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What is the best process to get a bunch of hot rolled plate chopped to parts?

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
I have to build 14 of these parts welded up and need to order all of the components cut in 1/4" A36 hot rolled.
Holes are 7/8"

So the cut list will be for each of the 14 assemblies:
3- 5"x8"
1- 5"x4'
1- 5"x28"
2- Side plates as below which are about 8"x5' sticks of material

What is the best bet for getting these cut clean at reasonable price?

These two drawings show installed and free assembly:

Assembly to build on left:
IMG_2966.jpg

Assembly to build on right:
IMG_2963.jpg

And the side plates:

Image 11-16-18 at 6.20 PM.jpg

I am hearing water jetted out of plate is the way to go?
I will get proper drawings done this weekend.

Thanks all
 
ok- thanks
These are exterior (under roof) timber framing components which will be painted so just need to be clean enough to not have to fight to weld up and not have to spend a month grinding to clean edges..
 
ok- thanks
These are exterior (under roof) timber framing components which will be painted so just need to be clean enough to not have to fight to weld up and not have to spend a month grinding to clean edges..

Then IMHO ordinary common or garden / run what ya brung plasma will be fine :)
 
ok- thanks
These are exterior (under roof) timber framing components which will be painted so just need to be clean enough to not have to fight to weld up and not have to spend a month grinding to clean edges..

Normal plasma should be fine, rotoblast the pieces after cutting,
with steel shot.

Will deslag & remove the hot rolled scale.

Will give everything a nice even course finish (like a sand cast aluminum
finish)
 
For that small quantity, your best to find a high definition plasma. Almost any steel yard should be able to do it.

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I have found weird local variations in price depending on market saturation of machines, between laser, waterjet, and plasma.
You should call around and get quotes.
In my area, laser is consistently MORE than waterjet, but I understand thats pretty unusual. But its true for me.
Depends who owns the machines, and how much of it they do.
Plasma, quality wise, is fine.

I have built my share of wacky timber framing brackets- even did em for a pair of geodesic domes once. I find the cutting being accurate is great, but more important is the jigging and welding being done right, or else they come out rhomboid, tapered, and warped.
tack em all around, check before welding, step weld and skip around, unless you have dedicated solid steel jigs made of heavy plate. ( and 1/4" aint "heavy plate"- 1", maybe) . I like to clamp things to my platen table- it weighs 4000 lbs, doesnt move too much.

Also, New Jersey must be WAAAY more advanced technologically than the wilds where I live- because "any" steelyard around here has a stoner with a hand oxy fuel torch. Hi-Def plasma, for me, is minimum a hundred miles, and the really reliable place is a 5 hour drive one way. Again, local conditions may vary wildly. Dont make assumptions about yours without calling first.
 
I have found weird local variations in price depending on market saturation of machines, between laser, waterjet, and plasma.
You should call around and get quotes.
In my area, laser is consistently MORE than waterjet, but I understand thats pretty unusual. But its true for me.
Depends who owns the machines, and how much of it they do.
Plasma, quality wise, is fine.

I have built my share of wacky timber framing brackets- even did em for a pair of geodesic domes once. I find the cutting being accurate is great, but more important is the jigging and welding being done right, or else they come out rhomboid, tapered, and warped.
tack em all around, check before welding, step weld and skip around, unless you have dedicated solid steel jigs made of heavy plate. ( and 1/4" aint "heavy plate"- 1", maybe) . I like to clamp things to my platen table- it weighs 4000 lbs, doesnt move too much.

Also, New Jersey must be WAAAY more advanced technologically than the wilds where I live- because "any" steelyard around here has a stoner with a hand oxy fuel torch. Hi-Def plasma, for me, is minimum a hundred miles, and the really reliable place is a 5 hour drive one way. Again, local conditions may vary wildly. Dont make assumptions about yours without calling first.

Very nice write up.

Odd is right.

In Erie, I have a couple of laser shops, a few waterjet, and 2 hi-def plasma.

I do not do the buying, but the shop I use normally, has all 3 process.

Waterjet is the most money (slow speed).

Unfortunately, it sounds as if the OP already has the material.
Every shop I listed, cut's their own stock. They nest it as well.

You send them a file, they make your parts, you pay them.
 
Hi Def plasma is probably the way to go but at least check pricing on laser before you order anything. I'm sure it depends a
lot on location but around here there are enough laser shops that I often find that for only a few pennies more I can get stuff
laser cut instead of plasma. Likely doesn't matter for what you're doing but laser will always give you crisper edges and tighter
dimensional tolerances...
 
What is the weld joint? I like to have one piece cover no more than 1/2 of the edge of the other for an outside corner weld, like a small long fillet weld. (1/8"x1/4" to 3/16"x1/4") Minimal joint prep (none) if you size the parts to work like that.
 
Where I am the highest cost always seems to be the labour,so I would spend an extra hour or two on the cad side making it all slot and tab together with nice corners to put welds into. Self jigging and less distortion. We have a good amount of laser shops in the area, probably 10 within a 50Km radius, I supply a step file and the parts are cut and bent in under a week usually.
 
