Cnc Machining 1/8 thick steel sheets

[ccm]

I'm back to finally finishing my cnc project, and now have purpose behind it. What I want to be able to do is machine out steel gaskets out of 2 mil steel sheet... well it's between 2 mil and 1/8 roughly. The gaskets are 3" by about 2.750" each. My questions are not about motors or chassis design but more like what type of bit would anyone recommend for this application ? I'm planning on fluid cooling / flood & spray type following the cutting bit.
Is a TiCn treated bit going to do it? or will Cobalt suffice with the extra cooling.

Thoughts, suggestions......

thanks,

Arthur

[E-Stop]

For material that thin I'm not sure you are going to notice much difference. I'm not sure what size mills you are going to use but the prices of solid carbide mills in the smaller diameters is really cheap, like a 1/4" solid carbide for less than $8 at MSC. I think that is what I would opt for. I'm wondering though, how are you going to hold the gasket wihile cutting it? If you have trouble with the mill trying to lift the part, you might want to try a left-hand cutter, if that's an option.

[ccm]

I planned on using either 1/4 or 1/8 sized mills, depending on what hardness they are, and to hold down the work piece I'm thinking vacum on the outer corners or unobstructive placed hold downs. I'm hoping to be able to cut 4 to 6 gaskets at a time, so holding the edges might be the only way I can go.

-art

[DareBee]

I find at least 4X the cutter life with the carbide cutters coated with TIALN and gettting them with an .020 corner rad also greatly helps strength especially if you will be plunging through.

[HuFlungDung]

How about getting them laser cut first? Thin sheet can sometimes be a bit of a bear to mill, because its rolled pretty hard. A person might cut a prototype on the mill, but after that...well, its just not as much fun as it should be

Considering that a laser is non-contact cutting, and cuts as fast as you can draw a line with a pencil, a small lot order would not be that expensive. Sorry if I took all the fun out of your project

[DareBee]

I bit off topic Hu, but that is what I normally do as well (the laser cutting I mean)

[ccm]

I'm planning on using flood cooling as well to not only keep the chips clear but keep the heat factor down. The mill will probably only be turning the bit @ about 2500rpm or less, I think this should suffice nicely for cutting the heavier material, too high an rpm ( if I was using a router ) I'd be smoking bits frequently is my assumption, that's why I decided to stay with the stock spindle configuration.
Here's one other concern, I there's others that have successfully done the H.F. Mini mill conversion, any typical issues that come up on these or should it work pretty consistently ... I know I've got to eliminate some backlash to get it perfect, but any veteran tips someone would like to share ? I'm all ears....

thanks for the info and suggestions guys,

-art

[caitolly]

Why not rough out your blanks, hold them in a regular vice, or a tool plate and clamp the outer edge of your blank, machine all the holes, bores, any other features, etc.
make a simple tooling plate ( using dowel pins, shoulder screws, etc.) using the machined feature's to locate and hold down the plate, then machine your outer profile.
If you don't have any tight radius to deal with you can always use a larger dia. endmill, also by using a larger dia. you may want to stack your plates on your tool plate, 2,3, 4 at a time?
Besides, vacuum plates suck!
It's not all science, it's art
caitolly