Messages

561

General Mach Discussion / Re: Dumb Turning Question

« on: August 09, 2011, 08:54:09 PM »

Yes....  I can tell you, without CAM, generating the toolpaths is a PITA!!   

Regards,
Ray L.

562

General Mach Discussion / Re: Dumb Turning Question

« on: August 09, 2011, 08:10:01 PM »

Hood,

If I'm understanding you....  You're suggesting using a tool with a circular profile, then program the movement along a circular path whose radius is the sum of the radii of the sphere being cut, and the radius of the tool?  Why didn't I think if that?  :-)

Thanks!

Regards,
Ray L.

563

General Mach Discussion / Dumb Turning Question

« on: August 09, 2011, 07:32:51 PM »

I'm doing something perhaps a bit goofy, but....  I need to make a batch of parts that basically look like a tootsie-roll pop - a cylindrical section, with a sphere on one end.  The cylinder is roughly 1/2" diameter, while the sphere is 1" diameter.  The goofy part is I'm doing it on my 3-axis mill, with a lathe tool clamped in my vise, since I have not yet gotten around to CNC'ing my little lathe.  I've got it programmed to do the right motions, but it appears to me it's not really practical to do this without using at least two tools - one right-hand, one left-hand.  Use the RH tool to cut the bottom half of the sphere (up to the "equator"), and the LH tool to cut the top half of the sphere.  Either tool can be used to cut the cylinder.  Is there a better way that I'm not seeing?

Regards,
Ray L.

564

General Mach Discussion / Re: Most Recommended USB Controller

« on: August 07, 2011, 06:26:30 PM »

Ray you would really like the Kflop you can run it either way. Gcode, C, VB ,etc A programmers pair of dice (;-)

(;-0 TP

Terry,

Yes, that does look tempting....  I really like being able to create custom screens, and that is a painful process with Mach3.  Is the KFlop robust and stable?

Regards,
Ray L.

565

General Mach Discussion / Re: Most Recommended USB Controller

« on: August 07, 2011, 11:02:22 AM »

There is also this one. http://www.planet-cnc.com/. It's being used a lot on the PhaltPrinter. You can read more about it on their forum http://www.phlatforum.com/viewforum.php?f=254

That is an interesting product, for a stand-alone CNC machine.  Does anyone here have any hands-on experience with it?  I REALLY like the idea that the machine can be controlled through a c# application.

Regards,
Ray L.

566

General Mach Discussion / Re: Most Recommended USB Controller

« on: August 04, 2011, 03:42:25 PM »

Keep in mind, you can buy a PC WITH a parallel port for less than the cost of a SmoothStepper.  My last two (2.4GHz, 1Gbyte, etc., one HP, one Dell) each cost me under $100.  A SmoothStepper is about $150, and does not fully support backlash compensation, which you will probably want if you're building a machine on a budget.

Regards,
ray L.

567

General Mach Discussion / Re: G31 Probe problem

« on: August 03, 2011, 10:36:44 AM »

It's also poor form to use:

While (IsMoving)
Wend

You should instead use

While (IsMoving)
   Sleep (1)
Wend

This turns control back to Mach briefly, so it can do other things, rather than spending 100% of the CPU time in the loop.  This is particularly important when the operation it's waiting for takes a long time (like a long move).

This is covered in the Mach3 Macro Programmers Reference I wrote several years back....

http://www.machsupport.com/docs/Mach3_V3.x_Macro_Prog_Ref.pdf

Regards,
Ray L.

568

General Mach Discussion / Re: Lagun and Supermax retrotfit advice sought

« on: July 27, 2011, 11:11:03 AM »

I'm sure those machines all have 3-phase spindle motors.  If so, then the answer to your spindle speed question is just a matter of putting them on a good VFD (Variable Frequency Drive).  This will generally allow you to double the max spindle speed by over-speeding the motor.

If your existing servo motors are working, there's no reason you can't continue to use them.  All necessary conversion parts needed to use the existing (I assume analog) drives and resolvers are readily available from pico-systems.com, and others.

On the quill drive - those heads look quite different from a standard BP head, which is what most quill drive conversions are designed for.  Designing a quill drive is a fairly straight-forward undertaking, the only really hard decision being how to attach it to the head.  Some use the four tramming bolts, others, like the Elrod, attach to the lower flange (where the lower end of quill feed-stop screw attaches), and to one or more of the covers near the top of the head.  On mine, I went with an approach I've yet to see anyone else use - I slipped a 1/2" plate between the head and the belt drive housing.  This was very simple, very solid, and required no modification whatsoever to the machine.  (see pictures below, with covers removed).  The other trick is making a rigid enough connection to the quill itself.  This is always done by attaching a yoke to the bolt that attaches the "eye bolt" for the quill stop.  The design of that yoke is tricky.

Regards,
Ray L.

569

General Mach Discussion / Re: strange self changing z axis value

« on: July 25, 2011, 11:48:31 AM »

im having a problem with my z axis changing its value....im cutting a guitar body, my wood is 1.75" high....the first cut is at 1.65" so it drops .1 and cuts, goes through the parameter and then goes to cut the second sweep around.  it resets itself at 1.85 evertime, however 1.85 seems to get further and further away from its last z position.  so it will not cut any deeper bc it gets further away everytime.  not sure why.   help   phillip

Sounds like your Z axis is losing steps when raising the head....  Try reducing Z velocity and acceleration by half, and see if the problem goes away.  If it does, then you need to either operate at slower velocity/acceleration, or beef up the drive (larger motor, better driver, higher voltage, etc.).

Regards,
Ray L.

570

General Mach Discussion / Re: Gecko 320x won't fault during test like they should.

« on: July 24, 2011, 12:51:34 AM »

Since you apparently have the encoders connected, but no the motors, try spinning the motor by hand.  The Gecko should fault.  Does it?  Sounds to me like you most likely don't have Step/Dir wired correctly, so the Gecko is simply not seeing any step pulses.

Regards,
Ray L.