Anyone have any experience machining Cast Iron in a CNC?

[thrown_hammer]

Left field thread of the day!

How do you keep the powdery chips from getting in the coolant tray and mucking everything up? I am working on a project that involves machining on a porous Titanium. (Titanium Monkey anyone?) The material is about 70% air so when we machine it we end up with a chip about the consistency of sand. This almost turns into cement when it gets into the coolant tray and settles. We are looking at a conveyer system that pumps the coolant into a holding tank and filters the coolant thru a paper media. (kinda like a 911 dry sump.) The problem is the chips still get into the coolant tank and is passed thru a pump. I would like to avoid that if possible.

Any ideas?

[dad911]

I'm a rookie, but can you cool with air and vacuum the chips?

[charleskieffner]

first..........what are you machining? titanium or cast iron????? you mention both.

next titanium is usually machined with uncoated insert.

cast iron is usually machined w/a coated insert.

now as far as your chips.......are you drilling/milling/turning/ threading?

im not at home so i have none of my sandvik bibles here. go to sandvik coromant.com and all the answers are there.

now back to chip problem. what kind of coolant? oil? water soluable? more than likely water soluable unless your on a swiss cnc making itty bitty parts. in the case of water soulable i would add more coolant spray volume.

color of chip will tell you alot.

curl on chip will tell you alot.

since its sand like, it sounds like very light cuts.

bottomline: you must always remove chips to allow carbide to last. you do not want to recut chips over and over. bad for carbide life, bad for part when you crash.

hope that helps.

also check out iscar.com/mitsubishi.com./kennametal.com etc.

twist the territory salesmans nuts. bypass the local distributor. if that doesnt work get regional mgr. involved.

[charleskieffner]

another question????

is this a long/medium/short run part????

to make a fine paste like substance like your sand chips go away..........you are going to have to add more volume and more than likely change coolant more often than you would normally like.


since you have asked this question, it is obvious to me you have never done this op or part before.

there is ALWAYS a reason why a part walks in thru your front door. and that reason is "MR PROFITABILITY"

ie. your competition couldnt make money on it.

[thrown_hammer]

The chips come off in chunks anywhere from .100" across to dust. It looks like very small Grape Nuts cereal.

The reason I mention cast iron is because our chips resemble the cast iron powdery type of chip and I figired there has to be a way already in use that keeps the very fine powdery type chips out of the coolant tank.

We have all the processing done and aren't having any trouble machining the material, it's keeping the powder out of the coolant tank that I am looking into.

We developed the material and machining process.

[charleskieffner]

so it is titanium. well uncoated inserts are the choice then. ridding yourself of this pesky sandlike substance really boils down to more coolant volume/better filtration.

since chips not staying at part, carbide will last longer.

now jes fer giggles.........try bumping up/down yer speeds and feeds and see if you actually can create a curling chip. start low and then go up.

remember.........someone else has machined this material before. is titanium domestic or off shore? find out from your supplier who else he sells the exact same rockwell titanium and then call them and see what the hell there procedure is for moving chips.

your distributor salesman gets about 1 days worth of carbide/coolant schooling out of a year.

for carbide and coolant call territory salesman and say its a "code red"!

if neither one of them satisfy your problem then call regional manager.

regional mgr. can contact factory and do exact mock up of your operation under ideal conditions and then give you exact MOT and mfg. of coolant and method of expelling chips. and how often you have to change coolant.

but..........ask yourself this. how many of these parts and how long do you plan on having job. if its a short run prototype..........bite the bullet, suck up, burn up carbide and coolant, quote the damn part high so you make some money and then move on.

[Tim Hancock]

Shawn, can you simply put a temporary cloth "pre-filter" over your coolant drain?

[lendaddy]

Try a veg oil based mist coolant rather than a flood?

[thrown_hammer]

Charles, We have the machining process dialed. Because of the material you will never curl a chip. No one has machined this material before. We invented it. We have the patent and are the only facility in the world working with this particular material. I really can't go into any more detail than that.

Tim,
The pre-filter idea is being somewhat used currently. The problem is the chips load up so fast the machinist is caught off gaurd.

Len,
The parts being machined are medical implants. Because of the porosity of the material "oil" of any kind gives managment the heeby jeebys.

Right now I am thinking of either a cascade style filter with baffling to capture the chips in holding tanks, or a paper filter conveyor system similar to those used in CNC grinders, but without having to pump the coolant out of the machine.

[lendaddy]

Had a thought last night on this. How about an alcohol mist? Excellent cooling and no residue.

[Tim Hancock]

Shawn here are a couple pics showing a custom pressure test fluid tank I designed for some power steering hose test machines we built a few years back at work (I just thought this might trigger an idea for you on a pre-filter). Of interest to you might be the roll of filter media (I think McMasterCarr still carries this stuff). The dirty fluid containing shards of rubber would spill onto the perforated metal tray covered by the filter media prior to returning to the tank below.

Maybe you can maker a small flat frame to cover your machine table drain and hold this type of filter media.

[lendaddy]

You could also do a multi-chamber cascading settling tank(s) prior to the filter.

[5axis]

Originally Posted by thrown_hammer

Left field thread of the day!

How do you keep the powdery chips from getting in the coolant tray and mucking everything up? . We are looking at a conveyer system that pumps the coolant into a holding tank and filters the coolant thru a paper media. (kinda like a 911 dry sump.) The problem is the chips still get into the coolant tank and is passed thru a pump. I would like to avoid that if possible.

Any ideas?

The conveyor filter system is pretty common on surface grinders and works well.
Cast iron is self lubricting so dry cutting is a option. It still makes a heck of a mess. Vacume systems like those used on carbon machines may help. No matter what we do the stuff still gets everywhere and is a big mess to clean up. I'd rather burn up inserts by minute, cutting PH 15-5 than the cast stuff.
Good luck

[thrown_hammer]

I am having a cascade box fabbed up to try. I did a couple experiments and it caught all but the very fine powdery stuff that floated on top. Even then I caught over 90% of the chips. We will see how it works.