cnc router cut or cnc plasma cut which one to use

[gary1]

Evening,
First up let me state that I,am not a boiler maker or a welder and what I know about welding you could write on the back of a stamp, that being said i might be getting an alloy fishing boat in the 5 to 6 mt length range built hopefully in the not to distant future.
All the hull panells and parts are going to be cnc cut before they go to the builder, now heres the thing I have been told that it is better to have all the parts cut using a cnc router. Reason being the plasma cutter can change the properties of the alloy due to the heat involved which could in turn affect the weld strength. Is there any truth in this all the alloy used will be marine grade 5083 ranging from 5mm to 4mm in thickness.
Thank's
Gary

[marshmat]

I've had aluminum successfully laser-cut, but have never tried having it done with a plasma unit. The intense heat will affect the alloy's temper near the cut zone, but since these same cut edges will be welded later, I'm not sure if that's much of an issue. Plasma and laser can both leave a pretty nasty edge if the operator is less than perfectly meticulous with the setup parameters.

In any case, I would prefer water-jet cutting (if available) for aluminum, but a router ought to work just as well. Neither of these methods should affect the adjacent metal to any significant degree.

[tazmann]

Alcotec's web site has a preety good writeup on the subject. certain grades of aluminum have problems with plasma. The first dinghy I built I used plasma to cut the panels and I could not tell any differance but that was on 5052.
Tom

[gary1]

G/day Marshmat,Tazman
Thank's for the input from the little I have been able to find out most fellas reckon the router cut or the water jet would be the way to go over the Plasma.
Thank's again
Gary

The waterjet is the way to prefer when ever possible , even on steel. The second best is the laser. The router is expensive and induces a heatload too.

[TollyWally]

Apex,
What are your thoughts on a plasma cutter?

We do´nt order plasma cut metal since laser and water are at the market.

[TollyWally]

I only ask since I have a plasma cutter and a waterjet or laser is quite a bit too expensive for me. Thanks for the insight.

Originally Posted by TollyWally

I only ask since I have a plasma cutter and a waterjet or laser is quite a bit too expensive for me. Thanks for the insight.

Do´nt get me wrong all the world used plasma cutting when it was available, but you know the better is the enemy of the good.

[TollyWally]

LOL
I thought that the perfect was the enemy of the good! So no problems for concientious but not perfect work?

Originally Posted by TollyWally

LOL
I thought that the perfect was the enemy of the good! So no problems for concientious but not perfect work?

There is NO perfect out there, you know, even if you look for thousand years. And we all called the first plasma tables "perfect solution", well, you know........

[TollyWally]

yep, it's hard to stay on the cutting edge of rapidly changing technology.

Originally Posted by TollyWally

yep, it's hard to stay on the cutting edge of rapidly changing technology.

No it is´nt!
It is harder to stay at the cutting edge of honesty! What is it worth when one can get a compromised quality at a lower rate than a honestly not A+ , but truly B+ at the same???

I might not have it said clearly: a good plasma table (with a sufficient power supply and the related aftercooling effect) was, and is a good tool! period..
All of us have been fine with it, and compared with a torch cut we have been miles ahead in quality, and time, and preciseness, read: quality and cost! What was good yesterday cannot be bad today, that is just a logical truth. Anything better than yesterday of course is a improvement, but that is by no means all times, or in every case a value worth to go for! So, how many plasma cutted vessel did fail? Any relation to torch cutting? Any to laser cutting? Any sensible comment on these "old", "outworn" techniques???
Have a fine and correct setup table, provide a true and honest fineness in cuts, do not tell them you are "as good" as a laser (which is not in every case a better choice, you can ruin a cut with every technology when you are cutting corners better than plates), have a reliable business, and you are not the last choice for your neighbouring yards! Believe me, I do as my predecessors did, (and Hamburg survived two world wars as the richest community in the entire world), have reliable partners, and the word of a proud, honest man, and you will not fail! But promise them once what you are not able to purchase, they will remind you for centuries.
The last millimeter is not yours, the last 5°C of heat affected zones are not yours (are submarine builders your everyday clientele?), and the roughness of your plates are miles away from a laser or water cut. Have you ever tried to make a 1/10 of a millimeter worthwile for a welder? You would hear them laughing from the first May 1499 until the backroads of Sao Paolo!

My best regards, a boat builder
Richard

[TollyWally]

Thanks

[TollyWally]

LOL,
Come on over, I'll issue you an unlimited license!