Cutting Stainless Steel with a CNC Router

Short answer: bad idea. February 23, 2008

I need some shapes cut out of 0.8mm thickness stainless steel. I normally get this done by a laser cutting company, but I recently bought a CNC router and I'm thinking I might be able to cut through the stainless steel using the router. Importantly, the cutting tip size must be no larger than 1.5mm. If I was to cut the material with two passes, would that do the job? I'm just thinking that the cutting blade would go blunt almost immediately. Would a diamond tipped cutter blade do the trick?

Forum Responses
(CNC Forum)
From contributor A:
Stainless steel is a ferrous material and the cutting action will generate sparks unless it is cooled by liquid. I would advise against cutting it on your router.

From contributor X:
I was once talking with my tooling salesman and he mentioned that he sells special router bits to a door company which uses them to rout steel covered doors. Apparently the process works dry and it works great for them. You can contact FS-TOOL - they may be able to help you out. I personally never used these bits or cut anything covered with steel.

From contributor T:
It seems like I have seen routers that have had a light mister adapted to the spindle in order to cut this type of material. They weren't very fancy, but very effective.

From contributor G:
I second the "router is not suitable" vote. Try away, but I'd wear heavy clothing and definitely have the safety glasses on!

From contributor J:
I believe the mist you are referring to is called Accu-Lube. We have a boating customer who uses this product to cut aluminum. I know some of our aerospace customers use them as well. Don't know whether this would be a good idea with steel. I would ask the router manufacturer for their best advice. If they don't say "no way, Jose" maybe they would have additional insight into what would help make this work.

From contributor R:
Stainless steel is really tough to cut. It's hard. You would need a spindle that will operate at slow rpm (around 1,000 rpm) and a coolant system. Stainless will not dissipate heat, so all the heat goes into the tool.

From contributor C:
You can get a good example of how hard stainless is by taking a good steel cutting jig saw blade and watching the teeth grind off. Definitely ask all around about it and figure if it's worth possibly screwing something up.

From contributor E:
In can be done, but I would advise against this. We have a 4 flute 1.5 end mill but you will need a mist system or a manual spray (I don't know the part size or quantity you have to run). If you don't use a mister, you will need a boat load of tools. 1000-1500 RPMs are required.

From the original questioner:
From reading all the advice given, I think I will not be cutting stainless steel! I actually thought this might be the case, but as laser or plasma cutting is quite expensive, I thought I might as well ask just in case.