LowRider-inspired Foam Ripper

New Home Forum Things You Have Made LowRider-inspired Foam Ripper

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    An avid RC’er, Mark Moebes (“moebeast”) made waves with his wildly-successful FliteFest-East 2017 MPCNC foam-cutting exploits… Ryan even featured his FT article here on this site (https://www.v1engineering.com/moebeast-flight-test/).

    Well, soon after returning from FFE/2017, he set about to… in his words, “see how inexpensive a machine I could build.” The resulting, loosely LowRider-inspired, foam-cutting machine — which he calls “Foam Ripper” — is not a competitor/replacement for LowRider. It is a light-duty machine, using standard 3/4″ EMT, having fixed-height (but adjustable) Y-axis rails, and sporting a Y-carriage with limited-range Z-lift and integrated needle cutter… and ultimately it uses one less stepper motor, about half the number of bearings, and a quarter of the hardware, of the MPCNC.


    He also wrote a second FT article describing its construction…


    And here it is in action…

    My planets have now aligned… and with my new “Texas rebuild” milling capability and a new needle-cutter slip-on flywheel assembly in development, I have decided to build Mark’s machine. It’s a dedicated machine for light-loads — needle-cutter, pen/marker plotter, drag-knife, laser, etc. — and is best suited to a generally “smaller-than-LowRider” work area. I’ve begun documenting my build in my lengthy needle-cutting thread over on the FT forum…


    My build has progressed to the point that I can begin testing and fine-tuning… first, the obligatory crown plot

    and a short run-up of the needle cutter, featuring the new slip-on (over the motor bell) flywheel assembly…

    Not needing the size or rigidity of the LowRider machines, my build currently uses an 32″ x 80″ interior door for the work surface, perched atop a folding table.








    One of my first tasks, is to needle cut three DTFB sheets to form the vacuum hold-down system featured in Mark’s article… Jason Hitesman (“jhitesma”) also did a video detailing its construction

    As CNC machines go, this may be one of the easiest machines to find room for… it can be made “knock-down” for portability and/or storage. The bed needs to only be large enough to allow for cutting to the extremes of a sheet of DTFB, or whatever sheet material you want to cut. The rolling gantry is easily rolled off the bed, is not-too-heavy (20 lbs?), and will stand up in a corner. The belts are simply clamped along the edge of the bed for use. The bed is stored away like any other panel. Saw horses or a folding table hold it all up in use. No computer required to operate, the LCD controller and electronics can be attached to the end plate… so it stores with the gantry.

    This has been a fun build. Eventually, I plan to down-size the work-surface and move this machine into the bedroom I’ve set aside for hobby storage and additional work-area. Cutting foam with the needle cutter is not terribly loud and generates little debris so hopefully it will be happy there, not occupying “center stage” in my living area… 😉

    — David




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    That is really slick. I saw some of your vids on youtube amd I was wondering what this was. It seems like a great combination of parts. I think one of those 3W lasers on a machine like this would be very cool. If you made the base light enough, you could even drag it outside to avoid all those toxic gas problems.

    Also, I like the square and straight edge trick.



    Thanks, Jeff.

    I really didn’t want to present it here until it was functioning pretty well. The build is being documented in my FT thread so don’t want to try keeping all threads in sync.

    Putting a laser on it would be super easy… but I’ve built so many laser machines I was happy to do something different for a change 😉






    I decided, when I found a small scrap of foam (DTFB w/o paper), that I could start playing with the needle cutter and give a quick demo. These were the very first ever cuts with this particular needle cutter. The needle is a little long yet but the results are still reasonable, with a lot of small detail…





    I made a video but it is uploading now… will post later.

    — David



    My apologies in advance. Intended to be entertaining, this video may be too painful to watch. Please feel free to turn away if you are squeamish. You may want to turn down the sound as well.

