New Foam Cutting Machine
By WXYZCIENCE, Section Mechanical Posted on Mon Nov 13th, 2006 at 04:47:12 AM MST
Four Foot, Four Axis

After all the comments on my last post and the successful test cuts, we put together this four axis wing cutter. The new machine is two of our older machines combined together to allow the three dimensional cut too be done in a single pass. The first machine is programmed with the profile and the size. The second machine is the slave and is controlled by the first machine and is programmed with the wing tip profile. The angle of the second profile can be shifted up to ninety degrees. The new cutter will be able to cut fifty inches of foam. We have also implemented a spring into the cutter wire to adjust the change in the wires length, due to thermal expansion and angular length difference. The cutter is now using a stainless steel wire. I have a hundred foot roll of stainless wire feed welder wire. The first test was twenty four inch, high lift profile. We will be trying some different lengths and tapers this week. We will try a forty eight inch cut with the good material once the pattern and the test cuts work well. Also the cut is very smooth over the entire length. This produced an excellent internal mold. Joseph

New Foam Cutting Machine | 14 comments (14 topical, 0 editorial)

Re: New Foam Cutting Machine (3.00 / 0) (#1) by pepa on Sun Nov 12th, 2006 at 10:07:24 PM MST (User Info)

Joseph, you just keep getting better. pepa

Re: New Foam Cutting Machine (3.00 / 0) (#2) by willib (willibur at comcast dot net) on Sun Nov 12th, 2006 at 10:22:53 PM MST (User Info) http://www.njwind.com/webcam.html#

Very neat ! what is the chord length at the top of the blade in the pic? what is your max chord length? sorry for all the questions Carpe Ventum (seize the wind)

Re: New Foam Cutting Machine (3.00 / 0) (#3) by badmoonryzn (badmoonryzn) on Mon Nov 13th, 2006 at 06:34:13 AM MST (User Info) Too much work too little time

What a nice job! When are you going to sell us some cuts so we can make molds or use them as a templet? Nice job! Badmoon I just wanna have some fun, maybe learn something new every day and make some friends in the process.

Re: New Foam Cutting Machine (3.00 / 0) (#4) by windstuffnow (elenz(at)windstuffnow(dot)com) on Mon Nov 13th, 2006 at 07:56:36 AM MST (User Info) http://www.windstuffnow.com/main

Pretty slick Joseph!  My attempts at cutting foam came out fairly well but its simply a hand drawn unit with a follower to form the shapes.  Looks like you have a pretty good handle on the CNC workings !  Tooo cool! . Have Fun! Windstuff Ed

Re: New Foam Cutting Machine (3.00 / 0) (#5) by Experimental (harogate@whidbey.com(no spam)) on Mon Nov 13th, 2006 at 11:07:19 AM MST (User Info)

Beautiful Joseph,     Something we found when we were building "wings", was -- the trailing edge caused us a great deal of troble -- it usually came out "wavy and was very suseptable to damage, when glassing.. We finally departed from the final form about an inch or so from the trailing edge on one side -- perhaps the top side !!   We left the trailing edge an inch or so thick, then began glassing about an inch or two behind the leading edge, wrapped the cloth around the leading edge and epoxyed to the finished trailing edge on the one side -- the saturated glass will extend about 1/8th inch, behind the trailing edge where we trimmed it off !!     After the epoxy has cured, you hot wire the last section of the trailing edge off , by using a hardboard form at each end -- we held that hardboard in place with a couple of nails, pushed into the foam -- that last inch or two, was hot wired off by simply pressing the wire against the form, as it follows the hardboard at each end -- we had a"bow" shaped hand held hot wire fixture for that !!   Now you have a sharp trailing edge, supported by the glass on the one side -- simply sand that glass joint, behind the leading edge (carefully) and do the same thing, finishing the other side -- the little overlap, at the trailing edge, will bond together, glass to glass and you will wind up with two layers on that leading edge -- if you feel you need more layers, again you will have to sand the "lap joint"...   You can buy the glass cloth in finished widths -- 2 - 4 - 6- 8 inches with finished edges -- much easier to worh with, but that finished edge always makes a "bump" if you try to glass over it and a little sanding is usually required for proper bonding, between layers -- but sand the resin, avoid sanding into the glass cloth !!    If you want to add stiffness to the blades, I have drilled holes, from end to end and bonded graphite arrow shafts into the blades (available at some sport shops) and "Aircraft spruce and specialty", in Culver city, California...    I hope this info is usefull to you and others -- happy building, Bill H..

