Central coolant distribution systems are finding their way into more machine shops than ever before. However when some systems are covering many square metres and have at their heart quite complex mixing systems, even including machine sump topping up equipment, we wonder if an opportunity is being missed here.
It’s a fact that coolant fluid management and care is on the radar of many machine shop managers as they continue to look for solutions to improve coolant handling and control on the shop floor. Traditional ways that cutting fluids and grinding fluids were managed are becoming extinct.
Thankfully most engineering companies have turned their back on the ‘bucket brigade’ where water mix coolants were mixed manually and then tediously transported by hand around the shop floor. Usually there is now a dedicated area where some type of automatic mixer unit is deployed to carefully control dilutions at each top up.
Its a small step from there to hook up some pipework and send the mixed coolant around a distribution pipeline system to locations on the shop floor where hose reels may act as coolant dispensing units to several machine tools. Usually this type of system is found in smaller machine shops where high flow rates, from the now central mixing unit, is not an issue.
Of course a simple system like this feeds coolant only at the maximum rate of the incoming water supply, typically around twenty litres/min.
Central Coolant Distribution System
Stepping up the game to the next level may mean installing a coolant distribution system that could have extended pipework runs and a more sophisticated central mixing and pump unit.
Whether the choice is a premix central system or a 'mix as you go' unit the central plant is going to need a supply pump, a mixer unit, solenoid valves, safety lockouts, sensors, control panel etc, well you get the picture.
Added to that if pipework runs are extensive then it may be that a steel pipework distribution system is more favourable than simple flexible or plastic hose lines. Additionally if the pipe runs are long, a large machine shop with many machine tools could need pipework in excess of 1000 metres, therefore the pipeline diameters need to be large enough to deliver the flow rates needed.
We have seen distribution pipelines so small as to completely ruin a half decent central coolant system delivery capabilities. Many such systems use petrol pump type nozzles to deliver the fluid to the machine tool where others opt for quite complex automatic topping up systems controlled by solenoid valves and level sensors directly at the machine sump. Auto top up systems have a cost and when multiplied by every machine tool eventually the costs become a considerable capital expense.
Every machine tool in a machine shop is an individual stand alone unit. Work rate, materials machined, spindle speeds, type of operation, all of these factors bring heat to the process at varying rates. Different sump volumes also play their part in that smaller volumes heat up more quickly and evaporate more water than high volume sumps. Therefore dilutions at each machine tool will be, by definition, quite different.
So how can a single set dilution from a single coolant distribution system control each machine at the same dilution ratio? The short answer is that it can’t.
If the ideal dilution is 5% and the top up dilution is 3% it may be that this is fine for one machine on light to medium machining while another on a high metal rate removal with a smaller sump may be falling through the floor at 10%. The fact is that a single set dilution rate top-up will never synchronise every machine tool, all will be different no matter where the bar is set.
By installing a coolant distribution system the issue of mixing and delivery to point of use has been solved. Unfortunately the labour intensive subject of control is still required. Daily dilution checks are necessary and topping up with different dilutions will be needed to gain parity across the shop floor.
So it appears that we are against cutting fluid distribution systems and favour only a full coolant supply and return management system?
No not at all.
Having played the devil's advocate here we are not against cutting fluid distribution systems, far from it. We manufacture and supply our own. However the larger the distribution system and the more extensive and complex the pipework system and topping up systems the more it seems to us that instead of coolant distribution the focus should be on a full coolant management system.
A Coolant Management Opportunity
The equipment available on this site will produce a solution which goes well beyond anything a distribution system can deliver. Our central coolant management systems deliver clean mixed coolant at the right dilution to every machine tool. That’s because we use a return pipeline system to retrieve coolant on a 24/7 basis.
This means that there is only one volume of coolant continually circulating. Its impossible for any machine tool to have a different dilution to it's neighbour no matter how severe the machining operation. That’s because every machine tool sump is connected as one. The coolant dilution set at the central plant will be the same as every machine tool in the shop and vice versa.Therefore the limitations of a ‘distribution only’ system are lifted. The main features of a complete and well engineered cutting fluid management system are:
Many systems have been installed over the years both distribution and full coolant management systems. Whatever is right for your machine shop is up for debate. Often a simple distribution system can be a great benefit in getting coolants under more control and we have seen that.
However we have also installed distribution systems in facilities more suited to a full cutting fluid management system – if only more consideration had been given before specifying.
The payback figures after commissioning a well designed and engineered coolant management system can be swift indeed. With so many of the frustrating day to day management issues removed we have seen systems payback within a year or two. When properly investigated the true cost of coolant care can be revealing and when fully analysed the cost savings can make a compelling case for a company CEO.Finally we have not mentioned cutting fluid performance. Is it likely that a badly contaminated coolant containing recirculating fines and tramp oil will perform as well as a coolant in permanently clean condition? We could write an entirely new article dealing with that question alone.
So if you are debating the installation of a coolant distribution system at least take a look at the systems on this site and ask yourself – will this be a missed opportunity?