Vacuum Web Coating

Forthcoming webinar & Converting School activities.

Next Tuesday 16th March is the next AIMCAL Webinar on 'Winding webs in vacuum' that is a 1 hour presentation on some of the basics winding problems that many metallizers / vacuum coaters see.

To register for this free webinar go to www.aimcal.org and follow the links there.

Then there are the following two courses to be held in Brussels.

To find out more about these two courses go to www.aimcal.org or go to www.convertingschool.com and follow the instructions there.

  Web Handling and Converting
Dr. David Roisum

April 13 - 14, Brussels, BELGIUM

In the Web Handling and Converting course with
Dr. Roisum, find out how to: eliminate wrinkles, baggy webs and apply effective spreading; eliminate winding defects; design and maintain web machinery, especially rollers; design and maintain control systems for tension, nip, guiding and more; design web products and processes for more reliable manufacturing; troubleshoot a variety of web, web handling and converting issues; and understand why the web world does what it does.

For the full course outline and description as well as registration, please visit the website.

Who will benefit from this course?
This class is targeted toward the technical person responsible for most any type of web machine. However, many other positions can also benefit such as lead operators, foreman, managers, mechanical and electrical maintenance, Q/A and customer service. The only prerequisite is a bit of technical aptitude and enough job experience to be familiar with the names for the: parts of your machines, basic functions and common web/roll defects.

 

 

Winding: Machines, Mechanics and Measurements
Dr. David Roisum

April 15 - 16, Brussels, BELGIUM

In the Winding: Machines, Mechanics and Measurements course find out how to: eliminate winding defects; know whether your defect is manufacturing or winding related or both; select and use the proper type of winder and settings for your product; design and maintain winding machinery; design and maintain winder control systems for tension, nip and torque; design and manufacture webs for more reliable winding; troubleshoot a variety of web, winding and operational issues; and understand why the winding world does what it does.

For the full course outline and description as well as registration, please visit the website.

Who will benefit from this course?
This class is targeted toward the technical person responsible for most any type of winding machines or wound roll product. However, many other positions can also benefit such as lead operators, foreman, managers, mechanical and electrical maintenance, Q/A and customer service. The only prerequisite is a bit of technical aptitude and enough job experience to be familiar with the names for the: parts of your machines, basic functions and common web/roll defects. However, it would be helpful to have the Web Handling and Converting class first as this course builds on that material.

Reformatted table of oxygen and water vapour transmission rates for a variety of materials

Film grade		Thickness	Oxygen transmission	Water Vapour
		microns	cc/sqm/day.atm	g/sqm/day
XM 1123	1 side coated PVOH   (chlorine free)	13	0.2	31
D 866	1 side aqueous PVdC coated  other side added print adhesion(813 type) pasturisable	14	7	7
D 887	1 side aqueous PVdC coated   pasturisable	14	7	7
D 888	1 side clear barrier (chlorine free) - other side added print adhesion(813 type)	13	1	25
D 889	1 side clear barrier (chlorine free)	13	1	25
M 30	2 side solvent coated PVdC.   Coating heat sealable	14	8	8
M 34	1 side solvent coated PVdC.   Coating heat sealable	14 or 21	9	9
M 44	1 side aqueous coated PVdC	14	8	8
M 45	1 side solvent coated PVdC film based on P25 thermoformable base	14 or 21	6	6
MC 2	1 side metallized film overcoated with PVdC on both sides. Coating heat sealable	14	0.15	0.6
CS	1 side PVdC coated special film for packaging individual slices of cheese	13	16	8
200RSBL300	Special PET barrier laminate for vacuum  insulation panels	61	0.00062	0.005
	Mylar M series are typically adhesive laminated to PE
	Melinex 813 has chemically modified surface for adhesion to nitro-cellulose based inks
	D series are the platelet filled coatings based on mica type materials
	PET / Blank	12	100	64.64
	PVDC	24	8	0.3
	EVOH	24	0.16 - 1.86 *	N/A
	m-OPA	15	30
	Aluminized PET (single) - Evaporation -   Al	~ 30 nm	0.31 - 1.55	0.31 - 1.55
	Aluminized PET (double)  - Evaporation -  Al	~ 30 nm each	0.03	N/A
	Aluminum on PE  -  Lamination  -  Al	7 microns Al	0.001	N/A
	SiOx on PET   -   Evaporation   -  SiOx	10 - 80 nm	0.35 - 10**	0.46 - 1.24
	SiOx on PET   -   PECVD   -  SiOx	10 - 80 nm	0.08 - 1.55	0.5 - 5.0
	Al2O3 on PET  - Evaporation, Reactive Evap.  - Al2O3	20 nm	1.5	5
	Al2O3/SiOx on PET - Evaporation - Al2O3/SiOx	50 nm	2.0 - 3.0	1
	Diamond-like Carbon on PET - PECVD - DLC	20 nm	2	1.5
	* depending on relative humidity & ethylene content
	** depending on used process
	Bare PET (Toray, 12mm)	-	175	41.4
	AlOx (eb)	17	4.7	1.04
	AlOx (sputt.)	17	3.75	0.78
	SiOx (eb)	40	3.35	1.06
	ITO (sputt)	24	0.65	0.58
	Bare PET (Melinex, 50mm)	-	36.33	3.86
	AlOx (sppa)	31	1.91	0.57
	AlOxNy (sputt)	57	1.96	0.11
	Bare PET (RNK, 12mm)	-	180	36.7
	AlOx (PAPVD)	10	4.8	1.61

