Thread: Surface grinder kicking up mist/fog

Over the weekend I have been playing with my new toy (a surface grinder). It creates quite a lot of mist. I have an unidentified dust extractor (creates tornado like suction) that came with the grinder. I have no idea if it can be used to extract the mist or if it is a dry unit only. It does not have a brand on the unit. It is labelled M15, has a foam lined box, a couple of hanging filters and the motor is made by ABB in Germany. Can anyone identify the manufacturer?

Can this be used to de-mist when grinding? If it is dry only, can I fit some sort of moisture trap to it?

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Hi Variant,

I'll be interested to know the same thing! I have since remedied the situation (to a point) by fashioning a shroud out of some black plastic damp course held with magnets. This collects some of the mist and directions it into to LH slash guard. It's hardly ideal though. I have also reduced the coolant flow to help. I never grind dry but when I dress the wheel is when the most mess is made. I'm yet to fashion a vacuum cleaner to the head, but then unless my shop vac has a HEPA filter or it's housed outside, it will most likely just spew the stuff out anyway.

I never envisioned the amount of mist that would be created by wet grinding, totally different to dealing with coolant with cutting, turning, milling etc. but I guess it's a fluid being pumped between two surfaces microns apart and spinning at some 5000 sfpm.

Simon

I could be wrong, but I always thought that when applying coolant to grinding operations the coolant was directed at the work and not the wheel so that it did not mist up (as much).

Michael

Hi Anthony,
Like Michael says i spray my coolant at the work, not directly on the wheel. The only time i spray it onto the wheel is when i'm dressing it. The Blohm came with a height adjustable rubber flap on the left side of the wheel guard, it does a great job of keeping the mist to almost zero. I don't think your guard covers as much of the wheel as mine either.
If you run the coolant on the job it will help tell you how close you are when touching off. It will start to "crackle" when you are getting close.
HTH,
Ew

I've never directed the coolant onto the wheel, always the surface of the job but it when the wheel passes over and coolant gets forced between the wheel and the job that the mist is created.

A makeshift shroud seems to be the go for you Varriant.

Simon

Originally Posted by Michael G

I could be wrong, but I always thought that when applying coolant to grinding operations the coolant was directed at the work and not the wheel so that it did not mist up (as much).

Michael

Thanks for the note on the general practice - I was not aware of this. I did try intially aiming at the work but it either ran dry for the first inch or so and did not cool as effectively. Aiming at the wheel and I get barely any sparks. But I do get more fog than aiming at the work.

IMG_0610.jpg

Originally Posted by Ueee

Hi Anthony,
Like Michael says i spray my coolant at the work, not directly on the wheel. The only time i spray it onto the wheel is when i'm dressing it. The Blohm came with a height adjustable rubber flap on the left side of the wheel guard, it does a great job of keeping the mist to almost zero. I don't think your guard covers as much of the wheel as mine either.
If you run the coolant on the job it will help tell you how close you are when touching off. It will start to "crackle" when you are getting close.
HTH,
Ew

Ew, interesting that you mention a rubber flap. There was a 1/4 inch rubber flap kicking around on my table. I was wondering why it was there (not mounted to anything). No mention of it in the manual. I will see if I can mount it up to the wheel housing. I reckon it will do the job to reduce the mist. I guess the challenge is keeping it out of the way of the wheel.

I have not heard the crackle. I will have to check that out. Thanks for the tip. Touching off is a bit of a challenge. The machine has power down feed so I have to be careful not to ram the wheel. I have been using the paper method and manual down feed when I am close. One interesting thing with this grinder is that you set your zero, then raise the head under power. Then power back down and it pulls up within a "safety margin" (the Gate) automatically. It then proceeds to grind to the depth you set on the electronic panel. All fully automated. When it finishes its cycle it returns to "home" (end of the part travel and up). Pretty cool stuff!

Originally Posted by simonl

I've never directed the coolant onto the wheel, always the surface of the job but it when the wheel passes over and coolant gets forced between the wheel and the job that the mist is created.

A makeshift shroud seems to be the go for you Varriant.

Simon

Agreed Simon. The flap seems like the way to go.

Ahhh the black mist of death

Gentlemen a quick visit to your local grinders that has been there for some years will answer all your questions

1 Computers are only 1year old as the mist vapour coats the boards in oily varnish and lets the magic smoke out

2 Walls and everything that has not moved in 3 months is a covered in a light black oily sludgy film the longer I sits the more built up it gets

I personally will not own one in my workshop for that reason unless its in a separate room (as in the old das they where or at least there own section)

Black mist?

Not sure what coolant you are using but I'm using Eccocool and it's clear like water. My main concern is not to breathe any of the mist in but any that hits a surface is just like water. it eventually evaporates leaving little trace. With the shroud I fashioned and improved techniques, mist is not mush of an issue anymore. I also only have one shed!

Edit: also I'm not using mine all day, everyday so it's easy to clean up any mess as you go.

