T800 coating delamination

[alvliew]

Hi there,

Has anyone came across with coating surface crack for the T800 powder? Help much appreciated. Thanks guys!

alvin

[Vadim Verlotski]

Hi there,

Has anyone came across with coating surface crack for the T800 powder? Help much appreciated. Thanks guys!

alvin

Hi alvin,

Cracks occur at lamella boundaries in upper of the layer. This means that the cohesion from upper mono-layers to one another is too weak and/or tensions between individual layers are too high.

This can happen if the mono-layers (layer per one pass) are too thick. To make mono-layer thinner, you must increase the relative movement speed of spraying (higher speed of the component and/or faster robot movement).

Regards
Vadim

[alvliew]

Hi there,

Has anyone came across with coating surface crack for the T800 powder? Help much appreciated. Thanks guys!

alvin

Hi alvin,

Cracks occur at lamella boundaries in upper of the layer. This means that the cohesion from upper mono-layers to one another is too weak and/or tensions between individual layers are too high.

This can happen if the mono-layers (layer per one pass) are too thick. To make mono-layer thinner, you must increase the relative movement speed of spraying (higher speed of the component and/or faster robot movement).

Regards
Vadim

Hi Vadim,

Thanks for the input. I will give it try per your recommendation and will let you know the outcome of it . Appreciate your time.

alvin

[KevinS]

Hi there,

Has anyone came across with coating surface crack for the T800 powder? Help much appreciated. Thanks guys!

alvin

Hi alvin,

Cracks occur at lamella boundaries in upper of the layer. This means that the cohesion from upper mono-layers to one another is too weak and/or tensions between individual layers are too high.

This can happen if the mono-layers (layer per one pass) are too thick. To make mono-layer thinner, you must increase the relative movement speed of spraying (higher speed of the component and/or faster robot movement).

Regards
Vadim

Some possible suggestions. If when preparing a mounted sample you are grinding this coating with a grinding stone, the coating surface can shatter like this and this could be a possible cause. Suggest you try grinding without a grinding stone at 150 rpm on SiC papers to see it the problem goes away, Another possible cause is hot mounting the sample, This may also create this type of cracking and can be corrected by using a cold mount material.

[alvliew]

Hi there,

Has anyone came across with coating surface crack for the T800 powder? Help much appreciated. Thanks guys!

alvin

Hi alvin,

Cracks occur at lamella boundaries in upper of the layer. This means that the cohesion from upper mono-layers to one another is too weak and/or tensions between individual layers are too high.

This can happen if the mono-layers (layer per one pass) are too thick. To make mono-layer thinner, you must increase the relative movement speed of spraying (higher speed of the component and/or faster robot movement).

Regards
Vadim

Some possible suggestions. If when preparing a mounted sample you are grinding this coating with a grinding stone, the coating surface can shatter like this and this could be a possible cause. Suggest you try grinding without a grinding stone at 150 rpm on SiC papers to see it the problem goes away, Another possible cause is hot mounting the sample, This may also create this type of cracking and can be corrected by using a cold mount material.

Hi Vadim,
Apology for late reply, I have tried the suggestion that you provided by increasing the traverse speed 10X faster. Unfortunately, I still see the delamination at the coating surface. the coating built-up per pass is 0.00014". See photo attached.

Hi KevinS,
Thanks your time to provide some suggestion as to why the delamination is happening. Our lab do not use grinding stone and we uses cold mount to cure the resin. The following are the steps that we use to prepare the mount
1 - 300RPM @ 120 SIC to remove 0.060"
2 - 300ROM@ 320 SIC to remove 0.005"
3 - 150RPM@ 9 micron for fine grinding
4 - 150RPM@ 3 micron for fine grinding
5 - 150RPM@ 3 micron for polishing
6 - 150RPM@ 0.4 micron for final polishing

Have you encountered similar delamination as describe? If yes, how do you resolve it?

[KevinS]

Hi there,

Has anyone came across with coating surface crack for the T800 powder? Help much appreciated. Thanks guys!

alvin

Hi alvin,

Cracks occur at lamella boundaries in upper of the layer. This means that the cohesion from upper mono-layers to one another is too weak and/or tensions between individual layers are too high.

This can happen if the mono-layers (layer per one pass) are too thick. To make mono-layer thinner, you must increase the relative movement speed of spraying (higher speed of the component and/or faster robot movement).

Regards
Vadim

Some possible suggestions. If when preparing a mounted sample you are grinding this coating with a grinding stone, the coating surface can shatter like this and this could be a possible cause. Suggest you try grinding without a grinding stone at 150 rpm on SiC papers to see it the problem goes away, Another possible cause is hot mounting the sample, This may also create this type of cracking and can be corrected by using a cold mount material.

Hi Vadim,
Apology for late reply, I have tried the suggestion that you provided by increasing the traverse speed 10X faster. Unfortunately, I still see the delamination at the coating surface. the coating built-up per pass is 0.00014". See photo attached.

Hi KevinS,
Thanks your time to provide some suggestion as to why the delamination is happening. Our lab do not use grinding stone and we uses cold mount to cure the resin. The following are the steps that we use to prepare the mount
1 - 300RPM @ 120 SIC to remove 0.060"
2 - 300ROM@ 320 SIC to remove 0.005"
3 - 150RPM@ 9 micron for fine grinding
4 - 150RPM@ 3 micron for fine grinding
5 - 150RPM@ 3 micron for polishing
6 - 150RPM@ 0.4 micron for final polishing

Have you encountered similar delamination as describe? If yes, how do you resolve it?

Try dropping all the grinding speeds to 150 rpm and see if the problem goes away