Re: New Foam Cutting Machine (3.00 / 0) (#6) by tecker on Mon Nov 13th, 2006 at 03:54:53 PM MST (User Info)

Saw some tungstan wire on ebay http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320048982701&fromMakeTrack=true

Re: New Foam Cutting Machine (3.00 / 0) (#7) by chinsettawong on Tue Nov 14th, 2006 at 12:31:54 AM MST (User Info)

Nice work! I have also built one foam cutter and have tried to cut a few using it.  The result was quite good.  You can see it at http://www.fieldlines.com/story/2006/2/28/1551/54276 However, I faced a problem with wire becoming too hot and melted the foam when cutting the curve.  Do you have anything to control the temp of the wire?  Do you have this problem? I haven't done anything yet since my last test cut.  My 2 finger bones wer broken from big Neo magnets crushing together when I tried to build a bigger rotor.  Since then, I'm still afraid of touching them.   Wachara C. Bangkok, Thailand.

Re: New Foam Cutting Machine (3.00 / 0) (#13) by WXYZCIENCE on Sun Nov 19th, 2006 at 12:55:11 PM MST (User Info)

Wachara, looked at your post. Very impressive. On my cutter the temperature is controled by a light dimmer and stepdown transformer. Four feet of the nichrome wire required about 30v ac to melt the foam properly. I cut slowly so the wire temperature can be set very low. Also the temperature can be reduced in tight radial cuts. Thanks for your input. Joseph. [ Parent ]

Re:First 4' Blade (3.00 / 0) (#8) by WXYZCIENCE on Tue Nov 14th, 2006 at 02:03:00 AM MST (User Info)

Spent most of the day working on the fume hood and foam mounting clamps. Bill programmed the controllers with the two cuts. He had to tweak the timing to obtain accurate synchronization. Changes to the cutter included a thinner nichrome wire and the transformer was up-sized to a twenty five volt 5 amp type. The first blade took less than two minutes to cut. A very smooth cut. The root cord length is 7" and the tips cord length is 3". This wing has no twist though. I need to read a little more on the twist angles that will work for this type of wing and others. Any suggestions would be welcome. The outside mold from this cut came out excellently and I will be testing the mold idea this week and posting the results. Joseph.

Re:First 4' Blade (3.00 / 0) (#9) by badmoonryzn (badmoonryzn) on Wed Nov 15th, 2006 at 06:46:06 AM MST (User Info) Too much work too little time

I still say what a great job guys I would love to get my hands on a few. Let us know when you are going sell some blades as i would like to make some out of kevlar or glass. I wish I had the time to build one too, but with the projects I have now I need another lifetime. What is the stand you have holding the blade? Dennis Badmoonryzn I just wanna have some fun, maybe learn something new every day and make some friends in the process. [ Parent ]

Re:First 4' Blade (3.00 / 0) (#11) by badmoonryzn (badmoonryzn) on Fri Nov 17th, 2006 at 03:13:55 AM MST (User Info) Too much work too little time

