CNC cut foam cores

[Jon Matcho]

Wow, they look great from here. It would be fun to see a movie of the cutting happen, so add that to your list when you get a chance.

 

Check the post above -- you should talk to Velocity.

 

Keep us posted -- the pictures are great.

[Kraig]

Steve sent me a sample of his cores over the holidays to compare to my featherlite cores. They are fantastic. smooth as glass and no variation from mine. They are quite crisp, even on the fragile trailing edges.

 

I was quite impressed. I only had my cores from featherlite to compare, so when I got his I confirmed that both are of super quality. Timing was good also as my cores are now jigged up and ready for the shear web layups to go on.

 

I am forwarding the samples to Randi and Chrissi, (Cozy Girrrls), so they can give us their opinion as well.

 

Keep up the good work!

 

Kraig

[chasingmars]

I've given some thought to doing something similar, on the idea that I'd like the precision of CNC... one of the things that I was thinking about though, I'm curious how you approach:

 

When you cut the cores by hand, you're following a template that's on the surface of the foam, whereas with the CNC machine, the "template" or, rather, tool path, is in the plane of the machines degrees of freedom. Where the ends have the same profile path shape, size and stations, this is irrelevent, but where, as with our wings, the templates are different, this changes the shape of the wing.

 

Do you calculate out from some sort of imaginary surface position where the templates would be and then generate your tool path from that extrapolation (and if so, how about cases, if any, where the templates aren't in parallel planes?), or do you use the CNC machine to guide your wire over a physical template on the foam the same as by hand? Some other way?

 

I was thinking about trying to do the extrapolation, it should just be a bit of vector mathmatics, but wondering if anyone has tried it already?

 

Craig.

[EZ AHAB]

Do you calculate out from some sort of imaginary surface position where the templates would be and then generate your tool path from that extrapolation

Basically, yes. If there is no taper or sweep, such as the canard for the most part (except for the spar troughs), the path that the machine moves the wire holder is the same as the shape in the foam. If there is taper and/or sweep, it's a lot more complicated. The machine must move the wire holders along different paths than what is cut in the foam. For instance, for a wing with taper, the axis on the root side must move the wire holder along the same basic airfoil shape but at an exaggerated scale. On the tip it will move it along a much smaller scale. You have to align the foam in the machine just right so that the path traced out by the wire will be just right in the foam.

 

This may sound like a lot of math, and it is, but luckily that's what computers are good at:)

 

(and if so, how about cases, if any, where the templates aren't in parallel planes?)

It's just a more complicated extrapolation. Luckily, I built my machine large enough to not have to do this. I purpose built it for making EZ wings. If you were to go buy one this large it would probably cost on the order of at least $6-$10k++. Even then, of the ones I've seen advertised on the web, they still have a very rudimentary wire tensioning device that doesn't look like it would work well for cutting profiles with as much taper and sweep as EZ wings. When I first started building my machine I put little thought in how the wire would be held. I just thought I'd use a wire with a spring on one end like all the ones I had seen had. It turns out that that works ok for small amounts of taper or sweep but not so well with the amount EZ wings have. Developing my own design of wire holding and tensioning device has been quite a project in itself. I have gone through a number of vastly different iterations but my current design seems to be working quite well now:D

 

, or do you use the CNC machine to guide your wire over a physical template on the foam the same as by hand? Some other way?

 

All my "templates" are digital only. I can print them to compare with the plans just to be sure they are properly digitized but I don't need to cut them out of ply or anything. When I cut the foam there is no physical template attached to the foam.

 

I was thinking about trying to do the extrapolation, it should just be a bit of vector mathmatics, but wondering if anyone has tried it already?

 

Craig.

Yup, they sure have.

[EZ AHAB]

Progress update.

 

I've been working feverishly on digitizing the remaining templates and figuring out how much of what size foam to buy for wings, winglets, and canards so I can set up a realistic price list. Both of these tasks are nearing completion. I've been finding better and better ways to get more use out of less foam which saves both material and shipping costs. I've found a somewhat local supplier of foam that I can use to keep costs down as well.

 

Here is my "introductory" price list:

 

Roncz Canard $200

Winglets $150

Wings $775

Everything $1100

 

This price includes foam but not S&H from me to you. S&H will be the shipper of your choice with an additional fee to cover packaging materials. I'll be looking into this in more detail in the near future.

 

If you already have your foam, you can ship it to me to cut at a reduced rate.

 

Be advised that the only finished core I've made so far is a Cozy canard. I've got a bit more work to do on block layout stuff for a LEZ canard but that should be done very soon. Next will be winglets and then wings. I will take orders on canards now but please stand by on everything else. I already have 2 orders for wings and I don't want to get a bunch of orders before proving myself. I would like to know if you are interested, however. That will give me a good idea of how much foam I need to purchase.

[DAVID W BURKES]

I have personally seen the man and his machine. Both are strictly top drawer.

If "perfectionist" doen't accurately describe him, it's real close. Needless to say he's cutting MY wings. Did I mention he's a great guy too?

[magnum]

:banana: :banana:

Cant wait!!!!!!!!!!!!!!!!!!!!!!!!!

[rpellicciotti]

When you do the Long EZ wing templates, consider also doing a root template for the E-racer. The Long EZ had a taper on the root end of the wing which creates a chink in the trailing edge. This was done originally so that the Vari-eze cowlings could be used on the Long. Builders of Long-EZs today often eliminate that kink in the trailing edge and build their wings straight. The E-Racer, Berkut also have straight trailing edges. If I were going to build an Open-EZ, I would also like to have the trailing edge straight as I would probably build my own cowlings as well.

