Cutting foam sheets... with a needle!

Springer

Member
Yup, I'm chiming in. . . My machine is actually based on one of the cheaper eleksmaker units. Mine came with a half watt laser (not very useful, but it was originally just to see how the laser and cnc worked) . The pro version you linked is no doubt a better starting point. It has a lot of stuff that I have had to purchase to make mine work well. That would include the wheels, side plates stand plates, etc. Not having the laser included is ok, as you can catch a 2.5 watt or larger one on sale. Mine came with the white nylon wheels that are just barely wide enough for the track. I switched to the black wider ones and it improved smoothness. I also, bought new AL sections to be able to cut 24"x48" MPF sheets. I learned that all 2020 and 2040 sections are not equal. The new sections had slots 1-2mm narrower than old and than the belts. I had to "Rube Goldberg" open the slot with my router and hand finish. So when ordering your longer sections, check the slot width! I ordered the 3 axis eleksmaker mana board, which was a seamless replacement for the original 2 axis one. Was around $30, I think. Lastly, I got a metal slide, worm drive Z axis unit from banggood. While this works fine, it sticks out from the x axis a lot, which prevents me from using the full Y axis length. Assembly, both original and as cutter was straightforward. I do have a 3d printer (anet A8) and have printed the needle frame, belt tensioner, etc. You won't need an expensive printer, but it will greatly enhance your abilities. I have successfully used the machine for needle and laser work, but found it a bit too flexible for the rotary cutter I recently added. This new function is still in the stumbling around stage. I will need 24v to get motor speed up to12k rpm, and am thinking I will really need a new stiffer frame and hardware. Thinking about resurrecting the original sections/ frame when I can find where I put it! Watching David develop his new Z axis is getting juices flowing! I really like that it has minimal offset from channel. You can see in the pictures if you browse back this thread that mine hangs out a lot.
 

dkj4linux

Elite member
More progress…

I printed several X-carriage plates before finally getting all the wheel and belt openings properly located, and X-axis rail modifications made, to accommodate a wider “wheelbase” and 2040 spacings…


Movement in all three axes. The Z-axis BB-bearings are noisy but movement is relatively smooth...


As I happened to have a length of silver 2020 already cut from the TimSav I dismantled after “retiring” the TimSavX2 hot-wire machine… it fit pretty-nicely between the tractors and on top of the existing X-axis extrusion. So I printed some “joiner” pieces to lock the V-slot together along their length and added it to the existing horizontal 2040 X-axis rail…

20200713_092416.jpg


There are four of these joiners holding the silver 2020 extrusion tightly to the black extrusion below…

20200713_092226.jpg


Here a joiner can be seen flush with the end of the added extrusion…

20200713_091911.jpg

https://us2.dh-cdn.net/uploads/db5587/original/3X/d/1/d17dbe5b5fd07775bb7a4846a83bf0745afda84e.jpeg
And now, the X-carriage wheel spacing is for 2040 (vs 2020 before) and, with eccentric spacers on the lower wheels, it is much more smooth and stable than before…

20200713_092253.jpg


I could, of course, do away with the need for the added extrusion by re-orienting the front X-axis rail from horizontal to vertical but I didn’t want to take time to modify and reprint the tractors right now.

Next I need to mount the laser onto the Z-axis and, hopefully, I should be back in business.

– David
 

dkj4linux

Elite member
Yeah, I'm eyeballing those but feel that particular board is probably way overkill for my needs. I may spring for one of the simpler 3-axis models though... those are probably enough for me and my KISS mentality. They're being discussed a bit over on the V1Engineering/MPCNC site as well... so I'll probably wait and let the pioneers/guinea pigs get it all sorted out first... :sneaky:
 

dkj4linux

Elite member
Well, I was still not satisfied with the belt-driven Z-axis. It’s doesn’t firmly hold its Z-position when trying to position the laser for a run… and focus is too easily lost. So, I downloaded 3DPRINTINGWORLD’s V2 printed screw-driven stepper slide and printed it off. Unfortunately, a couple of the parts have been revised and inexplicably no longer fit properly. Thankfully, the previous version of the slide shares those same parts and so I was able to download parts that fit… and finish assembly of the slide. No current video, here’s an old video of a previously-built slide that currently resides on my daughter’s laser engraver…


