comp for Mach3

[binfordw]

I'm in the process of setting up a new X3 cnc mill, and have been reading through the Mach3 software I have. I had planned on using my laptop to run Mach3, but from what Ive gathered I will not be able to, as it does not have a parallel port to connect to the breakout board. Mach3 specifically says usb to parallel adaptors do NOT work for this either.

Will I have to buy a new cheap desktop pc with a parallel port/ or a parallel port card to install on the mobo, or is there something else I can do?

[jacampb2]

I'm in the process of setting up a new X3 cnc mill, and have been reading through the Mach3 software I have. I had planned on using my laptop to run Mach3, but from what Ive gathered I will not be able to, as it does not have a parallel port to connect to the breakout board. Mach3 specifically says usb to parallel adaptors do NOT work for this either.

Will I have to buy a new cheap desktop pc with a parallel port/ or a parallel port card to install on the mobo, or is there something else I can do?

You could try the smooth stepper. Everyone that has them raves about it. It is a USB breakout board that works with mach3.

Here's a link:

http://www.warp9td.com/

Later,
Jason

[John Stevenson]

Don't bother the SS still isn't developed.
Just get a cheap desktop, I just bought 10 off Ebay for £85 the lot and even got them delivered.

[jacampb2]

Don't bother the SS still isn't developed.

Huh? I know two people running them. It has been available for over a year now. What do you mean by not developed? Still buggy?

[BobWarfield]

I have one. It works pretty well.

However, the device is still under development and lacks several key features. Support has been hit or miss for me because the owner doesn't really frequent his own support boards very much.

OTOH, I am told he is reachable via email, and I have seen some evidence he is a little more attentive to the boards. Also, I haven't really needed much support so far (knock on wood).

I would say there are enough of them out there that you can get one to work pretty well. Biggest missing thing for me is backlash comp, which has been promised for a long time but still isn't here.

As John says, for a newcomer, the easiest and most reliable approach would be to stick with a parallel port unless you just feel a need to experiment. That's Mach3's power alley, and that will be the config that works best, has the fewest bugs, and is the most up to date for the foreseeable future.

The Smoothstepper is also not especially cheap.

Cheers,

BW

[RB211]

You want an external stepper controller. Instead of relying on timed pulses from the computer which WILL vary due to other processes, you want the computer to offload the instructions to a dedicated stepper controller that drives the steppers without worry of timing issues. I developed a stepper controller for bipolar motors using an AVR 8 bit mcu. Granted being 8 bit, it would be hard to drive more than two steppers at the same time. I think a 16bit ARM processor with a Gcode interpreter would be the cats meow. Of course others have done it I am sure and sell it for an abundance.

[John Stevenson]

Perhaps you could post a link to one with the same features as mach for the same price ?
.

[beanbag]

Biggest missing thing for me is backlash comp, which has been promised for a long time but still isn't here.

BW

When I asked Tormach about Mach3's backlash comp, they claimed that it didn't work very well, for reasons that I don't remember. Tormach's Mach3 has this feature disabled.

[macona]

The backlash comp works fine with servos and so-so with steppers. Steppers just dont have the acceleration capabilities to compensate at direction changes. Lost steps can happen.

[John Stevenson]

Backlash comp is a kludge anyway regardless of steppers or servo's

When doing a linear move that changes direction the backlash cop has to apply so many steps to take this up before the next cut, as these cuts are at feed rate the speed normally isn't an issue with either steppers or servo's able to move fast enough as the pulse train is far faster than feed rates, unless we are talking about routers of something moving at very high speed.

Remember an early PII computer is far faster than a CNC machine.

Where backlash compensation falls over is doing circles, at each quadrant point it has to seamlessly change direction but the problem isn't the speed but the backlash itself.

Regardless of where the computer tells the tool to be as it changes direction the action of the cutting tool will allow it to grab the work and pull or push it depending on tool rotation and direction of cut.

Backlash comp isn't a servo v stepper battle but a battle over mechanical slop and rotating cutters.

.

[Hollowbuilt]

Mach 3 and desktops

I was told the main reason for not being able to use the laptop is that the 5 volts is not available.

Further, Window XP is the newest version of windows that works on Mach 3

There is a driver test that is used on the pc that shows whether the pulses on the microprocessors clock are stable enough to use .

I got a desktop for next to nothing and dedicated it for the purpose.

Regards,
Chris

[Hood]

I was told the main reason for not being able to use the laptop is that the 5 volts is not available.

The main reason Laptops are hard to get working with Mach is that they have lots of power management features to conserve battery power and they are often hard to disable, this can adversely affect the pulsing.

Further, Window XP is the newest version of windows that works on Mach 3

Mach will run under both Vista and Windows 7

Hood

[macona]

Backlash comp is a kludge anyway regardless of steppers or servo's

When doing a linear move that changes direction the backlash cop has to apply so many steps to take this up before the next cut, as these cuts are at feed rate the speed normally isn't an issue with either steppers or servo's able to move fast enough as the pulse train is far faster than feed rates, unless we are talking about routers of something moving at very high speed.

Remember an early PII computer is far faster than a CNC machine.

Where backlash compensation falls over is doing circles, at each quadrant point it has to seamlessly change direction but the problem isn't the speed but the backlash itself.

Regardless of where the computer tells the tool to be as it changes direction the action of the cutting tool will allow it to grab the work and pull or push it depending on tool rotation and direction of cut.

Backlash comp isn't a servo v stepper battle but a battle over mechanical slop and rotating cutters.

.

But all machines have lost motion no matter how well they are built. You can reduce it as mach as possible but you will have some. After replacing my thrust bearings on my CNC I got it down to .001 to .0015 but it is still there. Thats why all commercial machines have backlash comp.

Kludge or not it is still necessary, Mach's implementation is not optimal but it works. With the stepper systems I had built in the past the compensation times at direction time were slow due to slow accel of steppers. With the servo machines I have built much of that issue was eliminated. I get nice round holes with no marks at the quadrants.

[John Stevenson]

I get nice round holes with no marks at the quadrants.

Same here and I don't have backlash compensation enabled but I do take care with ballscrew mounting and double nuts.

[Hollowbuilt]

Vista and 7 on mach

Hood,
You seem to have a good handle on mach 3. I am finishing up my machine, and will be a new user of mach 3 mill. So I am relying on what people have told me. I was told that when mach takes over the processor to use its clock or pulse (not sure which it is) that windows tries to get it back or sees it as a threat? Is there a windows version that is best to use? Is 7 or vista better than xp?
Thanks,
Chris