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Cutting foam sheets... with a needle!

dkj4linux

Active member
Slight side-trip...

Playing with Image2gcode some more and a piece of 3/16"(5mm) plywood paneling I found in my scrap...

Images burnt onto the ply look like crap IMO so I decided to have some fun and try cutting through it. The single line just above the photo image was simply 5 passes at 100% and 100 mm/min, with constant Z all passes, focus on top surface of material. Surprisingly it cut through quite cleanly.

So I went into Inkscape and threw down some simple shape and set it for 5 passes, 100 mm/min, focus remaining on top surface for all passes. Not sure but I think my laser housing must be providing decent "air-assist"... it looks pretty good to me; i.e. no flames, flareups, minimal smoke staining, etc...

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One part fell out just turning the piece over...

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-- David
 
Good job getting the nice clean cuts. When I am doing cutting I like to use 100mm/min speed and as many passes as necessary to get cleaner cuts and I see that is what you were doing.

Most of my day was a failure - a big failure. I was trying to etch glass again today and part of the technique is to put a sheet of paper over the glass and wet it down. The fan on my new laser was pushing enough air that every attempt the paper would dry enough to make it start curling and lift off the glass. I would get some etching prior to the paper lifting but when it came up there was no more etching. I just could not get any good results.

So next I tried something else, I got a jpg line drawing of spider man and converted it to vector and etched that. I was pleased with the detail. Then I took a spider man image with a lot of gray scale and did a gray scale print of that. Again I liked the detail but a little dark so the day was not a total waste.
 

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dkj4linux

Active member
More 5mm plywood cutting...

That Spiderman grayscale image is impressive, WildBill. That's on a wood/MDF surface?

Encouraged that I'm now cutting material thick enough (~5mm) to do something more "structural" than with craft sticks, I decided to try my hand at a few more useful (to me) items. Downloaded the DXF files from here

http://www.thingiverse.com/thing:1026345

and brought them into Inkscape. Unfortunately the parts have been saved in "px" units rather than "mm" and so some scaling needs to be done. In addition, there's "something" about the line segments that causes them to retrace a couple of times... redundant lines? So, it goes way slower than it should and the 5 passes I set up turns into 10 or more... hence the charring (especially on the lower piece, first photo, and the top piece in the 2nd photo below). I've not yet figured out how to manipulate line segments in Inkscape well enough to join them all and get rid of redundant segments, etc. But, all in all, I'm real encouraged... may have to cobble together another light-weight machine using 2020 aluminum extrusion and plywoods plates, fittings... -- David

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dkj4linux

Active member
Uh-oh!

Postman was good to me today... slow-boat finally arrived! $79 (Banggood Black Friday sale), 3.5 watts, gonna be dangerous now! -- David

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Fantastic stuff. I'm sure you're going to break new ground with that David. I'm currently printing a hood with an option to add in a 3mm tube for air assist.

laser_hood1.JPG
laser_hood2.JPG

Mine is 40mm x 40mm x 52mm (Excl Fan) and lens. If yours is the same it should work as a clip on hood. STL file available if anybody fancies it (but lets see how mine prints.)
 

dkj4linux

Active member
Fantastic stuff. I'm sure you're going to break new ground with that David. I'm currently printing a hood with an option to add in a 3mm tube for air assist.
...
Mine is 40mm x 40mm x 52mm (Excl Fan) and lens. If yours is the same it should work as a clip on hood. STL file available if anybody fancies it (but lets see how mine prints.)
40mm x 40mm x 52mm... it is! You're doggone right I'd like the STL... soon as you feel it's ready. Thanks! -- David
 
Postman was good to me today... slow-boat finally arrived! $79 (Banggood Black Friday sale), 3.5 watts, gonna be dangerous now! -- David

View attachment 79725
I am sure that you are going to like that laser, and you should fire up the fan on that thing and see just how much air it moves. The only difference I see is that mine has a fan on the logic board as well as on the laser.

Well after my failures yesterday I was not going to let glass etching beat me so today I decided to try something new and different. With the fan on the laser drying the paper and making it curl I sat a while trying to think of something that would not curl. In the end I took a rattle can and painted the surface of the glass with flat black paint and being black I went with the Batman look. I then etched it at 100mm/min and while I did get a little etching, it was not enough. At that speed it takes a LONG time to see if my idea would work or not. Looking at it in many places it looks like the sharp point of the laser just took the paint off.

