Peristaltic Fine Spray: no mist: no fog coolant pump

[Jasonb]

I left mine at the setting it was last used at which is about mid way round for the speed control pot and let it run for 12mins. I would say 4.75mls, the red line is at 5mls. So about 25mls per hour

[Vixen]

Jason,
Thanks for doing that test.      By coincidence we are both achieving approximately the same flow rate, about 25 ml per hour.

Mike

[fumopuc]

Hi Mike,
so here we are.
Just getting the report from R&D.
First picture, the adjustment.
If 1,2 rpm is really 1,2 ? No idea.
System is without any pressure, so pump only working.
Next picture the set up under the nozzle.
Medium result after 6 Minutes showing next.
Finally the situation after 12 Minutes.


Conclusion, it seems to be that I am a bit more "minimum" than you both.

[fumopuc]

Maybe worth a remark.
At this set up, one side of the pumpe is working in scavange mode.
In normal working conditions, the scavange side is pressurized too.
To get the real status closer, a bigger volume should be used to catch Air/Fluid mixture.
Big enough, that the mixture can calm down and the air gets off without taking fluid with it.
Or I have to cut the normal Reservoir connection and the pump should be feed by gravity only.

[Vixen]

Hello Jason and Achim,

Thank you both for taking the time to make those flow rate measurements. The results are in...

Mike       pump 2.25RPM    5ml in 12 minutes        25 ml/ hour

Jason     pump unknown   4.75ml in 12 minutes   25ml/ hour

Achim     pump 1.2RPM      2.6ml in 12 minutes     13 ml/ hour

It looks as if we are all working well above the minimum  MQL suggested by Dave Otto. I am happy to continue to work within these measured flow rates (13 to 25ml/hour). I am sure we are providing plenty of lubricant, it can get into the hidden area inside a pocket, it does not make too much mess and a litre bottle of S3G will last for years.

Achim, Your ETG100 is a free cutting steel but I am sure it was the correct decision to use apply the extra lubricant. I use my lube system for all material, except plastics.
"If 1,2 rpm is really 1,2 ? No idea." You can always look at the centre of the peri-pump and count the revolutions.

A peristaltic pump is almost a fixed displacement pump. If the supply tank is close to the pump, tank pressure is not required. A distant supply tank may well benefit from some tank pressure.

Thanks again

Mike

[fumopuc]

Hi Mike,
I could not resist to make another experiment and as in real life, more experiments more questions.
below the new set up.
System pressurized, as in real working conditions.
And than the mess begins.
How much fluid is evaporated ?
How much is still as a film at all used additional equipment ?
Now after waiting another 10 minutes it is straight 2 ml and not more.
So why do we have less, than with the experiment before are the new questions.
But to be honest, for me it is fine as it is, the system is working and that is what I need.
It does not matter if I use 2, 3 or 5 ml per 12 minutes, important is for me that I can go relative fast with the feed rate in Aluminium and the cutter will survive it.

[fumopuc]

Additional findings.
Some patient seems to be necessary.
Now 60 Minutes later, we have nearly the same amount of fluid collected as with the first experiment and still some wet surfaces in the equipment.

[Vixen]

Hello Achim,

The more we play, the more we learn.

I have also noticed the S3G has a high surface tension, which adheres well to any surface. This adhesion is also responsible for forming a surface meniscus due to it's fairly high surface tension, the fluids molecules are attracted to the molecules in the wall of the glass beaker or workpiece.

Just like you, I am fine with the system as it is, the system is working and that is what I need. As I said earlier, 'I am happy to continue to work within these measured flow rates (13 to 25ml/hour). I am sure we are providing plenty of lubricant, it can get into the hidden area inside a pocket, it does not make too much mess and a litre bottle of S3G will last for years.



When I started this topic, two and a half years ago, my objective was to design and build a "Peristaltic Fine Spray: no mist: no fog coolant pump" similar in concept to Sebastian's Cool End system. I achieved that objective in two different ways:

1) Using a 'Grothen' peristaltic pump with a 60 RPM reduction gear head and DC motor under PWM control

2) Using a generic 'Chinese' peristaltic pump driven by a small stepper motor. The stepper motor can be driven from an external pulse generator, or by plugging into the 4th axis controller, or by LinuxCNC itself generating the step pulses. I use the latter method.

The basic components, for either system, can be bought for less than £25, Euros or Dollars.



We have now confirmed a good operating range is 13 to 25ml/hour (1.2 to 2.25 pump RPM). The best fluid to use is Jokisch/ Sorotec S3G Monos-Miko lubricant, which is now available in convenient 1 litre bottles. Although a water soluble coolant can also be successfully used.

A "Peristaltic Fine Spray: no mist: no fog coolant pump".... YES
A "Minimum Quantity Lubrication (MQL)" system.... perhaps we set the lubrication rate a little too generous for Minimum Quantity . Always. better to be safe than sorry.

Mike

[Vixen]

So, to make good use of all the measurement made from our different machines, I have reset the pump rate from 2.25RPM to 1.25RPM. The new flow rate is reduced to approx 13ml/hour, which provided 18 drops of SG3 per minute.

For Jason's benefit, I did a test machining on a scrap block of HE30 TF (6062 T6). Using a 6mm, 3 flute cuter, at 4,600RPM, 40%step over and 150mm/min feed rate; the outside profile and inside pocket were cut to a depth of 12mm in two steps.

The first image shows the blue speckled wetted surface after the outside profile.
The second and third images shows the blue speckled wetted surfaces after the outside profile and pocket.
There is only a tiny amount blue specked residue in all cases, which is wipes away easily. The chips were all blown well away by the air blast.







