Laser Cutters and glue joints?

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by addicted2climbing, Sep 20, 2019.

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  1. Sep 20, 2019 #1

    addicted2climbing

    addicted2climbing

    addicted2climbing

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    Hello All,

    I have a need for a laser cutter for my home business and need a large one to cut some pelican case foam inserts as well as other items. There are many options online and I use to run a very large laser cutter at my work and loved it. Min size that will work for my needs is 600mm x 900mm cut area, but there are larger machines out there and I am beginning to consider a larger machine for aviation purposes as well. My one concern is when a piece of wood is cut the ends are charred a bit and curious how that would affect a wood joint on a wooden airframe. Would I need to sand the char away thus making a CNC router the preferred method? I also have plans for a APEV Demoichelle and have the wing done in Solidworks. If I step up to the next size machine it will have enough area to cut a full size rib. Also I can see myself using it to Laser etch text in an anodized panel with placards and such. I could also cut the few wood doublers required as well. Or etch placards that can be riveted or glued in place. Needless to say I always found a use for the machine at work.

    Oh and in regards to the Demoichelle, I never built it since finding the spars in the USA was impossible. I got a quote years ago to extrude them here as I already have an extrusion vendor who do some custom extrusions I designed for my camera mounts. I might consider doing a run of spars to support USA builders of the APEV airframes.

    Thoughts?
     
  2. Sep 20, 2019 #2

    FritzW

    FritzW

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    There's a thread on the HBA somewhere where gluing laser cut wood was discussed in depth, worth a search.

    Why not build a CNC machine that has a laser and a spindle/router. I've been thinking about putting a laser tube on my Y axis and using mirrors for the X axis.

    There's not a US available OTS extrusion that could be adapted to work on the APEV Demoichelle?

    Whatever you build/buy make it as big as you can. For me, the benefits of having a machine large enough to take a full sheet of ply have far outweighed the hassle of the large footprint.

    EDIT: a Lowrider2 with a laser AND a router would be pretty cool.
     
  3. Sep 20, 2019 #3

    addicted2climbing

    addicted2climbing

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    Hello Fritz,

    Thank you for the reply. A lowrider as mentioned would be awesome, however it might be a nightmare optically on a CO2 laser due to the sawdust. Would be perfect for a fiber laser but those are pricey. I will have a look at that thread. I actually plan to also build a full sheet router as well eventually. I recently acquired a 1400sq' hangar to build some film equipment I designed and have a contract for and will use it double duty for aviation stuff. I think there is room for both a router and dedicated laser cutter.

    As for the APEV spar there is nothing close enough. the problem is the spar is 2mm thick wall and closest is .093" and nobody had a die for 2" x 4" x .093". So you say why not just go with .125" that adds 1/3rd more weight to the spar and its a significant hit over 8 meters. Also on that size box spar most vendors did not want to go below .13" as well. I have been down this road before, why not redesign the spar to use a tube or make it from extruded L angle riveted together, but to stay true to plans want to keep it as stock as possible to design. I am fine with converting it from metric to SAE sized tubes but don't want to reinvent the entire airframe due to one spar issue.
     
  4. Sep 20, 2019 #4

    TFF

    TFF

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    In the RC world, the good builders usually sand the burn off. The out of the box assemblers don’t. I’m one in between. Sometimes yes some no. I would if I was gluing to it, if I was sitting in it after it was built.
     
  5. Sep 20, 2019 #5

    FritzW

    FritzW

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    So just wiping off the mirrors wouldn't work? My garage will forever be a dusty mess (dry climate, years of sawdust). Will a little dust on the mirror get fried by the laser and ruin it?

    EDIT: do you think those cheap chinese 1000mm (allegedly 60w) co2 lasers are even worth trying to mount on a very dusty CNC machine? The tube would be shielded but the beam would be exposed. ...that might just be an accident waiting to happen
     
    Last edited: Sep 20, 2019
  6. Sep 20, 2019 #6

    Jay Kempf

    Jay Kempf

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    I just happen to have a 1000mm x 600mm 100 watt laser cutter/engraver. You can cut thin wood with a higher wattage laser at higher speeds with an excess of nozzle air and maybe a revised (3d printed) nozzle and get almost no charring on the edges. These edges from what I can tell bond adequately with both epoxy and CA. Built a lot of liteply structures that way, tongue and groove. It will get through 1/2" plywood if I push it a bit. Does not cut carbon or glass laminates. Just burns the resin out. Very handy easy to use high tech tool.

    I started with a 700 x 500 laser approx 50 watt, sold it an upgraded. The whole thing landed in my shop hooked up was just under $4k. It has autofocus, huge powered Z table, 4th (rotary axis), real chiller for water cooling, compressor for nozzle, runs on 220v. I built an exhaust filter system and a castered trolly to mount it on and get it up to USA height to make it more useful.
     