So next I shrank the image to 1/4 the size and went went to 50mm/min AND I de-focused the laser. I finally got the glass to etch. I took some pictures but the one that actually etched was small enough that it was hard to get a good picture of it. I used acetone to take the paint off the glass when finished. At the end of the day today I can say I won this round.

The first pictures shows the glass has been etched, and the second shows the paint has been etched off on the first try, but not enough etching of the glass.

Last thing for today - FedEx made a deliver, I got a whole bunch of 1500mm 2020 and 2040 rails so I can now start building my next project. I know you guys are using the MPCNC design but I have always had good luck using 2020/2040 rails. That is what makes if fun is we can all try different approaches for the same end goals.
 

Attachments

The hood just finished printing. Does it fit? Hell yeah!
hood.jpg

One oversight. The hole I included to accomodate an airline is obstructed by the body of the laser heatsink. For V2. I'll need to add a conduit on the outside and then route it inside once its clear of the heatsink. From the bottom of the heatsink to the bottom of the hood is 52mm so perfect for 55mm focus distance. I'm gonna try some tests but I think there might be enough airflow through the 10mm base opening. I sprinked some sawdust around the base to see what sort of airflow was present and it was ejected about 6 - 8 inches. I'll try some tests to see if its good enough.

print.JPG

I printed it laying flat(as above) with support under the cone, but looking back I dont think its needed as it builds up printing the bottom half and is then supported by itself for the top half.

STL file link;
 

dkj4linux

Active member
The hood just finished printing. Does it fit? Hell yeah!
View attachment 79763

One oversight. The hole I included to accomodate an airline is obstructed by the body of the laser heatsink. For V2. I'll need to add a conduit on the outside and then route it inside once its clear of the heatsink. From the bottom of the heatsink to the bottom of the hood is 52mm so perfect for 55mm focus distance. I'm gonna try some tests but I think there might be enough airflow through the 10mm base opening. I sprinked some sawdust around the base to see what sort of airflow was present and it was ejected about 6 - 8 inches. I'll try some tests to see if its good enough.

View attachment 79764

I printed it laying flat(as above) with support under the cone, but looking back I dont think its needed as it builds up printing the bottom half and is then supported by itself for the top half.

STL file link;
Outstanding, Dave! I'll see what I can do about getting it printed up. Thanks a ton! -- David
 
Well with the laser hood in place, i decided to have a go at engraving. image2gcode doesn't really work with Mach3, but I found a plugin written to work with it. It uses the laser ttl pin as a digital trigger and seems to work pretty well.

gmg.jpg

Fore any mach3 users, more details and a download can be found here; (don't use the one on the mach3 website, its outdated). More tests tomorrow, but if I enlarge and play with some settings, hopefully I can get a better result.
Anyway for now I better go spend some time with wifie before she forgets what I look like!
 

dkj4linux

Active member
New laser shroud...

So far so good... fits pretty good. Thanks, Dave. Now to see if I can get some fire out of it...

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Hello to All and Greetings from Germany!

I'm new in the flitetest-forum...but was reading for a long time.

A friend of mine has a real big industry standart CNC mill (may be 1,6m x 0,8m)...so I made a first try with the needle-cutter for Depron and EPP. The results with this "prototyp" are looking very fine.
Now I try to otimize the mechanic of the cutter - trying to minimize the bending of the wire for the use of thicker needle wire. ( We want to use this system to cut thick paper for gaskets)

Some of the motor driven tattoo-machines are using a clever solution for this
---> http://www.tattoosafe.org/en/Jack-S...ne-Rot.html?x624a7=la3eq3dueuf4h5lrvvsr2p4fb5
I'm going to try/build a mechanic like that (with some small ball-bearings)

You can see my first cutting results here ( using the cutting-head "free hand" ;) )
http://www.jokr.de/cutter/cutter-01.JPG
http://www.jokr.de/cutter/cutter-02.JPG

On my prototype there are two additional ball bearings to minimize the friction of the wire - this works well with only minimal heating up
http://www.jokr.de/cutter/cutter-03.JPG
The wheel is an old part (brazen gearwheel) which is heavier than plastics and therefor better absorbing the vibrations (and easier to balance?!?)