Wewbinar question re.temperature of cooled copper boat clamps

Q: what should be the best temperature of the contact block copper to cool the boats?

I needed to check this and have just received a response about the cooling of the copper blocks.  It looks as if nobody knows the temperature precisely but what they have is years of experience of what works in their systems.

There are various bits of information that are known.  The boats are running at a temperature of 1450 Deg C – 1700 Deg C (depending how hard they are being used).  The melting point of copper is 1084 Deg C.  However this can be reduced to as low a 550 Deg C if the aluminium has overflowed and alloyed with the copper forming a eutectic.

It is possible to use temperature stickers to measure the temperature along the copper length and look at the temperature drop with length. And from this an estimate of the temperature of the end of the block can be made.  It is believed that most blocks run at a temperature of 1000 Deg C or less at the end they connect to the boats.  It does depend on the design how far the cooling is away from the hot contact end.  Some designs have a replaceable end piece that allows an easy replacement in case the end gets damaged by arcing, overheating/melting or physical damage.  It becomes more important to keep the joint between the copper body and replacement end piece below the melting point of the copper otherwise will become impossible to replace the end piece when required.

I am sorry this does not give a definitive answer to your question but I hope it is helpful.

Best regards    CAB   

 

 

Answer

 

Webinar questions re. plasma treatment

Q: How plasma treatment enhances the barrier properties of metallized films?

Q: Do we have to use different gas mixtures for plasma to get better adhesion of metal and better barrier?

Q: Can you advise a good mixture gas?

 

Plasma treatment has often been thought of as a method of cleaning the polymer film surface of debris.  It was believed that the plasma neutralised any charge on the debris and so would eliminate any electrostatic charge holding the debris to the surface and so allow the debris to fall off.  This is only true for debris that is very large.  Debris less than 10 microns in diameter are held on the surface by Van der Waals force and so will not be neutralised by the plasma and so will remain on the surface. Thus plasma treatment will not change the level of surface contamination by debris by very much.  This type of contamination has to be removed by more physical means such as tacky rolls.

 

What plasma treatment can do is to help clean the surface of more chemical type contaminants such as oligomers or slip agents or other additives.  This is done by a variety of different processes such as direct sputtering of the surface where plasma atoms or molecules hit the surface and eject atoms from the surface. Or the plasma atoms or molecules can combine with the surface atoms and form volatile compounds will leave the surface and be pumped away.  The plasma can also bombard the surface and cause bond breaking than can make the surface more reactive enabling either any low molecular weight material to become bonded into the polymer surface or for the later deposited coating to bond to the polymer substrate.

 

Low molecular weight material can volatilise under the heat of the deposition process and this can reduce the coating thickness locally and so plasma treatment can reduce these variations.  Improving the adhesion of the coating also reduces the possibility of pick-off which is a possible source of pinholes.

 

Increasing the adhesion also allows the coating to be flexed or stretched more, without stress cracking, than for films with lower adhesion. This is not seen as an improved barrier performance in the film as produced but only as an improvement in the barrier performance of the film in use.

 

With respect to the gas to use, typically an argon/oxygen mixture with a ratio 90:10 is used. The argon provide the heavy atoms for surface bombardment and bond breaking with the oxygen as the chemical to bond to carbon atoms to make volatile molecules or to bond to the polymer and coating to improve the adhesion.

