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Cutting foam sheets... with a needle!

Chuppster

Well-known member
Alright, adopted the vacuum bed, and I'm a fan so far! Thank you @TEAJR66 for sharing your build! I opted for a 2" grid, with 1/8" holes in the middle and 1/4" holes on the outside and it works with a small floor vac we don't use anymore. My table that I salvaged for this made it particularly easy to make an airbox, only needed a piece of luan to cover the bottom of the frame. It's not uber-airtight but it works!

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Pointed bullets enter, do lesser damage, and then exit... leaving minimal debris and a smaller exit wound.
Thought I'd have a wee look to see what folks are currently getting up to and saw your neat analogy David - never a truer word said when it comes to cutting foam :)
It was Miles' video I saw, and what struck me was how useful it is to read (plod through maybe :)) previous posts for generic ideas to problems. It's always something to keep in mind too, 'don't overthunk it' :) What might seem an exceptionally great engineering solution can regularly be ripped apart by someone with zero previous knowledge (read engineering baggage) just actually doing what is necessary with zero frills :)
One thing I do keep coming back to is to simply use TWO bearings with a small 0.5mm 'ish washer between to hold the needle - the gap formed by the washer allows the piano wire wrap to sit neatly between. I'm still using the SAME piece of piano wire as I started with (how many years ago is that ??) - it's never popped off and it only has one turn. I've lost count of the number of cuts it's made - I will own up and say that it's always been depron and not FT Foamboard though.
I didn't watch Miles' video to the end and failed to see what software solution he used for servo operation - I still just use a wee hand cobbled post processor on my Mac to rip out the Z commands and replace with servo commands for my 3D printer driver setup - it just works - and if it aint broke :) I did have to replace the servo though - an el cheapo 9g hobbyking digital thing which was causing brownouts on the system - pulling down the 5V rail. I replaced it with a very expensive and reliable HXT900 analogue item - I'm sure it cost a whopping 2.65 GBP - around 3.34 USD :)
I DID make some changes to my machine last week, removed the home switches (they can be a PITA with noise on large cable runs - even with filters) - I just used the switch blocks as mechanical stops and force the stage mandraulically (with steppers off :) ) to the hard stops before starting another file.
Neil
 
Further adventures in laser-engraving…

First, I want to thank a few folks over on the V1Engineering forum. Victor for his really neat ImageToGcode program... and his help getting me up and running with the latest version. Also, I’ve also learned some pretty interesting stuff playing with Aaryn’s Laser Calibration Power vs Feedrate “thing”. And thanks go to Jamie for his really neat and handy Test Pattern Generator. I’ve been playing with all of these over the past few days and it’s been very interesting. I’ve learned a lot… but, an old man, I’m sure I’ll have opportunities to learn it all over again — several times — in future adventures. 😉

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First, a confirmation… definitely run from SD card whenever possible. Sending the gcodes across USB will have undesired and discernable effect on the image being engraved. These photos show the same files being run twice — once from Octoprint/Pi over USB and the other using LCD/SD — and show dramatically different results…

our old “shades of gray”…

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and Aaryn’s Laser Calibration Power vs Feedrate gcode (unaltered)…

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Then, using info gleaned from Aaryn’s gcode, I was able to get reasonably good images using laser powers, ranging from full down to 1/6 (17%), at various speeds and resolution with Victor’s ImageToGcode.

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Finally, I decided to try hand-editing gcode generated with Jamie's Test Pattern Generator... for laser vs. pen/marker. I had to brush up on my regular expression “skills” but managed to get Jamie’s code running with laser… and then used that to fine tune the steps/mm on my FoamRipper’s X and Y axes.

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A little parallax from the thickness of the ruler and the position of the camera but it’s dead on now…

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I’ll stop here… for fear of making a bigger mess of this post. But I wanted to get these posted before I forgot everything.

