[Whizbang]

Hey guys I'm hoping to get some input and suggestions from you guys cause I'm buried in trying to decide what I need.
I basically want 3 axis support with the option of adding a 4th rotary table.
ATC would be nice but lets just go with 4 axis to begin with.
I know I will need 6 limit switches (3 for homing)
I would like to use usb to control the system ( smooth stepper?) ethernet or usb? SmoothStepper Ethernet Motion Control Board for Mach 3 Automation Technology Inc
also automationinc also has this 3 Axis CNC USB Card Mach3 200KHz Breakout Board Automation Technology Inc
which is better and will work best?
I would like to have flood coolant as well and whatever else the basics feature most people use as far as inputs.
I would like a pendent to do manual machining.

I realize that if I get a smoothstepper i will have to buy additional boards for controlling the axis', but there are so many to choose from.

Lastly are closed loop steppers with the encoders worth the money. will they detect missed steps and keep my parts more accurate? They are definitely a lot cheaper than servos.

Any input would really help. I don't want to buy the wrong equipment.

Regards,

[BTP]

I know I will need 6 limit switches (3 for homing)

You can use the same switch for limit and homing, so you only need 3 switches (or 4 if your going 4th axis)

I would like to use usb to control the system ( smooth stepper?) ethernet or usb?

Smooth stepper is a great system. Some have had issues with the USB version however I have not. The machine I used the smooth stepper on was the USB version, mainly because at that time the Ethernet version was not available. Most of what I've seen around here, people prefer the Ethernet version.

I realize that if I get a smoothstepper i will have to buy additional boards for controlling the axis', but there are so many to choose from.

The smooth stepper handles all the motion control. That's why they call it an external motion controller. i.e. not using the parallel port. However, the board you need to buy is nothing more then a breakout board, which makes it easier to make your I/O connections. The board I chose was the C25 from CNC4PC. It mounts directly to the smooth stepper and makes the interface easy and simple.

Lastly are closed loop steppers with the encoders worth the money. will they detect missed steps and keep my parts more accurate? They are definitely a lot cheaper than servos.

This is personal preference. Theoretically a well built stepper system is just as accurate and reliable as a servo system. On my machine I have encoders on my steppers, merely for peace of mind. I wanted to be sure that if the steppers were to stall the software would notice this and stop all movement. Don't get it confused though, this is not true 'closed loop' It doesn't effect the actual position of the machine. Its more of a monitoring system to make sure the motors are in the correct position.

Hope this helps.

[bjones]

:wave:BTP aka starleper1

[Whizbang]

So closed loop steppers doesn't correct position? It just stop the machine, does it then let you correct and resume or what is the benefit.

[BTP]

So closed loop steppers doesn't correct position? It just stop the machine, does it then let you correct and resume or what is the benefit.

I'm assuming your using Mach3, which does not support closed loop through the controller. However if your using LinuxCNC, you can run a true closed loop system. I've never used LinuxCNC so I'm not sure of the details.

If you are in fact using Mach3, then it's a simple plugin that you configure to compare the commanded position versus the actual position. Within the configuration you can set how much of a difference you will allow. For instance if you have any backlash in your machine, then you encoders will always read different from the actual position (assuming your using backlash comp) and you will have to set this value a little higher or the machine will fault out.

But basically in a nut shell, it will just stop the machine and wait for you to remedy the issue. This can save you from crashing your machine.

[Whizbang]

http://www.automationtechnologiesinc...-boardshttp://

CNC4PC

(not affiliated with either)

There are lots of options but they don't really compare and say what the different features are. They also don't list the other equipment needed.. plugs and other boards needed.

Do you guys have any recommend sites for all this info.

[bjones]

how about this for comparison. << CNC4PC >>. your other link doesn't work by the way