Last edited by cropwell; 05-04-2015 at 10:32 AM.
While I understand what your saying about " Mini and Rolls" I still don't agree.! . . . Problem is this game is not an exact science and every machine is different, even if the same Make and model using same parts.
Each machine will and does react different regards resonance, also the combination of this plus drives motors etc affects tuning and how the machine performs and it doesn't always go to plan. Which if compounded by poor components, poorly assembled and wired can lead to a very frustrating time.
You are lucky as you have I presume John helping and advising who is very experienced but others are not so lucky and they don't have the luxury to be able to turn to knowledable person when plan goes south.!! . . . I help lots of people in this exact situation and this lack of knowledge combined with poor components is the most common cause of there troubles and frustrations.
Yes often I get them working quick enough and using the parts they bought but often the machine is capable of so much more and limited by components or build quality.
Also often the poor quality electronic parts or one part in particular, Ie BOB's are the reason for there troubles and if they'd bought decent electronics in first place they'd have been working weeks or months sooner and still have all there hair.!!
I'm long in the tooth know at this game and IME there really is no substitute for quality electronics. They really do pay off in the end.
If I buy the ballscrews, is it possible to cut them and turn the ends on my lathe or are they super tough? Would it be easier to get them cut at source like Zapp automation offer. But what length and fittings do I want? I know I need ballscrews, ball nuts. but what goes on the ends bearing and mounting wise?
Last edited by Fatoftheland; 05-04-2015 at 12:49 PM. Reason: spulling
Better quality screws are hardened deeper. Often the ends are ground not turned on harder quality screws, I know for sure Zapp grind not turn.
How you fasten the ends will depend on the conversion but in all cases at least one end will be "fixed" and use 2 x angular contact bearings fixed in a ridged housing of some kind to stop the screw floating. Often with mill screws being short then only one end of screw is fastened the "fixed" end and other end is left unsupported.
On longer length screws you would support both ends with bearings but only one end is Fixed and the other bearing free to float in it's housing to allow for expansion.
Really regards length and what exactly is required no one except someone who's done the exact same machine can tell you and even then I wouldn't trust without checking your own machine as castings etc change and often clearences, esp around the ballnuts are tight so best working from your own measurements.
Last edited by JAZZCNC; 05-04-2015 at 01:08 PM.
Having converted some machines I have to agree. Either pay the money or learn to live with backlash, lost steps and generally inferior results. Since going C3 ballscrews, hybrid servo steppers and a ethernet smoothstepper with good breakout boards, my dro matches my mach3 dro every time. Money well spent in my mindwww.emvioeng.com
Stocking more goodies than just Smoothsteppers
So Komatias, What smartstepper do you use and which breakout boards. I like the look of the c3 screws and also closed loop servo systems. I know I am talking a good bit of money but I can lose most of it through my business.
Also sent you a message to your website.
Without question the Smoothstepper to get is the Ethernet version. It is very reliable, has more onboard memory and is the one that Warp9 are looking to keep for future development (Mach 4 etc). I have had the USB cut out when the spindle motor would start or stop, in one case it happened when my girlfriend switched the oven on .
I am a big fan of the Leadshine hybrid servos due to the value for money they represent. Yes they are steppers and have the issue of decreasing torque as rpm increases but then again I know I am not losing steps and I can fit 3 axes for the price of one servo and driver. The Leadshine hybrid servos need to be driven by the paired driver so you need to buy the motor and driver. The drivers will need the usual DC voltage supply and a step/direction input. For the machine you re looking at you could probably use the Nema 23 3Nm motor and matching driver through a 2:1 reduction. The step/dir signal is given to the drivers from the motion controller, e.g. Smoothstepper, via a breakout board.
