How long does 1L of coolant last?

That depends on how much coolant you dispense with each pulse of coolant and the number of pulses in the cooling profile and the Cooling Time. There is a video in the ‘TechCentre’ in which a Thermublast MQL system is tested continuously with various cooling profiles to show how many pulses of liquid are dispensed from a full 1L resevoir and how long it takes to empty the resevoir. The data is provided as a table of values and gives an excellent indication of what to expect in the workshop, using typical cooling profiles as used by our customers.

Can I increase/decrease the droplet size for the liquid in each pulse?

Yes. This is done using the coolant pressure regulator which is the first (lhs) of the 2 regulators on the air input manifold(where the 8mm tube is connected for air input to the system). They are labelled as the ‘coolant pressure regulator’ and the ‘Airblast pressure regulator. The label also indicates the recomended operating pressure for each regulator.

The coolant pressure regulator should be adjusted counter clockwise to reduce the pressure of the coolant and also increase the droplet size; adjusting clockwise increases the pressure of the coolant and gives more liquid a higher pressure. Once the pressure exceeds 2bar, the coolant starts to produce more vapor and mist and this is NOT recommended. Try to keep the pressure around 1 to 1.5bar to maintain a spray of droplets rather than mist. If you need more liquid, experiment with increasing the number of pulses and also try increasing the duration of each pulse.

If the coolant pressure is reduced too much, the droplet size will get so large that each pulse may become 1 large drop(a ‘splurge’ is i think the technical term) and this is also undesireable. In the limit, if the pressure is reduced almost 0 then no liquid will be dispensed.

Finally, like with all pressure regulators, it is best to first reduce the pressure, to a value below your desired set value and then gradually increase it to your set value.

Why are there 3 valves on the valve block?

The valve block has 3 valves because 2 are required to dispense liquid and a separate valve is required to have an independant air blast chip clearing function. The connections to the valves are colour coded, so as not to get mixed up as this would stop Thermublast working. The top valve is valve number 1 and has a clear tube on the inlet from the coolant resevoir and a clear tube on the outlet to the 4mm push in fitting on the LHS of the mixing block. When valve 1 is switched on, liquid flows from the resevoir through the valve, down to the mixing block, through a tube inside(coaxially) the loc-line and to the nozzle, to be sprayed onto the tool. However, this will not happen unless we have air supplied through valve 2(the blue tube) which also travels separately to the mixing block and down the loc-line to the nozzle and only meets the liquid at the nozzle. It is this air, travelling past the liquid, in a small chamber inside the nozzle which draws the liquid from the bottle and sprays it through the nozzle and onto the tool in pulses of duration and number set by the lcd electronics controller. Valve 3 has black tubes and is for the independant air blast chip clearing function. The black tube connects to the main air input then to the input of valve 3; the exit of valve 3 also has a black tube which connects to the 3rd(RHS) 4mm push in connection on the mixing block. This continues via another 4mm black tube, alongside the loc-line and simply protrudes through an angled hole in the nozzle, to direct air blast pulses to the focus of the cooling spray, between 25 and 50mm from the nozzle.

Can the tubes or valves become blocked?

As with all coolant/lubricant dispensing systems, care must be taken to use liquids which are clean and without significant amounts of solid matter in them. When using aqueous coolants(those made up with water) it is advised that distilled or even better de-ionised water be used to make up the coolant as this will reduce the possibility of precipitation (solids appearing in the coolant) over time. With synthetic or oil based coolants precipitation is less of a problem.

However, even if solids are present, they will not damage Thermublast or the valves, but they will clog the filter(brass frit) on the tube which transfers liquid from the 1L resevoir to valve 1 and reduce the liquid flow from the nozzle and so impair the cooling and lubrication of the tool. The valves are high quality SMC units with a 5mm orifice so it is hard to see a situation whereby a piece of debris anywhere near that size could be drawn through the system, especially when the tubes all have a 4mm O.D. and an ID less than 3mm. Even if you removed the frit from the end of the tube in the resevoir(PLEASE DO NOT DO THIS!!!!!) in an attempt to increase the flow because of solids in the tube then you may eventually clog the system, but not damage the valves. If you do experience clogging or ‘slime’ on the outside of the frit on the tube in the resevoir, simply remove the tube from the inline fitting at the top of the resevoir and remove the resevoir. Empty out the contaminated coolant, rinse the frit in clean water, dry off and replace in the resevoir with new , fresh coolant, prime the system and start using Thermublast again.

Does the orientation of the nozzle matter?

Yes. The design is to ensure that there is little or no dripping or leakage from the nozzle between pulses of liquid and especially between cycles of Thermublast and when Thermublast is switched off. This will only be the case if the nozzle is directed toward the tool with the air blast tube vertically ABOVE the liquid output tube of the nozzle. The reason for this is can be seen if you look at the output face of the nozzle(make sure Thermublast is switched off). Make sure that the angled black tube for the air blast is vertically above the aluminium exit tube for the liquid. Just below this, you will see a 2.1mm hole and it is this which carries additional air to push out any liquid left in the nozzle chamber on the last liquid pulse, plus remove any liquid from the aluminium exit tube. Thus we avoid drips and make sure the last pulse of liquid in each cycle goes on to the tool and not the bed of the machine. If the nozzle has any other orientation , the efficiency of this operation is reduced and there may be some dripping or leakage from the nozzle.

Why is the photography/videography on this site so dull and boring?

That is because we are a team of mechanical and electrical engineers with little or no photographic talent. Hopefully what we lack in artistic flair, we make up for in overall enthusiasm .

What are the compressed air requirements for Thermublast?

Clean, dry air at a minimum 2bar; maximum 8bar.

Connect your compressed air supply via an 8mm tube to the 8mm push in connector on the input manifold block on the top right hand corner of Thermublast . The 2 regulators on the input manifold are labelled as ‘Coolant Pressure’(1-2bar) and ‘Air Blast Pressure’(1-6bar). Exceeding 2 bar on the Coolant pressure may lead to vapourisation and misting of the coolant which is NOT recommended as it could represent a health hazard. Similarly, exceeding 6 bar on the Air blast(chip clearing) pressure is equally undesireable (and unecessary)as it will affect the opening and closing of the valves(though it will not damage them).

So, stay within the recommended limits for coolant and air blast pressure. Once you are happy with the settings, just leave them as they are. Use the number and duration of pulses of liquid to optimise the cooling profile and the number and duration of Air blast pulses to optimise the air blast(chip clearing) profile.