There are two different screws provided with the download… and I used the most aggressive pitch

20200715_180608.jpg

https://us2.dh-cdn.net/uploads/db5587/original/3X/e/3/e3652e683ab2e83a613b8d4d882d986d9b4ffc59.jpeg
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Now installed on the machine and working nicely…
https://us2.dh-cdn.net/uploads/db5587/original/3X/7/0/706aaa1313a77f5eebce5c458755ef97c453fac6.jpeg
20200718_071216.jpg


so it’s back to playing with Lightburn…
https://us2.dh-cdn.net/uploads/db5587/original/3X/1/9/19a95d8c9eb347cef631d6658f734f13256e7e9c.jpeg
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https://us2.dh-cdn.net/uploads/db5587/original/3X/3/5/3525af6342080be1637800d7c01cf0a46e8b3566.jpeg
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Later.

– David
 

dkj4linux

Elite member
Finally convinced that a belt-driven Z-axis wasn’t a good Idea because it didn’t hold its Z-position – and thus laser focus – firmly enough while positioning the toolhead… I’ve simplified the X-carriage plate and mounted the new BB-bearing, printed screw-driven, V1 stepper-slider. That, in turn, carries the Eleksmaker 2.5W laser module and danowar’s laser air-assist shroud that I’ve used with this laser module on several machines in the past.
https://us2.dh-cdn.net/uploads/db5587/original/3X/f/c/fcdf4bf28ebccb622c6c3e005b0b4567e8bd45dc.jpeg
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The printed Z-axis slider assembly uses BBs for bearings and works surprisingly well…
https://us2.dh-cdn.net/uploads/db5587/original/3X/4/4/443d6b06156bd78e30b868e93a81e1ea81592273.jpeg
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https://us2.dh-cdn.net/uploads/db5587/original/3X/a/8/a81fb109f1036cd6041a00ce67413ae4d6af68b5.jpeg
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https://us2.dh-cdn.net/uploads/db5587/original/3X/5/9/592e792fc0b971f10394072eb6c54a41ebe2623e.jpeg
20200720_094521.jpg


The inexpensive (< $2) hobby stepper is hard to take seriously but with a simple unipolar to bipolar conversion actually works quite well for this application. The blue plastic cover is pried loose to expose the small PCB inside…
https://us2.dh-cdn.net/uploads/db5587/original/3X/f/9/f95f1b2bbf0756d7c8639a89da667fc7de115803.jpeg
20200721_102846.jpg


and the wide central trace is cut to disconnect the middle nodes of the two coils. The red wire is then snipped/removed from the 5-wire bundle…
https://us2.dh-cdn.net/uploads/db5587/original/3X/c/2/c28ce69d4011370d5e44a892ba60018aae3794fb.jpeg
20200721_103327.jpg


and the four remaining wires rearranged in the connector to match the stepstick driver pinout… in this case, orange-pink is one coil, yellow-blue is the other.
https://us2.dh-cdn.net/uploads/db5587/original/3X/9/1/911dfe294fb9a98c1609e031db22547580940baf.jpeg
20200721_122710.jpg


The air-assist shroud gives a stronger air stream using a small radial fan and printed shroud…
https://us2.dh-cdn.net/uploads/db5587/original/3X/7/6/76b91b6a77804032d5bf1891b9df61de235744d6.jpeg
20200721_104240.jpg


The laser lens focal length (about 55mm) can be adjusted, if necessary, with the ridged nozzle
https://us2.dh-cdn.net/uploads/db5587/original/3X/2/c/2c634106f6477de64462cf74efacef4f5e73b98a.jpeg
20200721_104304.jpg


and fine-focus is achieved using Ryan’s focus script.
https://us2.dh-cdn.net/uploads/db5587/original/3X/5/6/56d7d52d11e39e7153116a4955a93af5137f99a7.jpeg
20200721_120558.jpg


The two Charles Bronson image engravings and profile cuts used the exact same gcode file… before (right) and after (left) installing the air-assist shroud.
https://us2.dh-cdn.net/uploads/db5587/original/3X/1/9/191f41efdf2692b4e5154f0a05ffd524fb1d0a3b.jpeg
20200721_191918.jpg


I’m pretty happy with this machine now and doubt I’ll make any more drastic changes… miniFR lives!