— David
 

Wildthing

Well-known member
Further adventures in laser-engraving…

First, I want to thank a few folks over on the V1Engineering forum. Victor for his really neat ImageToGcode program... and his help getting me up and running with the latest version. Also, I’ve also learned some pretty interesting stuff playing with Aaryn’s Laser Calibration Power vs Feedrate “thing”. And thanks go to Jamie for his really neat and handy Test Pattern Generator. I’ve been playing with all of these over the past few days and it’s been very interesting. I’ve learned a lot… but, an old man, I’m sure I’ll have opportunities to learn it all over again — several times — in future adventures. 😉





First, a confirmation… definitely run from SD card whenever possible. Sending the gcodes across USB will have undesired and discernable effect on the image being engraved. These photos show the same files being run twice — once from Octoprint/Pi over USB and the other using LCD/SD — and show dramatically different results…

our old “shades of gray”…



and Aaryn’s Laser Calibration Power vs Feedrate gcode (unaltered)…





Then, using info gleaned from Aaryn’s gcode, I was able to get reasonably good images using laser powers, ranging from full down to 1/6 (17%), at various speeds and resolution with Victor’s ImageToGcode.



Finally, I decided to try hand-editing gcode generated with Jamie's Test Pattern Generator... for laser vs. pen/marker. I had to brush up on my regular expression “skills” but managed to get Jamie’s code running with laser… and then used that to fine tune the steps/mm on my FoamRipper’s X and Y axes.



A little parallax from the thickness of the ruler and the position of the camera but it’s dead on now…



I’ll stop here… for fear of making a bigger mess of this post. But I wanted to get these posted before I forgot everything.

— David
very cool, I wish you were my neighbor :)
 
Rarely will you ever see a real “product” coming off my machines… I’m usually just fiddle-farting around, trying different stuff. But I decided to actually try doing something “useful”, a photo, using Victor’s ImageToGcode program and what I’ve learned while messing around with it over that past couple of days…

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This was using 17% power from the 2.5 watt laser, feed rate of 10 mm/s, and resolution of 0.1 mm. Pretty slow feed and low power, for the cereal-box cardboard, it was a 4 hr, 45 min burn. I’m sure it could be done faster/better but, all in all, I’m happy with the result.

An aside: I’ve always been drawn to this photo (I didn’t take it…) as this is the somewhat unique view I had during the launch of our KA/EKA-3 aircraft from the USS Coral Sea during the 1969-70 time frame. I was always in the port-side catwalk (quite a bit closer to the engine than where this photo was taken from) to handle any last moment radio/avionics issues. Once the pilot gave me the thumbs-up that all was okay and the last deck-handlers rapidly cleared out from under the aircraft, the pilot ran the engines up to full-scream and launch was only a few moments away. When the plane finally lurched forward and started moving down the deck, the outer wing passed right over my head, and the last thing I saw was the plane “flap its wings” — one time — as it went over the bow and they took the full weight of the 80,000+ pound aircraft. I don’t think I appreciated how exciting that moment always was, then… but I do now 😉

— David
 
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Wildthing

Well-known member
Rarely will you ever see a real “product” coming off my machines… I’m usually just fiddle-farting around, trying different stuff. But I decided to actually try doing something “useful”, a photo, using Victor’s ImageToGcode program and what I’ve learned while messing around with it over that past couple of days…

View attachment 135591

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This was using 17% power from the 2.5 watt laser, feed rate of 10 mm/s, and resolution of 0.1 mm. Pretty slow feed and low power, for the cereal-box cardboard, it was a 4 hr, 45 min burn. I’m sure it could be done faster/better but, all in all, I’m happy with the result.

An aside: I’ve always been drawn to this photo (I didn’t take it…) as this is the somewhat unique view I had during the launch of our KA/EKA-3 aircraft from the USS Coral Sea during the 1969-70 time frame. I was always in the port-side catwalk (quite a bit closer to the engine than where this photo was taken from) to handle any last moment radio/avionics issues. Once the pilot gave me the thumbs-up that all was okay and the last deck-handlers rapidly cleared out from under the aircraft, the pilot ran the engines up to full-scream and launch was only a few moments away. When the plane finally lurched forward and started moving down the deck, the outer wing passed right over my head, and the last thing I saw was the plane “flap its wings” — one time — as it went over the bow and the long wings took the full weight of the 80,000+ pound aircraft. I don’t think I appreciated how exciting that moment always was, then… but I do now 😉

— David
You can look at that picture and not only feel the wind but you can hear every sound that went with it. They say a picture is worth a thousand words but in your case it is worth millions.
 