For the breakout board you will need to decide what control line voltage you want to use. 3.3V is too low in my mind, so I would suggest 5V, 12V or 24V. This will potentially govern which breakout board you will be able to use. I use 5V for most applications as it is easy to use some power from USB but also because the drive powersupplies I bought had a 5V auxiliary output. The breakout board does not have to be fancy, it can only be there to protect the expensive motion controller and computer or if you want a bit more it can also incorporate relays, switches etc. I like to have solid state relays and place them away from the electronic hence I like the C25 terminal boards: http://www.cnc4pc.com/Store/osc/prod...roducts_id=187
Most BOB's have a LPT type connector anyway and screw terminals. Take your pick.
The C3 screws have a measured max 0.008mm (8micrometer!!!) deviation per 300mm of travel. They are ground and come with an inspection certificate. Considering that any mill will be lucky to hit 0.02mm consistently I say that is one thing less to worry about. Because of the near perfect nature of the C3 screws, you can truly preload the nut and have a single nut do what other try and do with two nuts and springs, spacers and all manner of contraption. The axial forces will not be that big so a light preload should suffice. It does come with a price typically 6X that of the standard C7 roller screws and a standard lead time of 8-12weeks.
By the way when suppliers say zero backlash, that does not give you an indication of the preload amount. It just means that under no load there is no backlash.
Now, since you have gone with the ground C3 ballscrews, you may as well go full hog and get proper ballscrew mounting supports and bearings. Again, preload is important. You can either buy a complete flange type mount or just make you own hardware, the actual bearings though should be such that they do not have backlash built in. There are special angular contact bearings that fit the bill.
As for the belts etc, I like to use taperlok type pulleys or ones that are correctly keyed with HTD belts. Zero lash, strong and easy to fit.
I hope the above does not ruffle any feathers in the "I can do it cheaper" camp. The fact is it all comes down to what you want from your machine.
Stocking more goodies than just Smoothsteppers
All the signals from your Expensive motion controller go thru the BOB so if it's a cheap device with slow opto's then no point having a motion controller that's capable of 4Mhz if the BOB opto's are restricted to 100khz causing a bottle neck.!!
Like wise no point having those nice clean pulses coming from the motion controller if the poor quality BOB is going to distort and mess with them.!!
Bells and whistle's like Relays yes you can do without but not when it comes to quality of Motor Output signals and for this you need a quality BOB to match your motion controller.
Personally I wouldn't use any BOB with a Smooth stepper other than the PMDX 126. The C25 or any of the Cnc4Pc boards can't hold a Candle to PMDX products. I've got several Cnc4Pc boards here in my scrap/replaced Bin but you won't find any PMDX boards in there.!!
Now Jon if you want the BEST motion controller you want Cslabs Csmio products. They are not the cheapest but they are certainly the best by a long way in this price range.
I've used most motion controllers now and Non come close in performance, reliabilty and quailty. They DONT require a break out board like others with all input/outputs going directly to motion controller via supplied Terminal blocks to avoid exactly the Bottle neck problems mentioned above.
They use 24V Differential I/O so are very noise immune. Again far better than any other motion controller I've ever used. So much so that I can use my machine while welding with high frequency Tig welder right next to the CNC machine running on the same Ring main circuit. (Try that with a EtherNet smooth stepper and see what happens.!!)
Then we have the Software side, Warp9 or should say Greg the maker of the Smooth stepper are disgrace when it comes to Software upgrades or resolving issues. The software plug-ins are poor and Buggy and rarely updated unless half the world jumps up and down at same time. If you have a problem specific to your setup getting Greg to listen or acknowledge is like trying to get an audience with the Queen.
Cslabs on the other hand don't have many issues with Software to start with and the Plug-ins just work perfectly. If they do find bugs they are often very minor and release updates straight away. They also are constantly improving software and releasing updates.
If you do have a Specific issue to your system they will reply in resonable amount of time and often come up with an answer to the problem. (Often it's you not them to Blame.!!. . . .Don't ask how I know that.!! . .Lol)
Again you really do get what you pay for and no point having best of anything unless all the system is matched and balanced. Any machine is only as good as the weakest link and all too often that weak link is the BOB.!!
Thats a lot of info I have to look at and understand. When ordering ballscrews do I just measure the old ones or is a preferred way of mounting and fixing them
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