We will start testing to cut Depron and EPP 6+8mm on the CNC this week - will post the results here :)

Joachim

P.S.
I'm looking for a 5W DiodeLaserHead (violett???) for cutting very thin plywood.
The laser should have a power regulation via software!
I do not know if the Banggood Lasers can do so (only ON/OFF???)

Any ideas?
 
Hello to All and Greetings from Germany!
Hi Joachim and welcome.

Well done on the needle cutter tests. I like the idea of using the extra two bearings, that would help stabilise the needle. I've never had a problem with heat probably because I've been using a long needle which flexes along its full length and spreads the heat. I think I will try your idea on V2 of my cutter!

I sourced my laser from the UK. It's 3.5W and has TTL power control. It cuts 3mm ply no problem. If you use a small airjet to clear away the ash, I'm sure you could cut thicker ply with more passes. You can get the same laser on banggood for less money. Others here are using similar powered lasers with good success too. The only 5W lasers I can find on banggood do not have TTL power control. Basically you want to see a unit which comes with a separate control board so the power can be controlled from the CNC machines control box.

I suspect you would have good success cutting the gasket material with a laser too.

Cheers

Dave (in Ireland)
 
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dkj4linux

Active member
Hi Joachim and welcome.

Well done on the needle cutter tests. I like the idea of using the extra two bearings, that would help stabilise the needle. I've never had a problem with heat probably because I've been using a long needle which flexes along its full length and spreads the heat. I think I will try your idea on V2 of my cutter!

I sourced my laser from the UK. It's 3.5W and has TTL power control. It cuts 3mm ply no problem. If you use a small airjet to clear away the ash, I'm sure you could cut thicker ply with more passes. You can get the same laser on banggood for less money. Others here are using similar powered lasers with good success too. The only 5W lasers I can find on banggood do not have TTL power control. Basically you want to see a unit which comes with a separate control board so the power can be controlled from the CNC machines control box.

I suspect you would have good success cutting the gasket material with a laser too.

Cheers

Dave (in Ireland)
Welcome, Joachim!

I'd considered a couple of small ball-bearings placed near the entry to the needle guide but never actually carried the idea through... primarily for simplicity's sake. Your prototype seems to be working a treat however and I think it's a good move towards making it a bit more robust and "industrial grade" for the more serious work you are doing. The simpler version works well enough for home use -- if you don't push it to the limits of feed/speed -- and could easily be scaled up (mainly in motor shaft to needle guide entry distance) to handle thicker needles without too much difficulty. I also use a little cotton-wad "oiler"/stabilizer packed into the inflation needle's ready-made "reservoir" on mine and I think it helps.

I'm sure a laser could handle the gasket work as well. I'm getting ready to test the 3.5 watt laser I just received from Banggood but have been surprised at just how nicely my current 2.8 watt cuts plywood up to 5mm or so... if you are not in too big a hurry. Okay, I just measured my plywood again and it's actually only 4.75mm... 5 passes cuts it nicely. I'm sure another pass would handle the extra 0.25mm if necessary. It also makes nice wooden rulers... engraves and then cuts the outline from a 2mm-thick craft stick in a single-pass ;)

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BTW Dave, I whipped up a quick-change housing clamp, similar to the one on my current laser... that's it in the background. I hope to power up the new laser today sometime. Isn't it nice having a 3d printer -- to whip out small custom parts in short order -- for all this prototyping work? ;)

Again, welcome, Joachim. I look forward to hearing how it goes with your needle cutter :D -- David
 
Thank you for the welcome :)

I fixed the needle cutter to my friend's cnc mill a few hours ago...the small wooden prototyp looks realy strange on this big machine (x=1,80m,y=1,10m..weight by 400kg) ...but the results are impressive for such a simple system.
The cutting is fairly precise and much better for small Depron parts than milling ---> sharp corners, more traveling speed and no more problems with the milling tools.

Pictures - first results (the SD-Card is for the size)
http://www.jokr.de/cutter/cutter-10.JPG
http://www.jokr.de/cutter/cutter-11.JPG

The hole on this picture is 3mm...
http://www.jokr.de/cutter/cutter-12.JPG
...and not so nice as I would like to see.
May be, the solution will be a more precise guide for the needle and an optimized needle lenght for the 3mm Depron?!
By now, the needle is long enough to cut 8mm EPP! Have to try again
But by now, I do not know any reason for milled 3mm holes in Deprom ;) .... can mark the center and use a drill?!

