CNC fairing from 3D MODEL

[Williamo]

I am currently exploring the possibilities of bevelling frame edges once frames and keel are assembled, and the hull inverted, using a CNC. Planking fairing may be done in this way too. I don't suppose this is a particularly original idea, but it would be interesting to speak to anyone who has attempted it.

[herask]

well, the first thing that comes to mind is that CNC machine should be perfectly calibrated to physical model, and 3d model used for guiding CNC cutter should be perfect representation of the physical model (or vise versa). otherwise CNC cutter could shave off too much on one side, and too little or not at all on the other side, for instance. other than that, if done properly, this could be really useful and time saving method...

[Jack H]

Hello Williamo

I have seen AlexBaranov made shipmodel by this way（Or close to your idea）.You can search the keywords "cumberland"/"hms cumberland", he introduced the method in his buildlog.

 

[Jack H]

And my fancy is to planking on a substitute of hull (NC machining), and then transfer it to the actual hull, but strake was processed directly by CNC-I have done the experiment in this step.

[Williamo]

On 05/03/2018 at 2:45 PM, herask said:

well, the first thing that comes to mind is that CNC machine should be perfectly calibrated to physical model, and 3d model used for guiding CNC cutter should be perfect representation of the physical model (or vise versa). otherwise CNC cutter could shave off too much on one side, and too little or not at all on the other side, for instance. other than that, if done properly, this could be really useful and time saving method...

Yes. The critical thing is to have the workpiece very accurately and rigidly fixed before starting any cutting, or even a trial cut in foam first! I just have a thing about fairing hulls well.

[Williamo]

On 05/03/2018 at 3:08 PM, hjx said:

And my fancy is to planking on a substitute of hull (NC machining), and then transfer it to the actual hull, but strake was processed directly by CNC-I have done the experiment in this step.

Hello Hjx

, thanks for the reference.

Im not sure I follow your proposed technique here. Would you machine the external profile of the strake while it was flat on the bed of the CNC? Then plank the hull? That's innovative but you must be confident the frames are accurate first!

Edited March 8, 2018 by Williamo

[Jack H]

7 hours ago, Williamo said:

Would you machine the external profile of the strake while it was flat on the bed of the CNC? Then plank the hull? That's innovative but you must be confident the frames are accurate first!

Yes,It's flat on the bed of the cnc but the strake is curved,so it needs double sides milling.

I have some strange and eccentric ideas - but my behavior is normal, for example, in the Chinese forum, when I propose to use CNC to produce an independent figure-head - without any support or "bridge", many members were opposed or thought it's impossible, but I did it by the same machine without any "bridge".

 

Many people question that the plank was so thin that it is impossible to be machined by CNC. But they ignore that i can use a support, the rough stock of strake can be fixed on the surface of a support, then processed  it and installed it to the hull?

 

The frames produced by CNC will be very accurate, and the deviation may be within 0.1 or 0.2mm.-But this is not the traditional method of making ship models, there may be a lot of opposition.

Edited March 9, 2018 by hjx

[Williamo]

I am an artist and designer, so I am a great enthusiast of eccentricity. It often leads to innovation! Sometimes not, but always challenging and interesting. I have done a lot of work in the area of cutting planks to shape, both in plan and variable edge profiling, as well as complete frame and hull fairing, using CNC. I have also looked at adapting these processes for full size yachts etc. I just need to find someone who makes 90 mm thick marine ply economically!

I have also looked at profiling the inner surface of planks, (and the edges and ends,) then planking the hull and fairing the whole thing. I think this is the approach you are describing.

 

Don't worry about traditional methods.They have their place, but once were innovative and poorly regarded. Pioneers are by definition out in front, and should be aware that opposition and missiles will usually come from behind, not in front!

[Jack H]

On 2018/3/9 at 9:42 PM, Williamo said:

I have also looked at adapting these processes for full size yachts etc. I just need to find someone who makes 90 mm thick marine ply economically!

making full size yachts! good idea!I have visited a Chinese small dockyard who build small wooden ship,and some small dockyard(or workshop) in Europe can been found out on Internet.

 

They bend plank after heating them with steam,and some metal jigs are used.A large CNC milling machine can process such a large size of plank,  a friend of mine who has a furniture factory use this kind of machine.I think these machines can fully meet your idea.

 

I think the cost of processing wooden planks may be about the same as that of making furniture.I don't know the cost of processing in the European and American countries. In China, it is very cheap. The processing of large quantities will even be as low as 1.5 US dollars per hour.

 

The price of the machine is from about 4000 (3 axis) to $100000(5 axis).

Edited March 11, 2018 by hjx

[rtwpsom2]

I think CNC would be better to make the parts of the model, instead of using it after the parts are assembled.  You could use EdT's idea of drilling the iron bolt holes and using those as pins to align your parts during assembly and then there would be no fairing to do to after the fact, maybe just a little light sanding here and there.