling head is nothing more than a flash of white light and a brass spot on the dust collector. I glass bead blasted the port holder several times prior to have it clean and see how fast deposits occurred, usually about 5 minutes and they were there. After thinking about this I noticed a heat ring around the port mounting block on the right side. I threw together a different gun, not new but all different parts than were in the booth. So far with some tests ans limited production it looks good. I am hoping the cathode holder was a little tweaked, causing the arc not to be centered throwing too much heat to one side. But prior I did not notice unusual nozzle wear. Thanks for your help......Further testing in the am, wish me luckRolleyes
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04-02-2010, 04:24 AM,
#7
RE: Clogged powder ports on a 9MP ( New picture added)
(02-20-2010, 03:19 AM)garyt32 Wrote: I have changed the feeder, lines and ports. Gas flows and pressures are correct, It is always the same powder port from the back it is the one on the right side towards the top on a quad port holder. I swapped the lines on the port holder and still it is the one on the right. I changed everything except the color of the machine.Then I thought of something one of my aftermarket suppliers told me a long time ago (I am getting desperate now) that one of his customers was going through a lot of water channeling heads because the cathode holder on his gun was bent causing the arc not to be centered and was taking out the nozzle and then of course the water channeling head is nothing more than a flash of white light and a brass spot on the dust collector. I glass bead blasted the port holder several times prior to have it clean and see how fast deposits occurred, usually about 5 minutes and they were there. After thinking about this I noticed a heat ring around the port mounting block on the right side. I threw together a different gun, not new but all different parts than were in the booth. So far with some tests ans limited production it looks good. I am hoping the cathode holder was a little tweaked, causing the arc not to be centered throwing too much heat to one side. But prior I did not notice unusual nozzle wear. Thanks for your help......Further testing in the am, wish me luckRolleyes
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04-03-2010, 02:18 AM,
#8
RE: Clogged powder ports on a 9MP ( New picture added)
Hi Gary

How did the testing go? Have you managed to discover cause of problem and hopefully a remedy? I would be interested to know what powder and parameter set you are using?

Either way I do wish you luck Smile
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04-04-2010, 01:10 AM,
#9
RE: Clogged powder ports on a 9MP ( New picture added)
(04-03-2010, 02:18 AM)Gordon Wrote: Hi Gary

How did the testing go? Have you managed to discover cause of problem and hopefully a remedy? I would be interested to know what powder and parameter set you are using?

Either way I do wish you luck Smile

Nothing I have done has changed anything, when I put a diffrent 9MB gun on the line for the third time things are stable, not having to brush the ports more than every 2 hours. I have ordered a new gun to install and the equipment is going to be calibrated soon, I will let you know. It is one of those things where for some reason, we are getting by and trying not to talk about it for fear the equipment will here us talking about it
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04-16-2010, 02:32 PM,
#10
RE: Clogged powder ports on a 9MP ( New picture added)
Hi Gary,

Did you try to spray in other area of your spraybooth?
I have seen this problem one time and the problem was due to exhaust turbulence.

Regards

Diucky
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