Using CNC Mill for surface grinding

[anrsh2]

I have a question about how best to use a CNC mill for "surface grinding" forged damascus billets of steel coated in flux and scale.

I recently began forging damascus billets. These billets come out of the forge with flux and scale on them which needs to be removed. Next I need to finish the billet flat so I can effectively use me CNC machine to work the metal.

Rather than buying a dedicated surface grinder I would like to use a face mill or fly cuter perhaps to go through this process. My concern is that these billets are coverd in flux (melted glass essentially) and I am not sure what is the best tool to use to get me where I want to go. What is a safe and cost effective tool to use for this?

Any insights would be appreciated.

Shane Harvey

[Geof]

What are you making, sword blanks?

It is possible that machining is not the best approach. First the scale and flux is murder on cutting tools. To try and get acceptable tool life you need to run at a modest speed with a good depth of cut and a good feed to get below all the horrible stuff and peel chips off in clean metal. Which leads to the 'second'; because you are attacking a rough surface with and aggressive cut and feed you get a lot of impact on the part and with it being a rough forging you might have difficulty holding it firm enough. Grinding is a much lower impact method of removing a bad surface.

Have you tried getting these forgings roughed to smooth surfaces in a local machine shop. If you find someone to do it and the cost is acceptable then it may be easier than I anticipate and you may be able to do it cost effectively yourself. If you cannot find someone willing to do it on a CNC machine that could be a hint that it is a horrible job to do in which case you might want to reconsider a grinder.

[anrsh2]

Geof,

Yup, essentially I am making sword and knife blanks.

Thanks for you thoughts. I have considered using cheap fly cutters, cut kinda deep as you suggested to get the real terrible stuff off, and then perhaps using a face mill for a finishing pass.

I am taking you suggesting to try a local machine shop and calling around. Thanks again.

Shane

[anrsh2]

This video shows using a CNC machine to surface grind.

Does anybody know where to buy the tool doing the surfacing?

YouTube - SX3 CNC Surface Grinding 2
Shane

[nate]

The simplest and cheapest thing to do is to have these blanks ground on a Blanchard. Ie: a rotary surface grinder. it holds with a mag and grinds under flood coolant.

A blanchard is the IDEAL tool for this task.

Call your local grinding shops and ask if they do blanchard grinding or rotary surface grinding.

[Russ Kaiser]

I am wondering if bead blasting, sand blasting, or shot peening might remove the flux and scale allowing you to mill the blanks on your own equipment? What are you using for flux, anhydrous borax?