  7. Sep 21, 2019 #7

    addicted2climbing

    addicted2climbing

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    Hello Jay,
    1000 x 600 is the exact size I am considering as well with a Reci 100 watt tube. I may also consider a 900 x 600 by a local seller with awesome local support. I had an even larger machine at my old job but now longer have access to it. There are many 1000 x 600 machines on Ebay. Can you give me a link to the one you bought, or possibly the seller you used. Also I do have 220V in the hangar but at the opposite end of the shop. I was planning to just get it in 110V. My hangar is free electricity so think its not a big issue but curious if I gain anything else running it at 220V. If needed I can run another 220V line to the other side.

    On my work machine I cut a lot of liteply for a few project for my wife's 2nd grade class and it worked great. Have you ever tried to cut 2" thick soft foam. Like what is in a Pelican waterproof case? I am thinking it would work better with a 4" optic.

    Marc
     
  8. Sep 21, 2019 #8

    addicted2climbing

    addicted2climbing

    addicted2climbing

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    Hello Fritz,

    With a misaligned mirror say due to being bumped it would be an accident waiting to happen. I think best is to have both a laser and a router. I need the laser more for ablating anodize to etch characters in aluminum but also will use it to cut pelican case foam and likely lots of other things. When I had one at work, I always found a use for the darn thing. Was an awesome tool to make kids projects for my wifes 2nd grade class. However if you did want to build your own over buying one, maybe design a mostly printed laser... go to www.lightobject.com

    Marc
     
  9. Sep 21, 2019 #9

    Jay Kempf

    Jay Kempf

    Jay Kempf

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    https://www.ebay.com/itm/100W-1060-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

    This is the one I bought from this supplier. Make sure they actually have it in stock in the USA before committing. I had to wait about 30 days after first contact to buy. That was the only snafu other than after I committed they shipped too fast and I had to scramble to get the fork truck and get it off the truck. Packaged perfectly, as described or better.

    Re, 220v: I didn't put a 220v line to the laser as it was on the wrong wall in the shop. I was a bit size limited in the hangar in the heated room I wanted to use so I just used the 110v-220v converter that they sent with the unit. I actually bought a higher capacity converter but so far the one they sent works fine. I built a castered base wider then the unit so I could put the chiller on the right end and mount the compressor and a multi switched power strip to control everything. I also put a wireless dongle on it to make it like a wireless printer. I do that to all machines I have so I can run them from anywhere. The thing is pretty impressive. RDworks software seems hokey at first and then as you learn it it will impress you. It just all works. All repair parts are readily available and can be gotten in days not weeks so worry not.
     
  10. Sep 21, 2019 #10

    Jay Kempf

    Jay Kempf

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    Hi Fritz,

    There are a few things about the laser that make it want to be in a dedicated housing. First the laser is where you can burn your arm hair off running along the gantry axis. Not sure how I know that... :) Second, some expensive, supposed American made lasers don't have nozzle air and don't have structure around their mirrors and they are always fouling and burning. It isn't that you can't clean the lens and laser mirrors, it's that the dust on the lens becomes a concentrator or a contaminant when the laser hits the fuzz and it burns resin on that then damages the lense. Anything that catches energy overheats a mirror or lens. The higher wattage the machine the more chance of damage. A nozzle air supply system also cools the lens and mirror in that head. The way it works is the beam coming out of the CO2 tube is about #2 pencil size. It stays that size and invisible mostly until it hits the last mirror and heads straight down into the cutting head lens. That is where it becomes really dangerous and there is a lot of energy being focused.

    One an open bed CNC machine I see the thing bashing the lenses out from time to time and I also see the operator getting singed or even eye damage. Best to be in sheet metal with some sort of filtered windows.
     
  11. Sep 22, 2019 #11

    addicted2climbing

    addicted2climbing

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    Totally Agree. when the laser directing mirrors go out of alignment its a bit of a pain to get everything back to normal. If they were exposed it would happen often and could point at you without knowing.
     
  12. Sep 22, 2019 #12

    FritzW

    FritzW

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    I've thought a little about eye protection (curtains, shields, etc.) but I hadn't considered the possibility of accidentally bumping a mirror and shooting a laser beam across the garage. Even with an unfocused beam it invokes images from bad sci-fi movies.
     
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  13. Sep 22, 2019 #13

    Bill-Higdon

    Bill-Higdon

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  14. Sep 22, 2019 #14

    FritzW

    FritzW

    FritzW

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    I was thinking more like the scene in Raiders of the Lost Ark when they open the Ark.
     
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  15. Sep 22, 2019 #15

    Jay Kempf

    Jay Kempf

    Jay Kempf

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    No Mr. Bond, I expect you to DIE! <maniacal laughter>
     

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