[ipsllco]

Hi... newbie here needing insights and wisdom from you experienced DMV 4020 owners who are using filtration systems.

On the table. I'm an independant sales rep for a coolant manufacturer, but I am NOT trying to sell anything here at all... just wanting to learn.

Situation. I have a potential customer who is trying out one of my coolants on his low pressure machines and is having good success. The potential issue is his higher pressure machines, one of which is running a 10 micron Ilrim filter system. The potential issue is that our defoamer package adn one of our extreme pressure additives will be stripped out by the 10 micron system, and the customer is concerned about potential risk(s) which may be associated with increasing to a 20 micron bag which would cause no problems for our coolant at all. The catch at the moment is that he wants to only run one coolant.

To-date, I have not been able to get hard information on the fluid filtration specifications for the DMV 4020 unit, so I cannot determine if the 20-micron concern is an OEM specification issue or one of personal preference on the part of the shop owner.

QUESTION. Can any of you offer any insight into this filtration issue for me? The last thing I want to do is compromise my customer's equipment, but I also know that some people over-engineer things (like I do some times), and would hate to miss an opportunity to help this guy get better machine performance over an issue of preferrence that may not be based on something that is a real issue.

Thanks,
Pete

[ipsllco]

Well, I just heard back from Daewoo, and aparently the 10 micron filtration is an OEM specification. Evidently, the concern is potential damage to the accurate placement and movement of the positioning components, as best I could understand.

I guess the only thing I could potentially do next is sample some of the filter cake from within the filter and get a particle size distribution run on it to see how much of the captured particles are actually in the 10-20 micron size range.

[ipsllco]

I just heard back again from the Doosan Daewoo application specialist, and he is telling me that the shift to 20 microns should be no problem at all. The other guy I spoke with yesterday was in the Technical Management group, so his response could easily have been more theoretically driven.

Currently, I am planning to sample the filter cake and get a more definitive particle size distribution analysis run just for an additional sanity check.

Now, I guess I'm fairly surprised at getting absolutely no response from anyone on my initial post or follow-up posts. Is this forum not used very much at all, or is the fact that I am in a sales position the issue? Just an honest question.

Again, I would be grateful for some reponse.

Thanks

[MadMax]

Don't be insulted. I'm guessing that nobody here has specific experience with the DMV 4020 in regards to the Ilrim filter system that you're asking about. It seems to me that the crowd here doesn't like to speculate all that much when they haven't got a decently well founded answer for you. I'm an engineer so I'm haaaapy to speculate in a poorly founded manner with a hapless grin.

Disclaimer: my small business has been machining on a production basis for less than a year. Buying a nice Daewoo lathe on Ebay does not a production machinist make, but I think we're learning fast and we're doing decently well. I have a second machine now We are running a Daewoo Puma 200 MSA lathe and soon a Hardinge T42 lathe on production basis.

Anyhow, I'm wondering if the Ilrim filter system you're specifying isn't filtering the way lube or hydraulic oil for your customers equipment. 10 microns is a very small particle size for coolant filtration. I would think that a 10 micron bag would foul with tramp oil or small fines very rapidly. You'd need a progression of filters to keep it from clogging with tiny chips that would easily pass through most spray coolant nozzles. The only reason I could see for using a 10 micron filter would be to protect high pressure through coolant drills with very tiny coolant passages. 10 microns is starting to approach the movement resolution of most machines let alone the minimum diameter of most coolant passages. Even still, 10 microns is a very small particle size. I can only guess that worrying about 10 micron particles might be to improve surface finish by removing tiny abrasive bits from coolant, but you'd still have big scratchy chips in the vicinity of any chip forming operations.

The accurate guideways and positioning hardware of most cnc machinery is protected from coolant with various way covers and seals. Coolant does not directly contact anything particularly accurate in most CNC equipment. I currently run two coolant filtration methods. First is a screen in the sump tank with a #24 mesh (big honkin 700 microns) to keep out large chips from the oil skimmer section of the coolant tank. Second is a much finer 80 mesh (180 microns) screen at the pump outlet. 180 microns is about 1/9th of the smallest coolant port diameter I would expect to see in my machine so I figured it should be sufficient to protect my tooling.