– David
 

joji

New member
Hi everyone,

I am new here, hoping to make a needle cutter for my MPCNC. I have looked through hundreds of posts on this thread before deciding to post and I am honestly a bit overwhelmed by how much information there is. I apologize if this has been asked before.

I see that David's standard recommendation at the moment is the TimSav needle cutter adapted for the MPCNC which is what I have decided to go with. I am looking at the bill of materials and trying to figure out which components are for just the needle cutter (not the rest of the machine). I just wanted to make sure I'm buying the right components:
  • motor - same one from BOM
  • esc - same one from BOM
  • servo tester - already have one
  • welding tip - same one from BOM, can't seem to find less than a 50 piece pack :/ but that's fine!
  • bearings - same one from BOM, 12 of these total (i.e. 3 sets of 4)?
  • screws, nuts, bolts - will probably source all of them from McMaster
    • (1) M6 nut, ~3 mm thick
    • (1) M3 x 7mm x 0.4 mm washer
    • (13) M3 x 5 mm x 0.3 mm washer
      • From what I understand these don't exist, so I will have to buy M2 x 5 mm washers and drill them out to M3 size.
      • I saw an earlier post where someone glued the washers to a piece of scrap wood and then drilled them out which is what I will do. He linked both zinc-plated steel washers and brass washers, does it matter which type I use?
    • (5) M3 x 10mm screws
    • (1) M3 x 12 mm screws
      • the one thing I already have... :p
  • 0.025" straight music wire for needles
And then of course the 3D printed component which I will try printing tomorrow. Am I missing anything? I greatly appreciate the help, I just really don't want to goof this up. Once I'm sure I have all of the correct parts, I'll put in the orders.

Also, I may document the whole build process in detail (specifically for the ERC-MPCNC cutter) for people like me who are not very good at this sort of thing. :)
 

dkj4linux

Elite member
Hi everyone,

I am new here, hoping to make a needle cutter for my MPCNC. I have looked through hundreds of posts on this thread before deciding to post and I am honestly a bit overwhelmed by how much information there is. I apologize if this has been asked before.

I see that David's standard recommendation at the moment is the TimSav needle cutter adapted for the MPCNC which is what I have decided to go with. I am looking at the bill of materials and trying to figure out which components are for just the needle cutter (not the rest of the machine). I just wanted to make sure I'm buying the right components:
  • motor - same one from BOM
  • esc - same one from BOM
  • servo tester - already have one
  • welding tip - same one from BOM, can't seem to find less than a 50 piece pack :/ but that's fine!
  • bearings - same one from BOM, 12 of these total (i.e. 3 sets of 4)?
  • screws, nuts, bolts - will probably source all of them from McMaster
    • (1) M6 nut, ~3 mm thick
    • (1) M3 x 7mm x 0.4 mm washer
    • (13) M3 x 5 mm x 0.3 mm washer
      • From what I understand these don't exist, so I will have to buy M2 x 5 mm washers and drill them out to M3 size.
      • I saw an earlier post where someone glued the washers to a piece of scrap wood and then drilled them out which is what I will do. He linked both zinc-plated steel washers and brass washers, does it matter which type I use?
    • (5) M3 x 10mm screws
    • (1) M3 x 12 mm screws
      • the one thing I already have... :p
  • 0.025" straight music wire for needles
And then of course the 3D printed component which I will try printing tomorrow. Am I missing anything? I greatly appreciate the help, I just really don't want to goof this up. Once I'm sure I have all of the correct parts, I'll put in the orders.

Also, I may document the whole build process in detail (specifically for the ERC-MPCNC cutter) for people like me who are not very good at this sort of thing. :)
Welcome, Joji!

