27' Riva Aquarama Clone

[wet feet]

The operator has to lay the plate on a vacuum table, set the zero reference and push start. The bevel is determined by the DXF file I give him.

Could you just walk us through the process?

 

[TANSL]

Could you just walk us through the process?

Yes, I would also like to know about this process because it seems to be something relatively simple, which amazes me a lot. The programmer does not intervene almost anything, everything is done by the DXF file, is that correct or am I wrong?

 

[gonzo]

The plate gets set on the vacuum table. The operator sets xyz to zero at one corner of the plate. The file should already be uploaded. Then he hits enter, execute or whatever the CNC model uses. Wait until it is cut.

 

[TANSL]

Wise advice. That is the most important : "Wait until it is cut."
.... collect the pieces and assemble them as if it were a puzzle. Easy, isn't it?
Yes, but he needs to know how to hit enter.

 

[wet feet]

The plate gets set on the vacuum table. The operator sets xyz to zero at one corner of the plate. The file should already be uploaded. Then he hits enter, execute or whatever the CNC model uses. Wait until it is cut.

You really believe that is all? No explanation of how the drawing is converted to a form of instructions that the machine can execute. No mention of whether the piece is too big for a single sheet and how it might be split or joined back as a single unit. No description of the tools to be used or how to establish the correct offset.Most glaring of all, no mention of how a 2 dimensional graphic format file can be persuaded to generate a twisting bevelled surface for the toolpath to be generated from. There is an old proverb relating to speaking that might just as well be applied to typing.

 

[gonzo]

You asked about what the operator needs to do, which is to lay the plate down and set xyz at zero. He doesn't need to know how the file got generated. Finally, if you are using a 3 axis machine, the file will be 3 dimensional, not 2. For creating the file, it is relatively straightforward. Create 2 parallel planes spaced the thickness of the bulkhead at the station it is designed. The intersection of the planes with the interior surface of the hull generates the edges. Join the edges by creating a surface and you have a bulkhead file.

 

[wet feet]

I know how to do it.The machine doesn't and needs more input than you have described.It might be time to stop digging........

 

[bajansailor]

The Forum has not seen @terra for almost a week, ie since last Tuesday.
I guess that he has looked in occasionally without signing in, and then when he saw his thread being hijacked by petty arguments that are really not related to the wonderful Riva that he is building, he just sighed heavily.
Sadly, stuff like this seems to happen so often on this Forum.
But Terra, please do allow this to develop into a building thread - or even start a new thread if you like.
Same as how Leo and Tally Ho have an enthusiastic following, you will have many following your progress on here - especially if you post a Youtube video occasionally as well.

 

[TANSL]

It is possible that @terra has gotten tired of the things that have been said here, you will know it but I do not feel capable of affirming it. What I do affirm, and I will do it while I can, is that when someone says nonsense, or induces others to think that something that is very difficult for him to achieve is very easy, clearly showing that he does not know what he is talking about, in those cases, the OP must be warned of what the reality is and what advice is not worth it to be taken into account. Because being wrong is one thing we can all do (you too, probably) and another thing is stubbornly insisting on a stupid simplification of a very complicated process. Many times the desire to pretend that we are what we are not and that we know what we do not know, leads us to say what connoisseurs can describe as enormous nonsense.

 

[Ad Hoc]

It is possible that @terra has gotten tired of the things that have been said here, ...

Nope.
More like tired of your nonsensical asinine postings... as you resume your usual MO of hijacking each thread with such, whilst attempting to belittle others, like a petulant child.

 

[TANSL]

Thanks Ad Hoc, I love you too

 

[terra]

Haha sorry guys, had a few urgent work projects and got sidetracked.

Quite a discussion going on in here. Bottom line I am very familiar with CNC work. I've worked as an advanced manufacturing engineer in high tech medical development for the past decade in 3,4,5,6 axis CNC mills and lathes, robotics, additive manufacturing, and CAD/CAM. I'll have no problem using the CNC to apply a bevel on the edge. To chime in on the discussion, yes the CAD file moves to DXF, loads into a toolpath generator, and then CNC follows those toolpaths. Same process as 3D printing. A bevel can be accomplished with either a bevel bit or even using a straight edge end mill and stepping up and mover each time to create a stepped curve. The smoothness of that curve in the XZ or YZ plane would be determined by the number of Z steps. The smaller the step value the smoother the curve. I've done plenty of rounded edges in those planes with a 1/4" carbine straight edge end mill and it is not challenging. It does obviously take a bit more time. So in all reality what I'd do is cut to the large dimension and manually remove material to achieve the right slope for assembly. I've designed, built, and run many CNC mills as well as a workshop full of 3D printers for polymer or metal up to 4'x8' (smaller for metal). If a local CNC shop couldn't figure out how to create a beveled edge given a 3D drawing I'd look for a new shop. I've personally done complex curves in the XZ/YZ planes (like a smooth topo map) using a homemade 2.5D CNC mill with a straight end mill. Just takes forever.

As far as cutting multiples from a sheet, I'll be splitting each frame into 3 (top arch, left, and right) before reassembling into a solid. I'll do the layouts on 4x8' sheets because that's what my shop works most with.

Anyways don't worry about hijacking my thread. This is really just an advanced Q/A session before I start making purchases. I'm about 3 months out from finishing the workshop. I'll likely start by building my motors and then start laying out assembly jigs.

Thanks

 

[TANSL]

So in all reality what I'd do is cut to the large dimension and manually remove material to achieve the right slope for assembly

A very sensible decision. That is what everyone does when working with wood, with significant thicknesses. In the case of metal parts, it is done the other way around, cutting the profile of the part on the shortest side.

 

[wet feet]

It will be good to see the project progress and lots of pics always help to document the process.I had a feeling you were up to speed with the manufacturing processes.

 

[DogCavalry]

@terra , check out my build thread. Strip plank composite is an excellent construction approach. I ripped planks from the edge of dimension lumber. Worked very well for me. I believe 10' 2x8's gave me the most usable material per $, but the calculation changes frequently.

Dave Gerr's Elements of Boat Strength is a terrific resource.

May I just add that your resources and budget utterly dwarf mine. And I'll get there eventually. You will surely succeed, and enjoy every moment.

John