I guess WXYZCIENCE does not want to sell his products. Kind of like showing a kid candy and running away. WAH! Does anyone know if blade templates like this are sold? I would like to get a few to make some blades out of glass and Kevlar. I do not have much experience carving these #2*#$#! wood ones. They are kind of fun but I would hate to put them in my wind tunnel and watch the air move over them like a washboard! By the time I get The six footers smooth they will be one eighth inch two footers. I have not seen anyone talk about Kevlar, Why? I have used it in building chassis, rear ends front ends and other parts for 1/10 and 1/8 scale RC cars and was very happy with the results. Axles for the rear drive came out very strong and light and were lighter than titanium and much cheaper. The also flexed much less than and materials I used. We turned axles in a homemade lathe jig to get the size we wanted. We made ¼ inch and 3/8 inch axles anywhere from eight inches and up. We sold some to people at the track and they were liked. They do break but it take great force and regardless of what you make them from they do not like hitting an immovable object at top speed. The Kevlar breaks, the metal ones bend and the cars rear end comes apart in several pieces. They are all useless at that point, but the Kevlar ones get a new axle and they often go right back in the race without problems. Accidental sheer points. LOL I wish I could say I did it on purpose, but it was just luck. Many went from titanium to Kevlar/graphite because the titanium bends pretty easy and retains a memory of some sort. We sold a few, but we all had full time jobs too and time was at a premium. The chassis were easy to lay up and out of 20 or so I just broke one. I hit a steel pole with a 1/8 scale sprint car at about 65 mph. The chassis broke off the nose of the frame that held the front wing because I had ground it to look good and it was weak. My fault, so I did not worry about aesthetics again on the frame. Anyway, I understand the process and it is easier for me to work with and get some decent results. Thanks guys, you all make this site very informative and fun. Bad I just wanna have some fun, maybe learn something new every day and make some friends in the process. [ Parent ]

Re:First 4' Blade (3.00 / 0) (#12) by WXYZCIENCE on Sat Nov 18th, 2006 at 03:20:48 PM MST (User Info)

Badmoon, Thanks for the interest. I first have to get a quality product. I was checking into the cost of the 2" pink and blue foam yesterday and will come up with a method for getting some of the blades into the hands of people who want to experiment with different profiles. I think shipping will be ok because they don't weigh very much. Maybe you can be the first. Anyway it is my plan to move that way. I will be posting tomorrow some exciting update to the foam wing. Joseph. [ Parent ]

Re:First 4' Blade (3.00 / 0) (#14) by badmoonryzn (badmoonryzn) on Tue Nov 21st, 2006 at 08:07:45 AM MST (User Info) Too much work too little time

Were not worthy! You have really done a real nice job on that machine. A bud and I considered making one, but the amount of time involved is prohibitive. I just have too many irons in the fire and I would have to depend on my friend who has more projects that I do. Not going to happen at this point. I am curious about the first blades you made, as I have not played with that type of rotor, and I think it would be fun. I'm waiting for some parts so I can get on with my 10 footer and then the big one, but I have several gennys I can use to experiment with other types of blade designs. What are the sideways rotors called? Boy we have one heck of a storm blowing outside. I need to fix my big generators carburettor just in case we lose power again. I look forward to making a few smaller gennys while I build the alternators and the accursed six' wood blades for the big ones. Oh crap there went the power again. ARG! I got a few hours on battery, but I need the gas generator running if the power stays off for over a day again. I try to run one TV, a notebook, satellite dish on my battery backup system, but these batteries are crapping out, so I need to find some more used commercial ones to rebuild into a nice sized storage bank for the house. I would like to get three days out of it with 350-watt load. Having the wind and solar charging. I figure when I get the water wheel (10,000 watts with 110 and 220) going the wind and solar will be a nice backup for the wheel when it has problems. I had better get going on the gas generator or I might be in the dark tonight. CYA and thanks again Joseph. Badmoon   I just wanna have some fun, maybe learn something new every day and make some friends in the process. [ Parent ]

Re: New Foam Cutting Machine (3.00 / 0) (#10) by bj (jackbp996@msn.com) on Wed Nov 15th, 2006 at 05:13:40 PM MST (User Info)

Joseph--as has been said by many, including me, beautiful work.      bj thanks all bj

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