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Automatic Centralized Coolant Tank Maintenance System

kunalv

Plastic
Joined
Jun 4, 2019
Hey guys, long term lurker, but first time poster here. Not sure if this was the right section of the forum to post this. So if mods feel like shifting the thread, please feel free :)

So, we have been pondering over how to design a system that maintains the coolant levels (volume & concentration) in a number of CNC machining centres in a 'Cell' or 'Line'.

For eg., a Cell consists of about 15 machines. We want to design a system that would continuously monitor the concentration on each tank and this info would be fed to a centralized PLC which would then calculate and top-up the required coolant+water to maintain the desired concentration in each tank.

Now, measuring the concentration can be done by Inline Refractometers. if you guys have any better suggestions for this purpose, any help would be great!

Also, if anyone has had any previous experience with such a system, please do let me know in the comments.

Thanks and I look forward to hearing from you guys!

KV
 
Really ?

Your "about me" page is wee bit different than what your writing here......
 
I'm interested to see replies to this. I wouldn't think 15 machines is enough to apply this system, but I don't know. You mention 'cell' so same mat's? customer, specs, etc?
 
Really ?

Your "about me" page is wee bit different than what your writing here......

Why are you an ass to every single new poster* here?? :rolleyes5:

He doesn't appear to be selling anything, just asking a question...

* at least let them get a couple posts/replies/etc to see their 'motives' before you beat them down.:ack2:
 
Why are you an ass to every single new poster* here?? :rolleyes5:

He doesn't appear to be selling anything, just asking a question...

* at least let them get a couple posts/replies/etc to see their 'motives' before you beat them down.:ack2:
I am ass ? (to anyone other than you ....)

I'm beating some one ?

I merely asking why the 2 items don't seem to jive.
Hard to provide technical help, if the OP is an accountant eh ?
 
Really ?

Your "about me" page is wee bit different than what your writing here......

I don't know what you're talking about. There's nothing on my 'About Me' page. Would you like me to list my entire life history on it if that would make you feel better and not post useless comments like this?
 
I'm interested to see replies to this. I wouldn't think 15 machines is enough to apply this system, but I don't know. You mention 'cell' so same mat's? customer, specs, etc?

Well. A cell is the name given to a single 'Line' in the plant where a product starts from being a blank on one end, and comes out as the finished product after going through a series of machining operations. Usually such 'Cells' in a plant are meant for any particular parts for one customer. There are multiple 'Cells' in a plant. For eg. In an auto part manufacturer's plant, there would be cells for Ford, Hyundai, Suzuki etc.

Hope that clears it a bit for you :)
 
I am ass ? (to anyone other than you ....)

I'm beating some one ?

I merely asking why the 2 items don't seem to jive.
Hard to provide technical help, if the OP is an accountant eh ?

I am not selling anything neither am I an accountant. I handle Operations for my own company where we are in the process of developing this product. I have come here looking for advice so as to optimize the design of this product using real-world examples from you guys.
 
I'm interested to see replies to this. I wouldn't think 15 machines is enough to apply this system, but I don't know. You mention 'cell' so same mat's? customer, specs, etc?

Also, why do you think 15 machines in the system is not enough?
 
Well. A cell is the name given to a single 'Line' in the plant where a product starts from being a blank on one end, and comes out as the finished product after going through a series of machining operations. Usually such 'Cells' in a plant are meant for any particular parts for one customer. There are multiple 'Cells' in a plant. For eg. In an auto part manufacturer's plant, there would be cells for Ford, Hyundai, Suzuki etc.

Hope that clears it a bit for you :)

LoL! I know what a cell is. :cheers:
 
Also, why do you think 15 machines in the system is not enough?

Not saying it isn't, just thinking it might not be... Are they big machines with big coolant tanks? I am thinking (from my own experience) 50'ish gallon tanks X 15 is only 750 gallons. I would think it would be easier to manage one machine at a time vs setting up a whole centralized system- plumbing, monitoring, safeties (ever overfill a 50 gallon tank and make a lake? I couldn't imagine 500+!), etc... I don't know I could be way off base here...
 
Will a single type of coolant provide for all the needs of the different machines? Are you machining different types of materials in different machines? Coolant that works good for tapping aluminum might not be the right coolant for turning titanium.
 
usually you consult with company that makes centralized coolant systems and they design what you want. for example temperature chilling to within 1 degree F is often wanted but obviously adds cost to the system.
.
also need pipe valves to isolate machines so if there is a problem you dont have to shut whole system down which often means all the machines wont run without coolant system running. thus coolant system often has 2 pumps for everything if one not working you switch to backup pump.
.
a lot more what ifs, need to be asked. even shutoff valves often need 2 valves in a row on same pipe. if one valve wont shutoff 100% its annoying to have 10 to 100 gallons leaking by on to floor per hour. for example if main coolant tank is 6 feet higher even with pumps off if no valves can shut off 100% it will gravity flow and leak. got to think about backups or what ifs this or that not working as expected
.
many central coolant systems have a plc or computer that controls the system. hard to describe just saying usually you work with company that designs those systems. that is the other company designs, installs, tests system. turnkey is you dont pay 100% of cost til they prove its working as promised and then they turn it over to you then and you pay the rest owed for the system. many a company has had lawsuits about installed machines and delays and costs to get fully running. usually the law says you need to give them time to get their stuff running as expected. not unusual that can mean many months. until they turn system over to you it still belongs to the equipment installer , design company. you cannot touch their equipment til its turned over to you
 
