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Panel Cut: Laser or Water Jet

RudiGreyling

RudiGreyling

Well Known Member
Hi Guys,

My first time to attempt to cut a panel, Drawing is ready done in CAD.

1) Which is better Laser or Water Jet?
2) What is the cutting width for tolerances?
3) Looking and my image (Green is cut lines) any other tips?

Thanks in advance,
Regards
Rudi
PS: Feel free to send me a private message if you don't want to openly discuss.
rudi_cad_panel.gif
 
Rudy, could I get a copy of your cad file? It's been on my list of things to do, but it would be a great help to have the contour dimensions as a place to start.

chappyd-at-charter.net

I've seen water jet stuff cut, most is ok, a little rough on the finish. Could be cleaned up easily with a file. Have no experience with lasar cut parts.
 
Dave check your email..if you only just want to panel profile, All of them are available from Van's web site, just remember the bottom 1" is not use-able since it is bend 90degrees.
 
I had mine cut with a waterjet & it worked great. The shop had me draw the lines exactly where I wanted the cuts & the accounted for the width of the cut. Laser or water should work fine. The waterjet cut edge that looked sandblasted (i.e. not shiny) & required virtually no work prior to paint & installation.

Here's what mine looks like:
901jh_panel_3_frontview.jpg


If it helps anyone, my CAD files are here: http://www.thedukes.org/rv/20050526.html
 
You want to use water jet

Water jet will make a cleaner cut. It's difficult to eliminate the build-up of dross on the exit side of laser cuts in aluminum. Water jet leaves a clean cut edge because the process doesn't melt the material.
 
I had mine cut by the same guys that cut Mick's. The slag on the back looked bad but it only took me about 5 minutes to clean it up and it came out great. The tolerances were great and all the holes lined up perfectly. I've never seen water jet cutting so I don't know how they compare, but I would do the laser cut again if I needed a new panel.
 
Mickey, your results do look bad, but they by no means are representative of what laser cutting can do. I've been involved in laser cutting for more than a decade now, and it is all about which laser they use and how they set it up.

One area of set up that can mess things up is if they don't take enough time to get the tool offset (accounting for the width, or kerf) of the laser for your material. This means holes will be too large or too small. Another is if they don't do the initial "pop through" burn in the middle of the field of material to be removed. Instead, lazy guys will just pop through along the final edge, making a big splatter area.

Don't know much about water jet cutting, but similar issues may be present.

There are guys in our area who have had their panels cnc machined, and that may be the best overall way to go, with the most consistency and potentially lowest cost. They will use any cleanly done cad file to make it, and the tolerances will be very good.

But, regardless of which method used, be sure to discuss with the shop exactly what your requirements are.
 
I have cut several with water jet and you can clean them up quickly with a 1 inch dia. cut and polish 3-M wheel for the round holes.
 
Saying one is better than the other is king of like tipup/slider, nosewheel/taildragger.

We've had panels cut by every imaginable method out there, and short of a few other shops I think we probably cut more than most people have/will.

We've tried everything including water jet, Laser, turrent punch, cnc mill/router (which do probably the best job), and of course cutting by hand.

What do we use now? We have them cut by a shop that has a brand spanking new laser/turret punch combo machine. The laser is super high power (which is imperative for aluminum - lower power lasers result in lots of kerf and a result like Rudi's when used on Aluminum). A high end laser will have a tolerance of less than .005" and can be accounted for in the CAD/CAM. Waterjets can be as good, but in general they leave just a little bit dirtier cut. Not bad, and as others have said it can be cleaned up easily, but the panels we're getting cut now are literally good enough to pull out and use!

It totally depends on the person running the machine, the power of the machine, and a few other variables. Each one done improperly will be poor. Each one done properly with good equipment will be great.

Just my 2 cents as usual!

Cheers,
Stein
 
Wow those laser cut pictures are MESSED UP! There was something wrong with that guys laser. I've done several panels and all were clean as whistle as they came off the laser table. All were accurate to within .001" and fit was perfect.

I guess it warrants seeing a sample of the laser cutters work before haning him any dough.

Bob
 
The latest lasers beat the waterjet hands down. They have the optics pressurized and use an argon shield around the head of the laser. I have a friend that has both a waterjet and a laser in his shop, since he got the new laser last year the waterjet is only used for heavy jobs. Right now the laser is set up for a job making brackets for RR jet engines cutting inconel that's .250 thick with less than .001 kerf. Inconel is tough stuff to cut and the laser zips thru it like butter. Aluminum is no less of cake job, and does it perfectly with no burn marks. The really cool thing that can be done with this particular laser is that it has a rotary indexer, and can cut profiles on tubing, even on square tubing. I had my instrument panel and a backing panel cut on this laser, which I originally modelled in Solidworks. Solidworks will take into account the k-factor of the sheet metal bend at the bottom and will compensate in the flattened state so the panel has the correct dimensions once bent. It takes all of maybe five minutes to load my Solidworks model into the machine as an exported .dwg, and maybe ten minutes to get it set up and cut. When I did my panel it actually took two passes with the laser, because the bend had to be made at the bottom before the large areas were cut out. The large cutouts at the bottom are for frontpanelexpress switch panels and a Garmin GPS III.

