laser cutting

[hornbeam]

Hi,

I'm thinking of building a 0-4-0 tank loco, and am wondering does anyone know of a company that offers a laser cutting service? I'm after having some buffer beams and frames cut. Buffer beams are less of an issue as I could use wood/ cut material for these.

Thanks.

[AllWight]

Hi

I use Model Engineers Laser Ltd for the frames on the radial tank. Dick Allen also used them for the Pullmans and the frames of his D Class. They are on the web.

Mark

[MikeWilliams]

If you are able to draw them yourself using a CAD system, then there will probably be a laser cutting firm near to you prepared to do it more cheaply.  Look in yellow pages.

If you need somebody to do CAD for you I'd be happy to help.

Mike

P.S. Whatsitfor?

[keith Bristol]

Hornbeam

How fortuitous, I am literally bleary eyed from correcting the DWG for Mark 1 coach sides TSO and BSO ready for sending to two companies for laser cutting. I will let you know how I get on. I will be having some 03 footplates and frames cut soon as well, I could include yours with that.

The cutter will need a .dxf file from you to drive the tool path, there are also thickness and diameter constraints depending on the material, each supplier is slightly different depending on their machine.
Given the nature of the work I suggest model engineers laser is best.

As Mike says if you need a hand with CAD.. PS Picking up unit this weekend so I can make the brake shoes next week. Running it with allwight on Blackgang outing at Exeter show.

Keith

[midnight miller]

Hello All

Being a nosey sod at the best of times , Could I also join Mike in a what is it please ?




                                                                           John

[hornbeam]

Thanks for the help guys. I don't have access to CAD so may well need some help. I've got an accucraft edrig boiler that was going to use in my Y6 but it's to long. I also have a smoke box from it as well. I've now the body work as well. These are chunky locos so I've decided to build a industrial tank so need the frames, buffer beams and foot plate. I Plan on using skaters wheels and the only steam plant available- the GRS steam unit. Keith will drop you a line sorry I've been rubbish in contacting you I don't mean to be rude.

[MikeWilliams]

I am sure Keith has his sources for laser cutting.  Only thing I'd add is that Model Engineers Laser are in business and need to make a profit.  Going direct to the laser company should give half his advertised prices (i.e. £10 per pair of frames rather then each), and if you manage to find a local firm happy to slip our tiny quantities in between other jobs for cash, expect to pay half of that: i.e. a quarter of his advertised prices.

Mike

[hornbeam]

Many thanks for the help guys.

Well, ive contacted a guy I used to work with and for a few beers he will draw the frames up for me on CAD.

Ive had a thought (they happen you know) and decided on the steam plant. Not sure if you have head of Regner? They do a loco called Lunberjack, thats powered by a twin ocsillating unit. I had one of ther single cylinder engines ( both are geared) and it pulled a good load. Ive contacted the UK importer and the unit costs £145 plus gears. the bore snd stroke are bigger than the GRS units. Its about 46 mm wide so will fit beween frames. only issue is the gears are designed for a 4mm shaft, so hoping i can re-drill these.

if it works it will be cheaper than the GRS ones and hopefully more powerfull. I shall let you know how I get on.

[hornbeam]

One last question, can holes me made via lazer cutting?

thanks.

[AllWight]

Yes they can be it wood laser cut kits(such as the Wickham trolley kit by IP Engineering) or metal frames for the locomotives such as the radial tank that i am developing with a little hep(done by model engineers laser).

Mark

[MikeWilliams]

Hornbeam,

As a general rule the hole should be no smaller in diameter than the thicknes sof the metal, as it will otherwise be ragged.  If you'd care to give me a call (number on www.williamsmodels.co.uk) I'd be happy to chat over the fundamentals of laser cutting.

Mike

[andrewfoster]

If possible, it's a good idea to see examples of your laser cutter's work before placing an order. There are different machines and different skill levels in the operators that can affect the quality of the finished part.

The positioning of the parting off points varies, and can be a real pain when you are deburring if they get it in an awkward spot. If you can specify it on the drawing, or highlight banned areas, it helps.

I'm getting consistently good results with .067" diameter holes in .040" aluminium alloy, but have not had to go any smaller.  The positioning of hole centres is as accurate as your CAD data, so where a tightly held diameter is needed, have them cut it slightly small and then ream it out - the results are usually good.

For thick parts it can be worth looking at water jet cutting. The finish is good, a good machine will give a vertical edge, and there's less deburring to be done. I hate deburring!

Andrew

[MikeWilliams]

Water jet cutting.

That's intereting Andrew.  I agree it can give a better edge finish and does not harden the metal, but it is more expensive, not so easy to find suppliers, the cut is wider, so minimum size of holes is larger and I've not managed to get the vertical cut you describe as the "draw" is more than with laser cutting.

I've recently had some parts laser cut for a friend, making a 7mm scale 1838 Bury 0-4-0.  Not only is it a tiny engine, but it has bar frames (i.e. no plate frames).  Laser cut in stainless steel, the edge quality was superb and included frames, motion plate, eccentrics, valve rods and all other parts for the chsssis with working valvegear.  Laser cutting was well up to the task and waterjet could not have produced the fine detail.  I'm pleased that he's putting it together and not me!  It will, by the way, be a kit eventually.

Both processes have their place I guess.

Mike

[MikeWilliams]

Andrew,

Thinking again about your posting, and particularly getting a vertical cut from waterjet cutting.  I'd be very interested to hear how this is done.  Maybe the jet is angled to counteract the draw?  I've never heard of this before.  Laser cutting also has draw, so the edge is not square with the face of the metal.  I've never seen any description of getting around that problem with either process.

Thanks,

Mike

[andrewfoster]

Mike -

Yes - I agree that you can't compete with the laser for small intricate parts.  One of my suppliers operates both processes, and when we were developing a quite small part (part of the trunnion assembly for the GME bascule bridge) in .25" thick aluminium alloy, the laser version came out like a lump of porridge. The water jet gave clean edges, and while the holes were, not surprisingly, tapered, they were accurately positioned and cleaned up easily for 3/32" rivets. There's no perceptible draw on the outside edge.  As you say, it's a slightly more expensive process, probably due to the consumable material needed.

I visited another local water jet shop recently, and the owner proudly showed me some one inch steel plate he had cut with what looked like dead square edges: his customer can use them without any finish machining. It's a new machine (http://www.wrenwaterjet.com/tools.html) and I don't know how the jet achieves this. I'd guess that the nozzle is automatically angled away from the material by the cutting program.

I'd love to see pictures of the Bury 0-4-0!

Andrew