how to make smooth cut?

I'm new to machining and just got a bridgeport to play with. I've trammed the head and all but I can seem to get smooth cuts. I go slow and use alot of cutting fluid but I'm never really happy with what I get I can always see and feel ridges or waves. even after going over the same area several times on the same pass and up cutting only a few thou on the last pass very slowly. I get this weather I'm using the bottom of the end mill or the side to cut with.


Any help would be great
Thansk
grinch

If you want a super smooth finish then i would either use an inserted facing mill or a fly cutter. Also if you use a big radius it helps. As far as getting completely rid of the little swirls... dont count on it. you should be able to get to a point where you cant feel any steps though.
It would help to know what type of material you are machining???
hope this helps.

You say you are "getting this whether using the side or the bottom of the mill"

Are you taking the lost motion out of the screw and locking the table against the cut in the axis not being used to traverse the work? If you (for instance) move the saddle "in" (toward the column) and are cutting on the side toward you, when the cutter hits the work, the saddle will try to move in more until it hits the backside of the screw threads (takes up the play) which resists it. Then, if the cut is heavy and the saddle is not locked, it will bounce agains the screw as the cut progresses and each tooth of the mill hits. If you are cutting "with the end" of the mill, the teeth will first try to drag. the saddle out, then shove it back in, as the cut progresses, if it is not locked.

So take up the lost motion, and lock the travels not in use (should go without saying, lock the quill too.)

Also, get with someone who can check if your gibs are correctly adjusted, so the table is not sloppy when it is in motion.

Good luck!
smt

I've been cutting aluminium mosty.

Whats an "inserted facing mill"?

no I havent been locking the table in the diection not being used I will do that. I'm alos betting my gibs are not just right also now that youi mention it. When I brought the mill home I had to remove the table and I did it my self I I'm not sure what is exactly right.

Thanks for the help guys I'll do as you say them try again.

Thanks
grinch

Something you might want to try. If you need a good finish, be sure the cutter is sharp for the last pass and are you using a cutting fluid? WD-40 works well for aluminum.
Michael

A few months ago I adjusted the gibbs & split nuts to where they should be. Big improvement in surf finsh. Locking down all but the axis that is moving helps too. On the axis that is moving I snug up the lock just to get the slop out of it such that it still moves easily and freely.

I'm no expert either.

I forgot to add to my post, do you know what kind of aluminum it is? Some aluminum is hard to machine. Be sure it is something that is machinable like 6061 and it will finish nice.
Michael

Hi Grinch

I would suggest the following:

1) Make sure your collet and spindle are clean.
2)Retract the quill and lock everything down- quill, knee and saddle.
3) IMO Aluminum machines best with a very high rotational speed, be sure to use cutting oil and get agressive on chip removal with a vacuum or air nozzle.

Hope that helps.
Check to make sure the part is secure in the vise.

Are you edge milling the part, face milling, or cutting a slot. If you are edge milling (cutting with the side of the end mill) you will want to lock the axis not being used and climb mill (cut in the direction of the tool rotation) as well as come back with out moving the piece over. I find that soem times when I am climb milling I will get a rippled finish if I am going too fast and just going back the other way helps take those out.

If you are new to machining, you might want to check out Sandvik coromat.

http://sandvik.saloneit.com/student

I took their home study course where they gave you a book and you would read each chapter and answer questions and mail or fax them to be corrected. You don't get a grade but the book is informational and is not a sales brochure. It appears that they are now offering the courses online as well.

If you are looking for relevant, current, and good information, I would highly recommend checking out the link