[Paraprop]

I am looking for a wood CNC router solution which would allow:

1. digitize the shape of an existing wooden propeller.

2. view the digitized prop on a cam software. Eventually modify it and then,

3. cut a wooden prop based on this modified data.


the max sizes of such props would be :

X = 135 cm / 53"

Y = 15 cm / 6 "

z = 7.5 cm / 3 "


Eventually it would be nice if I could put several router heads one next to the other so as to cut 2 or 3 props at once.


What would be the best drawings published in this forum to base the construction on ?

recomended rails / guides, motors, controller, software packages, digitizing head to be put instead of the router,....

I am thankfull for any advise.

Budget 1000 - 2000 US$.


Thanks

Daniel.

[cncadmin]

Wow those are big props 53", their is some digitizing probes you can use to get the profile into a program. I myself have not used such yet, but it should get you a good result, most machine here on the site are small in nature you needed at least a 53"+ x travel, most designs here could be stretched, did you look in the download section for the plans available there?

[ger21]

Maybe this? http://www.data-cut.com

[CNC Darren]

I havent seen one in use, but shop saber has a digitizing probe in there options listing.

[Zoff]

Offered price will just cover invitation to a dinner.

[Paraprop]

Hi,

Thanks for your first input guys

CnC admin & ger 21, I think with a slightly longer X length, the data-cut model should do the job as the spec shows X to be 49" most of my props are between 39" and 50 ". I will check out in this forum if I can find any similar drawings.
Then I need to find out if stepper motors will do the job for digitizing or if I need servo motors for this. And also the required power rating for the motors. Any clues about this issue ?

CNC Darren,

I cannot find the shop saber. do you have a link ? I would like to have a look at the probe.

I think I have to find a suitable probe and also the matching software which can provide a control routine for the router to move the probe step by step based on the last reading and adjusting automaticaly the X,Y & Z position of the probe as required for the next step and storing the previous coordinates where the probe did touch.

There is one from Heidenhain, the TS 220 or 230 but very expensive and I do not know with which interface and software I can have the digitizing done automaticaly.


The second step, is then that the software should be able to smoothen the digitized data into nice surfaces and show a 3D model of the prop.

The third step, is that I must be able to change propeller length, shape and most important, the pitch.

Once this is done, I need a recomendation of a good CAM software and CNC software

Any experienced guy can give me a hint on what probe and software packages would do the job without ruining me ?

Do you think the digitizing software and control part has to be different from the cutting software and control part or can the same be used for both ?

What do you think is a reasonable budget for such a setup ?


Looking forward to hear from you guys.

Daniel Reinle

Paraprop

Thailand.

[ger21]

Do you think the digitizing software and control part has to be different from the cutting software and control part or can the same be used for both ?

DeskCNC is a machine controller with built in probing. And the probe is under $300, I believe. http://www.cadcamcadcam.com

And both TurboCNC, and Mach2 will do probing as well. http://www.dakeng.com and http://www.artofcnc.ca

[buscht]

I think I have to find a suitable probe and also the matching software which can provide a control routine for the router to move the probe step by step based on the last reading and adjusting automaticaly the X,Y & Z position of the probe as required for the next step and storing the previous coordinates where the probe did touch.

I'm definitely not an expert here, but I do own a Roland 3D digitizer. This machine will move the probe and store the points as you suggest. The more control points you have, the longer it takes. It will output a STL file which cannot be modified. I have heard that for doing sweeping curves like you need, fewer control points are recommended. You could probably do this without a probe, by putting a pointer in the router collet, manually moving the machine to the proper point and just writing down the coordinates for later entry into CAD.

The second step, is then that the software should be able to smoothen the digitized data into nice surfaces and show a 3D model of the prop.
You need to do this in a CAD program, RHINO seems to be a good choice for this. You would have to create surfaces by connecting the points.

The third step, is that I must be able to change propeller length, shape and most important, the pitch.Again, I think that you can do this in RHINO once you've created the surfaces.

Once this is done, I need a recomendation of a good CAM software and CNC software.

Try downloading RHINO, it has no expiration date, but the demo limits you to 25 saves. Price is around $700US

MACH 2 is a great controller program $150US


Do you think the digitizing software and control part has to be different from the cutting software and control part or can the same be used for both ?

This depends upon time and money, If you want to cut alot of props and the machine is tied up digitizing, you might need seperate setups, otherwise one setup will definitely save money.

What do you think is a reasonable budget for such a setup ?

A wild guess to do this properly and produce good parts would be $7000US for machine and software.

[CNC Darren]

heres the link: www.shopsabre.com I belive ther probe works with Rams 3D wich is the CAM which comes with thier router, there is a link for Rams on the shop saber website.

[buscht]

http://www.shopsabre.com/

[trent2530]

I've been trying to do the same thing for some time now. Some of my results are blogged at http://www.machinecnc.com

Trent

[Paraprop]

Hi trent,

went trough your website but can't find any concrete information about the issues I have raised in it.

Best regards


Daniel.

[trent2530]

I guess that's why I said "some results". I'm in the process a redoing the whole company and website.

[imserv]

I am looking for a wood CNC router solution which would allow:

1. digitize the shape of an existing wooden propeller.

2. view the digitized prop on a cam software. Eventually modify it and then,

3. cut a wooden prop based on this modified data.

