Sort of beginner question larger cnc cutter

[Latexgurl]

Well the general plan was to use a U shaped HotKnife blade so it would be more like a hotwire system.

Actually I was looking at the possibility of using hotwire to get the blank down to size and then do the hotknife thang but Viper is right about going with the hotknife and having it almost finished maybe....

The Hotknife/wire system would be mounted on a gantry and the blank would be rotated as it cut.

I am wondering if I would need the stronger steppers for the rotation system and not as strong for the other axis's.

Suggestions and setting me straight always welcome!!!!!

Ashley

[ViperTX]

How much does the unshaped foam weigh? Yes, the rotation axis will require more torque then the other axis...hope that straightens ya out....*smile*

[Latexgurl]

But I am 5'9" and 127 pnds ..... and the foam I want to cut will be dimensions

8 feet X 2 feet x .5 feet so with eps at like 3 pnds heavy per cubic foot so under 25 pnds definitely to get all scary. Basically want to be able to do a blank at least 7'10" by 20" wide and with the curve of the board(lot like making and airfoil)would like depths of at least a Foot 1Ft so it is basically sculpted out of the foam.

Hope that helps

Ash

[Latexgurl]

Just wanted your opinion on whether these motors will work for this project.

I just bought four of them on Ebay and I am wondering whether I will just have to turn around and sell them cause they are not strong enough or for other reasons.
Thanks once again for all your help I dont think I would have the experience neccesary to do this without help and suggestions from y'all on the board. Much Lub

cheers
VEXTA 2 Phase STEPPER MOTOR PK268M-01A
Speed vs. Torque Characteristics

Size 2.2inch
Holding torque 191oz
Rotor Inertia 2.6 oz/inch
Rated Current 1Amp/phase
Resistance 8.6
Basic step angel 0.9

http://www.orientalmotor.co.jp/cgi-b...frameSize=56.4

[Latexgurl]

Ok post above made me think that I might need to reiterate the full idea.

I want to have a larger scale machine for cutting prime EPS blanks for surfboards, cutting plugs for composite vaccum bagging, and at most in the future I might retrofit it for cutting balsa although that is a secondary concearn.

The actual machine will have a MIG welded steel frame that will sit on the concreate floor and will have demensions on the order of X x Y x Z of around

8ft x 4ft x 5ft in a configuration like this but with a few adjustments in the cutting, materials, and layout for better stability and to eliminate flexing.

http://www.demandhotwire.com/twister.html

My primary questions now are

Size, type, torque, power of stepper motors?

Driver boards? Can I just build up 4 or 5 of the boards from Electronic Utopia? or do I have to go with something better like Gecko or Other?

Ballscrews or something like the Ball linear track system ?

Best program to use? I have access to Mach2, DeskCNC, turboCNC? Any suggestions on something that can control the motors and the rotating center section well.

Accuracy the best I can afford for under like a $thousand all together for the project.

I already have the materials for the frame and hopefully the motors above that I bought will work, also have all the computer stuff I need including power supplies(computer and otherwise) but dont have the Driver Boards/4axis5axis Driver setup?

Once again thank you for all of your help so far and the brainstorming and the jokes, VIPER, Fusion, Mac Knife

thanks again guys much luv.
All suggestions and setting me straight are more than welcome. Love the pain!!!



ashley

[ViperTX]

...like the vertical frame......so, the welded steel framing was what was on my mind as being the most economical....since we have to rotate a blank that is 20 to 24 inches wide the table frame should be 9 X 3 ft. That would give us the room to place the cutting structure on and it would have an envelope of 8 1/2' x 30" x 30". I'm thinking that anything around 400 oz-in would be acceptable. Drivers....sticking with low Amps per phase allows you to use the low-cost drivers....I would not worry about that at this time...just have a general idea.....Oops you already have the motors...no problem we can always adjust the torques with timing belts and pulleys.

If you really think you need a larger envelope....then now is the time to size that.

9 foot ballscrews are going to be about 150 each.......and another 40 for the ballnuts....

[ViperTX]

Ashley...just looked at the torque specs....well she'll be cute but slow......torque really drops above 200 rpm....

[Latexgurl]

I might just have to put them back up once I receive them and get some that are better for the job.

Any suggestions on what I should be looking for in a stepper motor to get not fast speed but adequate speed. I am not going to be a manufacturing facility but would like to be able to do more than one board a day :-)

Thank you once again you have been a real doll about things,

Ashley

[ViperTX]

I've got the links at work....will get them to you tomorrow....any thoughts if you want to go with ballscrews & nuts or ACME (cheaper, but require more torque)? A "doll"....isn't that like a playthingy....*smile*...yw Ashley.

[erase42]

wow i have a lot to say on this one. tell you what, email me latexgurl. Ive been cutting kayak blanks for a buddy of mine on a machine that i built in my shop. it is possible for you with a 3 or 4 axis machine a very precise blank. all you would have to so is some light sanding to take off the small ridges where one straight wire cut intersects with another. the router aspect really isnt nessesary as long as you dont need to sink pockets in below the surface. a U shaped wire loop is possible, im using something similar on another machine, however for for what you are doing the surface would probably be less than desireable. its almost impossible to "feather" one cut into the next cut. where the cuts overlap and it has to cut that very thin layer of foam, there is no structure for the melted foam to recess to so it sort of goops up on the wire till it drips off melting a deep hard hole into the foam. not easy to sand at all. anyway drop me an email and we can talk thru email if you have any questions or want to see pics of the setup.
Ed Rees erase42@Aol.com florida
ps im a friend of danny ray

[anthony-whalen]

I have shaped a couple of surfboards by hand and I am not great at it. I don,t want to spend the next five years shaping to become great. I have found a CNC router designed for shaping boards in Australia for about 65,000 witch I can,t afford. I thought I might try to make one. I have a realative with a machine shop that has built CNC machines and can give me sound advise. He works with metal and all I would need the machine for I polyester foam. If anyone reading this knows the motor requirments needed to power each axis. The machine I found at http://www.shapers.com.au/ will shape a board in about 8 minutes. I do not need this router to run that fast, I am going for the most economical machine for the money.
I found a set of plans that look pretty sound to me at- http://www.inshorepowerboats.com/cnc.../CNCROUTER.htm
The estimated cost of producing this machine is estimated at 5,000 dollars witch is a lot better than 65,000

[GAWnCA]

Has anyone built their own hotwire controller and/or pendant?

[astatue]

hey folks I see $25000 is a little much for a 4 axis foam cutter so check us out at www.astatue.com under 10,000 delivered set up and 2 days training.
custom designs for stand alone lathe and table router possible too. call and we will help.