    My story (and I’m sticking to it)… apparently a hairy gorilla broke in, rendered me unconscious, and thought he could do a better job of my needle-cutting demo than I could. Idiot! He was as ill-prepared, fumbled around, and was even more shakey than I am… ;)😉

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    Haha. Those gorillas are ornery!

    Good looking cuts. What planes do you like to cut?



    Far less the end user (building/flying) now, I seem more interesting in the tools/tooling nowadays. Shakey, spastic thumbs make the flying too much the challenge for me now 😉

    But back when my now-deceased buddy and I first started in the RC stuff, we were cutting all kinds of “foamies” and flying them in my pasture…  most were only one or two sheets of foam. We had great fun…

    Just a few…













    I have tried a few flying wing (bank amd yank types) and a nutball (that was the most forgiving) and an FT arrow. They are all a ton of fun, but I have a hard time getting my head around pitch and speed when I’m “in the moment”.

    Those planes look much tougher to fly though. Sometime, I’ll need to try fpv with one of these foamies.

    I’m the same way with building tools and machines instead of really making things with them. The bar is much lower for shop projects.

    I’m kind of the se way with planes and quadcopters, actually. Once I fly them, I lose interest and want to build another one.



    My buddy, Henry, was the far better flyer than I was. I was really partial to the RCPowers parkjets with their 3d fuselages and score-and-fold methodology (perfect for needle cutting)… that was why I initially did my needle cutter development over on the RCPowers site. I enjoyed the cutting and building of airframes just to see what they looked like… and then I’d give them to Henry to actually fly. I never enjoyed finishing/painting… we would simply shoot them with a light coat of spray paint (me, orange… him, not orange) just to tell them apart and see them against the sky.

    We began our journey on a quest to see just how cheaply a person could get into RC. As kids, in the 50’s and 60’s, RC was a rich man’s game… thousands of $$$ and hundreds of man-hours spent building balsa-and-tissue, gas-powered models that, more often than not, were destroyed when taking off on their maiden flight. Today, $2 worth of foam and hot glue, $35-$40 worth of servos, esc, motor, and receiver, a couple of batteries and a charger, and a $40-$50 transmitter… and you can go from “zero” to tons of fun in short order. Our pasture flight sessions were more like demolition derby – fly, crash, quick tape/glue field repair, throw it back into the air… and repeat. Last man flying wins! When a plane was beyond field repair and too far gone to fly again… we’d just go cut another one, quickly hot-glue it together, transfer the old electrics over to the new airframe… and we were ready for another flying session. What fun!

    I suspect we’re exactly the same… I’m far more interested in functionality vs. form/finish. I never truly finish anything. I build things to the point my curiosity is satisfied and/or I get bored with it… and then I’m ready to move on to something else. — David



    I love the build. Perfectly suited for that foam. I think the gantry can use two less bearings and bolts sort of like my rollers have. Two on top 1 on the bottom. Lighter and cheaper, it looks to have enough weight to also ditch the lower wheels as well like the LR2. I haven’t had any issues with that yet.

    I do think you should stick a sharpie on there and do a “tool change” add some offsets and decorate the foam a bit. Why do vinyl when you can draw directly on it!

    I am the same with flying them. I can’t seem to find anywhere nearby for my amateur pilot fingers to get some air time without one heck of a drive. So I will stick with the machines and maybe one day I will find an open space without fences.



    Thanks, Ryan.

    For this first build, I’ve tried to stay true to Mark’s design as much as possible… with the exception of the Z-body/cutter, which allows for continued development of the needle cutter and flywheel assembly. As far as the lower wheels, I already had the wheels on hand (ordered when I was thinking of building a LR1) and the end-plate DXF already had the slot… so I populated it. When I decided to put the 32″ wide door on the 30″ wide folding table, however, I had to drop the lower wheels to their lowest position… and they are now just hanging there. And, it seems to work fine without them!


    I don’t know, Ryan… that tool-change stuff is starting to get pretty fancy. I’ll have to warm up to it… 😉





    Adding some custom graphics might just get everyone on board….