I am happy with that result.

Mike

[Jasonb]

It will be interesting to see what gets deposited around the machine after a few hours use. When using paraffin the table, slots and the trough around the table can be wet with paraffin but come the next day it is all dry and the swarf can be brushed or vacuumed up.

We have slightly different cutting methods. I also go with 6mm deep as my usual with a 6mm cutter and 5000rpm which is not far off your 4600. But I tend to go 10-15% (0.6-1mm) stepover but feed a lot faster at 5-600mm/min. So both get the job done in a similar time.

[Vixen]

I actually reduced the flow rate by half, to approx 13ml/hour (pulse command rate changed from 20 to 8 ) and have modified the text in my previous post to match.

I chose a reasonable aggressive pocketing strategy (40% step over) to push the limits, I would normally use closer to your numbers.

I don't think the S3G will evaporate away, it may actually thicken with time. Best to wipe the chips and any residue away at the end of the day's play. I haven't got any big jobs lined up, so we will have to wait to find the answer to how messy it can become after couple of hours. Achim also runs at 13ml/hour, what does he find?

Cheers   

Mike.

[Dave Otto]

I guess what ever works for you guys, but that does seem like an excessive amount of oil to me, ..........

Dave

Hello Dave,

I agree, it well may be an excessive amount. That's why I asked the question about what everyone else was using. If you could find the time  measure the time take to deliver a know quantity of fluid, It would give us another data point. I DO like numbers. 



Mike

Hi Mike

I had some time check out my Micro-Drop delivery this last weekend. It was about empty so I cleaned it out and purged the lines, then added fresh fluid.
Running both lines at the mid dial setting for 2 hours I collected just about 5ml. This was with no air so they were just dripping into a graduated cup.
This is the setting that I use mostly and have always had good results. The MD-7 is a pretty viscous fluid (oil), I don't know the viscosity is, but the specific gravity is .83

Dave

[fumopuc]

I actually reduced the flow rate by half, to approx 13ml/hour and have modified the text in my previous post to match.

I chose a reasonable aggressive pocketing strategy (40% step over) to push the limits, I would normally use closer to your numbers.

I don't think the S3G will evaporate away, it may actually thicken with time. Best to wipe the chips and any residue away at the end of the day's play. I haven't got any big jobs lined up, so we will have to wait to find the answer to how messy it can become after couple of hours. Achim also runs at 13ml/hour, what does he find?

Cheers   

Mike.

Hi Mike,
I do owe a answer here still.
The "steel" swarf has been made exactly  10th of July, so 6 days ago.
Today was the day for some cleaning now.
I can confirm, that parts of the fluid evaporate and a very thin oily film remains on everything.
During the last 8 to 10 days we have a very high humidity here in the air, up to 90%, but I can not detect any corrosion.
To remove the mess, I use a dry paint brush and the vacuum cleaner.
Five minutes later everything is clean and well prepared for new swarf again.
The rest of the very thin oily film on the vice and the machine bed  can stay, it is good protection against corrosion.
Maybe every 6 to 8 month, I use some WD40 for wet cleaning the entire mill, but not more.
See attached pictures.

[Vixen]

Hello Dave and Achim,

Thank you both for taking the time for some more measurements. They all add to the data base of common experience of how to get the must from our (pumped) low volume lubrication systems. Here is a summary of what we have so far.


Mike (1)   pump 2.25RPM     25 ml/ hour (command rate 15)     15:1 oil emulsion cutting fluid, used mainly to cool, I may increase the oil/water ratio to improve lubrication. Although fluid is mostly water, it evaporates leaving a slight oil film. Good results in use for several years. No rust issues.  A good, low cost, alternative fluid.

Mike (2)   pump 1.25RPM     13ml/hour (command rate 8 )   Neat Sorotec S3G  Very good lubrication, high surface tension adheres well to any surface. Cleans up easily.

Mike (3)   pump 0.75RPM     8.2ml/hour (command rate 5 )   Neat Sorotec S3G  adequate lubrication, high surface tension adheres well to any surface. Cleans up easily.

Jason (1)    pump speed unknown   25ml/ hour   Mostly paraffin on aluminium. Good results, but potential paraffin/ silicon pipe comparability issues.

Jason (2)   pump speed unknown   Flow rate unknown.   Neat Sorotec S3G    Awaiting evaluation.

Achim     pump 1.2RPM      13 ml/ hour    Neat Sorotec S3G. Good results in use for several years. Evaporates slowly, leaves oily film, cleans up easily.

Dave Otto  Microdrop system.   2.5ml/hour.   Neat MD-7    Good results in use for several years.  2.5ml/hour must define the lower limit for MQL systems (Minimum Quantity Lubrication)


It looks as if we (the European contingent) are all working well above the minimum  MQL suggested by Dave Otto. I am happy to continue to work with Sorotec S3G at 13ml/hour flow rate (or maybe less). I am sure we are providing plenty of lubricant, which can get into the shadow area inside a deep pocket, better to be safe than sorry. It does not make too much mess and a litre bottle of S3G will last for years.

Unfortunately, I have not been out in the workshop for several weeks now and I cannot see that changing in the near future, so I cannot add to the experience of using S3G.

Mike

[Admiral_dk]

Hi Mike and co

I got inspired enough to order the Perestaltic Pumps, Air-Compressor and Sorotec Fluid last Saturday.

I got the compressor and the Sorotec yesterday  - the perestaltic pumps will arrive before first week in September 

Just realized that I haven't got any usefull Nema17 steppers - so I have just ordered two + Drivers - they should be here later this week 

Now for my question - what do you all use as 'the Delivery Nozzle' etc. ?

Per