True 4th Axis vs Fake 4th axis?

[microbeast29]

I have a chinese 3 axis router, and to my dissapointment, the company says I cannot add a 4th axis since I have DSP control.

I am ordering a rotary attachment and have to cannibalize the Y-Axis for rotary control. Can someone explain to me the disadvantage of this when creating 3 dimensional objects? I don't want to make only cylinders, can I still create some complex objects with a fake 4th axis?

Thx

[awerby]

It's going to be more trouble switching back and forth from 3-axis mode, but there's no inherent problem running a 4th (A) axis motor off the same driver as is used for the Y axis motor (as long as they're the same type of motor). You will need to figure out a way to fix the Y axis in position at the Y=0 point, though, since it will tend to freewheel if it's not held by the motor.

Just switch the Y axis leads to the A axis motor (assuming they're compatible) and reassign the Y axis to A. I'm not sure what software you're using, so I can't give you detailed instructions on how to do this, but if it's difficult you can alternatively just edit your G-code to substitute Y for A.

To generate the G-code, you can use DeskProto (it's free for the first month). Pick an "along X" 4th axis strategy, and it should work fine, even for relatively complex objects, since only the X, Z and A (formerly Y) axes are used.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

I have a chinese 3 axis router, and to my dissapointment, the company says I cannot add a 4th axis since I have DSP control.

I am ordering a rotary attachment and have to cannibalize the Y-Axis for rotary control. Can someone explain to me the disadvantage of this when creating 3 dimensional objects? I don't want to make only cylinders, can I still create some complex objects with a fake 4th axis?

Thx

[dominicburke200]

can you just tell me what dsp control is and what the better control set up is? I've searched but it all seems to simply state it uses dsp to control rather that say what its limitations are.
is it limited to how many axis movements can be made at once?
Thanks

[Ashish B]

See, 4th axis is nothing but a indexing head which can rotates (independtly) & slowly in combination with tool. So, simultaneous cutting & rotating (of Job) happens.

A simple example to give you is how would anyone machine a screw of 200 mm pitch...
The answer is only 1...(4th axis attachment)

Hope it helps.

[4dwood]

I have a 4th axis two parallel spindle (homemade) machine, of 4 coordinates are used all, we make cabriol legs, and in most cases without 4th coordinates is impossible.

Excuse for my bad English.

[sk8nmike]

can you just tell me what dsp control is and what the better control set up is? I've searched but it all seems to simply state it uses dsp to control rather that say what its limitations are.
is it limited to how many axis movements can be made at once?
Thanks

DSP = Digital Signal Processing

Without knowing more about your controller I really can't give you much info on it, but I see no reason you sholdn't be able to use the X or Y axis for the A. Software can be tricked into carving a flat pattern onto a round stock.

[MonoNeuron]

I use a DSP for my laser control and swap out the Y axis for the A (rotary) axis.
I save a separate config file for rotary and flat cutting after setting them up and then just select the config I need for a particular type of job and import it into the DSP.
It's very easy to do but you need to remember which one you used after swapping them back. :-)
I use 4 pin plugs made for microphones and wire them up so I just have to plug in which axis I need after setting it up before hand. Do turn off the machine BEFORE you disconnect the leads as most stepper drivers don't like to have nowhere for the electricity to go and will burn out.
Rich.