Barfeeder Efficiency & Practicality

[Smrtman5]

I havnt had much experience with barfeeders, so i figured I'd throw the question out.

I need to determine whether the initial investment in a new barfeed, and very possibly a new Mazak lathe would be worthwhile. We are a small shop, but I we have a strong customer base and good potential to expand.

Here is the job: 7/8" Hex stock, 303 stainless, about 1.25" long. One side has a 3/4 NPT thread, the other has some profile turning and through the center is a .255-.257 hole. Monthly usage was quoted at 3,500 pcs/month.

We are currently running a small quantity on our Mazak, blanking each piece and running two operations, one to turn the NPT, the 2nd to turn the back profile and bore the through hole.

In my research I've read about the benefits and dangers of lights out production, as well as vibration issues from warped or non-round stock. (Keep in mind the .002 tolerance on the through hole).

What else should I consider? Does anyone have any advice or anecdotes? Thanks!

[Geof]

3,500 a month and you are not using a barfeed?????

You don't need to worry about lights out stuff just start using a barfeed so you don't have to cut the stock and load every part twice.

Vibration is only likely to be an issue if you want to use a really fast spindle speed but machining 303 hex is not going to be that fast. You can also control vibration by having shorter length bars which is often needed anyway if you get a magazine type feeder.

The part you describe could probably be done in one operation and parted off complete and just needing a deburring operation on the parted end.

[PixMan]

A single-tube hydrostatic bar feeder would be the cheapest way into bar feeders, but you should really consider a 32mm CNC Swiss-style machine with a FMB bar magazine loader to make those parts complete in one operation.

I can recommend a few to look at if needed.

[Nastyzen]

3500 pcs ,poor you!
On my Colchester lathe I installed a $ 1100.00 bar puller, bar feed too expensive for this small shop.I then built a floor bolted structure on which I mounted 2.00'' pillow blocks with uhmw insirt bushings every 12.0''.
Now I can put a 12.0ft bar in the machine and go work on something else while the lathe makes parts till it runs out of material.I even rigged a green and red light in the shop window so that I can tell if it's running or not from the house.
A bar puller is basically a clamp that mounts on your tool post.
enjoy!