Goofing up is a pretty big -- and necessary -- part of the learning process... and, at 74, I still do it routinely! And getting "good at this sort of thing", of course, comes with practice... so it's a temporary condition. But since you're focused on the needle cutter itself, you really can't mess up too bad... it's a relatively inexpensive build that, despite it's simplicity, will teach you a ton, as you get it dialed in and cutting nicely. The parts list you've compiled looks pretty good AFAICT... and the metric hardware can probably be best had in one of the assortment packs off Ebay/Amazon/etc. I don't know where you're located but I found Mig welding tips at any of the local big-box stores, in the tools department, with the welding stuff... a blister card of 10-12 IIRC for just a few $$$. I even found them at Walmart on one occasion... :eek:

The printed parts are simply Edward's flat parts, assembled in CAD and fitted with the MPCNC "Burly" tool mount, and then printed as one piece. If you are reasonably proficient with any sort of CAD, it's a pretty simple -- and instructive -- thing to take existing STLs and mod/meld them into a form more suited to your need. I look forward to seeing how your build progresses.

Again, welcome to the party!

-- David
 

joji

New member
Welcome, Joji!

Goofing up is a pretty big -- and necessary -- part of the learning process... and, at 74, I still do it routinely! And getting "good at this sort of thing", of course, comes with practice... so it's a temporary condition. But since you're focused on the needle cutter itself, you really can't mess up too bad... it's a relatively inexpensive build that, despite it's simplicity, will teach you a ton, as you get it dialed in and cutting nicely. The parts list you've compiled looks pretty good AFAICT... and the metric hardware can probably be best had in one of the assortment packs off Ebay/Amazon/etc. I don't know where you're located but I found Mig welding tips at any of the local big-box stores, in the tools department, with the welding stuff... a blister card of 10-12 IIRC for just a few $$$. I even found them at Walmart on one occasion... :eek:

The printed parts are simply Edward's flat parts, assembled in CAD and fitted with the MPCNC "Burly" tool mount, and then printed as one piece. If you are reasonably proficient with any sort of CAD, it's a pretty simple -- and instructive -- thing to take existing STLs and mod/meld them into a form more suited to your need. I look forward to seeing how your build progresses.

Again, welcome to the party!

-- David
Thanks so much David! It's very reassuring to hear from someone 51 years older than me that it's OK to mess things up in the process... I often forget that. :) I hate to admit it but I just graduated with a degree in engineering, and I still don't feel very confident applying the theory I learned to projects like this.

As for the welding tips, I'm in the US so I will try Home Depot or Lowes. Thanks again and will keep everyone updated on my progress!
 

dkj4linux

Elite member
Thanks so much David! It's very reassuring to hear from someone 51 years older than me that it's OK to mess things up in the process... I often forget that. :) I hate to admit it but I just graduated with a degree in engineering, and I still don't feel very confident applying the theory I learned to projects like this.

As for the welding tips, I'm in the US so I will try Home Depot or Lowes. Thanks again and will keep everyone updated on my progress!
Joji,

I had the advantage of being a fire-control and avionics technician (trained in the Navy during Vietnam) before ever graduating college with my EE degree. Upon graduation, I went to work for a very large and well-known, multi-national, Dallas-based, electronics firm... in their military equipment group. Back then (and I suspect it's the same now), almost all newly-graduated EE's aspired to be "design engineers". But it was those many late-night sessions in the lab that taught you all the stuff they didn't teach you in the college classroom... and separated the real engineers from the wannabe's. Chasing powers/grounds/noise/etc and trying to figure out why your "perfectly good/logical" design would work only at room-temperature but not at the extremes of temperature and vibration... that's what brought many aspiring engineers to the crushing realization they weren't cut out to be "design engineers" after all. And the absurd irony of it all is that those same "design flunkies" who couldn't "hack" the engineering side of the house (the "technical ladder") would move over onto the management side of the house (the "management ladder")... and eventually become your [usually unreasonable] "boss" and make tons more money than you.

So, I didn't get rich but I enjoyed the fool out of my work... at least, the 10% or so of it that was actual "design" and making stuff "go". The rest of it -- paperwork, meetings, customer interface, etc -- not so much. And, now that my time is my own... making stuff, that's what I still get a big kick out of today. So, dig in, get your hands dirty, and enjoy the ride. Yogi Berra, the great NY Yankees catcher/philosopher once said something to the effect, "In theory, theory and practice are the same... in practice, they're not."

