Powder build up on powder port

[ruudlam]

Hello everybody,

We are spraying a CrC-NiCr coating with a 7MB gun for a long time now.
But recently we have the problem that the powder is building up at the powder port, so it blocks eventually.
Does anybody has a clue what is happening there?

If I lower the hydrogen flow, I get to many unmelted particles in my coating (and it is not that high at this moment: 5 NLPM).

Thank you for any help!

Kind regards,
Ruud Lammers

[Vadim Verlotski]

Hello everybody,

We are spraying a CrC-NiCr coating with a 7MB gun for a long time now.
But recently we have the problem that the powder is building up at the powder port, so it blocks eventually.
Does anybody has a clue what is happening there?

If I lower the hydrogen flow, I get to many unmelted particles in my coating (and it is not that high at this moment: 5 NLPM).

Thank you for any help!

Kind regards,
Ruud Lammers

Hi Ruud,
It may be that your powder has become finer or contains now more fine particles than before.
Also possible that the hole of powder nozzle has become larger due to wear (slower feeder gas flow).

You can solve the problem by increasing the flow to feeder gas.