Step Pulse Multiplier

[RotorRouter]

I am starting the developing a cnc filament winder to produce composite helicopter blades. Some windings will be lengthwise (fast motion parallel to the X-axis) and other windings will be a wrapping about the X-axis (rotation of the A-axis with a slow advance along the X-axis).

The travel speed along the X-axis will be very different between the above two windings.

I am wondering;
1/ Will there be an advantage by using the G340 (or the G320 + G910) to drive the X-axis servomotor and thereby utilize the step pulse multiplier?
2/ Also, it is feasible to have remote electrical switching of the 'Multiplier Header'; either by a manual selector switch or by g-code at the start of each new winding run? Or, will some of the trimpots have to be changed at the same time?


Or is it just dumb idea?


Thanks

[ger21]

The ONLY reason to use the G340 is if your computer can't output steps fast enough for the G320. ANd, no, you can't change it with g-code.

[Bubba]

RotoRouter,
Why worry about changing the gecko physically??? If you use a "standard" controller like TCNC or Machx, simply set the feed rate to a different speed.
If you are moving in only the X direction this time, set it fast say 80 IPM or whatever and when you are doing the wrap, set a slower speed and the machine will reach the end points at the same time (if I read your scenario properly). To me, the second would be simular to "cutting a thread" except you are winding the filiment on top of the piece. From a starting point of X0 A0, you might issue a command of G01 X5 A1800 F10 which would give you 5 turns spaced at 1 inch helix. Obviously, I have pulled numbers out of the air for this example.

[ynneb]

I like the idea of this filament winder. I have never heard of this b4, but I suspect it is something that is comonly done, yes?
is this the sort of thing they use for carbon fibre?

Do you have any pictures?

[RotorRouter]

ger21 and Bubba

The objective is to have the fast travel on the X-axis at approximately 24 ips. The slow travel winding around the X-axis will be similar to "cutting a thread" but with approximately 20 revolutions per inch of travel.

1 idea down Thanks.


ynneb,

Yes, it is used for carbon and fiberglass fiber etc.

Here is a sketch of the basic filament winding operation;


A small winding machine;


Applying the tow;


A few products;



There are also other CNC methods of applying composites, such as tape laying etc.

Thanks again.

Dave J.

[ger21]

Originally Posted by RotorRouter ger21 and Bubba The objective is to have the fast travel on the X-axis at approximately 24 ips. The slow travel winding around the X-axis will be similar to "cutting a thread" but with approximately 20 revolutions per inch of travel. 1 idea down Thanks.

Not sure if you understood Bubba's post, but he showed exactly how to do what you want with g-code.

[ynneb]

This has got me thinking, Lets say you were wrapping an irregular shape that varied in diameter along its travel. This would cause an uneven wrapping, unless there is CAMware out there that you can insert the shape and it will work out the variable feeds along the way.

Also, how would you go wrapping a shape with divits in it. The divits would be flattened out by the ssurrounding mountains stopping the wrapping from going down.

EDIT: Maybe I am wrong. 1 rotation of the item = 1 rotation , regardless of the diametr of the item. I guess the wrap just feeds on faster for the larger diametre stuff. Confusing, I cant get my mind around this, because the x travel would need to slow down too ? Gee I dunno.

[ger21]

Originally Posted by ynneb This has got me thinking, Lets say you were wrapping an irregular shape that varied in diameter along its travel. This would cause an uneven wrapping, unless there is CAMware out there that you can insert the shape and it will work out the variable feeds along the way. Also, how would you go wrapping a shape with divits in it. The divits would be flattened out by the ssurrounding mountains stopping the wrapping from going down.

Filament winding is usually used for tubular shapes, not irregular shapes.

[ynneb]

Filament winding is usually used for tubular shapes, not irregular shapes.

I am starting the developing a cnc filament winder to produce composite helicopter blades

Then I wonder if this will even be suitable for him? It might be worth checking the shapes of the blades and if the will wind correctly.

[RotorRouter]

ger21,

Your answer got to the point quickly and clearly. Then Bubba's post 'fleshed out' yours.


ynneb,

You are correct. The shapes are definitely beyond simple tubes, but fortunately, there aren't any concave 'divots'. The helicopter blade is intended to incorporate Active Blade Twist, which is new. The two primary components of this blade are the Torque Tube and the Spar.


I am fairly new to CNC machines but trying to learn as fast as possible. Mach2 is going to be loaded into a new computer, when it arrives. Initially, I thought that by using Mach2's 'Flood' and Mist' output signals to electrically change the 'Multiplier Header' it might speed up the long 11 foot travel, when paying out threat to the spar. This was of particular appeal because the G-code for the spar will come from a custom written Basic programming code, not from a cad drawing.

Any additional thoughts or concerns will be much appreciated.

Dave J.

[ger21]

Originally Posted by RotorRouter Initially, I thought that by using Mach2's 'Flood' and Mist' output signals to electrically change the 'Multiplier Header' it might speed up the long 11 foot travel, when paying out threat to the spar. This was of particular appeal because the G-code for the spar will come from a custom written Basic programming code, not from a cad drawing. Any additional thoughts or concerns will be much appreciated. Dave J.

First of all, use Mach3, not Mach2.

Second, as was already stated, everything you want can be easily handled in the g-code. I would think your basic program would make this even easier than a CAD>CAM route.

[RotorRouter]

Posted by ger21 First of all, use Mach3, not Mach2. Second, as was already stated, everything you want can be easily handled in the g-code. I would think your basic program would make this even easier than a CAD>CAM route.

Thanks for the two points.
1/ I will assume that Mach3 is no longer in Beta, plus
2/ I will forget the unorthodox idea.

Dave J.