 

This is not to say that other compositions will not work. I know others have used plasma treatments with anything from 0-20% oxygen in the argon.  The 0% oxygen does not mean that there is no oxygen in the plasma but only that the quantity is limited because the source of the oxygen is from the outgassing from the chamber surfaces and whatever moisture is trapped in the roll of film or absorbed into the film.  This can be a variable as it partly depends on the humidity and length of time stored. Thus a change in season can result in a change in plasma treatment. Hence it is always better to deliberately add oxygen to the plasma to make sure there is always sufficient available to react with the surface to clean and functionalise the surface.

 

I hope this answers your questions.

Webinar question re. web tension

What web tension is usual for e.g. 50my PET within the machine?

 

Answer

Below is an example of the calculation that can be used to determine a starting tension for any polymer film type and thickness.  The modulus of elasticity should be available from your film supplier on a data sheet.  Using this information and film thickness and then deciding on the maximum stress you want to impose as a limit on the film the tension can then be calculated as follows.

 

 

Modulus of elasticity.    PET 14,000-38,000 kg/sq cm       ave.  26,000 Kg/sq cm

 

If you want to limit the stress in the film to, for example, 1% of its elastic limit.

 

Thus 1% of 26,000 = 260 kg/sq cm = 2.6 kg/sq mm

 

For a web width of 2m and the film thickness of 50 microns then the cross sectional area (CSA) is 2000mm x 0.05mm = 100 sq mm

 

Therefore the maximum tension = 2.6 kg/sq mm x 100 sq mm = 260 kg total web tension

 

This is equivalent to 130 kg/m width

 

 

This is a good starting tension but it can be modified as desired. Reducing tension can be advantageous during the metallization process as the above calculation is for the modulus of elasticity as measured at room temperature. The value is likely to be reduced at an elevated temperature and so reducing the tension is desirable.  Care needs to be taken in reducing the tension as this can result in a reduction of the heat transfer coefficient between the polymer web and the chilled deposition drum and this can then result in the web temperature increasing and so further changing the polymer mechanical performance.  Hence the calculated value should only be used as a guideline. 

 

I hope this helps.

 

Response to question about SiO2 evaporation

In response to the question

I am trying to thermally evaporate 5nm of sio2 (quartz granules) using a tungsten boat ). However it hasn’t gone to well (sublimation, high melting point hardness, low evaporation rate etc…) My evaporator has a cheat sheet that recommends boats for different deposition materials and it recommended using tantalum boats to deposit quartz. What I don’t understand is if Tantalum has a lower melting point then tungsten and can handle less current, how is it better then tungsten for depositing quartz? Is there any other boats that would do a better job? Filaments etc…….

 

 Answer

Generally W, Ta and Mo can be interchanged.  Where one of these is not recommended it is usually because of a material interaction either directly between the evaporant and source or between an intermediate compound formed from the evaporant and the source material.  I have not checked prices recently but it used to be that W was the most expensive and so was only used where the others could not be.  Ta, although it has a lower melting point than tungsten is still more than high enough that it can be used as an evaporation source for silica where the temperature only needs to be below 2000 deg C.

 

 

SiO2 tends to be supplied in granules or powder form.  Heating has to be uniform and slow enough for any moisture to be removed during the initial heating to prevent little explosions that can spit out the powder.  This is particularly true for electron beam sources where the heating can be localised and very rapid.  Evaporation sources usually are slow enough for this not to be too much trouble.

 

Silica has a melting point of 1730 Deg C with evaporation starting at 1250 Deg C.  If the temperature is kept down to between 1500-1600 Deg there is little decomposition of the silica however above 1600 Deg the silica decomposes with oxygen being lost and SiOx coatings formed. As the temperature and rate increases the decomposition increases and it is common to find oxygen being introduced into the vacuum system to help increase oxygen content back towards stoichiometry.  At higher temperatures the Silica can attack the Ta, Mo or W and form volatile oxides.  Alumina coated evaporation sources have also been used at temperatures up to 1630 Deg C.

 

As it is common to add oxygen to the system some have found it easier to evaporate SiO from a pellet (I have used pellets at approx 8mm dia and 8mm high) from either a Ta or Mo source.  The evaporation starts at around 1025 Deg C (lower than for SiO2) and typically the sources are run at a temperature between 1150-1250 Deg C.   Above 1250 Deg C the silicon monoxide also decomposes and will lead to oxygen deficient coatings.

