Hi we are machining an aluminium plate 40x170x200mm Long. Currently it is machined on two machines (CNC Mill, Lathe, the back to the mill.) I beleive it can be done on the CNC Mill alone.

The 40mm is faced down to 39mm (Machined both sides) - This is the only reason the lathe is being used as the cut is continuous and there are no step over marks. If we do this operation with a facemill on the CNC mill, we end up with step over marks on the face because the cutter dia. is not big enough to take one cut accross the whole face.

Besides buying a larger facemill, does any one have any ideas to eliminate the step over marks on when using the cnc mill?

Thanks:

confused:

Does your current face mill have inserts with a nice corner radius ? If not, try that. Larger the better. Also make sure your mill is trammed right.

Multiple passes with a good face mill should leave a totally flat smooth surface. There will be visual marks, but this texture is very very fine. It's not a 'step'. You can see the texture, but you can't feel it. This visual texture can be removed by buffing or etching (such as done before anodizing). If you can feel a step by moving your finger over the surface then your mill isn't trammed.

Colin

Thanks for your response. From what I've been told we don't get a step with our face mill, the finish is pretty good. The visual texture seems to be the problem. The part in question is in clear view on the machine so they want a visually uniform surface.

Would buffing or etching look good and in terms of the time it would take to buff or etch,would this be more efficient than slapping it onto the lathe?

Thanks

cant you use a fly cutter instead of a face mill, a fly cutter with a nice radius tip should do a nice job since 1mm total is really not deep

Yes I agree fly cutting with a good radius is the way to go,I don't know what your tolerances are?Use a DTI to check the tilt of your head,attach it to the spindle and swing it across the plate ,adjust,or else you may end up with a concave surface,the wider the fly cut the easier it is to set up?Believe it or not!!

Try an Abrasive-Bristle Cup Brush
You can get them from McMaster-Carr and a 7'' brush can spin at 6,000 rpm.
They are silicon carbide and you can sweep the entire surface after milling.

sandvik 245 series with a wiper insert works great also

Use a circular tool path and overlap the passes by half the tool diameter. Take a very fine finish pass at high feed rate. Axial depth of cut about half the radius of the insert. Climb mill.

I am with Mazaholic, brushing can verily give you a great finish in a very short time. Orsborn is another company that sells these.

Lars