Cam software which you will use to generate toolpaths in g code seem to vary as most software does, some are easier to learn than others from what I have seen so far.
Anyway, I'd advise anyone considering either to at least download the software(for no other reason than there are some handy conversion utilities even in the trial ....eg import gerber, export DXF etc)....
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.
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.
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?
The issue with the PP is speed, and stability.
Even with a rock solid system, the PP is still limited to the number of pulses it can output, which for the majority of users isn't an issue, but for those running a system needing high step counts, it's an issue. Speed isn't just a Mach issue, it's a EMC issue aswell. There is also the issue PP isn't good at handling quickly changing inputs.
As for stability, it's a typical driver issue. For CNC the PP has got to be perfect, and no driver is ever going to be 100% perfect on every system.
The PP driver has been completely re-written for Mach 4, and all reports are it's solved a lot of issues, however it won't ever run on anything past windows 7 or 32bit, due to how MS are locking down the core of windows in 8/64bit onwards.
As for the original USB Smoothstepper, and the Ethernet SS, the ethernet is more expensive because of the additional ethernet bits, and I think it also has more onboard memory. The main benefit of the ESS, is reliability. USB can have issues with interference causing the SS to lose communication and requiring a complete system reboot to work again. If you have the money, I'd get the ESS, as it eliminates a possible issue. And yes, if you don't want to risk cooking the SS, a BOB is still recommended, plus it makes wiring far easier.
Thanks everyone for the helpful replies. Looks like most guys have already stressed over PP issues enough to make me just want the smooth stepper from the get go.I now need to research which smooth stepper most people are using, and the corresponding BOBs.
One rather simple question for folks; why use hardware and software beyond the requirements of the machine in use? Windows XP SP3 with Mach 3 or LinuxCNC with 2 to 3 Gig of RAM and a solid PP or Ethernet connection is more then enough to run a machine at very high speeds. I know, as I do that. Now the area not to skimp on is the drives and hardware on the machine side of things.
- Good quality drivers that are in line with the need of the machine and the product to be produced on it (a hobby machine does not need digital drivers and is a cost over run).
- A solid machine that not only meets the rigidity needed but has enough work and cutting area to truly be useful (remember that it is good to have clamping points set up outside your work area).
- Quality BOB that makes sure the signal gets to the drivers and a motion control card if you want to improve the ability of the machine and unload the PC from a good bit of signal processing.
These things and a good bit more important then having a computer attached that is so far overkill that anyone who truly understands CNC knows you are either a tech geek or gadget geek with little to no understanding of what is needed (truly needed, not pretty lights, bells and whistles). Heck the amount of folks on here and other forums that are trying to get speeds out of motors that will do them but not with the very low voltage that they are using (and where told by the seller of said motors that the power supply with them was all that was needed) is just sad. There are a good amount of folks that try to help and there is also folks talking out their backside (Don't mean to offend, just being blunt and honest). For the benefit of your wallet before you start any of this go back and really figure out what you are going to use it for and how much time you have to invest in learning all there is to learn and building the data base of information that you are going to need for your machine and the materials that you use as well as the programs. I spend about 3 hrs per week on just going through the manuals (even ones I have read completely) to brush up my skills and learn new ones to improve my ability to use my machine better and get better results.
To the OP, The work flow you have will works with the plugins mentioned for your data flow and part of your control flow. I would suggest learning an additional CAD program as while sketch up is increasing in use by a lot of folks it is still NOT an industry standard and still gets costly to run if you are using serious data for not only yourself but clients. Now if it is only for you, great go for it. CamBam is great, I love it and it has a great support forum and I am biased towards it (Though there are other CAM programs I use). The down side of CamBam is that to truly use it well means learning it and doing the full set up for your machine and your tooling and getting all the data in there and keeping on top of your MOP's and everything for different materials and tooling. Mach3 is another one that takes time to use it well. Simple set up is one thing and it will work. Getting the most out of it is another entirely and requires not only set up on the machine but also the software.
To all those on this forum and those who are no longer on the Forum (please pass the word to those not on normally), I thank you. I have learned a lot and it has helped me and my business grow. I hope this helps you newbies that are serious.
Thanks gents for ALL the VERY helpful posts...
- Afraid that personally I just don't have enough capacity left in my head :-( to even consider using another O/S like Linux.
- Hadn't heard of SKETCHUCAM so will have a serious mosey at it as an alternative to the Plugin+CAMBAM if I've understood correctly.
- I have just started looking at CNC-USB and think it looks appealing! So will download and research it further....
I may even go with the CNC-USB software+hardware instead of Mach3+ESS+Bob if I've understood things correctly. They seem to be much of a much-ness both functionality and cost wise?
Using any type of Parallel Port just doesn't appeal to me... I don't have a PC with a PP, and really wouldn't want to acquire any obsolete technology even if it's lots cheaper or free. Am also applying a vaguely similar "logic" when it comes to digital drives.
I will use ESS if I do stick with Mach3, but it strikes me that the prime function of ESS is really a workaround for various potential PP problems...
Last edited by WandrinAndy; 14-12-2012 at 08:06 AM. Reason: Thanks Hank... corrected name to CNC-USB
CamBam is great, I love it and it has a great support forum and I am biased towards it (Though there are other CAM programs I use).
Michael, sorry hope you don't mind me asking but as you know this is all new to me. You said you loved cambam but you use other cam packages as well, think you mentioned on another thread using different packages as well. Can I ask why you do that ?? Why swap between different packages if you like cambam so much. I tend to stick to what I know so don't want to be using lots of different programs ( hate learning to use new software lol) so I am hoping that just one cam program will cover any needs I may have.
On the over the top computer subject I think it is just how some people are led to believe it is the right thing to do. I have seen it on other forums when a new version of what ever software they use is released they feel they have to rush out & buy it, everytime ms bring out a new operating system they have to upgrade. Some of it is obviously people just wanting to have the most up to date tech yes I agree but there also seem to be a lot of people who would be happy to stick with what they have but are told by others that they are making a mistake & should upgrade.
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