Simon

Sorry Simon to say its an inherent issue with coolant and Grinders

I have worked in manufacturing for many years and the grinders I have dealt with all suffer from the black death syndrome

The water based coolants all evaporate over time leaving the oil / vegetable base lube any where the mist falls

Bruce

Back last century (literally in this case) I saw a picture of a device around a manual mill (or manual /CNC conversion). These days people believe in deluge coolant and CNC machines with guards so I could not find a photo, but it worked something like this -
coolant shroud.jpg
I doubt it would have done much for cooling the cutter or workpiece but if you had the flow you could probably adapt something like that for a surface grinder. The coolant directing part was bolted up to the spindle and the coolant was pumped in and then exited as a thin continuous film in a circular shape around the cutter. I think it was for use when cutting things that would be dusty but used on a grinder it may capture in the coolant wall the loose mist that is floating around. May be worth thinking about an adaption?

Michael

Originally Posted by variant22

Thanks for the note on the general practice - I was not aware of this. I did try intially aiming at the work but it either ran dry for the first inch or so and did not cool as effectively. Aiming at the wheel and I get barely any sparks. But I do get more fog than aiming at the work.

IMG_0610.jpg

Your picture to me, look's like you have a general flex line that doesn't move with the cross travel of the wheel? There's your problem. You have to flood it to get the coolant across the work. Any decent set up will have a spout, that's mounted on the wheel guard, and moves across with the wheel. You only need a fraction of the flow, because its just passing enough coolant to cool / lubricate under the wheel where its working.

I'm away from home at the moment, or I'd get you a picture. Uwee, or Ray & Josh would have the same set up. Maybe we can plink a pic out of them.

Under one stroke, the right to left one, it's laying down the coolant after the wheel has passed. That will cut your misting by 50%.

Regards Phil.

Phil I assume the J&S is a "standard" SG in that the table moves in and out not the head like on your machine? If thats the case the spout attached to the column/ whatever should be fine. I'll dig up a pic of mine.

Originally Posted by Michael G

Back last century (literally in this case) I saw a picture of a device around a manual mill (or manual /CNC conversion). These days people believe in deluge coolant and CNC machines with guards so I could not find a photo, but it worked something like this -

I doubt it would have done much for cooling the cutter or workpiece but if you had the flow you could probably adapt something like that for a surface grinder. The coolant directing part was bolted up to the spindle and the coolant was pumped in and then exited as a thin continuous film in a circular shape around the cutter. I think it was for use when cutting things that would be dusty but used on a grinder it may capture in the coolant wall the loose mist that is floating around. May be worth thinking about an adaption?

Michael

Interesting idea Michael. I will have a closer look. I like the idea of the water trapping the mist.

Originally Posted by Machtool

Your picture to me, look's like you have a general flex line that doesn't move with the cross travel of the wheel? There's your problem. You have to flood it to get the coolant across the work. Any decent set up will have a spout, that's mounted on the wheel guard, and moves across with the wheel. You only need a fraction of the flow, because its just passing enough coolant to cool / lubricate under the wheel where its working.

Regards Phil.

Ew clarified above in terms of the J&S design. The head is stationary except for going up and down.

Originally Posted by Ueee

Phil I assume the J&S is a "standard" SG in that the table moves in and out not the head like on your machine? If thats the case the spout attached to the column/ whatever should be fine. I'll dig up a pic of mine.

I checked out the rubber slip mentioned earlier. It does not have any holes for mounting so the mystery deepens.

For last nights job I clamped some paper towel to the dust extraction pipe. It cut down the mist by ~50%. Not enough, but a temporary fix. I noticed that it was kicking mist in both directions (left and right) last night.

As a side note the grinder is running great despite the mist. I ground a part last night using the absolute full extents of the available travel (660mm). It looks nice and even though it's dry I have a job to pry it off my surface plate. It feels magnetic on my granite plate. I will post some photos when I finish it off.

Photos of the grinder at work. Wide flat coolant spout on the right. On the left is the suction for the mist extractor. In the second photo is the coolant tank. It has a fan on the top of the coolant pump that sucks the coolant mist up and blows it back to the tank. It works really well we don't have much trouble with mist spraying around. Any chance of some more photos of your extractor unit?

Originally Posted by snapatap

Photos of the grinder at work. Wide flat coolant spout on the right. On the left is the suction for the mist extractor. In the second photo is the coolant tank. It has a fan on the top of the coolant pump that sucks the coolant mist up and blows it back to the tank. It works really well we don't have much trouble with mist spraying around. Any chance of some more photos of your extractor unit?

Snapatap, I can see how your extractor would do a good job. I have a great dust extractor that is attached to the rear of the wheel guard (tough to spot in the photos). It is an integral part of the design. Unfortunately I have no idea if it should have moisture run through it.

If only my coolant tank was the size of yours. Mine is a monster with 3 separate traps in it. Nothing overly special, just separates out the heavies.

A couple more photos of the dust extractor internals..

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I will have to take some photos of the dust extraction hose and mount on the grinding wheel guard.