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

[apex1]

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?

[apex1]

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.

[apex1]

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?

[apex1]

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.

[apex1]

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! :)

[CTMD]

Gary the short answer is yes router is better than plasma. Since you're in Aus check out www.platealloy.com

[gary1]

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

[boltonprofiles]

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)

[apex1]

[QUOTE]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.
Right
There are also items like stitch cutting to consider to be cut out later when strength of parts are important during construction.
Or transportation!
Sure, laser or water jet is the best cut without any surface problems but at a price.
At the larger companies today (at least in Europe not that much more)

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.
To the usual (6 to 10 mm), the larger tables (you say beds in the US) are pretty compatible today. And they have a advantage, they do the egde bevel at the same time!
I would say if marking and price is not an issue, then in order of quality of choice, water jet, laser, high - definition plasma.
Concur, but price comes closer, at least in EU.
I am no expert on the router, only on wooden kits.
Me too, and there it belongs.
Regards
Richard

[Landlubber]

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.

[boltonprofiles]

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)

[alidesigner]

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.

[Black River]

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