-- David
 
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joji

New member
Joji,

I had the advantage of being a fire-control and avionics technician (trained in the Navy during Vietnam) before ever graduating college with my EE degree. Upon graduation, I went to work for a very large and well-known, multi-national, Dallas-based, electronics firm... in their military equipment group. Back then (and I suspect it's the same now), almost all newly-graduated EE's aspired to be "design engineers". But it was those many late-night sessions in the lab that taught you all the stuff they didn't teach you in the college classroom... and separated the real engineers from the wannabe's. Chasing powers/grounds/noise/etc and trying to figure out why your "perfectly good/logical" design would work only at room-temperature but not at the extremes of temperature and vibration... that's what brought many aspiring engineers to the crushing realization they weren't cut out to be "design engineers" after all. And the absurd irony of it all is that those same "design flunkies" who couldn't "hack" the engineering side of the house (the "technical ladder") would move over onto the management side of the house (the "management ladder")... and eventually become your [usually unreasonable] "boss" and make tons more money than you.

So, I didn't get rich but I enjoyed the fool out of my work... at least, the 10% or so of it that was actual "design" and making stuff "go". The rest of it -- paperwork, meetings, customer interface, etc -- not so much. And, now that my time is my own... making stuff, that's what I still get a big kick out of today. So, dig in, get your hands dirty, and enjoy the ride. Yogi Berra, the great NY Yankees catcher/philosopher once said something to the effect, "In theory, theory and practice are the same... in practice, they're not."

-- David

I think I can guess the Dallas-based electronics firm you're alluding to... :unsure::LOL: But man, that quote sums it up nicely. Theory definitely isn't enough to gain the intuition for designing robust engineering systems. Fortunately a lot of people emphasized that to me early on and I got involved in my own personal projects (RC planes, 3D printing, MPCNC, CAD) as well as club projects at school. It wasn't enough to make up for the gap between theory and reality, but the hands-on stuff is what kept me motivated through school. It's just so much fun! I'm interviewing for a job right now that will give me at least a little hands-on exposure, but at the very least I'll make enough money to fund my fun side projects, despite the paperwork and other boring stuff :D And I hope one day I can retire and keep tinkering like you!
 

graza

Member
Hi Joji & David,

I'm also looking at building a foam ripper of some description so that my son and I can cut down on the build time in scratch builds. I discovered this thread a few months ago and have been checking in with it now and then since. We're new to the hobby but my son's excitement as we started to maiden our first build makes me want to build more. That, and the fact that you're a true gentleman David and have inspired me to participate here. :)

Before I saw the needle cutter idea, I was thinking about/investigating different drag knife designs. Having done a couple of scratch builds by hand, it always seemed to me that a drag knife would make a mess of DTFB (not to mention the CNC programming complexity). The needle cutter just seems so much easier and clean.

I don't have an MPCNC and I missed out on getting one of EdwardRC's Timsav kits. I like the idea of the low rider inspired design but, not having built a CNC before, I wonder whether it's just easier to go for a full V-slot based approach for X and Y?

Also, the designs I've seen all move the entire welding tip and motor assembly up and down together, and some of the videos I've seen of these cutters in action show the needle bending to an extent, perhaps leading to inaccurate cuts. It occurred to me that you could leave the welding tip down close to the DTFB and just move the motor up and down, with the benefit that the needle doesn't bend as much? But maybe there isn't going to be much benefit to that especially if the needle extension beyond the welding tip is kept to a minimum.

Anyway, some 3D printing of parts has started while I get other bits of hardware in. With me being in Galway in the west of Ireland, everything has to be ordered in, so it's gonna take a while to get it all together.

Graham.
 

TEAJR66

Flite is good
Mentor
Also, the designs I've seen all move the entire welding tip and motor assembly up and down together, and some of the videos I've seen of these cutters in action show the needle bending to an extent, perhaps leading to inaccurate cuts.

Graham.[/QUOTE]

The needle is moving up and down pretty fast. Before the carriage changes direction, the needle catches up.

Plus, feed rates are fully controllable. Adjust as necessary to achieve desired accuracy.

