SFA

I am curious for those of you that run CNC's and Polishers what you do to filter your recycled water if you do not use a filter press. I am currently running a filter press and really want to get away from using it, but also understand that we need clean water for polishing.

Please share how you filter your water and to what micron. Also, are you filtering to a different level for through-spindle water vs. halo water.

Thank you,

Joe Duszka
CCS

For polishing it might help to compare micron size (for filtering) vs. abrasive grit#s.

30 microns is about 600 grit
15 microns is about 1,200 grit
9 microns is about 1,800 grit
3 microns is about 8,000 grit

Not all the water contaminants are highly abrasive like SC or diamonds, but this is a good way to explain and/or understand why you might want 10 micron or 5 micron filters in front of polishers. It will filter out any abrasive contaminants that could compromise the polish.

I've seen guys in the members area who use mainly weir settling systems (series of tanks) that catches most of the larger sediment. You can pull water from any of the tanks in the system based on how clean (settled) you need it. Use the filter of your choice in front of critical processes (machine spindles or polishing).

Hi Joe,

We run our polishers on Fresh water, since they do not use that much per polisher (although we do not have a small army of guys polishing like some shops might) Most CNC manufacturers require very clean water to go through the center spindle. Your halo can usually be filtered to ~50 micron. However, the cleaner you make your recycled water the less accumulation you will have in your lines and equipment.

We have a Park Industries HydroClear 80 system which is made by Full Circle Water. The water that comes out of the storage tank is ~50 micron if I remember right. The rapid settling system (angled plates in the settling tower) do a much better job than just bulk storage and relying on settling of the heavier particles.

There are a few shops that run a filter press on top of this setup which produces really clean water. If I remember right, I think Dave at Slabworks said they added a rapid settling setup to their filter press system and went from changing the press bi-weekly to once every 3 weeks or a month!

We have an additional bag filter right before our CNC to catch anything before it goes into the CNC halo. You can get filter bags from 50 micron to 2 micron. The bags cost about $2-8 each depending on the filtration level. Just like the filter press you notice a drop in pressure when they are trapping more slurry. Takes about 10 minutes to clean and reinstall a new bag. If you want to rush you could get it down to 3 minute changeouts.

If you are considering adding/changing more than just a bag filter I would give the guys at Park a call to see what setup would be best for you currently and in the future. I wish it was just as simple as adding a bigger pit, tank, and a pump however, there are many dynamics involved in achieving the quality to keep the slurry out of your equipment that you already spend a chunk of money on in the first place.

Good luck,

Rick Graff.

We use a settling trench "system" (basically a trench around the shop with a few blocker boards in places) and run our saw, router halo, and line machine with it. We use fresh water for the hand polishers and the spindle on the router. The discharge from the overflow helps keep the recycled water cleanish and we have virtually no maintenance on this system aside from shovelling out the trenches once a month or so...which can be done while machines are running. I tried bag filters and we were changing them twice a day to keep water moving.

We run a clarifier by ECS Eich. The water is cloudy and has particles of around 10 microns. We even run this water through both CNC's. We have a pool filter that filters the water down to 1 micron through the spindles only. The cloudiness of the water doesn't/hasn't hurt anything. We do not use any flocculant in our system. With all machines running, we use about 120GPM. I love not having to clean a filter press every week. With our clarifier, we open it once per year and power wash it out, that's about all the maintenance we have to do to it.

Mark Meriaux wrote: ↑

Thu Oct 15, 2020 10:40 am

For polishing it might help to compare micron size (for filtering) vs. abrasive grit#s.

30 microns is about 600 grit
15 microns is about 1,200 grit
9 microns is about 1,800 grit
3 microns is about 8,000 grit

Not all the water contaminants are highly abrasive like SC or diamonds, but this is a good way to explain and/or understand why you might want 10 micron or 5 micron filters in front of polishers. It will filter out any abrasive contaminants that could compromise the polish.

I've seen guys in the members area who use mainly weir settling systems (series of tanks) that catches most of the larger sediment. You can pull water from any of the tanks in the system based on how clean (settled) you need it. Use the filter of your choice in front of critical processes (machine spindles or polishing).
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Thanks for this useful info, I was also looking for it

We filter down to 50 Micron, but we just run through a 100 micron bag filter for our line polisher and it polishes like glass. I thought the cloudiness would effect polish, but it seem to not matter. FYI