    This does make me want to try a little slow flyer. Something I could actually fly at a small park. It is getting so cheap to get into this stuff now. My friends kids are in 3rd and 4th grade. They need some old school fun in there lives. I bought one of them a estes rocket….but a plane would be more fun, maybe a lil wing.



    I flew a nutball and it was pretty forgiving:


    Plenty of room for a logo on there.



    All the FT plans are available as a free PDF download… and they have quite a few trainer and fun-fly designs to choose from, as Jeff is suggesting.

    I would absolutely love to have you guys “pioneer” the combo decorate-and-cut procedures. I’m sure that would be a great selling point… and bring some folks on board. It doesn’t really have to be a Foam Ripper, either… a needle-cutter and marker holder combo could be devised and strapped to virtually any machine 🙂

    — David




    a needle-cutter and marker holder combo could be devised and strapped to virtually any machine ?

    Yours is already waiting….that pen is so sad that it just has to watch the needle cutter have all the fun. You are right though, I could get my feet wet as well.

    I have seen the guys fly the nutball on the youtube videos a few times and they do really have a good time when they do. Seems most builds there is a ton of concentration going on and that nutball is so slow and funky they all just laugh and have a good time. Maybe that would be cool to try. I’ll check my calendar.



    One of the advantages of “foamie” aircraft is that they are so cheap, the anxiety level is greatly reduced. At $1 a sheet from any dollar store and many/most fun-fly planes taking no more than a sheet or two, they are easily replaced if/when they need to be… especially if you are machine cutting them. The electrics/electronics most often survive typical crashes and are easily transferred to a new airframe, so this can be a reasonably economical hobby.



    I flew a nutball and it was pretty forgiving:


    Plenty of room for a logo on there.

    One of these days I want to go check out their new location.  They’re about 3-ish hours away from me.


    Also that F-15 is cool looking!  Brings back memories!



    Also that F-15 is cool looking! Brings back memories!

    If you are talking of the last plane in my post above… from that angle it does have a bit of a F-15 look to it but it was actually a RCPowers Mig-29 V3 airframe I built up.




    They had a pretty neat Parkjet V3 PDF plan bundle I purchased… it included F-35, MiG-29, F-117, and F-18. I really liked the score-and-fold technique they used to get a 3d look to the fuselages… it’s was perfect for needle-cutting. The F-117 was my favorite of the bunch though…


    It was fun to fly and really looked cool in the sky over my pasture! 🙂









    As kids, in the 50’s and 60’s, RC was a rich man’s game… thousands of $$$ and hundreds of man-hours spent building balsa-and-tissue, gas-powered models that, more often than not, were destroyed when taking off on their maiden flight

    My grandpa and his buddy was (according to my dad) in one of the model airplane magazines in the 60s for installing retractable landing gear in a model aircraft. My dad always was interested but even when he was making them in the 90s they were gas powered and it was expensive to learn. Luckily there were simulators.



    Ahh, from that angle it does look different.



    Hey guys, been rather out of the loop lately (See my post on David’s thread over at FT if you want the details – it’s kind of personal and pretty gut wrenching so you’ve been warned.)

    Anyway – I just had to chime in that I wouldn’t recommend a nutball as a first build.  It’s easy…and it was my first…but…it doesn’t really fly like a normal plane and can be tricky to get the hang of.

    The FT Flyer is a better starting point IMHO.  But even better would be the mini scout or tiny trainer.  They’re slightly more complex builds but fly MUCH better.  The mini scout is probably my all time favorite plane.  I’ve gone through 3 wings on mine and the fuselage is starting to fall apart – but I it’s just a joy to fly.  Uses cheap parts (I have an 1806 quad motor in mine that runs about $10 along with a $8 ESC and $5 Radio…toss in 2 cheap ($3 or so) servos and you’re set.)  It also uses small 500mah batteries which are a lot cheaper to stock up on than the bigger batteries larger planes need.