I was sceptical when I started using a needle cutter. Now that I have used one, it is the only way to go, short of a laser.
 

dkj4linux

Elite member
Hi Joji & David,

I'm also looking at building a foam ripper of some description so that my son and I can cut down on the build time in scratch builds. I discovered this thread a few months ago and have been checking in with it now and then since. We're new to the hobby but my son's excitement as we started to maiden our first build makes me want to build more. That, and the fact that you're a true gentleman David and have inspired me to participate here. :)

Before I saw the needle cutter idea, I was thinking about/investigating different drag knife designs. Having done a couple of scratch builds by hand, it always seemed to me that a drag knife would make a mess of DTFB (not to mention the CNC programming complexity). The needle cutter just seems so much easier and clean.

I don't have an MPCNC and I missed out on getting one of EdwardRC's Timsav kits. I like the idea of the low rider inspired design but, not having built a CNC before, I wonder whether it's just easier to go for a full V-slot based approach for X and Y?

Also, the designs I've seen all move the entire welding tip and motor assembly up and down together, and some of the videos I've seen of these cutters in action show the needle bending to an extent, perhaps leading to inaccurate cuts. It occurred to me that you could leave the welding tip down close to the DTFB and just move the motor up and down, with the benefit that the needle doesn't bend as much? But maybe there isn't going to be much benefit to that especially if the needle extension beyond the welding tip is kept to a minimum.

Anyway, some 3D printing of parts has started while I get other bits of hardware in. With me being in Galway in the west of Ireland, everything has to be ordered in, so it's gonna take a while to get it all together.

Graham.
Thank you, Graham, for the kind words... and welcome!

As you've probably realized all these machines and needle cutters are DIY projects that can be both a blessing and a curse. No "no-brainer" kits and too many options... but also lots of opportunity to alter/explore and use whatever materials you may have on hand.

I think that as a first-time machine builder, Edward's TimSav machine -- even without the availability of a his kit -- is probably the simplest and most inexpensive way to go. It's quite well-documented, has a large and active following (especially the FB group, which is not my cup of tea but others seem fine with it), and with enough care/patience in assembly, and possibly a mod or two from the community, this machine can be made to operate pretty effectively. There is a TimSav thread here on FliteTest that also may be of help.

The LowRider and derivatives (Moebeast's Foam Ripper, my FoamRipper/MiniFR, etc) are probably the next best machines with sufficient capacity for foamboard and needle cutting... but they (the derivative machines) are not as well documented and widespread enough to have solid community support. I've not put my latest miniFR (inspired by Geodave's rolling plotter and my previous FoamRipper) out on Thingiverse or adapted it for a needle cutter yet but if I were building a new machine, specifically for needle-cutting, I think this would be my machine of choice; i.e. it's basically just a gantry rolling on a hollow-core door and can be made as large as you like.

20200801_111836.jpg


20200801_103308.jpg


20200801_103719.jpg


If you're interested, my miniFR build starts here, evolves over a couple of pages, and ends about here... just a few posts before you introduced yourself. My TimSav build was never constructed, complete with needle cutter (didn't need one)... I only built the basic X/Y motion machine, to satisfy my curiosity, and then built/added a second TimSav to come up with my TimSavX2 hot-wire machine, built for a specific project. It has since been dismantled.

MPCNC is always a good candidate machine -- this very thread started with MPCNC as the CNC of choice (LR and others didn't yet exist) -- for needle cutting but is a more complex and expensive build by comparison. It's generally not recommended in a larger format, sized for foamboard, but will work fine for lighter loads such as needle-cutter, laser, drag-knife, etc... much as I was using it back in the beginning of this thread. At that size, however, it does have a pretty large/bulky footprint and takes up quite a bit of valuable workshop space. MPCNC is also currently undergoing a version upgrade so there's a little bit of "growing pains" confusion and long-term uncertainty there, but, of course, all that will settle out in time. MPCNC Primo, like it's predecessors, is an amazing design and the community support is outstanding.

Of course, with the pandemic playing havoc with shipping and supply, it's a bit less predictable where best to source all the materials for whatever machine you decide to go with... but I've eventually gotten everything I've ordered online. Hopefully the same will be true for you.

Again, welcome to the party. Please let us know how we might help.