Not saying it isn't, just thinking it might not be... Are they big machines with big coolant tanks? I am thinking (from my own experience) 50'ish gallon tanks X 15 is only 750 gallons. I would think it would be easier to manage one machine at a time vs setting up a whole centralized system- plumbing, monitoring, safeties (ever overfill a 50 gallon tank and make a lake? I couldn't imagine 500+!), etc... I don't know I could be way off base here...

Monitoring individual tanks would definitely be a lot easier. But it all boils down to the cost. Because each 'online' refractometer itself costs around 2000USD, so it doesn't make a lot of sense economically to have one sensor in each tank.

Thus the need for a centralized system. Although we are aware of the limitations.

For the problem of overfilling the tanks, maybe a level sensor can be used right? Don't coolant tanks usually come with a level sensor that does this job?
 
Will a single type of coolant provide for all the needs of the different machines? Are you machining different types of materials in different machines? Coolant that works good for tapping aluminum might not be the right coolant for turning titanium.

This is definitely something we have considered as a limitation of this system. It will only work if all the machines in one Cell work with the same coolant (different concentrations can be worked with by adjusting the top-up volume)
 
usually you consult with company that makes centralized coolant systems and they design what you want. for example temperature chilling to within 1 degree F is often wanted but obviously adds cost to the system.
.
also need pipe valves to isolate machines so if there is a problem you dont have to shut whole system down which often means all the machines wont run without coolant system running. thus coolant system often has 2 pumps for everything if one not working you switch to backup pump.
.
a lot more what ifs, need to be asked. even shutoff valves often need 2 valves in a row on same pipe. if one valve wont shutoff 100% its annoying to have 10 to 100 gallons leaking by on to floor per hour. for example if main coolant tank is 6 feet higher even with pumps off if no valves can shut off 100% it will gravity flow and leak. got to think about backups or what ifs this or that not working as expected
.
many central coolant systems have a plc or computer that controls the system. hard to describe just saying usually you work with company that designs those systems. that is the other company designs, installs, tests system. turnkey is you dont pay 100% of cost til they prove its working as promised and then they turn it over to you then and you pay the rest owed for the system. many a company has had lawsuits about installed machines and delays and costs to get fully running. usually the law says you need to give them time to get their stuff running as expected. not unusual that can mean many months. until they turn system over to you it still belongs to the equipment installer , design company. you cannot touch their equipment til its turned over to you

You do make a lot of valid points and we understand that installation of such a system (let alone design) would be a difficult task. But, we just feel that the industry needs something like this as the benefits of the system are massive!
 
If you're trying to do this on the cheap (and it sounds like you are) I would consider not monitoring every single tank at the machines, but rather constantly circulate all of the coolant from all of the tanks. Monitor the levels of the individual tanks and control it with proportional valves on the infeed and outfeed. Easily removable screens everywhere to scrub off chips. Filter the return to the main tank and the main line out to whatever micron level is appropriate for your work.

Your refractometer goes on a side circuit of the main tank, can add water and coolant to the main tank as needed.

PLC to monitor and control everything, I think should go without saying.

Feel free to reach out to me directly if you want to outsource some or all of the design - I do a lot of smaller projects like this (usually locally, but whatever works.)

Good Luck!
 
Agreed. Refractometers cannot be provided on each machine. What we have decided so far is we will draw a certain quantity of coolant from each machine into our 'Measurement tank' where a refractometer would analyze the concentration & feed to the PLC. The PLC would then actuate valves & a pump to deliver appropriate quantity of coolant & water to the tank to maintain concentrations at desired levels.

Having said that, I have a few queries which I would really appreciate if you guys could throw some light on :-

1. Drawing liquid from the machine coolant tank into my measurement tank will require a pump. Now I am not sure if I have to install a pump next to each coolant tank (cumbersome), or my centralized unit will have a pump that will draw liquid from number of machines (what about the suction head? as the machine may be a good 50 feet away!). Which type of pump would be suitable for such an application?

2. After measuring the concentration, I have to feed coolant at appropriate concentrations back to the Coolant tank. I guess delivering pre-mixed coolant (coolant mixed with water at required concentration) would be better than delivering coolant concentrate & water separately into the coolant tank right?

3. How do I measure & control the flow rate of liquid? Flow-meters are expensive.

Any help would be greatly appreciated. Thanks
 
Also, the formula used for calculating the make-up quantity & concentration of coolant to refill the tank due to evaporative & drag out losses makes use of a very important factor - existing quantity of liquid in the tank!

How do I determine that in an automated process?
 








 
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