Next tests with the CNC on Friday :)
..................................................
Thanx for the info with the laser... I will not buy a laser-head with no power regulation.
The 3,5W is looking fine...I found some post that the 5W is not so good focused and therefor the cutting power will not be much better than the 3,5W?!?
Have to find out how to implement the laser-control in the CNC-System...looking to use the controls for the milling motor

Greetings form Germany
Joachim
 

dkj4linux

Active member
Thank you for the welcome :)

I fixed the needle cutter to my friend's cnc mill a few hours ago...the small wooden prototyp looks realy strange on this big machine (x=1,80m,y=1,10m..weight by 400kg) ...but the results are impressive for such a simple system.
The cutting is fairly precise and much better for small Depron parts than milling ---> sharp corners, more traveling speed and no more problems with the milling tools.

Pictures - first results (the SD-Card is for the size)
http://www.jokr.de/cutter/cutter-10.JPG
http://www.jokr.de/cutter/cutter-11.JPG

The hole on this picture is 3mm...
http://www.jokr.de/cutter/cutter-12.JPG
...and not so nice as I would like to see.
May be, the solution will be a more precise guide for the needle and an optimized needle lenght for the 3mm Depron?!
By now, the needle is long enough to cut 8mm EPP! Have to try again
But by now, I do not know any reason for milled 3mm holes in Deprom ;) .... can mark the center and use a drill?!

Next tests with the CNC on Friday :)
..................................................
Thanx for the info with the laser... I will not buy a laser-head with no power regulation.
The 3,5W is looking fine...I found some post that the 5W is not so good focused and therefor the cutting power will not be much better than the 3,5W?!?
Have to find out how to implement the laser-control in the CNC-System...looking to use the controls for the milling motor

Greetings form Germany
Joachim
Those are really encouraging results for a first test run, Joachim. I don't know how "sloppy" the needle-in-guide fit you have but I agree that it and the needle length may be the reason that small circle isn't better. Do you know the needle diameter and the guide bore? A 3mm hole really ought to look like a 3mm hole if the needle is stable and tracking properly... it's best if you can keep the guide tip within a few mm of the top of the material. Or, it could be that small CNC machine you're running on may be just too light-weight and inaccurate? ;):rolleyes:

I'm anxious to hear how things go tomorrow. Good work! -- David
 
Those are really encouraging results for a first test run, Joachim. I don't know how "sloppy" the needle-in-guide fit you have but I agree that it and the needle length may be the reason that small circle isn't better.
I'm also in full agreement with David. This was exactly my first experience until I shortened the needle and now get much better results. The needle just needs to clear the top and bottom of the material with enough depth to allow all of the point pass fully through. Otherwise it bends behind the cut. You will also notice this in 90degree turns where it takes a moment for the spring in the needle to change direction too. Excellent first run Joachim, I look forward to seeing more.
 
1)...I don't know how "sloppy" the needle-in-guide fit you have
...
2)...that small CNC machine you're running on may be just too light-weight and inaccurate? ;):rolleyes:
...David
Hi David,

1)...looking on this photo you will see that the guide is build up quick_n_dirty...and the needle (0.6mm) is very long.
I also have to optimize the distance between needle-guide and foam
cutter-03_cr.jpg
I will not try to modify this "prototype" very much (may be with a 0.8mm nozzle as a guide)...and will build a next one which should be more professional
Next try will be on 5mm EPP :)

2.)...even a big CNC has to be controlled from time to time and has to be serviced :)
The milling motor also is a real big one (8kW - water cooled)...so you can imagine how heavy/strong the load on the rails is, if you are running a big milling tool.
We made a test with 4 points (1x1 meter square), travelling back and forth in both directions...everything is still looking fine.
------
Gonna order the 3,5W laser for testing...hopefully with not having trouble with the German Customs ;) :confused:

Greetings...Joachim
 
I've been going a bit "CADMAD" today. I'm absolutely loving FreeCAD. It's no Autocad but it certainly is very capable of the sort of things I need to do. Here's my latest which is a variation of the standard drag knife holder. I havent printed it yet as CURA says it will take 2hrs 15 and its after midnight.

drag_knife_dg_v12.JPG

Link to STL file