    I even strap  little all-in-one camera/vtx on the top and fly it FPV sometimes.  Barnstorming the picnic shelters at the local parks is a blast as long as no one else is there 😀

    My Scout’s first flight (almost 4 years ago…not bad for a $1 airframe!)

    And a year ago doing a little FPV with it:





    Hey guys, been rather out of the loop lately (See my post on David’s thread over at FT if you want the details – it’s kind of personal and pretty gut wrenching so you’ve been warned.)

    Wow Jason, that is incredibly sad. I am so sorry for your loss. I feel for you and your daughter and I can’t imagine how that feels. Just know we’re here for you, however we can be.

    Thanks for the tips about those planes. I’m going to have to get back into these planes.


    Mike Thorn

    Jason, I am so very sorry for your loss. My wife has had surgery on her thyroid also and they made it sound so minor and I guess in her case it was. I also have a daughter and a two month old boy, I just can’t imagine not having my wife. Again I’m so sorry for you loss.




    Okay… it’s all good 🙂

    Finally got FoamRipper in shape to cut those three sheets of DTFB for the vacuum pad… and things went quite well. No interrupts or squirrely things happened and all three sheets were completed and look reasonable.


    Here are videos (turn down the sound!) showing the needle cutter in action… cutting the slots and holes in three sheets of DTFB.

    First, the vertical slots…also note the cable support that flexes while still holding the cables clear of the workpiece… one of those giant nylon cable ties from the hardware store 😎

    then the horizontal slots…

    and finally the grid of holes…

    I decided Elmer’s school stick glue (goes on purple!) from the dollar store would probably work fine for what we’re doing here so glued the two slotted layers together and weighted them down while they dried… while I watched the golf tournament. They seemed reasonably flat, after golf, so cut the 5 ports to receive the 5 ends of Mark’s plenum. I really wasn’t sure I needed to glue the hole grid sheet and decided to try without glue… it’s also the spoilboard, remember, so it’ll eventually be replaced with a new sheet at some point down the road. Also decided to forego a frame of any sort at this point… I’d like this to be the minimalist version.

    The three cut sheets… the slotted sheets are the two bottom layers with holes on top…


    Mark’s vacuum fitting, a fun and impressive print…


    So, here it is in action. Spotted the hairy gorilla in the yard and called him in to help out… he did better, with supervision, but he’s still a crappy actor. Go Navy! 😉

    There it is… $3 worth of foam board and a printed vacuum fitting. And, it sucks! Hopefully the shop vac — a small 2.5 gallon unit — will not overheat with the restricted air flow in the time it takes to cut a sheet. I guess that’s the next on the agenda for testing… actually cut a plane and see how it does. Since Jason is fond of the FT MIni-Scout… maybe that would be a good one to try 🙂

    — David

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    Ryan, BT


    I’ve moved the FoamRipper machine back into my work area. This machine currently runs Marlin firmware on an ArduinoMega/RAMPS board stack… and runs headless, using an LCD screen and SD card for control and input. The bed is a 32″-wide interior door which I’ve cut down from 6’8″ to 4’8″ to make handling a bit easier. I installed the gantry and tried not to bang things around too much while moving it… thankfully, it powered up first time and seemed to be pretty much in the same condition I left it, from before Christmas last year.




    This is the candidate machine I’ve selected for permanent installation of LinuxCNC and the inexpensive LinuxCNC interface board set I’ve been developing, subject of another thread. This machine is somewhat similar in form (moving gantry) and function (foam-cutting) to the old BuildYourCNC-inspired wooden CNC machine, running LinuxCNC/EMC2, that I used before there was ever a MPCNC to discover and start playing with. Ever a fan of Ryan and his brilliant machines, this project is, for me, simply a fun and interesting way to come full-circle and duplicate the form and function of that old machine — including using LinuxCNC — using MPCNC/LowRider/FoamRipper construction ideas.

    The 3-sheet stack of DTFB in the middle is the vacuum pad I was testing when I put the machine away in anticipation of family visits during Christmas. It needs further testing… primarily to reduce noise.