 
The laser cutting option has been and education, at least for me...

Problem 1) The kit comes with a blank panel cut to the correct profile and correct mounting screw holes. The laser cutters can't align an existing cut plate with accuracy, (unless they have very expensive machines which the one of guys don't have, the expensive guys want you to cut at least 100 to talk to you, in South Africa at least) so I had to buy a new flat sheet of Alclad 2024-t3 to be cut from scratch.

Problem 2) The kit supplied panel come with a 90 bend with a +/- 10mm radius on the bottom to stiffen up the panel. If you cut the instrument holes to close to this bend line and try to bend it afterwards these holes warp, defeating the object of laser cutting. Finding a 10mm radius bender is another story in South Africa. So I will laser cut my holes close to the bottom and then rivet a reinforcing L Alu angle along the bottom and nobody will know any better! There is already a L Alu angle along to top to stiffen the top, so I will repeat it on the bottom!

Then I had a TEST sample of my panel cut by 'Laser Options' in SA. The initial cut is just in cheap soft aluminium.
rv_panel_01.jpg


Then I started trail fitting some instruments in the TEST cut to confirm my measurements.
rv_panel_02.jpg


I had to make a couple of changes and will get the FINAL cut done this week.
One is the MAP box in the tip-up is lower down!!! Check your top clearances on the TIP up canopies!

Groetnis,
Rudi
 
CNC Bridgeport does very nicely

Here's a shot doing a panel on our CNC mill. Using a .125" 2-flute end mill we get a near mirror finish on the inside edges of the cut-outs. And of course accuracy is +/- less than .001.

instpanel_old04.jpg
 
Questions...

Bill Wightman said:
Here's a shot doing a panel on our CNC mill. Using a .125" 2-flute end mill we get a near mirror finish on the inside edges of the cut-outs. And of course accuracy is +/- less than .001.
......[/IMG]
Click to expand...

Bill... what are all those screw heads doing?

Did you have to come up with some sort of solid jig to hold the panel down on the mill?

For the laser/water jet guys.... how is the panel held down on the machine? ...are any extra jigs needed?

gil A
 
az_gila said:
what are all those screw heads doing?
Click to expand...

Gil,

Not trying to answer for Bill, but the screws hold the "cut out" pieces from shifting as the cutter completes each hole and either a). getting shot across the room or b). interfering with the cutter blade and making horrible, expensive noises and possibly ruining the panel. Some mills have a vacuum table underneath that holds everything in place, but perhaps his mill doesn't have one. I'm sure Bill will elaborate on the other points.

I've been cutting wood with a friend's CNC mill, and it sure is fun! Maybe I'll have to try doing it with metal now. :D
 
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Another option is punching. if you have access to a larger sheet metal shop they may have a CNC sheetmetal punch. It does a super clean job of punching.
 
az_gila said:
Bill... what are all those screw heads doing?

Did you have to come up with some sort of solid jig to hold the panel down on the mill?

For the laser/water jet guys.... how is the panel held down on the machine? ...are any extra jigs needed?

gil A
Click to expand...

Hi Gill,

For my laser cut they just put some heavy steel weights (off cuts pieces) around the edge to ensure it doesnt buckle warp temporary while cutting and heated a bit and moving away from the table.
 
Unconventional hold-downs

Gil:
The panel is screwed to a piece of 3/4" particle board as a way of holding the work in place. Buck is correct in assuming that we used screws in the center of each hole to hold the waste piece from chattering against the delicate .125" mill after the cut is finished.

Buck:
No we don't have a vacuum table on this machine. Its a standard 48" CNC Bridgeport and metal cutting is its primary job, although I did make some fancy wooden birdhouses on it once :p For metal cutting, the work must be held pretty tightly or it will move. We use wood sometimes as a way of holding sheetmetal work.

Here's a pic of James screwing the panel blank down:

Panel3%2012.jpg
 
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Complete plans in Solidworks or AutoCAD

Does anyone have any of the RV planes complete plans in AutoCAD or Solidworks?
I purchased a complete set of plans for an RV4 and started building the parts in Solidworks so I can water jet cut them and I am finding a load of errors in the drawings. I am hoping to find someone who has already been through this so I am not guessing what the corrections are.
Thanks,
Del:D
 
+1 for a saber saw, drills, and files to finish. Have a hard time seeing why it has to be complicated.

 
I cut my panel by hand and it was one of the most enjoyable projects that I have done on the -7. Mine is all steam gage (no square holes). I spent a lot of time on planning, layout and practice hole cutting.
 
Water or Laser

Used a water jet to cut mine. Holes come out with a little rough edge but it cleans up quickly and easily with scotchbrite. Regardless of which you choose, you will need to do this anyway.

Size the screw holes just undersize and finish drill to final size.

Haven't used laser, but you won't be disappointed with waterjet provided you have a good shop.

Keith
355RV
RV9A
 
Cheaper option -plasma

I use plasma table to cut my panels. It's very cheap but there is a lot of cleanup especially if the settings aren't close for alum. If time is money, then a good laser is hard to beat.
 
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