Air jets cooling cross type

[Spark]

Hello,
Is there anybody could help me to explain how it works with the air jets cross for F4 plasma gun ?I m puzzled by it, what is the effect to the coating ?
Best regards

Spark

[Vadim Verlotski]

(04-28-2016 12:17 AM)Spark Wrote:  Hello,
Is there anybody could help me to explain how it works with the air jets cross for F4 plasma gun ?I m puzzled by it, what is the effect to the coating ?
Best regards

Spark

Hello Spark,
Air jets cooling cross type with the flame spray and plasma spray systems are used for "blowing out" of fine particles out of the flame. This is necessary during the coating of metallic powders such as, for example, NiCrBSi. If you let the fine metallic particles in the flame, this bring a large amount of oxides in the layer. The cross cooling should not be too strong so that the large particles do not cool down too much.

[Spark]

(04-30-2016 07:58 AM)Vadim Verlotski Wrote:  

(04-28-2016 12:17 AM)Spark Wrote:  Hello,
Is there anybody could help me to explain how it works with the air jets cross for F4 plasma gun ?I m puzzled by it, what is the effect to the coating ?
Best regards

Spark

Hello Spark,
Air jets cooling cross type with the flame spray and plasma spray systems are used for "blowing out" of fine particles out of the flame. This is necessary during the coating of metallic powders such as, for example, NiCrBSi. If you let the fine metallic particles in the flame, this bring a large amount of oxides in the layer. The cross cooling should not be too strong so that the large particles do not cool down too much.

hello Verlotski:
thanks for reply,it's very interesting，i did a test for it last week, i tired to develp a new parameter for amdry 960（NICrAl）,when i fixed all the parameters except for air jets cooling , the spray distance is 130mm, i try to use cross for 3 bars in 160mm, the coating surface seems more clean, i caculate the DE, around 64%， then i try to incrase the air jet to 4 bars, i was superised by the result, that DE incrased up to 74%, then i tried for second time,...result still the same. so i'm puzzled... now the sample was send to the lab waiting for analysis. what your opinion on it?
so what kind of powder you normally use the air jet cross type? only metallic? how do you choose the cross distance and air pressure?

best regards

Spark

[Vadim Verlotski]

Hello Spark,
air jet cross type helps in the fight against overspray. So, this can also be used with non-metallic powder. Main problem - cooling of particles. But I can imagine, that for too hot particles this cooling may even give rise to better DE. The pressure and distance you must test purely empirical. I can just recommend to replace the compressed air with nitrogen for cooling (for metallic powder).
Regards
Vadim

[loriolo]

Hi Spark
The air jet with the cross-jet, could be used for several applications, first is applied parallel, in order to cool the particular been sprayed, in a second case could be used as corrosion protection from the external media, in a thirst case could be used to increase the speed of the flame an powder in order to have a denser spray coatings and without oxides, some time in order to protect and accelerated the spray stream, a special air or nitrogen air jet with angular holes (about 6 or 10 holes), to create a radial pinch effect, every material has his own cross-jet distance, and with F4 gun, as the spray stream is faster than in old guns, there is not needed a cross-jet, but some time I used it in order to increase the quality of the coating