NEJE Diode laser success with Hobby Lobby FB

[hunterdave99]

After a good bit of experimenting, I finally had success with my diode laser and Hobby Lobby black foam board (black paper and a black core). My laser is the large Neje 3 Max with the A40640 laser head. I clean up the plans with Inkscape and burn with Lightburn software. The lightburn auto detects the different colors and sets up a different cut for each color. For a full cut I go 3 passes, 100% power, at 6000mm/min speed. For a score cut I go 2 passes at 70% power, same speed. For a shallow score (like a blue line on a wing) I go 1 pass at 50% power, same speed. If I just want to cut the paper (like for peeling it) I go 1 pass at 25% power, same speed. Finally, if I just want to leave a reference mark on the paper without cutting it I go 1 pass at 15% power, same speed. By keeping the speed real high, it prevents the laser from lingering and reduces melting. It only takes a couple minutes for a full sheet. All cuts are with air assist.
Cost: the hobby lobby foam is $2.99 per sheet but it is worth the cost for the convenience.
Weight: it is a little heavier. I weighed 5 sheets each of Hobby Lobby black, Dollar Tree black with white core, and regular DTFB. The DT black weighed 103.4 grams. The regular DTFB weighed 112 grams. The Hobby Lobby black weighed 158.2 grams. I made up some of the weight by adding holes to internal sheets such as wing spars and doublers (see pictures).
Strength: this HL foam seems a little stronger. The paper adhesive seems a little stronger as well. It also takes spray paint as long as you go multiple thin coats. See the picture of the canopy that I painted. Blue painters tape sealed well and was easy to peel off.
For my first plane I tried Airc-Pirate's 50mm EDF Goshawk. Overall it turned out pretty good. I call it the "Bat Jet" I will have to wait till spring for the maiden.
Here are quite a few pics.

 

[Old and rusty]

Wow, took a quick spin around the Internet today looking at foam board to see some of the other brands available...the vast variety, as well as the price differences were somewhat staggering. So far I've only used the Dollar Tree Adams foam board (white), but lately have been wondering if some brands were superior to others. Went from the Adams DTFB all the way to the 16.00 (on sale) per sheet Gatorboard, (which, hands down looked the best to me) and pretty much everything else in between. At one time had thought the different brands were all actually the same just carrying different labels...but couldn't have been more wrong about that.
I think I'll go middle of the road price wise next time and check out some of the Hobby Lobby black foam board at 2.99 per sheet and see how that goes.

 

[Mr NCT]

Wow, took a quick spin around the Internet today looking at foam board to see some of the other brands available...the vast variety, as well as the price differences were somewhat staggering. So far I've only used the Dollar Tree Adams foam board (white), but lately have been wondering if some brands were superior to others. Went from the Adams DTFB all the way to the 16.00 (on sale) per sheet Gatorboard, (which, hands down looked the best to me) and pretty much everything else in between. At one time had thought the different brands were all actually the same just carrying different labels...but couldn't have been more wrong about that.
I think I'll go middle of the road price wise next time and check out some of the Hobby Lobby black foam board at 2.99 per sheet and see how that goes.

I used the Hobby Lobby board on my first simple cub because you can get different colors. I didn't realize a the time the weight difference, the Hobby Lobby is almost twice as heavy per sheet. It didn't increase the overall weight by double but it did make it tail heavy.

 

[Old and rusty]

I used the Hobby Lobby board on my first simple cub because you can get different colors. I didn't realize a the time the weight difference, the Hobby Lobby is almost twice as heavy per sheet. It didn't increase the overall weight by double but it did make it tail heavy.

View attachment 244022 View attachment 244023 View attachment 244024

Like the idea of different colors...guess it would depend on the type of paint, but do you think the plane constructed of the HL heavier foam board would weigh more than a fully painted plane made with the Adams foam board? Did you use clear tape over the colored covering? Is the HL foam board much sturdier...I appreciate the info.
...the cub looks great, by the way
...

 

[Mr NCT]

Yes, the HL board plane was heavier than the DT painted plane.
Didn't use clear tape on the HL, somewhat sturdier.
The simple Cub is prone to tip stalls if you don't keep your speed up in turns and my first two (second was DT painted) died in dramatic manor this way. I skinned my third one with printed paper skins and finally learned to fly it.

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[TOMinSATX]

Found this thread looking for some leads on cutting foam for a build I'm busy designing parts and molds for. The refs in the lead post gave me some answers that I tested this evening. I've got a 12.5watt Creality Falcon 2 laser cutter and like others I've messed with cutting different foam boards including one experiment to black paint (water based) the Dollar Tree black papered white foam after stripping the paper. The result was a very messy cut through, at any power and speed settings. This last week I bought two sheets of the Hobby Lobby black foam and spent more that a little time stripping paper. I'll be doing some plug framing with the paper on, but the end product will not have paper so that's why the effort.

I'm attaching some photos of my second test run looking for the best speed and clean cuts. The first picture shows the results from the front and the second from the back after taping the pieces together and flipping over left to right. The results indicate that I can use 6000 mm/min at 60-75% with two passes and get a clean cut. I'm guessing I can increase the speed some and still be good. My measurements on the stripped foam get a .165"/4.20mm thickness. I'll be doing an accurate weight test later. I'm hoping that this information will help some others. BTW I do have a 300CFM exhaust system on the laser cutter hood that vents outside the garage.


