cnc router cut or cnc plasma cut which one to use

Discussion in 'Metal Boat Building' started by gary1, Aug 16, 2009.

  1. CTMD
    Joined: Dec 2007
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    Location: Melbourne, Aus

    CTMD Naval Architect

    Gary the short answer is yes router is better than plasma. Since you're in Aus check out www.platealloy.com
     
  2. gary1
    Joined: May 2006
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    Location: australia

    gary1 Senior Member

    Afternoon,
    Apex1,Tollywally,thanks for the input not really sure what you said for the most part but thats alright.
    Chris thanks I have seen the platealloy site and heard a few good things about their designs and how their boats handle.The Router cut seems to be the way most builders are getting their plate cut from what I have seen so it's all good
    Thank's again
    Gary
     
  3. boltonprofiles
    Joined: Oct 2005
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    Location: Liverpool - United Kingdom

    boltonprofiles Senior Member

    Hello Gary1,
    Most people come to us for high - definition cut plasma metal boat kits for two reasons, one - to have all the parts cnc marked with water lines, part numbers, fold lines and so on and two - for the compromise between cost, quality and speed.
    There are also items like stitch cutting to consider to be cut out later when strength of parts are important during construction.
    Sure, laser or water jet is the best cut without any surface problems but at a price.
    Also, thicker material (for say the skeg/keel) and physical size issues can crop up, for example most normal laser/water jet have smaller beds and are better at cutting thinner material quality wise. I know some have large laser/water jet beds but this is not the norm in the UK. Plasma is better quality than laser on thicker items but not as good on the thinner.
    I would say if marking and price is not an issue, then in order of quality of choice, water jet, laser, high - definition plasma.
    I am no expert on the router, only on wooden kits.
    Hope this helps a bit.
    People keep coming to us for kits though which would indicate they do not have a lot of problems with the potential heat problem.
    Paul
    (now Northwest Metal Profiling - not Boltonprofiles)
     
  4. apex1

    apex1 Guest

     
  5. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    We plasma cut alloy in China, but the bed is wet, the plates are just under water, very clean and smooth finishes, ready to weld.
     
  6. boltonprofiles
    Joined: Oct 2005
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    Location: Liverpool - United Kingdom

    boltonprofiles Senior Member

    Hello all/Landlubber,

    I used to have an underwater plasma and used an additive in the water which helped to prevent corrosion acceleration after it's ducking. It also helped the plate to remain 'blue' in colour. It was a messy business though and is now regarded as somewhat old fashioned.
    I wonder if this is just plasma and not high - definition plasma?

    The reason I got rid of it eventually was because we found for whatever reason we sometimes had problems drilling through plate and chamfering edges after cutting and for some reason it seemed to harden the steel, if not over the whole plate, at least in places.

    Paul
    (now Northwest Metal Profiling)
     
  7. alidesigner
    Joined: Nov 2006
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    alidesigner Senior Member

    Plasma is fine, the big commercial yards have been using it for years and class societies have been approving it for years. It's cheaper than router and faster cutting rates are possible. The down side is you need to sand the cut parts before welding.

    Router cutting is relatively new. It gives a cleaner cut so no sanding is needed. Shipyards favour it for this reason and that they can recover the swarf to sell as scrap and dont have to worry about cleaning the sludge from the water table. Make sure you wear gloves - it leaves very sharp edges, so some sanding is going to be needed. Cut widths are limited by cutter diameter, usually 6mm.

    Onesteel offers both and offers pen marking and labelling with both.

    Personally I would pay a bit more for router to avoid the sanding.
     
  8. Black River
    Joined: May 2009
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    Location: South Africa

    Black River New Member

    CNC Router

    Ive cut a bit of aluminium from 3mm to 50mm on my machine mainly 6mm ±60 sheets by 6meters long, the sharp edge is removed in a few seconds by using a deburer and all the swarf is collected and resold. Its fairly quick, a sheet loaded with frames and a whole lot of smaller pieces would take about two hours this is with engraved part numbers location lines etc and one pass per sheet with a 10 or 8 mm cutter.
    My feelings about waterjet is little particles of agrigate left behind, laser and plasma damages the face, both leading to a lot of filling, I would not sand, again agragite left in the face, all leading to a bad weld
     
  9. gattward
    Joined: May 2010
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    Location: UK

    gattward New Member

    Laser cutting gives the highest accuracy with a good square cut edge. 12mm plus (1/2") thickness's are no problems now. Waterjet cutting is a little mis-leading because it is garnet that is carried in high pressure jets of water. This can leave grains of garnet in the cut edge. Plasma comes last with large angled kerf and loads of heat input. Fid a laser cutter that can cut easily the thickness you want. I have one that cuts 12mm thickness, and can put holes in at half thickness of the material.
     
  10. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    There's a caveat on this one: The guy programming and operating the machine has to know what he's doing. I've seen beautiful square edges from laser cutters.... I've also had parts laser-cut from aluminum plate that came back with ragged edges and giant blobs and burrs on the back side. Setting the thing at the right power output and speed for the material is critical.
     

  11. David White
    Joined: Oct 2011
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    Location: Brisbane Australia

    David White Junior Member

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