milling square cutouts in a panel?

[PGale]

I've just bought a Syil X2 CNC mini mill and am jumping in feet first! so, some very basic questions...

My first project is to cut out some square and rectangular holes in 2-3mm ali front panels.

I'd like to get the inside corners as close to square as possible for some of the connectors that will be mounted in them. Maybe a radius of 0.5mm or 1mm, although I've yet to check what tolerances my connectors will allow.

So, what methods should I use to remove as much stock as possible from the corners?

I was thinking of using a 3 or 4mm (or even larger?) dia mill to rough out the main hole and then maybe use a micro size end mill (1mm or 2mm???) to trim out the corners. Is that feasable and a good way to do it?

My mill has a top spindle speed of only 2500 (although I've ordered a belt drive conversion which will take it to 4300). Am I right in saying the smaller mills need a much higher spindle speed?

I don't have any cooling methods - and probably won't get one unless really necessary?

Thanks,

Paul.

[One of Many]

A short 3mm would be reasonable for a decent feed rate. Then use a file to make the corners sharper. Using a smaller cutter can work, but a file will probably get the job done 10 times faster. Small cutters make small chips very slowly, even at high rpm.

You may be surprized that the units that go into these square holes have plenty of clearance at the corners.

DC

[PGale]

Thanks

Should I trust the feed rates in some of the apps I've been testing (Mach3 and RhinoCAM) - or is there a good chart somewhere?

I've ordered the swarfrat series of videos, so hopefully will get a lot of the really basic noob questions out of the way after that arrives!

[Al_The_Man]

Originally Posted by PGale My first project is to cut out some square and rectangular holes in 2-3mm ali front panels. I'd like to get the inside corners as close to square as possible for some of the connectors that will be mounted in them. Maybe a radius of 0.5mm or 1mm, although I've yet to check what tolerances my connectors will allow. So, what methods should I use to remove as much stock as possible from the corners?

If your connectors overlap the hole, what I do is use a 3mm endmill and when the corner is reached, just angle outward at a 45deg tangent for ~1-1.5mm, this works in most cases even where the hole is exposed.
Al.

[PGale]

Thanks

[JROM]

If you need dead sharp corners to clear for the parts that mount there you can drill a small hole right on the corner just large enough to clear the rad. of the endmill you use.
Then you just run a regular pocket toolpath and your there!

[PGale]

Ah yes - good idea, I'd not thought of that