Lathe Bed Scratch repair

[shantanu]

Hi All,

Customer has this huge grinding machine where the bed has developed scratches leading to fall in pressure and oil leakage

It is required to fill up these scratches by coating

Max depth of scratches is 2 mm

The scratches has embedded oil. Blasting is not permitted

Any coating applied would have an oil film over it and would continuously see a sliding movement over it

Any ideas?

Regards

Shantanu

[Laurent]

Hello Shantanu,
Scratches, you probably mean cracks.
Cracks can be repaired by welding, especially if it's a wet environment.
What material the bed is made of?
thanks
cheers

[Vadim Verlotski]

Hi All,

Customer has this huge grinding machine where the bed has developed scratches leading to fall in pressure and oil leakage

It is required to fill up these scratches by coating

Max depth of scratches is 2 mm

The scratches has embedded oil. Blasting is not permitted

Any coating applied would have an oil film over it and would continuously see a sliding movement over it

Any ideas?

Regards

Shantanu

Hi Shantanu,

There is a technology of cold spraying low pressure, which is ideal for such cases:
https://www.youtube.com/watch?v=ZzhPXgrYdsA
https://www.youtube.com/watch?v=ghD7xeA_1_w

Regards
Vadim Verlotski

[djewell]

Forget about cold spray. It works best with soft materials. Lathe/grinder beds are made of hardened steel. There is no way a cold spray coating would ever be able to securely bond to it. Even if it could, the coating would not be strong and hard like you need for this type of machine.

I suggest degreasing the machine, grinding out the gouges to make room for a filler material, and either welding them or filling them with an HVAF applied coating. HVAF can apply the 2mm required thickness. Ideally, your coating should be the same steel as the lathe or at least have the same hardness.

HVAF has some of the same characteristics like cold spray, like low oxidation and high velocity, but it also has more temperature, which makes even hard materials soft and plastic. On impact, they deform and embed themselves in the substrate, forming a strong bond. Because of the high velocity, HVAF coatings are not so sensitive to latent oil on the substrate.

[shantanu]

Hi,

Many thanks for your replies....

Don't have cold spray or HVAF. Also, the job needs to be done at client site hence HVAF or a JP 5000 type coating is ruled out

I was considering a self bonding Ni-Al or a aluminum Bronze kind of coating using powder flame as the surface cannot be blasted and also overspray would need to be removed using mechanical scraping.....

Comments....Gordon and guys?

Shantanu

[loriolo]

Hi Shantanu
As you don't have the possibility to use arc spray aystem, or any other, but only powder flame system, so you must degrease very accurately, and after this you must heat, in order to burn every trace of oil, and as you could not blast, so you must roughen the surface whith meccanical tools, doing new and clean scratches, then Ni/Al could be Ok, but Cu/Al I think is too soft.