My gut feel is that a 10 micron system is likely to be used to protect accurate slideways, ballscrews, or hydraulic mechanisms rather than filter coolant which doesn't contact those elements.

[Geof]

You do not explicitly mention TSC, 'through spindle coolant" but most times when high pressure coolant is used it is TSC.

TSC requires rotating seals and if the system pressure is low these can be fairly simple and there are no fine passages to block. However, with a high pressure system the rotating seals could be labyrinth seals; I have no idea if that is what Doosan Daewoo uses but if they do these seals are sensitive to small particle contamination. Labyrinth seals have fine working clearance and the rotating parts do not actually make contact. Instead they allow a small leakage through a tortuous path (labyrinth) which keeps the seal cool. If the clearances in the labyrinth get clogged with particles too large to pass through you could have serious problems.

[ipsllco]

Geof and Madmax... thanks for the replies and insights.

As to being offended at lack of response, I am not. I've been an active participant in a Ford Truck forum for a number of years, and am well-versed with how this sometimes happens. My only concern was that my being a salesperson might have been a holdback on people's willingness to respond. Either way, it's not an issue for me.

As to the machine and coolant filtration, the coolant does pass through the spindle, and is not for the slide ways only.

Like you, Geof, I'm not sure if Doosan is using labyrinth type seals, but I do know that they are ceramic. The shop owner's main concern is that he doesn't want a decision to increase filtration from 10 to 20 microns to end up voiding his warranty on his almost brand new spindle. I'm in the process of working through this final determination with Doosan, and expect from my conversation yesterday that this will not end up being a problem because they have documentation showing where they've already increased filtration up to 25 microns in some cases with no trouble.

Also, this guy is machining 80% copper, 10% aluminum, about 10% stainless, and a smidgen of tungsten. Therefore, "finish" is really not a concern for most of their work (their words, not mine).

A little more context, just for a bigger picture. When I and a coworker were charging up two of this guy's machines for a bucket trial with our coolant, we were also helping the operators clean the machines thoroughly before making the switch to ensure a completely clean startup with "old coolant' or "dirt/grime/bio" contamination issues from the old coolant. As my partner walked up to one of the two machines, the owner had been spraying his water hose in the upper track regions near the hood, and as water had migrated into the control panel, the machine shut down. Turned out to be a blown board and $1800 in repair charges to get the machine back into production. All of this on an older Bridgeport VMC which the owner had purchased and rebuilt himself several years ago. The only points here are that teh water infiltration had to be due to either poor condition seals, misplaced water spray, or both... none of which is a result of anything we did aside from ask that the machine be thoroughly cleaned before switching to our product.

Obviously, this is a very unfortunate set of circumstances, but the timing of the board blowing and my partner's presence has created a bad impression in the owner's mind in terms of it happening while we were there helping clean out the machine. He admits that it is the kind of thing that "just happens sometimes", and also recognizes that we did not do anything ourselves to cause the problem. All the same, he is quite sensitized at the moment to "something new".

Therefore, I am working hard to do due diligence to ensure that things go properly and that whatever we (me and my company) recommend will not compromise the customer's operation at all. Even though we are not technically liable for any damages in this situation, if I can overcome the filtration barrier (again without equipment risk), I am trying to see if we can offer a demonstration of "good faith effort" in the form of a very large discount on the first order to help offset some of those maintenance expenses incurred by the owner - not as any form of admission of liability, but again just as a means of demonstrating our value for our customers and their operations.

Again, guys, thanks for the insights.

BTW... I am also an engineer with nearly 25 years of real-world process optimization and design in very large industrial manufacturing plants which utilize extremely hazardous chemicals and processes, so I have a strong appreciation for the issues you guys face in your daily operations and the value of protecting your investment in these costly machines.

[ipsllco]

Doosan is confirming in writing that their DMV 4020 comes with filtration options up to 25 microns, so increasing from 10 to as high as 25 will not affect any warranty issues on OEM supplied equipment.