-- David
 
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effdubya

New member
Hi Joji & David,

I'm also looking at building a foam ripper of some description so that my son and I can cut down on the build time in scratch builds. I discovered this thread a few months ago and have been checking in with it now and then since. We're new to the hobby but my son's excitement as we started to maiden our first build makes me want to build more. That, and the fact that you're a true gentleman David and have inspired me to participate here. :)

Before I saw the needle cutter idea, I was thinking about/investigating different drag knife designs. Having done a couple of scratch builds by hand, it always seemed to me that a drag knife would make a mess of DTFB (not to mention the CNC programming complexity). The needle cutter just seems so much easier and clean.

I don't have an MPCNC and I missed out on getting one of EdwardRC's Timsav kits. I like the idea of the low rider inspired design but, not having built a CNC before, I wonder whether it's just easier to go for a full V-slot based approach for X and Y?

Also, the designs I've seen all move the entire welding tip and motor assembly up and down together, and some of the videos I've seen of these cutters in action show the needle bending to an extent, perhaps leading to inaccurate cuts. It occurred to me that you could leave the welding tip down close to the DTFB and just move the motor up and down, with the benefit that the needle doesn't bend as much? But maybe there isn't going to be much benefit to that especially if the needle extension beyond the welding tip is kept to a minimum.

Anyway, some 3D printing of parts has started while I get other bits of hardware in. With me being in Galway in the west of Ireland, everything has to be ordered in, so it's gonna take a while to get it all together.

Graham.

Hi

I am currently building EdwardsRC timsav, up to now it has gone together well. I did not purchase the kit from him but sourced all the bits in the UK . Mostly from Ebay.

I have decided to fit it with a variation of the needle cutter using one designed by zero_o on thingiverse. It is designed to use linear bearings and a geared servo lift. This gives (imho) a much more secure and accurate needle cutter.

If you'd like to take a look its here https://www.thingiverse.com/thing:4330662

Hope this helps :)

Frank
 

dkj4linux

Elite member
After Mike (@dart1280), over on the V1Engineering site, gave a link to some super-inexpensive laser modules about a month ago, I ordered not only a 3.5W laser module (which later had to be subbed for a 6W unit) but also a cheap (~$215) Vigotec laser engraver machine that sported a 20W laser. After “delivering” my TX-bound order to an address in MD, they resent my order and it was delivered a couple of days ago. Far more compact than TimSav, of course -- but quite probably part of the inspiration for it -- I got it primarily for the so-called "20W" laser... I've never had a chance to play with one of those higher-powered units.
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A few minutes putting the pre-assembled axes and laser module together with about 6 thumb-nuts and I had a brand new machine. Thankfully, I decided to see if the firmware (which I suspected was proprietary) was already loaded and sure enough it connected first try… and greeting me with a familiar generic-looking Grbl v1.1f header. So I simply hijacked the USB connection to my miniFR 's Pi3b+ and in moments had a machine that seemed to operate perfectly. I roughly focused the laser on a piece of chipboard and ran a handy test file I had on hand… and immediately started a small fire on the chipboard with the same file that cuts normally with my 2.5 watt laser. So, it does appear a bit more powerful, judging by this simple test.

So now I’m replacing the 2.5W laser on miniFR with this new laser and going to see how well I can focus using a fully-implemented Z-axis and Ryan’s focus script.
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Looks as though it should be a straight-forward substitution and I hope to start testing it later this evening or in the morning. Or, I may just kick back in the recliner and celebrate my good day… ;)

Later,

– David
 

dkj4linux

Elite member
Commandeered the “20W” laser module from the new laser machine and fitted it to miniFR…


The laser module has a familiar 3-wire connector (+, -, S) and cable and the little Nano-based 3-axis Keyestudio CNC controller I had originally put on miniFR didn’t… so I dug around in my stash and found an “old faithful” 3-axis Eleksmaker controller that had a 3-pin laser output. Set up the Grbl $-parameters to match my previous controller and made the swap. The laser cable matched up perfectly with the laser output on the board and the laser operates normally.

A raster engraving run at 2000 mm/min and just 12% power yielded this cool dithered image on cereal-box chipboard that has an almost “bleached” look to it in the lighter areas…

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Doubled the power to 25% for the right-most image...
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Let the fun begin!

– David