Coolant maintenance when running ductile iron

[wmpy]

About six weeks out of the year, I run a ductile iron job in one of my lathes. The rest of the year, it's usually running 6061 aluminum. Do any of you have suggestions on how to best maintain my coolant with this mix of materials? I would like to filter out the fines in some way because I have noticed some black debris on the ID grooves of the aluminum parts. Continuous filter? Filter all the coolant and clean the sump once I'm done running iron? Toss the coolant after running iron? Magnets in the sump to catch all the fines? I'm hoping someone else regularly runs a mix of iron and has this figured out.

 

[michiganbuck]

Could you let it settle overnight/weekend and then slow pump all but the last 1" into another container? scrape the tank clean ..and then filter drained back into the coolant tank.

 

[Houdini16]

We bought a Freddy vac, it has 10mic filters, works great and fast, and EXPENSIVE $8k.
also I have added in the past a secondary coolant storage container with a size #1 1micron bag filter in its lid, I then use a 1/10hp coolant pump, and just leave this on 24/7 to clean any micro fines out after
a sump cleaning.

 

[EmGo]

Do you absolutely need the coolant ? Most of the time I run cast iron dry. It's a lot easier to clean up.

Cast iron and coolant is a nasty combination.

 

[GiroDyno]

+1 for dry; we constantly revisit the debate about running coolant on our cast iron process, but never changed our minds.
I couldn't imagine switching back and forth and not tossing out the coolant.

 

[david n]

I used to run 1 cast iron job……came around once a year or so. I amortized the cost of all new coolant and a thorough machine cleaning into the job. Ran it on a machine that had marginal coolant to begin with. I tried salvaging the coolant in the past. But it was an act in futility.

 

[Mtndew]

Siphon it all out, wipe it clean with soapy water, fill with water and maybe a sprinkle of a cleaning agent.... run the coolant for a few minutes to clean the lines, drain, wipe the tank clean again. Fill with coolant and start making chips.

It's a lot of elbow grease and machine downtime but it's effective. Our coolant rep has a team that will come in and do this for us (for a fee of course) at night.

 

[camhead420]

We do what Mntdew does, plus pull all the tools out of the turret also, pull the chuck off and take it apart. Cast gets into everything, just like bronze.

 

[michiganbuck]

One big problem with coolant on cast is the high heat ..and the carbide fracturing from the heat..so when coolant is used Flood is better..
Hight HP, and stout machines and holding fixtures.
Thicker carbide so as to absorb more heat.
The direction of cutting forces to get the most rigidity of the part.
Very smooth edge tough carbide and a negative land can be good.
I have a lot of cast iron cutting tool experience, grinding, purchasing, testing, and engineering..

 

[Vancbiker]

In my early manual machining and CNC years we ran lots of cast iron, mostly turning with secondary mill ops. Tried dry on occasion but always went back to coolant for dust control. Going home every evening and blowing black snot seemed worse than coolant maintenance.

Dust collectors on the machines might have been the better solution, but that was not gonna happen at that shop.

 

[michiganbuck]

cast iron dust is also a fire hazard.

 

[david n]

cast iron dust is also a fire hazard.

First time I heard that??? Dust maybe?................but not chips...............

 

[Vancbiker]

First time I heard that??? Dust maybe?................but not chips...............

With cast iron, where there’s chips, there’s dust.

 

[GiroDyno]

We were looking into a central dust collection system and had to get our chip/dust content tested, barely rated as explosive but that's enough to require a serious unit. After speaking with some specialists apparently you can design the dust collection system in a certain way/add proper vents, valves, etc... to avoid requiring any sort of 'certifiable' explosion proof system.
Of course that all probably depends on your jurisdiction... I have a suspicion that regulations for that kind of thing in WA are different than CA are different than SC, so YMMV.

 

[wmpy]

We bought a Freddy vac, it has 10mic filters, works great and fast, and EXPENSIVE $8k.
also I have added in the past a secondary coolant storage container with a size #1 1micron bag filter in its lid, I then use a 1/10hp coolant pump, and just leave this on 24/7 to clean any micro fines out after
a sump cleaning.

Is your secondary coolant storage connected to your sump? Or is it completely separate?

 

[wmpy]

Do you absolutely need the coolant ? Most of the time I run cast iron dry. It's a lot easier to clean up.

Cast iron and coolant is a nasty combination.

I hadn't really considered running dry. I might be able to. I drill a 1/4" hole through the part which is about 7/8" long. That would worry me doing that dry.

The thing about running dry, though, is that the chips and dust are still going to get everywhere inside the machine. When it's time to run a different material with coolant, I'm afraid that fine dust is going to just get washed into the coolant no matter how well we wipe down the inside of the machine. I'd be particularly concerned about getting the chip conveyor clean.

 

[wmpy]

+1 for dry; we constantly revisit the debate about running coolant on our cast iron process, but never changed our minds.
I couldn't imagine switching back and forth and not tossing out the coolant.

Do you have machines where you machine cast iron and other materials? Or are do you dedicate machines to your cast iron parts?

Regarding running dry, are you doing any drilling dry?

 

[Dan from Oakland]

From experience- dump the coolant, scour the machine and replace coolant. The long term solution if you don't is you will need to buy a needle scaler to get the cast iron fines out of your machine.

 

[wmpy]

I used to run 1 cast iron job……came around once a year or so. I amortized the cost of all new coolant and a thorough machine cleaning into the job. Ran it on a machine that had marginal coolant to begin with. I tried salvaging the coolant in the past. But it was an act in futility.

This may be what we end up doing. I'm not even worried about the coolant cost. It's a small tank.

 

[david n]

With cast iron, where there’s chips, there’s dust.

Duh.....I know there's dust...............just never heard cast iron dust is flammable....................