 

Evaporation of silicon monoxide and using an oxygen atmosphere can be a cheaper option as the source material can be a lower cost and the evaporation rate higher. It does require being able to safely add oxygen to the process. Often this is done as an argon/oxygen mixture with the oxygen being equal to or less than 20%. (above this would require oxygen safe pumps & oils).  Sometimes to reduce the oxygen proportion the gas that is introduced is excited into a plasma so that the reactivity is increased allowing a lower pressure or oxygen proportion to be used more efficiently.

 

 

If you want more details about the deposition of SiO then below is a contact web address for R.D.Mathis. 

 

Typically the evaporation of pellets or powders is done using an enclosed source so that there is no line-of-sight between the evaporant and substrate. If you check out the website and request the articles, shown below, they may be of interest even thought they are for silicon monoxide.  Also contacting R.D.Mathis about you particular system they may be able to recommend a source that is optimised for your power supply and volume that you wish to evaporate.

 

 

 

http://www.rdmathis.com

 

 

Evaporation of Metals From a Covered Boat Source- Describes techniques for successfully thermally evaporating volatile metals while eliminating particulates from the vapor stream.

Silicon Monoxide Evaporation with the Multi-Baffled Box Source- Discusses the problems and solutions of achieving pinhole free dielectric coatings and the elimination of particulates in your vapor stream.

Silicon Monoxide- Properties and evaporation techniques- Describes and illustrates characteristics and thin film properties of silicon monoxide as well as thermal evaporation techniques and sources specifically deigned for depositing silicon monoxide.

 

 

 

I hope this helps.

CAB

 

Question on free span metallizing from the recent webinar

Q: what are the major disadvantages to a free span metallizer?

 

Generally the limitation of free span metallizing is managing the heat load. As there is no heat removal from the web the deposition rate is usually limited.  This usually limits the coated products to thin coatings for any single pass deposition.  This can be improved by the use of pre-deposition chilled roll and a post deposition chilled roll.  If the requirement is to only produce thin coatings this may not be a limitation.

 

The advantages of free span deposition are that the web can be coated across the full width as there does not require to be any edge shield to protect a deposition drum from becoming coated.  As the web is not in contact with a deposition drum it is free to expand and contract as required.  The friction between the web and deposition drum can result in wrinkles forming. If the temperature rises too much the web wants to expand laterally and the tension pulled on the web combined with the friction between the two surfaces can prevent the web moving to relieve the stress which can result in the web buckling from the surface as a way of relieving the stress, causing wrinkles.  Free span allows the web to freely expand and so there is no constraint and so wrinkles do not form.  The danger is that as the film temperature will rise to a higher temperature than for a drum cooled film process, with the same deposition rate, and if the temperature rises too high the yield stress of the film may be exceeded which will result in a permanent dimensional change in the polymer film.  The web will be under tension in the machine direction this permanent set will result in the web becoming longer but narrower. This may not be a problem for some films and products.  Some webs may not have uniform residual stress in them as they may have been slit from the edge of a film production mill roll and so the residual stress may be changing from one edge of the roll to the other edge. In this case the relaxation as the yields stress is exceeded may result in uneven dimensional changes from one side of the web to the other which can result in the rewind roll being less than ideal.  The winding system can be designed to separate out the tension between the unwind zone, deposition zone and the rewind zone.  This can allow the tension in the deposition zone to be minimised specifically with the aim of minimising the stress whilst the web is at the high temperature to try to minimise any permanent dimensional change.

 

 

If you are metallizing embossed structures then managing the temperature may well be more important than for other applications. This depends on how the embossing has been achieved. The danger is that the higher temperature will relax the polymer and the embossing will degrade in depth, or if there is a permanent set in the film dimensions the spacing may be affected too.  The deposition drum systems may not be immune from this problem as most systems are driven hard and the process is usually speeded up to operate close to the limit and so the temperature of these systems will also be close to yield point too.

 

Most films will have some dimensional change even if the yield stress is not reached simply because of residual stress in the films from the biaxial orientation process. Once the yield stress is exceeded this dimensional change can increase significantly and so become more of a problem.

 

Hence the major disadvantage of any free span process is the management of heat particularly for thick coatings.