Thanks, Jeff. I appreciate that. There was indeed a lot of wind and sound... though the screaming engine I was only a few feet away from pretty much drowned out everything else. So much sound, so close... that, even though I always wore ear protection, I lost a great deal of my hearing in those years, during and after the Navy, that I worked around jet aircraft.

It's interesting now that as I look at the "original" of that picture again (I found it oniine...), it looks as though it may be a painting rather than a photo... that looks as though that might be a signature in the lower-right corner.

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Either way, it still "works" for me... capturing both the moment and the view :)

-- David
 
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jhitesma

Some guy in the desert
Mentor
Great work on the laser stuff David, I'll have to look through those cal routines myself when I get a chance.

I really need to finish clearing out my backroom and getting my CO2 laser settled in so I can work with it more, it's been gathering dust (and projects I don't have homes for which are just sitting on top of it) for months now.

I also finally got my Mk3 back together last night - but am still having nothing but frustration from the MMU :( I was really hoping the latest firmware would help but it doesn't seem to be so far. Still a few calibrations I need to redo so it may work yet...but my initial tests with the MMU were just as unreliable as before and the new IR sensor in the extruder seems to still be causing most of my problems.
 
David,

Nice work as always!! Makes me want to go get a laser just to create some cool photos!! I am assuming you could dial this laser up and burn into pine--lite wood??

Thanks for your Navy service as well!! I'm retired USAF jet engine mech, worked all the heavy lifters while on active duty. Now I work on the fast fighters in engineering!! The C-17 was the best, and yes I agree, you really think about those military days when you see old photos or if you are lucky you still see the jet flying around.

Chalie
 
Thank you, Jason and Chalie.

My little brother is a dual-service veteran and has a birthday coming up in a few days. Only the best for him, I’ve spared no expense on his birthday card… :rolleyes:

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Okay, okay... I'll go out in the shop and see if I can round up a piece of wood ;)

— David
 

TEAJR66

Flite is good
Mentor
Alright, adopted the vacuum bed, and I'm a fan so far! Thank you @TEAJR66 for sharing your build! I opted for a 2" grid, with 1/8" holes in the middle and 1/4" holes on the outside and it works with a small floor vac we don't use anymore. My table that I salvaged for this made it particularly easy to make an airbox, only needed a piece of luan to cover the bottom of the frame. It's not uber-airtight but it works!

View attachment 135144
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Very cool. Glad it is working out for you. I feel like the vacuum table makes a world of difference, both in convenience and consistency.
 
Startling discoveries... and pleasant to boot!

I went to my stash of hobby plywood and found some 1/8" (3.18mm) stuff from Revell... it actually measures 3.34 mm or so right now. I engraved the BD card with the exact settings (2/3 power, 20mm/s feed, 0.2mm resolution) for the cereal box cardboard (is this really what they call "chipboard"?) and got pretty mediocre results. But it's starting to push 100 degrees outside now and I really didn't want to go out and cut and sand the card outline. So, I started playing with my air-assist setup again to see what it would take to cut the 3.3mm ply with the laser...

I've started using a modified version of Danowar's Air-assist shroud and nozzle recently (documented a few posts back) and saw/felt little difference between the MIN and MAX settings on air-flow actually coming out the stock nozzle. But I had seen a much stronger, higher-pressure, air-flow when I choked it down with one of those flexible Loc-Line coolant/air hoses and smaller nozzle. So I got into Onshape and whipped up a little extender nozzle that fits onto the end of Danowar's stock nozzle. The OzarkTrail air-pump is actually for inflating air-mattresses and other inflatables... and is spec'd to actually pressurize them to a few psi. Sure enough, the nozzle extender concentrated the flow of air around the laser beam significantly and I was actually able to cut 3.3 mm plywood in only 2 passes at full-power and 100 mm/s feed rate with my little 2.5 watt laser!

The nozzle extender...

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"Installed" on the stock nozzle...

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Silly me! I was going to make 3 passes for the outline -- just to make sure I got a complete cut -- and then accidentally bumped the gantry and it skipped a step or two on the last pass. Since this is just a practice piece now, I picked the piece up on completion of the last pass and, to my surprise, the card all but fell out on its own. Two passes had been enough to completely cut through the plywood!

More later. I need to get up earlier than normal in the morning -- one of those pesky golf games broke out -- so I'm going to stop here. I'm stoked!

