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Laser cut 6061-T6 ? or use a router ???

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Pops

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Thanks guys, still amazed at the skills that are still out there, Pops love the pic, Plan is to develop the LMA into a Kitfox type STOL kit, will be making an alloy wing, then later a CrMo Airframe, so bits can be swapped around, Found some guys on YT recently fitting Cessna 172 wings onto Super Cubs, they fly really well apparently !!! Hope to start cutting metal over the winter, when it's too cold to bond the current airframe.
Back in 1995 I designed a 4130 steel tube 4 seat fuselage and with the used of C-172/175 wings and straight tails, tail dragger with a Lyc-360. Then the 4 seat Bearhawk came out and decided to build it. Sold all of my Cessna parts.
 

Iwerk

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For the Zenair CH-701 scratch build,
I'm using an OLFA laminate knife to cut the aluminum.

Here's a youtube video that shows how it's done.
 

Rik-

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It depends, for my applications it depends upon the thickness of the material.

Laser is good on aluminum as long as the aluminum is not thick as thick aluminum will slag when laser cut.

Water jet will leave no slag but on thick or hardened material it will not cut 90 degree, rather there will be some draft angle to the cut. Also, there will be a "sandblast zone" with water jet as the media will rough the area around the cut a little. If ultimate cosmetics are a concern then have the aluminum covered with a protective film prior to cutting.

Router waste material as you loose the diameter of the cutter in the processor so a tight nest does not work well. Small radius cuts might be limited as the diameter of the router bit being used might be to large.

Also depends upon what is near you. Waterjet is really common so finding a laser locally might not be an option regardless. Even harder to find a router table cutter in some areas.
 

ScaleBirdsScott

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Regarding routers and waste material, In reality I've had the best luck with using a 1/8" single-flute carbide on the router. 1/8" of kerf is not much. And when needed I've been able to get parts nested pretty dang tight, figure .150 is plenty of gap between parts. I am hard pressed to find a part where I need tighter corners than a .080 inside radius. (Technically you can get down to a 1/16"R of course but always good to avoid sharp corners in the toolpath and let it get even a tiny sweep in the corners.)

I've seen a number of kits, including some well known ones, shown using laser cut panels for the skins and such. For such parts it doesn't seem HAZ has been found to be a major issue. On spars, I'd consider the ramifications differently.
 

flywheel1935

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It depends, for my applications it depends upon the thickness of the material.

Laser is good on aluminum as long as the aluminum is not thick as thick aluminum will slag when laser cut.

Water jet will leave no slag but on thick or hardened material it will not cut 90 degree, rather there will be some draft angle to the cut. Also, there will be a "sandblast zone" with water jet as the media will rough the area around the cut a little. If ultimate cosmetics are a concern then have the aluminum covered with a protective film prior to cutting.

Router waste material as you loose the diameter of the cutter in the processor so a tight nest does not work well. Small radius cuts might be limited as the diameter of the router bit being used might be to large.

Also depends upon what is near you. Waterjet is really common so finding a laser locally might not be an option regardless. Even harder to find a router table cutter in some areas.
Within a 10 mile radius of my home is all the available cutting options, its more a case of cutting the spars so I can move them to the Hangar, as a 4m (13+ft) x 4 ft sheet would be difficult to transport in one piece,
 

Jay Kempf

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Regarding routers and waste material, In reality I've had the best luck with using a 1/8" single-flute carbide on the router. 1/8" of kerf is not much. And when needed I've been able to get parts nested pretty dang tight, figure .150 is plenty of gap between parts. I am hard pressed to find a part where I need tighter corners than a .080 inside radius. (Technically you can get down to a 1/16"R of course but always good to avoid sharp corners in the toolpath and let it get even a tiny sweep in the corners.)