AIMCAL Fall/Autumn Technica Conf - Call for papers

AIMCAL Fall Technical Conference
and
24th International Conference on Vacuum Web Coating
October 17 - 20, 2010
Myrtle Beach Marriott
Myrtle Beach, South Carolina

The AIMCAL Fall Technical Conference is an Industry forum for the global technical community involved in web coating processes.

Topics of interest for this year's conference include, but not limited to the following:

Vacuum Web Coating Process optimization and preventive maintenance in the vacuum web coating processes Leading edge roll to roll technologies, products and markets including flexible displays, flexible semiconductors, superconductors, thin film battery, flexible solar cells, super barriers, film sensors, anti-counterfeiting films and papers, OLED, holography, and solar control Machine and equipment accessories upgrade cost / benefit Advances in substrate technology Advances in process control and measurement Patterning and edging of vacuum coated films and papers New coating processes, tools and equipment Advances in barrier performance, process and measurement Atmospheric Web Coating and Laminating Web Coating Technology related to applications and fluid rheology Process Measurement including coating weight, defects, viscosity, process modeling Laminating processes including alternatives to laminations, process optimization, web variability, modulus, guiding and tracking Coating Operations: An overview that compares/contrasts various coating techniques, roll coating systems, slot die/curtain coating techniques, extrusion coating, coating thin on metallized films, toll coating Substrates and liners technology including new technology and performance, innovations, and applications Web coated product markets - technology and market overviews Cost reduction/ process optimization for web coating and handling including such techniques as Six Sigma, Downgauging, Lean, etc. Interest in papers related to films and other substrates Specialty Web Coating Novel or developing web coating technologies Nano coating technology Photovoltaics technology Developing web coating technologies and markets Specialty substrates and coatings technology RFID technology A session on Market Trends in the Converting Industry is being scheduled. Topics of interest are global market and technology trends, future role of converting process in growth industries and integrating product development through the supply chain.

Presentations for the Fall Technical Conference are selected upon the following criteria:

• Applicability to the advancement of the manufacturing process
• Uniqueness and innovativeness of new technology and its contribution to the Industry
• Value to the technical/production community

The audience for the Fall Conference is Technical Professional personnel in R&D, Manufacturing, and Marketing. Presentations should be at a technical level of interest to this audience. Papers covering related subjects, not specifically addressed in the call for papers should still be sent for committee review.

For consideration as a Presenter to the 2010 AIMCAL Fall Technical Conference, please go to www.aimcal.org and follow the link to the preferred option of proposed submission.

AIMCAL Converting School 2010 Schedule

February 16 - 18Nip Roller Workshop
Rochester, NY

February 25 - 26Drives in Web Handling and Converting
Schiller Park (Chicago), IL

March 16 - 17Web Handling and Converting
Atlanta, GA

March 18 - 19Winding: Machines, Mechanics and Measurements
Atlanta, GA

April 13 - 14Solution Preparation and Mixing
Philadelphia, PA

April 13 - 14Web Handling and Converting
Brussels, Belgium

April 15 - 16Web Coating and Drying
Philadelphia, PA

April 15 - 16Winding: Machines, Mechanics and Measurements
Brussels, Belgium

April 20 - 22Web Wrinkling and Spreading Workshop
Rochester, NY

May 4 - 5Solution Preparation and Mixing (Europe)
Brussels, Belgium

May 6 - 7Web Coating and Drying (Europe)
Brussels, Belgium

June 8 - 9Optimizing Extrusion-Based Lamination and Coating Technology
Rochester, NY

June 15 - 17Center Winding Workshop
Rochester, NY

August 17 - 19Roller Performance Workshop
Rochester, NY

October 5 - 6Web Handling and Converting
Philadelphia, PA

October 5 - 6Web Coating and Drying (Europe)
Brussels, Belgium

October 7 - 8Winding: Machines, Mechanics and Measurements
Philadelphia, PA

October 7 - 8Drives in Web Handling and Converting (Europe)
Brussels, Belgium

November 9 - 10Solution Preparation and Mixing
Cleveland, OH

November 11 - 12Web Coating and Drying
Cleveland, OH

Visit www.AIMCAL.org or www.ConvertingSchool.com for more information.

Cooling water quality - process effects.

Below is an article posted on the PVD Forum by Eric Kurman.  It primarily deals with the problem of conductivity of water for use in magnetron sputtering sources.

 

However many plasma cleaning units are based on the same magnetically enhanced design as the sputtering sources and so the same factors apply.  

