Messages

2361

General Mach Discussion / Re: Motors not moving in Motor Tuning Menu

« on: June 28, 2019, 04:24:21 PM »

Hi,
I'm not familiar with Wantai drivers but now they are well represented in the market.

I've seen a number of recommendations for Leadshine's AM882 driver, it is 80V capable.
Gecko are the gold standard when it comes two phase drivers but are somewhat more expensive.

The real trick to buying steppers and drivers is:
1) Buy low inductance motors. 23/24 size motors look for 1mH or less and reject any over 2mH. 34 size look for
    2mH or less and reject any over 4mH. Low inductance is as important as holding torque.
2)Buy the highest voltage driver you can get, 80V seems the industry wide max, and then use a transformer type,
   preferably a toroidal transformer, power supply of 72V or more.

Craig

2362

Mach4 General Discussion / Re: Breakout board will not enable, Mach4, ESS and C11G Breakout board.

« on: June 28, 2019, 04:12:10 PM »

Hi jpm42166,
how did you get on? Its nice to get a response from people you try to help, whether it was successful or not and
whether you came up with a solution that might help others in turn.

Craig

2363

General Mach Discussion / Re: UC300

« on: June 28, 2019, 04:04:47 PM »

Hi,
to date none of the CNCDrive boards that do have a Mach4 plugin (UC100, UC300, and UC400) have many realtime supports
like backlash comp, lathe threading, realtime THC, laser vectoring/rastering or spindle PID.
It seems unlikely therefore that CNCDrives new controller AXBB-E will have them either if and when CNCDrive get around to
making a Mach4 plugin for it.

CNCDrive boards preform very capably with Mach3 and have a large following. Their Mach4 plugin is still somewhat behind
the curve however.

Craig

2364

General Mach Discussion / Re: Motors not moving in Motor Tuning Menu

« on: June 28, 2019, 03:50:19 PM »

Hi,
those RnR USB boards have a very poor reputation.

There is almost no information about them. If you search the forum you will find hundreds of people who struggled
and failed to get them to work. You may also find some who did get them going and maybe you could ask them.
Good luck.

If you want a decent external controller I could not recommend any Chinese made boards. There are plenty of good US/European
made boards which work as advertised AND you get GREAT manufacturers support.
Ethernet SmoothStepper by WArp9
UC300, UC400, UC100 by CNCDrive
57CNC, 57CNCdb25 by PoKeys
Hicon Integra by Vital Systems
CSMIO by CSLabs

If you decide on a UC100 don't buy one of the rippoff Chinese made copies on EBay or Amazon, buy direct from CNCDrive
or their nominated distributor. You don't want a rippoff they just don't work lie the real thing.

Craig

2365

General Mach Discussion / Re: Send PWM signal from Geckodrive G540 to PC

« on: June 28, 2019, 03:38:38 PM »

Hi,
I assume that you are using a parallel port into which you have your G540 plugged in?

The G540 and parallel port is a great combination and is very simple. It has some limitations, particularly it has very
few inputs. This is fixed by the parallel port itself.

If you had a second port on a PCI card you will have more inputs. You could, and I would recommend, that you set Mach
to treat the second port pins 2-9 as inputs. The second port would then give another 13 inputs and 4 outputs.

You could then use several inputs to signal Mach and with a Brain (ladder logic code) Mach could determine what is required
from the several different options, ie de-code the inputs.

You would require a PCI card with a parallel port. Beware that not all, in fact not many work. I know PMDX sell a card which
has proven to work. You would also need a simple parallel port BOB, and it would need to be bidirectional, a C10 at $23.00
would be a cheap solution.

Craig

2366

General Mach Discussion / Re: Half Speed Drive

« on: June 27, 2019, 03:10:01 PM »

Hi,

Those Vexta's are serious stuff, and pricy

Yes they are. I paid about, on average, $250 for each stepper and 10:1 low lash (less than 2 arc min) planetary gearbox.
The drivers, on average, cost $150 each. Of course it was all second hand.

Not withstanding the cost I have never regretted the decision, it has been superb. I have not 'lost a step' in four years
and with the 10:1 gearbox and 5mm pitch (C5) ballsrews have 15kN thrust. Of course the 10:1 gearbox means its slow,
my 'rapids', if you can call them rapids, are 1200mm/min. I limit the acceleration because my 250kg mill starts throwing itself
around the workshop unless I tie it to the wall!

I was new at CNC at the time. If I had to make the same purchasing decisions today I would go for Delta or DMM servos instead.
Good AC servos have much reduced in price over the last few years.

Craig

2367

General Mach Discussion / Re: Newbie with a few questions

« on: June 27, 2019, 02:48:58 PM »

Hi,
if building a new machine consider Mach4. It has all the features and more of Mach3, is less buggy and far more flexible.

If you have a 64bit OS that PRECLUDES a parallel port, you MUST use an external motion controller.