+1 on getting quotes from different places and not worrying about whether it's waterjet plasma or laser. I too have seen surprising prices. Let them quote. And +1 on tabbing them together to aid assembly. Or since you are making 14 of them you could invest in a bit of a jig for this.

Hey I was going to suggest getting a laser tube cutter shop to look at it but those parts are pretty big and you probably can't find 4"x 5" though maybe the design could change a bit. Also at that size the cost of the material getting removed would be a lot. But it would be interesting to get such a thing quoted. I've been looking for an excuse for a laser tube cutting project for ages.
 
Ok- thanks.

A couple of points from above.

- I don’t have the stock- I want a shop to cut and ship from their stock.
(Dc metro area- so we would just pick up if close)

- I am doing sourcing: the fabricator here will weld up.

- Tabbing?
That sounds perfect but sort of loops back to cut process accuracy.
I have never drawn up plate for being cut to that sort of assembly- clearance for tabs?

- The fabricator is a capable careful worker.
I talked over what jigging to provide for him and he seems confident that the interior plates will be enough to get him sorted.
I am willing to make any needed changes or order for jig components if it helps get this done.

- Joe public will view these parts installed at a posh place so they need to look ok.

- Cost is not the most important part here...

- These parts are basically tubes with 5”x8” interior dimension.
I could change whole process to use tube stock if available and the cut work could be done.
(This would knock site fabrication down to welding in the two 5”x8” plates and painting- great if possible.)
 
I would be going laser cutting over here, with 14 assy the costs will be very very cheap. over here theese days theres so much competition with laser cutting, this kinda thickness material is almost always cut that way, sure plasma may be a cheaper process, but the laser times so readily available and cheap its not saving much going plasma. Equally most of the bigger laser places have fully automated sheet handling and run lights out as std, hence whilst a more expensive process per say than plasma, the delivered cost of parts at your door price really has next to nothing in it. Not even sure of anyone here offering plasma on sub 20mm any more. Plasma around these parts generally sees most use on 1"+ thickness range were it really comes into its own. Though fiber lasers have made going thicker than 3/4" with laser nothing like as costly as it use to be in both machine and cutting costs.

I would get them cut in pickled and oiled material, the cost difference is slight and it saves a lot of time in cleaning pre welding - pre surface finish - paint. If you want water jet scale free edges, for just a little more cost and im talking single digit percentages more, some of my laser suppliers will cut upto 8mm on nitrogen, again pre weld prep and pre paint prep time savings can really make doing this pay off.

Cost wise im not sure, most of my stuffs a lot smaller and with a lot more smaller complex features cut in it. But i know your 7/8" holes cost me less than 10p each to get cut in 6mm plate as i have 2 parts one with and one without a hole, its almost always cheaper to get the holes cut than even remotely contemplate drilling them.

Most places will want DXF's of the profiles, so save thoes off, and email them out for quoting.
 
Makeing - cutting that out of tube is possible, but its a lot of hand work, may be easier to eliminate some of the welding by simply bending it up. Hand cutting and cleaning up this kinda stuff to a high std is doable, but IMHO won't generally come out as nice as properly bent and fabricated parts will.

If i was making those, i probaly would do it as a 2 channels, welded up on the middle of the long and short narrow sides. If it cleared my suppliers swan neck tooling i would bend the long deep channel side up and weld in just the short side. But im pretty certain it would not clear there tooling doing a 8x5 channel. were as a 8" with 2.5" leged channels will easily clear and make for a dead simple if long weld.

You could tag the bits in, honestly though im kinda not a fan of tagging, result never looks as clean and the corners of tagging are great stress rises - places to start cracks and the sharp corners also soon bump cutting times. Tagging kinda has its place, but really does not gain you much on simple stuff like this in these kinda qty's.
 
What is the weld joint? I like to have one piece cover no more than 1/2 of the edge of the other for an outside corner weld, like a small long fillet weld. (1/8"x1/4" to 3/16"x1/4") Minimal joint prep (none) if you size the parts to work like that.

The fabricator was talking 1/8” overlay on corners when we were talking 3/8” plate for this project.
Plate was sized down to 1/4 and I didn’t get from him what he wants carried over.
The dimensions above are for this rough drawing and don’t reflect that- so the actual side plates would be 8-1/4” width.
 
If i was making those, i probaly would do it as a 2 channels, welded up on the middle of the long and short narrow sides. If it cleared my suppliers swan neck tooling i would bend the long deep channel side up and weld in just the short side. But im pretty certain it would not clear there tooling doing a 8x5 channel. were as a 8" with 2.5" leged channels will easily clear and make for a dead simple if long weld.



Ok- I was pondering changing this to fabed with single bent channel with the 8” legs.
I will draw up as two channels and see about getting that quoted- that middle 5”x8” plate is load bearing so needs to be reached to weld up well- I was hoping for weld on top and bottom of plate- I will chat up the fabricator and see what he thinks.
 
I would laser cut it because I have my own laser. And as adama mentioned, HRPO sheet. Hot rolled can cut nice on a laser if you grind the scale off first, HRPO has no scale so cuts very clean with laser.
 








 
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