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A big project!

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  • Pat
    Hi Pat, I will try to answer your questions as well as I can in English, my two English-speaking engineers don t know the words for lathes except in Spanish,
    Message 1 of 62 , Jan 19, 2013
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      Hi Pat,

      I will try to answer your questions as well as I can in English, my two English-speaking engineers don't know the words for lathes except in Spanish, and the most knowledgeable person here in charge of the machine shop and repairs doesn't speak much English at all, although he is studying. Please bear with me and if what I say doesn't seem right, don't hesitate to question it.

      I am attaching a picture of a lathe of a customer here, but this lathe is much too small for some of their repair work. You can see that the workpiece is fairly good-sized and taxes the lathe considerably. This lathe has a capacity of 6 tons and can handle a piece up to 80cm in diameter. The piece we and they can't do that needs reclaiming of wear areas has a diameter of 1.3 meters and weighs 9 tons, and there is another of 1.5 m, but none larger. We need a lathe with a 1.5 volteo, I think that's swing in English but not sure. These particular pieces are used in mining here, and Mexico has a lot of mines. The larger pieces are sent to the US, right now, or an American company comes down with big trucks of equipment and works behind locked doors (I'm not kidding, they do, but now we know about thermal spray, too). These are jobs we'd like to start doing here ourselves. I hope this explains why we need such a large size lathe. We can grit blast or thread to prepare a surface for spraying, but all these types of pieces need to be turned. It is easier, of course. We decided we could also, after turning, mount a spray gun on the side and spray extremely large rollers and shafts. It would help apply a uniform coating and cut down on waste, whether or not we had to finish the sprayed surface. Some of these rollers can reach 10 meters, and replacing them is horribly expensive.

      With these different uses, we don't see how anything other than the lathe could do them all well and give us the flexibility we need. We 're sort of stuck right now, we have slowly acquired the other equipment but the lack of a large lathe really limits what we can actually do.

      The cost of a large chuck is not a concern, it seems, I explained your questions carefully and let one who understands most of English read it; all of them said it would not be that difficult or expensive to get a chuck adequate for these large pieces, but I did not go into why, they just told me to tell you it isn't a problem here. We do make a lot of parts, I know, and do bartering with other shops for a bit of work, too. I will be happy to find out more about this when we get further along, but right now everyone is too excited over this project to give me an explanation, even if I had asked, which I didn't.

      I appreciate your answering me so quickly and trying to find help, especially for the concrete estimate. I wish you could have seen everyone's eyes light up when I told them you answered and would try to help.

      Thanks again and I await your comments at your convenience. Have a nice weekend!

      Best regards,
      Alexis


      Enviado desde mi oficina móvil BlackBerry® de Telcel
    • Dr. Alexis O'Neill
      Rodrigo, Forgive the delay, I ve had a lot of fires to put out over the weekend and just got back to this. I have attached a basic report on anti-corrosion
      Message 62 of 62 , Jan 29, 2013
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        Rodrigo,

        Forgive the delay, I've had a lot of fires to put out over the weekend and just got back to this. I have attached a basic report on anti-corrosion applications of thermal spray and hope it answers your question about the suitability of sprayed zinc coatings on petroleum pipelines as well as other installations in the field.

        Good luck in your research.

        Regards,
        Alexis

        Enviado desde mi oficina móvil BlackBerry® de Telcel

        From: Rodrigo <rcaetano22@...>
        Sender: multimachine@yahoogroups.com
        Date: Fri, 25 Jan 2013 17:31:19 -0200
        To: multimachine@yahoogroups.com<multimachine@yahoogroups.com>
        ReplyTo: multimachine@yahoogroups.com
        Cc: multimachine@yahoogroups.com<multimachine@yahoogroups.com>
        Subject: Re: [multimachine] A big project!

         

        Does anyone know if this process of thermal spray coating could be used as a external protection in pipelines?