 

It is also worth noting that over time ‘dirty’ water can fur up pipes, fittings and deposition drums which can adversely affect the cooling performance. Often this furring process will take many months or even years and so the changing performance may not be noticed easily. Also it may be assumed that a slowly degrading performance is just the machine aging.  So periodically during major maintenance it is worth checking that pipes are remaining clean and that the flow is not being restricted.  

 

 

 

‘Dirty’ water cooling of magnetron sputtering sources.

 

There is a little more to the story on water.

First of all, "dirty" is really a misleading term, the water does not have dirt in it, rather it has dissolved ions leading to an increase in conductivity. This is common in Process Cooling Water loops or so-called "house" water and can come from two sources.

a) Intentionally, from treatments placed in the water to inhibit corrosion.
b) From corrosion due to wetted surfaces in contact with the water.

Most engineered PCW systems exercise very close control on which surfaces are allowed to be "wetted" in contact with cooling water. However, most thin film systems in my experience have a profusion of wetted materials including various polymers, brass of different types, copper, zinc, tin, chromium, stainless steels of different types, and occasionally target materials from directly cooled targets.

Another problem is that grounding is often sloppy in thin film systems and the machine frame is used as a common for power line ground and return current from a deposition component like a sputter cathode or electron beam hearth.

As others have pointed out, the conductivity of the water needs to be measured. However it might not be as simple as "replacing the dirty water". The DI water can corrode certain materials particularly copper and brasses. Once this happens the water is no longer "DI", and once the conductivity of the water increases, there is the potential for electrochemical corrosion due to dissimilar materials being wetted and voltage applied to components in the loop.

Even in the case of the heat exchanger technique (we used to call them "mini-loops" ) mentioned in previous message, often the water does not stay "DI" for very long. I have looked into the reservoirs of many a mini-loop to see stuff that looks like it belongs in a mud puddle.

The only way to continuously maintain low conductivity is to include a polishing bed in the recirculating loop....kind of expensive but, if you are running production, often worth it.

Knowing the conductivity of the water one can estimate the power drop due to conduction through the water circuit. Electrical power flows from the high voltage component to the nearest ground or return component. You will need to know the internal cross sectional area of the tube or pipe and its length.

Let's assume you are cooling with typical drinking water that has a conductivity of 0.01 S m^-1 and that you have a magnetron cathode running at 500V, connected to ground with two 1/2" (12.7 mm) plastic tubes that are each 1 m in length (two tubes, inlet and outlet, 1 meter long each). Our tube has a wall thickness of 1/16" and an internal diameter of 3/8", thus its cross sectional area is 0.71 cm^2. The series resistance of this water-filled tube is resistivity times length divided by area, namely (10000 Ohm cm)*(100 cm)/(0.71 cm^2) = 1.41 megOhms (1.41E6 Ohm).

The two tubes are in parallel so the total resistance is 700 kOhm.

Note that we had to convert from conductivity, measured in Siemens (facilities and water people always deal in conductivity) to its reciprocal, resistivity, and to also convert from meters to centimeters. Thus 0.01 S m^-1 = 10000 ohm cm.

Your sputter cathode will conduct 500V / 700E3 Ohm = 712 uA to ground. Total power dissipation through the water is about 356 mW. This might be a lot, if you are running a small R&D cathode at a few Watts, or it might be negligible, if you have a bigger system running at 30, 50, 90, etc., kW.

Note that power loss through the water depends only on the voltage drop and will be the same for a small system as a large system for the same water conductivity and tube sizes.

If we repeat the same calculation using seawater (4.8 S m^-1) as the coolant, resistance is 20 kOhm per tube, 10 kOhm total, power drop would be about 24 W for a load at 500V. Water is just not very conductive, even seawater!

So you have two main choices: change the water, or use a longer tube. The latter is a surprisingly effective way to go. It is not that big a deal to coil up 50 or 100 feet of poly-flow tube, tie-wrap it in place, and fix the problem.

If you are running an EB setup at 10 kV or 20 kV or higher, or maybe an X-ray tube at 50 kV to 100 kV, you have a bigger problem. Low conductivity coolant and a long path length is a requirement here. Oil coolants can be used but they have lower heat capacity than water and a big headache as well.

So....do the measurements. ...do the math....analyze and determine a solution.

 

"Eric Kurman" <ekurman@yahoo.com>