Added Notes:

I weighed a panel of the HL foam that is 15.15" x 15.15" (229.5 SqIn)
(This was sized to fit my Laser cut limits)
and got these results..
60.61 grams with 2 sides w/paper
44.52 grams with 1 side w/paper.
28.42 grams with no paper.

In order to get a best assumption on weights for future estimates...
Actual weight measured on a 20"x30" piece was 158.4 grams or 0.264 g/SqIn.
Based on sample weights:
Full sheet (20x30) should weigh
With Paper = 158.4g
Subtract Paper = 84.1g
Net Weight = 74.3g (0.1238 g/SqIn)

 

[Dan-O]

I know this is an older post but really intrigued by the ability to cut black foam with a diode laser. I've been using a cnc and the smallest end mill I can find but the cuts are kind of sloppy. Very frayed and, well, just not great. I really dig making foamies and while a C02 laser would be great I would need a huge one and cost way more than I could swing. But...while it would not be cheap a grand for a Neje with the expansion kit might work for me. Hmmmm.

 

[LitterBug]

Black foam should be easy even with lower power settings. The white foam is a problem as it disperses the UV energy rather than absorbing it and burning. I have been able to do white foam with a 10W diode laser under ideal conditions. Speed, Focus, air-assist level, etc. need to be spot on. It helps some starting with black paper on white foam since the black paper heats up more than white paper.

I have been using my cutter just to mark the foamboard and finishing with a knife. The settings I use etch the paper and foam enough that they guide the knife very well. I haven't taken the time to expand my cutter to do a whole sheet yet, so I have been doing smaller builds and parts that I can get on my 400x400 bed.

 

[Dan-O]

Appreciate the reply. I have a small 15 watt diode laser that I bought several years ago and haven't tried it on foam. It has a small foot print which would limit a lot of airplane stuff. But just to test it might be interesting. I do have a very small drag knife that I made an attachment for to run on the cnc. Mainly used that set up to cut vinyl adhesive lettering. The CNC has a pretty large cut area of about 4'x4'. It might make more sense to use the small drag knife to score and mark the foam then follow up with a knife.

 

[Mr Man]

I’ve been cutting black foam with a 20w laser, but I don’t use the full 20w. Here’s my thread: https://forum.flitetest.com/index.php?threads/cutting-foam-with-a-diode-laser.79245/

 

[Dan-O]

Cool. I'll check it out.

 

[Dan-O]

Well, I ordered the Neje Max 4 with the expansion kit last night. The little Ortur hobby diode laser I bought five years ago has been fun to play with but it's pretty weak and has a small cutting area. Among many other things I want to use it for I also want to cut foam for some rc planes and am fine with using black foam board. Or with etching the white and then finishing up with a knife. It would be really nice if a company made foam board with white sides and dark foam! I'll share how it all goes. First order of business will be to build an enclosure. I've made them before for several CNCs as well as the little Ortur laser but this one I want to be a little better.

 

[Dan-O]

Oh, sweet. Hmmm, wonder if this would work. White sides, black foam...

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[Mr Man]

Oh, sweet. Hmmm, wonder if this would work. White sides, black foam...

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Looks like it would work…. I wonder how much it costs though 🤔

 

[Bricks]

Looks like it would work…. I wonder how much it costs though 🤔

Not cheap

12PACK Black Foam Board 24x36×3/16 inches,5MM Poster Board $69.99 $5.83 sheet.​

 

[Dan-O]

Yeah, a lot more than the white but might be worth a try.

 

[Dan-O]

Well… first test cuts are super promising! Finally got the Neje Max4 set up and enclosed and did a little testing tonight. All kinds of possibilities with this set up. Used Dollar Tree black foam. I need to get some magnets to hep hold sown the boards.

 

[Mr Man]

Nice! Mine can cut though black just as well! Except it's super inaccurate in the y axis...

 

[Dan-O]

Thanks. These circles seem extremely round, I drew them up at 30mm and they measured around 29.8 with calipers. Plenty good for the goofy stuff I tinker with. I've been checking all the local Dollar Tree and Dollar General stores around here for months. None had the black Adams foam board. And then a new huge Dollar Tree just opened up (next to a new-ish Harbor Freight - that I also spend probably too much time in) so I dropped in today to check. Didn't see any foam board of any color on the shelf. I asked a worker there and she said she would see if they had any in the back but she said she doubted it. She came back with a box of the white - I asked if they had the black and she said yep. So... I have a very local source for it.

 

[Mr Man]

Thanks. These circles seem extremely round, I drew them up at 30mm and they measured around 29.8 with calipers. Plenty good for the goofy stuff I tinker with. I've been checking all the local Dollar Tree and Dollar General stores around here for months. None had the black Adams foam board. And then a new huge Dollar Tree just opened up (next to a new-ish Harbor Freight - that I also spend probably too much time in) so I dropped in today to check. Didn't see any foam board of any color on the shelf. I asked a worker there and she said she would see if they had any in the back but she said she doubted it. She came back with a box of the white - I asked if they had the black and she said yep. So... I have a very local source for it.

Wow, that’s insanely accurate! Especially since the foam and paper probably melted back a bit