I've seen a number of kits, including some well known ones, shown using laser cut panels for the skins and such. For such parts it doesn't seem HAZ has been found to be a major issue. On spars, I'd consider the ramifications differently.
Are you cutting aluminum dry? Single pass on depth? What's the thickest aluminum you have cut? Just fishing for a real data point. Speeds and feeds?
 

autoreply

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Waterjet can give a perfect finish on alu/steel, just slow waaaaay down. I've seen 200 mm steel plate (that's 8") that would've only needed light sanding for a perfect finish. More $$$ than lasercut though because you have to go slow.
 

ScaleBirdsScott

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Are you cutting aluminum dry? Single pass on depth? What's the thickest aluminum you have cut? Just fishing for a real data point. Speeds and feeds?
I really should make a blog post or something about this as I've helped a few people out. But basic rules of thumb for me cutting aluminum 6061-T6 on a CNC router using a 2.2kw spindle, and not having like, the most heavy duty of machines, is roughly as follows:

1/8 single flue carbide (name brand endmills only) dry cut, materials up to .032 cut at full depth thru with a little extra, usually spec a .040-.050 DOC to account for any variations in spoilboard level. Anything over .032 thick, take .025 or less DOC passes, with one pass "above" and one pass "below" the material, again to account for variations in spoilboard level. (If your machine has a fresh surface or a more stable spoilboard than, say, MDF, you can dial that in better.) Moving in the 30ipm range.

If I'm cutting thicker materials (.125+) I will often be standing by with a can of WD-40 and once there's a pass or two around the perimiter I'll give the occasional shot into the channel to help clear chips and add some lubricity. If cutting very thick parts with a small perimiter, heat buildup can be an issue so more WD, or cut halfway down, let it cool for a bit, then resume the cut. Anything to prevent chipweld.

I've cut a little bit of 2024 as well. It is harder, so maybe do about 80% of the above as a starting point.

A heavier duty machine can probably do about 150% the above numbers as a starting point, but mostly in that it can accurately push through a heavier cut. It needs to be able to throw good chip to move at the higher speeds otherwise the heat buildup is still the #1 issue I've run into.
 

Jay Kempf

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Thanks,

Can you post a picture of the bit you are using? My machine is super rigid. I am installing a 2.2kw water cooled spindle now. Was using a 1.5kw water cooled up til now. Mostly I have been carving foam molds. I'll do some experiments with aluminum dry. I have a small compressor and some nozzles for misting if I need to.

And I have been following your progress and I love the innovation and roll the sleeves up approaches. Kudos.
 

pictsidhe

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We use Castle Thrust at work as spray cutting lube. Seems much better than WD40 for the task. Somewhat thicker, so sticks more. I like it a lot. It's 'free', too!
I like to drill steel and cast iron with a little smoke. That's fairly fast, but not cooking the bit. No smoke for aluminium.
 

ScaleBirdsScott

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We use Castle Thrust at work as spray cutting lube. Seems much better than WD40 for the task. Somewhat thicker, so sticks more. I like it a lot. It's 'free', too!
Hard to beat free if it works! I'd like to give that stuff a shot tho. After using about 2 cans of WD40 in a day to remove blue rust inhibitor from the newest additions to the shop, I'm by no means enamored with the stuff.

I'll do some experiments with aluminum dry. I have a small compressor and some nozzles for misting if I need to.
An air blast or lube mist would not hurt at all with cutting. Should enable a bit more aggressive cut in theory. For sure some airblast can help if you are doing thicker parts with multiple thin DOC passes for chip evac from the channels. The lube mist just has to be such that you aren't getting a lot of lube into the spoilboard ideally so figure out the right amounts or maybe turn it off when running final layers?

And I have been following your progress and I love the innovation and roll the sleeves up approaches. Kudos.
Thanks!
 

pictsidhe

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Thrust is a bit sticky and messy. That's no problem. The other aerosol always in my cart is 'shop solv'! We also have chlorinated brake cleaner, but that stuff's a bit too nasty for me to want to use much. Mostly for a final clean before threadlocking inserts.
 