[CP Tomes]

Maybe I missed it, but where are you located?

[EZ AHAB]

I am located in Abilene, TX.

 

As far as the E-Racer root templates go...I don't have E-racer plans. I do have original plans for the VariEze, Long-EZ, and Cozy Mk IV but nothing else. If someone wants something else, I can cut it for them, I just need a set of templates to digitize. I can cut pretty much anything you want given a template to go by. I plan on making several other parts for my EZ with my machine. For instance, I plan to build a new cowling using the machine to cut out a foam mold.

[airwrench]

I am certainly interested, for the time being, in your cnc canard foam products. How may I place an order with you? I have made some hand cuts which look pretty good but, naturally would prefer to glass something on the order of "precision". The canard you cut is the 1145 correct?

[EZ AHAB]

Yes, the canard I cut is the Roncz 1145MS sized for a Cozy Mk IV. I've got a little bit of work left to do to make the Long-EZ variant. You would think it would be easier because it's smaller but it isn't. At any rate, I hope to be ready to cut Long-Ez canards by the end of the weekend. If you want to order one, you can send me a private message or email through the forum and I'll get you my email address. I don't like to post it directly on the forum because of the spam it attracts.

[EZ AHAB]

Progress report:

 

I accidentally short circuited a motor driver the weekend before last and had to order new parts. While the machine was down I decided to do some modifications I've been needing to do in order to cut full scale wing cores and for LEZ canard cores. I added a couple of inches of useful travel to both x and y. That is now 98% complete. I just have to tweak the leadscrews a bit to make sure they don't bind. Oh, the motor driver is now fixed too.

 

I also bought and have been working on a foam toting trailer. I found that I couldn't get many of the large blocks in my Suburban (only 4 and I had to cut 2 of them into smaller pieces). My trailer should haul 20+ blocks! This project is probably at 75% completion. The cold wx has been slowing things down a bit as it takes forever for the paint to dry.

 

I believe I will be able to get foam from my supplier at about the same price as it would cost for someone to ship me their foam, that is, at the rates UPS charges. I still need to research the best way to ship this stuff since I know that UPS is expensive. If anyone has any good ideas, let me know.

 

My wife and I are going on vacation from tomorrow till next weekend. We are going on a cruise in celebration of 10 wonderful years of marriage (you wouldn't believe what she lets me keep in our garage......oh, maybe you would;) ). Anyway, I know a lot of people are anxiously waiting for me to start full scale production and I didn't want them to think I'd slowed down. Quite the contrary, I've been very busy lately. There's just a lot of grunt work to be done getting everything ready and I still have my "real" job to do as well.

 

Well, everyone keep warm. Now where did I put my bathing suit?

[Jon Matcho]

Congrats on your milestone, and have fun! We'll be waiting patiently...

[EZ AHAB]

Hello from Belize! Having lots of fun and it's nice and warm here:)

 

I'll be back Sat night.

[magnum]

Your cutting cores in Belize? :yikes: LOL!

Have fun and enjoy your stay!!!!!!!!!!!!!!!!!

Press on

Tom

[EZ AHAB]

Cruise was outstanding! Now it's back to work.

 

The CNC machine is back in operation and progress continues. I've been working on the winglets since I have to cut some for Jon and because they are even more difficult than wings in some respects since they have so much taper. I've cut both left and right ones at 1/2 scale in small cell extruded polystyrene and they turned out really nice. Note how perfectly they line up with the red printed lines in the photos. Since there are no physical templates used with a CNC hotwire, I use these drawings which I print from a CAD progam, to ensure the machine is cutting the shape it is supposed to be cutting. I'll be cutting the full scale winglets by the end of the week.

 

I've also been working on my foam toting trailer so I can get a motherload of foam perhaps on Monday. I would have finished this long ago but it takes forever for paint to dry when it's cold.

[Jon Matcho]

My my... they look like they've come out of a machine! Looking good!

[EZ AHAB]

Thar be foam here!

 

This is about 3 airplanes worth.

[Jon Matcho]

What density foam did you manage to get?

[EZ AHAB]

It's the same Dow product that Wicks sells. I'm fairly certain it's the same that ACS sells as well but they didn't know the product number. I only weighed 1 of the blocks I bought on Monday and it looked like it was close to 2 lb density. I believe the material properties vary a bit between batches. A "batch" is at least 36 7x14x109" blocks. It looks like it is probably manufactured in a huge blocks which are then sliced into smaller ones. The material properties may even vary somewhat within the same block. I plan on weighing and measuring all the blocks I have to test this theory. The foam I bought on Monday is a bit darker blue than a few pieces I bought from the same supplier over the holidays. Based on my own experiences and info I've gleaned from the canard pushers, Cozy newsletters, and the internet, I think the density varies between about 1.6 to 2 lb/ft^3. This would explain the discrepancy between the densities listed on the Wicks and ACS websites.

[EZ AHAB]

Here are Jon's winglets. I'm still working on the lower ones.

[satch]

Ohhhh ... Pretty!

[EZ AHAB]

The winglets are finally done! The bottom ones were a challange to figure out how to cut with the machine, believe it or not. I've got it down now though. I also spent something like 12+ hours working on CAD stuff for the wings today. I hope to start on those this week if I have the time.

[EZ AHAB]

I started cutting wing parts today. I cut the tip section and a winglet.

 

Yes, that's the right winglet sitting next to the left wingtip. I just wanted to see them sitting next to each other.