Consider an external motion controller like an Ethernet SmoothStepper. You will have more IO, in the case of an ESS 3 ports
worth or 51 inputs and outputs, capable of 4MHz pulse streams, Ethernet comms being more noise resistant than USB
and manufacturers support unlike Chinese junk. In addition the ESS has both a Mach3 and a Mach4 plugin.

The single most overlooked specification of steppers is the inductance. Inductance determines how badly the torque will reduce
with speed. The lower the inductance he better.

For 23/24 size look for steppers with 1mH or less if possible. Reject any over 2mH.
For 34 size look for 2mH or less and reject any over 4mH.

You want the highest possible voltage driver and power supply to maintain torque at speed. Leadshine AM882's are good value
and 80V capable. Gecko's are the gold standard. You want a 72V power supply, preferably with a toroidal transformer
being that much more robust and less electrically noisy than a switch mode supply.

Fusion 360 is free to hobbyists for a year and is worth checking it out. If you have used AutoCAD it will come easily. I don't
much care for Autodesks subscription model though.

I personally am leaning to Vectric Aspire ($2000), I want the 3D toolpaths which the cheaper versions miss out on.

A lot of jobs on a mill don't require a CAD/CAM program. Simple operations chained together are adequate.
For example face a piece of material, cut a rectangular pocket and drill a rectangular bolt hole pattern. It can take more
time with CAD/CAM to do it than the job takes to cut!. Try out NFS Mill Wizard ($75), it adds what amounts to conversational
programming to Mach.

Craig

2368

General Mach Discussion / Re: CV settings for Router work

« on: June 27, 2019, 05:01:05 AM »

Hi,
CV is all about trying to keep your machine going as fast as it can as long as it can.

When it comes to a corner it rounds it a little in order to keep up its momentum. The thing that BEST allows
a machine to follow a toolpath, with corners especially, is acceleration.

Have you tuned your machine to have the maximum acceleration the steppers can manage? It might even be worth turning
the maximum speed down a bit if it simultaneously means you can turn the acceleration up.

Craig

2369

General Mach Discussion / Re: GOTO ZERO works for Y and Z, but X changes each time...

« on: June 27, 2019, 04:56:02 AM »

Hi,
I have and like a VistaCNC P1A.

Craig

2370

General Mach Discussion / Re: Half Speed Drive

« on: June 27, 2019, 04:22:23 AM »

Hi,

My steps per are set to 400, I guess I should halve that ?

For a given set of parameters (pulses/rev, ballscrew pitch, gear/belt reduction) there is one and only one right answer. You
cannot set it at will UNLESS you also change the parameters that determine it.

Are you going to change ballscrews? No, I didn't think so. The parameter of ballscrew pitch is fixed.

Are you going to put gear or belt reduction instead of direct drive? No, I didn't think so. The parameter of gear/belt reduction
is fixed.

Are you going to change your stepper drive microstep regime. You certainly can, it easy and costs nothing.
On the one hand you want to set the pulses per rev (PPR) as high as you can to get the smoothness of motion that
microstepping offers. On the other hand high PPR means high pulse rates and so Machs parallel port may limit the ultimate
speed of your steppers.

The calculation with the existing PPR setting of 2000:

25,000 /2000  x 60 = 750 rpm. With a 5mm pitch means a max velocity of 3750 mm/min

If you want to go faster then you have a couple of choices:
1) increase the parallel port kernel........OR
2) get an external controller like a SmoothStepper which can output up to 4Mhz....plenty.....OR
3) reduce your microstepping regime to 1000 PPR say.

If you choose the later then the same max speed calculation becomes:

25,000 / 1000 x 60 = 1500 rpm or (5mm pitch assumed) 7500mm/min.

I rather doubt you'll be able to get your steppers to go anything like that speed, especially with such a low voltage supply,
however Mach's parallel port will give you that head room.

The potential resolution assuming 1000 PPR, 5mm pitch and direct drive is:

5 / 1000= 0.05mm......which is probably quite adequate for  a router.

If you assume 1000 PPR the last parameter is now determined. The 'Steps per Unit' in the motor tuning page is:
1000 / 5 =200 steps per unit. Once again this is fixed by other choices you have made, the ONLY way you can change it is by
revisiting the choices you made for those parameters.

To get your steppers to go as fast as you can you should use the highest voltage that your drivers can handle. They are rated to 50V.
You should be using a 48V supply. I have seen different recommendations for the voltage, including one formula that looked
interesting but the bottom line is use the highest you can, in your case 50V.

I have Vexta 5 phase steppers with genuine Vexta drives. Each drive has its own power supply built in, you just hook it up to
230VAC and the drive does the rest. The DC voltage the drives use to move the motors is about 150VDC!!! It really makes
those steppers sing. They can do 3000 rpm with pretty good authority, ie not losing steps, but I run them at 2400 rpm max
just to be on the safe side. I doubt you'll find any drives for two phase steppers to match those but it does show the principle.....
high voltage equals high speed.

Craig