-- David
 
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Further adventures with a 2.5 watt Eleksmaker laser, cutting/engraving, and air-assist...

Here's my nozzle extender and the stock nozzle for Danowar's most-excellent air-assist shroud...

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All these pieces (no, he doesn't need ALL of them but I needed a test subject...) were cut and engraved with the same 2.5 watt laser.... starting with the cereal-box cardboard (chipboard?) on the far left and -- going clock-wise -- 3mm birch plywood, stencil board, and the last two, 5mm luan plywood from the big-box store...

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For cleanest, crispest detail, I've found that the nozzle-extender cone is best used for cutting and the stock nozzle for engraving... thankfully it's simple to put on and take off. Engraving -- with the extender -- I got a "smudged"/"smokey"/"charred" look... without the extender, I got the lighter, crisper, cleaner engraving. Below, the same file, same material, and exact same laser settings... but with the extender (left) and without (right)...


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These two plywood pieces were engraved with the same file and laser settings.... the darker engraving (background) was with the extender cone, the lighter one without...

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With the extender cone and, strongest air-blast, I was able to cut materials I haven't been able to cut previously... all the way up to 5mm luan construction plywood/paneling...

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This is not fast, mind you... but it is possible, with patience. I'm not sure exactly how many passes it actually took to cut completely through on the outline cut... but I was sure it was cut through after 11 passes at full-power, full-air, and 100 mm/min feed rate. It could have been 8, 9, 10... or 11. I use a rather crude way to not lose count... placing another item in the string when starting each 6 minute outline run...

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With patience -- and ABSOLUTE BEST FOCUS and STRONGER AIR-ASSIST -- it is possible to work your way through material a lot of folks say is not possible to cut with such a low-power laser. I really think it is the smaller spot size. I was a bit surprised, several years ago, to find that my first 3.5 watt lasers didn't seem any more "powerful" than the 2 and 2.7 watt laser I'd played with previously... so I'm pretty sure its a "power density" thing; i.e. 2.5 watts concentrated in a "unit area" is more "powerful" than 3.5 watts spread over 4X that "unit area".

I'm going to stop here for now. This has been fun...

-- David
 
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jhitesma

Some guy in the desert
Mentor
With patience -- and ABSOLUTE BEST FOCUS and STRONGER AIR-ASSIST -- it is possible to work your way through material a lot of folks say is not possible to cut with such a low-power laser. I really think it is the smaller spot size. I was a bit surprised, several years ago, to find that my first 3.5 watt lasers didn't seem any more "powerful" than the 2 and 2.7 watt laser I'd played with previously... so I'm pretty sure its a "power density" thing; i.e. 2.5 watts concentrated in a "unit area" is more "powerful" than 3.5 watts spread over 4X that "unit area".
I'd make Patience bold as well :D I was able to cut my FT firewalls with my 3.5w laser...but even with good focus and high pressure air assist it took several slow passes making patience the largest limiting factor :D If the motor mount holes weren't smaller than 3mm (my then smallest endmill) I would much rather have just cut them with the spindle and been done in a fraction of the time without the smell or charring of the wood that leaves my fingers black ;)

Spot size really is key though. That's why there are such diminishing returns with the higher power diode lasers - they're higher power but they also have increasingly large spot sizes. It really is like the old bed of nails (I actually got to lay on one a few weeks ago with my daughter at the AZ science fair...was more fun than I expected!)

Have you tried putting masking tape over the wood before engraving/cutting? I know with co2 lasers it's a common trick to cut down on the smudging from smoke. At least when cutting...not sure how much it would help when engraving or if a diode laser would have the power to deal with the tape and still do decent engraving. Honestly not sure it would make sense or help with engraving at all...but might be fun to try at least.

I almost wonder if a fan blowing sideways across the work while engraving would help more...or suction pulling the smoke up and away....
 
