Hobby-CNC Workflow - SKETCHUP + CAMBAM + MACH3

[martin54]

A lot of bobs have a seperate 5v power connection so if your parallel port runs on a reduced voltage then you can supply the 5 volts from a separate power supply. One of the main reasons for people switching to smooth steppers is not so much the problem with the parallel port voltage but the operating system they are running, you need a 32 bit system for mach3 to work with a standard parallel port bob, those with 64 bit systems have problems with the parallel port drivers which is why they go down the smooth stepper route.

[JAZZCNC]

A lot of bobs have a seperate 5v power connection so if your parallel port runs on a reduced voltage then you can supply the 5 volts from a separate power supply. One of the main reasons for people switching to smooth steppers is not so much the problem with the parallel port voltage but the operating system they are running, you need a 32 bit system for mach3 to work with a standard parallel port bob, those with 64 bit systems have problems with the parallel port drivers which is why they go down the smooth stepper route.

No your wrong Martin.? It doesn't work like that and is a common mis-understanding of BOB's and the PP.!

The parallel port (PP) voltage relates to signal voltage and has completely nothing to do with the powering the BOB.
When you see BOB's stating can be run from 5V that doesn't mean it comes from the PP and actual doesn't. Often they take it from either a USB port or a separate external supply.

Regards the low power parallel ports the problem comes from the way drives and control system deal with the signals. Drives/Control sys expect or watch for the signal to have only 2 states.? ON and OFF also known has HIGH or LOW.
The way the system distinguish's between HIGH / LOW state is by watching the PP signal voltage and setting a threshold IE: 0-2.4v = LOW 2.6 - 5v = HIGH. I'm genralising the voltage has it fluctuates but a good system will have a clear separation with LOW being close or = to 0V and HIGH nearer 5V.
So if you have a 3v or 3.5v PP the system still expects LOW to be in the 0 -2.4V range and HIGH 2.6 -5V but with a 3V PP you only have 0.5v margin left to distinguish HIGH from LOW and this low margin is what causes the problems.
It's just not enough margin to keep a clear line drawn in the sand so to speak and makes for a very unstable system.!! Just the slightest electrical noise can flip the signal either way and cause mayhem.!!

I can tell you now 90% of smooth stepper users buy them to get away from the PP or because there PC is modern and doesn't have a PP more than to use 64bit PC's.

[m.marino]

Okay,

being a Smooth Stepper user, the reason that I went that route is noise issues on the parallel port cards that I tried with the computer that I use for the shop. Personally, having used more then a few different CAD and CAM software packages I have to say horses for courses and be very careful before laying out your money (I wish I had not bought about £650 of software that I do not even use these days). A Smooth Stepper is just plain faster then current PP set ups. Having said that, Mach4 maybe changing the playing field there and there are some interesting developments in 64 bit computing using parallel ports so will be interesting to see.

I use ViaCAD 2D/3D v8 and ViaCAD Pro v8 for almost all my CAD work as it is very cost effective and for myself smoother then sketch up and produces .stl files which so many CAM program prefer (it also has a rather wide range of import and export available). Next is CAM and for that I go to CamBam, PhotoVcarve, and on the rare occasion BobCAD V21. I plan on upgrading the CAM options in the near future for ease of use but will be seeing on that. I use Mach 3 with Gerry's screen as once it is set (I have three set ups so far for cutting profiles in Mach3 to help deal with different materials). That does pretty much all I need. I have looked at some very high end stuff and the price just does not do it for me, not when I can get what needs done for much less money. There is high end worth paying for, Aspire and VcarvePro come to mind and a few other ones.

Doing CNC properly is work. A good bit of it and a lot of learning. I know a huge amount more then I did 4 yrs ago and I still have a whole lot more to learn. I tend to be more for the practical and what gets the job done to the best ROI more then what is new and flashy. After all is not the reason for having the machine the ability to earn income from project that the machine can do better or that can only be done effectively with the machine?

Michael