Rik-

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I really should make a blog post or something about this as I've helped a few people out. But basic rules of thumb for me cutting aluminum 6061-T6 on a CNC router using a 2.2kw spindle, and not having like, the most heavy duty of machines, is roughly as follows:

1/8 single flue carbide (name brand endmills only) dry cut, materials up to .032 cut at full depth thru with a little extra, usually spec a .040-.050 DOC to account for any variations in spoilboard level. Anything over .032 thick, take .025 or less DOC passes, with one pass "above" and one pass "below" the material, again to account for variations in spoilboard level. (If your machine has a fresh surface or a more stable spoilboard than, say, MDF, you can dial that in better.) Moving in the 30ipm range.

If I'm cutting thicker materials (.125+) I will often be standing by with a can of WD-40 and once there's a pass or two around the perimiter I'll give the occasional shot into the channel to help clear chips and add some lubricity. If cutting very thick parts with a small perimiter, heat buildup can be an issue so more WD, or cut halfway down, let it cool for a bit, then resume the cut. Anything to prevent chipweld.

I've cut a little bit of 2024 as well. It is harder, so maybe do about 80% of the above as a starting point.

A heavier duty machine can probably do about 150% the above numbers as a starting point, but mostly in that it can accurately push through a heavier cut. It needs to be able to throw good chip to move at the higher speeds otherwise the heat buildup is still the #1 issue I've run into.
What is your IPM? If paying a company to do the job, this can raise the pricing if to low of IPM.
 

Rik-

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Within a 10 mile radius of my home is all the available cutting options, its more a case of cutting the spars so I can move them to the Hangar, as a 4m (13+ft) x 4 ft sheet would be difficult to transport in one piece,
You have your material delivered straight to the company cutting the parts out for you. Then, ideally, you arrive after the job is finished and transport the smaller parts back to your project.
 

Armilite

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AMES, IA USA
Hi Guys just need a basic lead ref cutting sheet 6061-T6 (For a wing spar) is laser cutting or routing the best way or waterjet , as these are the options open to me from local subcontractors ???? spar length a 13 ft long
==========================

You can cut 6061 Sheet/Plate on a Table Saw with the right Blade.
 

Keyepitts

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Joliet, Il USA
For 1/16” and thinner sheet, you can also use handheld electric shears. For ribs and stuff like that, I’ll use my Milwaukee shears to rough the blank out, then use an mdf template and a router to finish to final shape. They could also be used for a spar blank, again, I would leave it about 1/4” oversized, then trim close to the final edge with hand snips, leaving the last 1/16” or so to trim with a vixen file. Sounds like a lot of work, but if you only have a few to do, it goes pretty fast.
 

pfarber

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Laser edges have a pretty significant heat effected zone. Not sure you want to go there for anything critical like a spar. Water jet isn't as bad as people make it out to be a little light sanding/polishing and you have nice parts. No heat effected zone. Cheaper and real easy to program, just a DXF. Router really nice if you have one yourself and you know what you are doing with aluminum takes some experimenting. Harder to learn to program. Probably more expensive than water jet.
Not any more. New fiber lasers cut that down to a few thou (definitely less than .005) which is little more than a pass with a file or wheel.

Not sure why people are all upset about super clean edges.. ever see what a pair of snips can to do aluminum?
 

Gareth

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I had all my 6061 t6 spar sheet watercut sharp edges but 80 grit sandpaper on a hand polisher works fine it was 2.3mm thick for main web spars and 1.6mm for rear spars easy as
 

robertl

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Heath Springs, S.C. USA
Cut all the ribs for a CH-701 with a router and used a flapper wheel on a drill motor to debur and smooth the edges. Worked great ! I chucked the flapper wheel in the drill press and held a scrap piece of aluminum to it in two places to cut groove, then debured the ribs.
Bob
 
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