After starting this project over the winter and then putting it aside for a while I have finally finished putting a FoamRipper together. I actually finished two weeks ago but was too busy building new planes to post about it :)

I still have some work to do, such is putting a point on my needle, adding some sort of needle guide (right now it is only running through the MIG tip), and probably doing some work to fix up the X axis as the carriage tends to jump a little when homing and I can see and feel a slight wobble on one side where the bearings aren't all making contact with the conduit, but overall it works pretty well. Ideally I would like to switch out the X carriage to DJ's version, but I currently can't be bothered to rip the entire thing apart since it is working well enough at the moment. I am using TMC2130 stepper drivers for the first time and doing sensorless homing on the X and Y axis, but I was mostly amazed at how much those drivers quiet down the stepper motors compared to my 3D printer. I am probably going to have to order another set of them now.


After this video I did end up having to fix a number of things as the screws I used to allow easy adjustment of the X and Z zero points for homing were falling out from the vibration and MIG tip unscrewed itself from the T-nut I attached it to. A little blue loctite has fixed those issues up for now, but I am guessing this will be an ever evolving machine just like my 3D printer.

Thanks to everyone for all the work in creating and improving this machine, it really made it a fairly painless build process!
 
What a great looking build, Nesteffe! And, welcome to this little corner of the FoamRipper community!

You've got some really interesting stuff going on there... especially the endplate construction. It's really fun to see an entire machine suddenly "presented to the world" like this... without any fanfare or advance notice that it's coming . Please tell us more about yourself and your machine's construction details. And we love pictures! :D

I'm really enjoying my FoamRipper. I'm not sure exactly why -- I have several machines to play with -- but I really seem to be getting more enjoyment out of working/playing with this one right now... :unsure:

Thanks for sharing with us. And, again... welcome!

-- David
 
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I'd make Patience bold as well :D I was able to cut my FT firewalls with my 3.5w laser...but even with good focus and high pressure air assist it took several slow passes making patience the largest limiting factor :D If the motor mount holes weren't smaller than 3mm (my then smallest endmill) I would much rather have just cut them with the spindle and been done in a fraction of the time without the smell or charring of the wood that leaves my fingers black ;)

Spot size really is key though. That's why there are such diminishing returns with the higher power diode lasers - they're higher power but they also have increasingly large spot sizes. It really is like the old bed of nails (I actually got to lay on one a few weeks ago with my daughter at the AZ science fair...was more fun than I expected!)

Have you tried putting masking tape over the wood before engraving/cutting? I know with co2 lasers it's a common trick to cut down on the smudging from smoke. At least when cutting...not sure how much it would help when engraving or if a diode laser would have the power to deal with the tape and still do decent engraving. Honestly not sure it would make sense or help with engraving at all...but might be fun to try at least.

I almost wonder if a fan blowing sideways across the work while engraving would help more...or suction pulling the smoke up and away....
Hey, Jason!

I'm not really worried too much about the smoke. You'll remember -- way back when -- we first started playing around with air-assist, we saw some real benefits... cleaner, less smoke-stained, engraves, for one. We were playing with shrouds and different sources for the air (compressor, aquarium pump, etc) and it all helped getting cleaner/faster cuts/engraves... to a limited degree.

I think this latest testing, however, shows a lot more promise. I've never had this strong an "air blast" to work with, as I'm seeing with the inflatables air-pump, speed controller, and Danowar's excellent air-assist shroud/nozzle. And, being in a rush to get my brother's birthday card/plaque finished, I've really not had time to fully explore what the nozzle extender brings to the party... but it obviously brings significant effect, judging from the "with" and "without" engraves. So I really just need to explore its effect and learn to control it.

It could be just a hotter, more aggressive, burn, with the enhanced "blast" provided by the extender cone, and I can just dial back the power for engraving... if I want to leave the extender on there "permanently". I'm sure I'll want it on there anytime I want to try cutting relatively thick materials. And now that I've delivered my brother's birthday card, I hope to start playing around with it some more.

PATIENCE is indeed a virtue. And I realize people with adult responsibilities DON'T have the kind of time I do... and want to get the job done as fast as possible. But I was going to be playing with the laser anyway... so, in my mind, I'm "killing two birds with one stone". I can devote full-time to a task, if necessary, and if the project warrants it, as this one did, I don't mind that it took a dozen passes to cut the material with my little laser; i.e. I was not only interested in a completed "product", but also in seeing what the little laser could, and could not, do. Besides, I hate the setup time, noise, and debris of the router in the house... and it's too hot to go outside to work in the shop. I know you'll sympathize... ;)

-- David