Concentration Control of Cutting and Grinding Fluids by Using a Refractometer

Описание: This is a funny and educational video to help people who use cutting and grinding fluids (commonly called coolants) to machine metal using large milling or grinding type machines. The video has two characters, Clark is the machine operator and Devin is the TRIM® representative who helps Clark understand how to take care of the cutting fluid in his sump so that he gets better tool life and avoids rust and odor issues.

Starring:
Clark M. Callis
Devin O. Sizemore

Special thanks to Misco for the use of one of their Palm Abbe Digital Refractometers and to Owens Community College for the use of their machine shop.

Below is a narrative of the dialog:
Clark: Hey Devin, I've been having a lot of trouble with my machine lately.
Devin: What seems to be the problem Clark?
Clark: My tool life is all over the place. One day its great, the next I'm changing tools constantly. One day I have foam all over the place, the next day hardly any. And sometimes I get rust on the tooling.
Devin: Well, that sounds like you may have some concentration control issues with your machine.
Clark: Really, I always thought that as long as I have coolant in the sump, I should be fine.
Devin: Coolant does a lot more than just cool the tool. It also provides lubrication, corrosion prevention, and helps control stink. How often do you check your sump anyway?
Clark: I look at it every day. If it doesn't seem right, I either pour in more water or more coolant.
Devin: Right there is the source of your problems. You really need to check your sump concentration with a refractometer and then add properly prepared makeup fluid.
Clark: You mean one of these? (holds up old refractometer) I've seen these used before, but whenever I try to use one, I just see a big gray fuzzy line.
Devin: You probably have a lot of way oil leaking into your sump. A digital refractometer eliminates having to guess the brix refractive index because it gives you a number.
Clark: My machine does leak way lube into the coolant. (pause)
Clark: How do you use a digital refractometer anyway?
Devin: It's easy. You calibrate the unit with clean water, just a few drops on the lens, shut the lid and press the ZERO button. Then you clean the lens, and add a few drops of well mixed coolant you've collected from a discharge nozzle, shut the lid, and press the READ button - And you have your reading in just a few seconds.
Clark: That does sound easy, and it sure beats guessing about a fuzzy gray line. What do I do next? I've been told to run the machine at 8%, so if the unit shows 8% brix, I'm all set right?
Devin: Maybe, it all depends on what the brix refractometer index factor is for the fluid you are running. Many soluble oil fluids have a factor near 1, but semis & syntheitics can have very different factors.
Clark: I don't know the factor. Where would I find it?
Devin: It's right on the pail or drum label. It is also on the Data & Information sheet.
Clark: Here it is. It says the factor is 1.22, so should I multiply my brix reading by 1.22 to get the actual concentration?
Devin: That's right. So if the unit displayed 12% brix, your actual concentration would be 14.6%
Clark: So, I'd be running way high. And that would explain my foam issues.
Devin: And low concentration can lead to shortened tool life, rust and bacterial problems.
Clark: I really would need a display of 6.6 % brix to get my sump at 8% concentation.
Devin: You could then track and post your readings in either % concentration, or % brix, whatever is easier for you to understand.
Clark: Since the refractometer factor is 1.22, & I don't want to do the math in my head, it would be eaiser to set up the chart using just % brix.
Devin: That's true. Since you want to run MicroSol 585XT between 7 & 9 %, with a target of 8% concentration, you want your readings to be 5.8 to 7.4, with a target of 6.6.
Clark: Well I'm going to start charting today. This is going to simplify my job.
Devin: That's right. You're not going to have rust, poor tool life, and stink when your machine is in control.
Clark: Thanks for showing me how to use a digital refractometer to monitor my sump concentration.
Devin: No problem, I'll see you later.