    This past weekend, my internet connection was broken for about 30 hours? No forums and no streaming movies/TV… I finally decided that I could do something about tidying up my parallel port interface board set… the rubber bands are simply not going to cut it


    Without internet, however, my favorite online CAD tools are unavailable. But I’ve got OpenSCAD installed on my Mint box… and, for something as simple as a mounting plate, it shouldn’t take too long. So I fired it up and began to play… and soon was able to print a test plate


    After a few adjustments to the height of the standoffs, I printed a second plate



    Much better. A dab of hot glue on top of the standoffs and it should be good enough to hold the boards in place. The plan is to hang the board set on the gantry end plate… where the Mega/RAMPS used to hang


    I am really impressed with the design of these little CNC shield boards. All the pins for external connections are neatly grouped together and the hookup of that 4th “A” device is very versatile. With just a couple of jumpers, the “A” device can be used as a clone of the X, Y, or Z axis… or used for a 4th axis.

    For FoamRipper, I’ve got 2 motors driving the gantry along the length of the work surface… and the other two are single motors. So I intend to clone A to Y (as marked on the shield), and then hook up the X step and dir signals from the breakout board to this axis so I have two motor connections. Then Y step and dir from breakout board to X (as marked on shield) and, finally, Z to Z; i..e. I’m swapping X and Y (as marked on the shield) to simplify the wiring for the two-motor X axis. I’m also thinking I may want to use 1:16 microstepping rather than 1:32. We’ll see…


    — David

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    Alright! Finished putting the parallel interface board set together and installed it onto the gantry end-plate, where previously the Mega/RAMPS had been.

    I am really impressed with the design of these little Uno CNC shields. All the pins for external connections are neatly grouped together and the hookup of that 4th “A” device is very versatile. With just a couple of jumpers, the “A” device can be used as a clone of the X, Y, or Z axis… or used for a 4th axis.


    For FoamRipper, I’ve got 2 motors driving the gantry along the length of the work surface… and the other two are single motors. So I cloned A to Y (as marked on the shield)… and then hooked up the X step and dir signals from the breakout board to this axis, where I now have two motor connections. Then Y step and dir from breakout board went to X (as marked on shield) and, finally, Z to Z; i..e. I’ve swapped X and Y (as marked on the shield) to simplify the wiring for the two-motor X axis. The two jumpers just above the blue screw connections cloned the A device to Y (not populated yet)… and these two right-most devices are my new X axis. I’ve also setup DRV8825 1:16 micro-stepping rather than 1:32… just for grins. A dab of hot-glue holds the boards (hopefully securely!) to the standoffs on the mounting plate.


    Installed interface on the gantry end-plate. BTW the USB cable is simply supplying +5v logic power to the interface… no data.


    Yeah, it’s bulky but it can be broken down pretty easily/quickly… and sized to cut full-size foam sheets of interest to most RC’ers 😉


    and first moves! Air-milling the EMC2 logo from precious tests…

    I’m quite pleased with my morning’s work. Time for a nap… 😉

    — David



    Getting closer….

    Set up a FoamRipper configuration. Loaded a SVG file I’d created using the Blackstripes extensions into Estlcam and created a gcocde (.ngc) file. Not too bad for a ballpoint pen… though there are a couple of small ink blobs I wish weren’t there. Took a little less than an hour to print.





    — David



    That’s pretty cool!



    Ok… time to move on. I know folks are getting tired of me showing these machines in operation… doing everything but needle-cutting foam. But there is a method to my madness…

    Several have mentioned that it would really be of great utility and interest if we could do artwork/linework/decoration on a plane’s parts prior to cutting it out using the needle-cutter. Shouldn’t be a problem as far as the machine is concerned… but finding appropriate software to accomplish it might be.