         

        We have been using a polyethylene coating and cathodic protection to provide corrosion resistance, but i don´t know if the thermal spray is cheaper or better. I´m working with an iron ore pipeline here in Brasil and we have a great amount of pipes of 24" to protect.

         

        Rodrigo




        Em 22/01/2013, às 10:21, "Dr. Alexis O'Neill" <alexiso_nl@...> escreveu:

         

        The thermal spray process allows the melted wire to cool almost instantly, we spray with a standoff distance of around 6-9 inches, and by the time the particles hit the substrate, they have almost cooled. I can't comfortably touch a workpiece instantly after spraying, but within a minute or two I can. The adhesion is a mechanical process, there is no heat distortion with thermal spray. This is why we want to introduce the thermal spray here, we can reclaim worn areas over and over again with over-heating them like we do when weld-repairing. Our only problem is too much cold-working before or after spraying that can harden some types of steel and make it hard to grind a nice polished surface, such as equipment/installations in food or medical areas. We need a milling machine, too, but that's down the road, right now we can't properly prepare those huge shafts for spraying, so the lathe is critical, a milling machine would be nice, once we can get everything sprayed correctly. What we would mill would be big and heavy, too, ss plates weighing over 1-2 tons each. Back to the lathe, however.

        We do have plenty of big trucks here, we have a nicely developing trucking industry and the trucks here are the same as I've seen on US and Canadian highways. There are more and more new ones, which means old junked ones, and their trailers, so I think we could find parts without a problem. This idea seems interesting, I'm printing it out for Anibal's and Juan's perusals. Anibal works with pantographs and robotics, he will understand this idea and I'll pass on what he thinks.

        We don't care about pretty, just what works and is safe to use.

        Alexis

        Enviado desde mi oficina móvil BlackBerry® de Telcel

        From: "David G. LeVine" <dlevine@...>
        Date: Tue, 22 Jan 2013 02:00:56 -0500
        Subject: Re: [multimachine] A big project!

         

        On 01/20/2013 01:50 PM, Shannon DeWolfe wrote:
        Would this work? I know it isn't a concrete lathe but what is needed is 
        a solution to a problem, not an exercise in how big a lathe can be built.

        I don't think so because the surface will be so hot that I think the rollers would degrade.  That was why the head and tail stock.  With that kind of load a trailer can flex many inches.  Sorry, that doesn't seem to be a good choice.

        Now, support that roller only by the ends and unload the carriage and you could grind things pretty well, but that takes a LOT of power and the measurement tools are not cheap.

        Now for the "sneaky" side.

        Take a semi trailer and line it up with the head and tailstock (no load on the trailer means it stays relatively flat.)  It can carry the head and tail stock, but they set on the ground or concrete slabs.  Even a 500 pound carriage won't really flex the trailer much, and the grinder can be pretty light (relatively), but it will have to remove quite a bit of metal, let's say no more than 20 HP.  Rotation can be fairly low powered, under 100 BHP.  Now for sneaky:  Cheap laser diodes can be had (eBay or laser pointers) for a few dollars.  Mount two in the headstock (or more), use them to shim the tailstock and the ways into alignment.  Now, vertical doesn't matter much, remember I was trying for a few thousandths.  So the carriage can move and either grind or spray, two carriages can do both.  Air bearings make good sense, as do really stiff ways which won't bond to slag.  Let's say polished granite.

        Let's see what resources are available!  If a tractor (as in a tractor-trailer) with a PTO and a compressor, a semi-trailer and a little hydraulic power is reasonable, maybe we can ask some right questions...  The headstock and tailstock sit on the ground or pads (pretty low tech and cheap!)  The trailer goes between them and the ways get shimmed to the lasers.  Power comes from the truck, as does air and hydraulic drives.  With compressed air, we can clean the ways as we work.

        It isn't pretty, but it could work.  If we can get some fancy stuff done, the laser diodes can be used to find high spots...

        I have to look into laser interferometry.

        Dave  8{)

        --


        "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

        Mohandus Ghandi, An Autobiography, Page 446.

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