DeskCNC is a Windows based machine controller that can run fast enough to permit production of complex surface shapes such as a propellor. It uses the serial port and an external electronic card ( approx 2 x 2 inches) to provide dedicated hardware control of step and direction signal generation and probe input.

DeskCNC with the probe (as mentioned above) will scan the surface of your propellor, smooth the scan data, and reverse compensate for the probe tip diameter. It then asks you for the name of an .STL file in which to save the data. The .stl file is a common CAD file format and can be easily processed with DeskCNC (or other Cad and/or CAM programs) to scale, rotate, or position the shape, and create a CNC program to reproduce the scanned shape.

It should work with any of the step and direction motor drivers available for both stepper and servo motors. Either stepper or servo will provide enough accuracy to scan the parts, but a servo driver can provide higher speed cutting than a stepper drive.


Fred Smith - IMService
http://www.cadcamcadcam.com

[Paraprop]

Fred,

I have studied the information posted on your site. From your comments it seems to be exactly what I am looking for.

However I am a bit confused between the pictures and the version of your control boards posted. Further, others mostly use parrallel port but yours is serial port, could you may be elaborate on this ?

What would you recon what be the proper size of stepper / servo motors to go for let's say I intend later on to put 3 router heads one next to the other so as to cut 3 props at once ?

Earlier in the thread I got some recomendations for CAN & CAD software already. So now the next point is which kind of guides, pinion and rack or screws, and what frame can be most easily sourced here in this country.


Best rgds.


Daniel.

[ger21]

However I am a bit confused between the pictures and the version of your control boards posted. Further, others mostly use parrallel port but yours is serial port, could you may be elaborate on this ?

DeskCNC uses an external pulse generator, which plugs into the serial port. Software that uses the parallel port generates the step pulses in windows and sends them through the parallel port. The serial port is'nt fast enough to do this. By using the external pulse generator, DeskCNC is able to run under any version of windows, on just about any speed computer, and is able to output steps signals 3X as fast as Mach2, for example, which only works in XP and Win2K, and ideally needs at least a 1 Ghz PC.

[Paraprop]

In the meantime I think that the right way to digitize propellers and later to machine them is with a 4 axis setup.

The DeskCnc solution looks interesting from the software, probe and main controller board.
However I am not sure if the servo controllers and the proposed servo motors are adequate for the requirement.

Has anyone experience with these motors in a similar application ?

[ger21]

You don't have to use DeskCNC's motors and drives. You can use Geckos and any motors you want, you just need their contoller board.

[Rance]

ParaProp,

I assume that you are willing and have the wherewithall to build stuff yourself. If so, then try http://www.indoor.flyer.co.uk/probe.htm for your probe. It's almost FREE. Look around the rest of his site for more CNC stuff. Cool.....

I'm still a newcomer to this cnc stuff (maybe speaking out of turn too) but $2000 seems WELL within reason for your goal. $7000 just seems rediculous to me but I'm one of those guys that LIKES building things.

My off the cuff recommendations:
-Use steppers over servos. Steppers are cheaper & more redilly available. 150-175oz size will prob. work fine for you.
-Try out the FREE software before purchasing one for megabucks. Once you USE IT, then you'll really know what you want.
-I'd suggest the FREE CNC plans (Very similar to MVaughn's CNC machine) from what I can see. Only prob. might be the 53". This may require a rail that can be supported along the whole length of the X travel.

So much for the neophyte speaking here. Prob. putting my foot in my mouth. some advice is worth what you pay for it. Hope you attain your goals. Keep asking questions.

Rance

[Evodyne]

Hmmm...what about a little different approach on the digitizing side. This is conceptual, but those of you more adept with CAD/CAM can add your thoughts.

Take the prop and lay out some reference lines: say down the leading edge, trailing edge, and down the thickest part of the chord.

Lay out station lines perpendicular to the reference lines-running from leading to trailing edge. For the sake of the discussion, let's say every inch.

With the prop on a level surface, facing upward, measure the height to the leading edge line and training edge line for each station.

Imagine in your head drawing this on several sheets of paper-one per station. If your used the bottom edge of the sheets as a reference you could measure up and lay out the "heights" of the leading and trailing edges. Connecting those layout lines with a line having the chord length of the station (taken from a direct measurement) you know have a chord line of the correct length and pitch.

Let's add the foil shape. Sacrifice the blade, get a saw, and cut (as accurately as possible) through each station lines to get a series of profiles of the prop. Scan these using a desktop scanner into a series of images. In AutoCAD I know I can set an image as the background and then "trace" around it. My trace could be nothing more than spaced points that are later connected by one or more polylines to recreate the airfoil shape.

Once I had the shape for a station I would draw a line from the leading to trailing edge (a chord line), then scale the whole thing using the chord line as the reference vs. the actual measured chord for the station. Set up height reference lines in CAD and move the profile to match the real-world measurements, thus reestablishing the pitch in CAD.

Set a z-level for this station in CAD corresponding to the offeset of the real world station from the center of the prop, i.e. one inch offset, two inces, etc.

Offset the profiles side to side to line up with the real world points corresponding to the line you drew from the center of the prop to the tip down the thickest part of the chord. This will reestablish the blade shapes or curves (straigh leading edge, elliptic leading edge, whatever).

If you've read this far, you've just encountered the end of my CAD knowledge. Someone else will need to add to this to tell us all how to generate the 3D mesh from the separate shapes in 3D space.

Anyone know what to do from here?