    Here, I’ve used Inkscape to create an outlined hatched-circle pattern, shown below. I’ve used the Eggbot extension to cross-hatch the inner circle — representing an arbitrary “filled” area — and moved it to it’s own layer… this is the “artwork” to be done with pen or marker. The outer circle is the “outline” to be done with the needle cutter… and is moved to it’s own layer. Not sure at this point how valuable this “layering” will be but it seems like a good idea to me.


    So I saved the SVG (contains both layers) and then imported it into Estlcam (which I think ignores the layers). There I selected all the artwork to be “engraved” with the “pen” tool and created a gcode file for “artwork”. I then deleted all the “artwork” toolpaths… and selected the outer circle to be engraved with the “needle” tool. After previewing to insure just the outer circle would be engraved, I then saved the gcode file for “outline”.

    My machine currently mounts both a needle-cutter and a pen-holder… the offsets between the two will be determined later. But for now — for quiet/quick/compact and less wasteful reasons — I’m using paper and pen (rather than foam and needle cutter) for both the artwork and outline runs. The procedure should not change.

    So, I placed a clean sheet of paper/foam on the work-surface and moved the pen/marker into a starting position over the material… setting this location as X and Y “home”. I then lowered Z to find the top of the material and set this as Z “home”. IMPORTANT: I then manually pressed on the pen (this could be automated I suppose) to insure a small mark was made on the material surface… this is for registration purposes for the next operation. I then ran the gcode for “artwork”.



    Upon completion of the “artwork” step(s), I ran the pen out over to a random area and UN-homed the machine… losing all origin information. I then jogged the pen back into the vicinity of the registration mark and then “sneaked up” on it, first in X and Y, and finally Z. Setting the “jog rate” slider on the Axis interface to a low value and using the keyboard made this quite easy to align the pen tip (needle tip) with the registration mark.



    and, finally, run the “outline”/cutting operation


    Carefully done, this should yield “good enough” registration between the “artwork” and “outline” operations… for all but the most “picky” of us 😉

    So, that’s the plan… as I see it now. I think identifying software and generating the artwork… with dark lines and filled areas suitable for CNC… may well be the “hard” part.

    Thoughts? Ideas?

    — David



    That’s a good idea.

    Method a) I haven’t ever tried to do multiple tools in Marlin, but I think you can set specific tool offsets, so if your were at 0,0 and then selected tool #2, and moved to 0,0 the new tool would be over the work’s 0,0 location. This would be great in the long run, because you could store the information in the firmware, where it belongs, and only change it if you added more tools or whatever, and your old gcode files would still work fine. The trouble, of course, is the learning curve. I know offsets confuse people (they confuse me, at least).

    Method b) If I were doing this (and I was considering a similar problem for the low rider laser vs milling bit), I would probably calibrate the offset, write it down and do something like this:

    G1 X0 Y0 Z0 ; Move to a happy place
    G1 X10 Y20 Z0.5 ; Move by the calibrated amount between the two tools
    G92 X0 Y0 Z0; Tell the machine that this is it’s new home

    I would do that because I understand that gcode, and I would be able to look out for trouble like burying the bit before each command.

    Method c) I like your solution, though. It definitely is easier and easier to understand. I would probably just switch it around so you aren’t losing your home position, you are just putting the new tool on the registration mark and doing a new G92.

    A long time ago (in the days when a home CNC was a pipe dream), I wanted to make a settlers of catan board from laser cut wooden boards. I’ve since not played catan enough to justify it, but I would still like to do it. The pieces can’t be cut out with my wimpy laser though, so I would need to etch with the laser and cut the parts using the dewalt. It’s a similar job, I think.

    I also think there’s quite a bit to be gained from “just” getting something drawn on the plane. Even if it doesn’t align exactly, you’ve got a tool that is much more versatile and can apply some very neat designs.

    The hard part is definitely finding some art, applying it to the design of the plane cut file, and then forcing it through CAM. It would almost be more useful to have some neat art that you could apply to the whole sheet, and then cut out wherever the wings and parts end up. Say, there’s a great sand tool I know of that can make attractive patterns that scale well…

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