[dent424]

The title really says it all. I'm kind of a machining newbie I'm wondering if its possible to face mill a block of hardened High Speed Steel with Hrc 64-68. I'm looking to take off between 1-3mm. Currently when this happens I use a grinder, but it takes forever and I'm looking for a faster way to do it.

Any ideas would be greatly appreciated.

[txcncman]

Sure. Just use a tool harder than Hrc 64-68.

[dent424]

Thanks!

So a quick follow up. Is that really all there is to it? The reason I ask is that when I look at the tool catalog for our current standard supplier (Mitsubishi), it doesn't have a section for tools that can cut anything above HRC60. I don't know if its because I'm looking in the wrong section or whether its just that Mitsubishi doesn't make such tools. What would inserts that cut material this hard be made of usually?

Thanks

[txcncman]

That is the problem. I am not aware of any. Call the tool makers and ask. Don't just look in catalogs. Some carbides can handle up to about 55 RHC. If you were turning, you might could get diamond tips to cut it. You will probably be stuck with grinding. The abrasive grit in grinding wheels has a hardness close to diamond.

You do not give any details on the parts you are making. Possibly you can re-engineer your process and use a different material and machine the parts then heat treat to the required hardness.

[victorofga]

i think the problem is not that carbide wouldnt be higher hrc..

virtually any carbide more than hrc 68..

the problem comes from the hardened steel structure..

i know theres a grinding method where grinding wheel is metal and works like edm...

http://download.springer.com/static/...27d21&ext=.pdf

i think this is the method grinding in one pass deep flutes on carbide endmills.. but i cant tell you if it works with your hss.. i think even you can access one of this type machine, it wont be cheap or affordable..

as others suggested you, very possible you need to change technology.. means first milling the untempered part.. or stay with grinding..

best would be asking directly seco or some other brand..

[dent424]

Thanks for the help. Just a little more context to see whether anyone has a good idea.

Basically, what we do is keep heat treated HSS pieces around to make various kinds of broaching tools. We keep a large variety on hand as we handle orders in many different sizes. In general this is not a problem as we have stock that allows us to grind off a few tenths of a mm with a standard surface grinder.

The problem comes when we get a particularly large order. In that case, we may have to grind down a much larger piece that we have in stock. At the worst, this can be grinding something down by three or four mm, which as you might imagine takes forever.

One of the options certainly is starting with the raw material, getting it down to approximately the right size, heat treating and grinding, but since we get the heat treated stock cheaply, if we can get the grinding time down sufficiently, there would be a cost advantage in using the heat treated pieces.

Any advice would be greatly appreciated.

[txcncman]

Look up other grinding methods, such as creep grinding and Blanchard grinding.

[victorofga]

have you considered wireedm? they are very efficient for this work.. 0.1 mm wire cut very sharp corners...

you can calculate about 10-20 sqrt inch capacity.. means 1inch thick steel about 10-20 inch per hour

also the simplest of wireedm has already U-W axis ... means they make undercuts..

they can cut ready size the tools.. migth need no grinding, or just a very minimal..

on ebay you can find from 5K and about 10 you can get a well working machine..

[dent424]

WireEDM is not a bad idea. I may look into that and see if it meets our needs. I'm pretty sure we would have to do some minimal grinding afterwards but I'm sure the process would be much faster than what we are doing now.