Caterpillar earth moving equipment & vacuum metallizers.

            What, I hear you ask, have Caterpillar earth moving machines to do with vacuum deposition systems.  Good question.   There has been a huge amount written about re-cycling polymer films including metallized films. To try to keep up-to-date I was reading various articles about re-cycling and came across one that not only included the product produced on the machines but also included the machines that the products were made on.

            Typically machines are run into the ground.  Sometimes they are refurbished once or even several times, others are maintained just enough to keep them running for as long as possible. Eventually a decision will be made to end their life and they get scrapped.  At this point they are either dumped and left to rust or stripped and the metal recovered.

            What this article was suggesting was that this need not be the end of the equipment. It was suggested that most equipment contains sufficient large basic components that could form the base for a complete re-build.  One of the examples given was of Caterpillar, who recovered more than 60,000 tonnes of equipment in 2008 and who then were able to utilise 93% of the recovered material.  The article was not detailed enough to find out all the information as to what the 93% did or did not include.  To me the figure of 93% sounds high but if this was purely on a weight basis then it might be more understandable as the engine and gearbox with its relatively high number of moving parts represents only a very small fraction of the total weight of these earth moving machines where the rest of the metal work is substantial.  I would expect that much of the large metal items do not wear out but may start to look aesthetically tired (a fancy way of saying tatty).  

What, as a buyer of one of these re-built machines, I might have a concern about would be some of the longer term failures that might occur such as fatigue failures.  This type of failure can occur even in substantial metal components simply because of the large repetitive stressing and a small imperfection that can grow with time. Having metal that has been through one lifetime of work already could mean buying material that is so much closer to the point of failure.  Bringing this philosophy back to vacuum coating systems I would have specific concern with re-using a vacuum vessel that has already seen one working life. Vacuum vessels are repeatedly stressed as the vacuum is pulled and released and the welds that are present on most vacuum systems are prone to fatigue failure.  It is common for old machines to have had welds re-done as they have failed in service, sometimes on more than one occasion.  However I am sure that this problem could be addressed by a combination of testing, rework, warranty and price.

            So should old vacuum metallizers be scrapped or re-built?  I can see the argument for re-building them but this does impose various constraints that may make the process more difficult to achieve than it first appears.  The trend is for metallizers to accept longer webs and wider webs.   Thus a machine that is built in one decade is likely to be too small to be ideal for the market a couple of decades later.  Using a machine that is smaller than the current standard can increase costs and make the product uncompetitive.  Thus I think the practicality of rebuilding machines is the easier part of the process with the more difficult part being the economics.  There are things that could be done to make the width better by using an extension ‘tube’ to the chamber and wider rolls but there is little that can be done for the web length.  Increasing the width does add a further problem of what to do about increasing the pumping.  As you can see rebuilding can also require an amount of re-designing. Technology will also have progressed and unless the system have been systematically upgraded then all the up-grades of winding and motor technology, operating system and software will be required.  The costs and time associated with recovering the machine, stripping and assessing the quality of material, to decide what can be re-used and what needs to be replaced, look as if they could be at least as long as designing and building from new.  This would suggest that there would be no financial advantage to re-building but only a way to re-cycle old metallizers. This would then need a detailed carbon footprint assessment to see which would be preferable, re-working to re-build or to simply scrap the metals for re-processing.

            Caterpillar has the advantage that their equipment is sold in much larger numbers and so they have been able to develop a complete business for recovering machines in large numbers.  Compare this to vacuum metallizers that have very limited numbers of systems sold each year and this then makes developing a business for re-building or re-furbishing metallizers more difficult.  Thus from what initially looked to be an interesting opportunity that might provide a greener route to disposing of old metallizers I think I have argued myself out of it being a practical proposition.  If I also consider that many of the metallizers that are scrapped by one company may well be shipped to Asia and kept running for many more years the benefits of re-building become even less clear.       

Comments

[farm machinery equipment]

Hi,
Nice post.The suggestion you have given that most equipment contains sufficient large basic components that could form the base for a complete re-build is correct.

[drain cleaning equipment]

Vacuum vessels are repeatedly stressed as the vacuum is pulled and released and the welds that are present on most vacuum systems are prone to fatigue failure. It is common for old machines to have had welds re-done as they have failed in service, sometimes on more than one occasion. thanks for posting. i learned a lot.

-mike-