complete conversion kit for AMA25LV

[bogstandard]

Don't worry Jon, I was in the same position a few months ago when I started on my journey.
If it wasn't for a good friend guiding me along the way and explaining to me what everything was for, I would have been in the same position as yourself.
I am lucky in that I have almost 50 years machining in my background, and some of that in the computer peripherals industry, so I can understand that side of things.

It is the CAD/CAM and Mach 3 that is going to be the killer for me. As you get older, it gets more difficult to bump start the old brain cells.

John

[JAZZCNC]

Hi,

Please Don't take this wrong way John as I'm not putting or pulling you down but some of those suggestions I wouldn't take up on. Here's why.

The Drives are cheap but they are old analog techonlogy often easily affected by Resonance which affects performance and smoothness of motors. So With converting a milling machine which are often using a ratio then the operating rpm of the motors will fall in the mid band region of the drive/motor that is most affected by resoancne so not ideal really. Esp given that mills tend to be stiff and resonant anyway.
Newer digital drives are much better at handling resonance, giving a very smooth running motor, esp at lower speeds. Those Leadshine Closed loop steppers while expensive are perfect for creating a very accurate milling machine as they are Digital and Closed loop so very accurate, they are also 3 phase with 1.2deg step angle so give finer resolution with a very smooth motion.

The Motion control card is a good idea but not USB.! Ethernet is by far better.
I've tried just about every motion control card (including this one) and all that use USB give troubles in some way at some point. This is often down to electrical noise or the PC and how it's configured regards USB but still USB is flaky in my experience and prone to dropping out.
Often people blame control software when troubles starts when in fact it's often the USB port dropping out or being affected by some other windows process. This Esp true if the device is solely relying on the USB for power rather than having an external power source. USB is rubbish at providing stable power and should never be used or trusted.

For ballscrews then either Chai at linear motion bearings or Fred Lee on Ali express are the men to see. Either will machine ballscrews to any dimension you send and really not worth trying to do your self for what they charge. Fred Lee is the one I'd use as is screws do seem slightly better quality than Chai's.

If your converting a mill you may want to look at better quality than Class 7 (C7) and look towards C5. If you want much better then go for ground screws rather than rolled. Only use good quality angular contact bearings in nice solid and sealed mount as they take a pounding which soon becomes backlash.!!

The suggestions made by John will get you going and work ok-ish while being resonably cheap but IMO it's false economy as often components are much lower quality so die quicker with high potential for reliabilty troubles. The performance is often compromised by rough running motors or poor quality giving relliabilty issues with high potential for sleepless nights and much frustration. In my experience with all things CNC it really does payoff to spend that bit more on the electronics.
Some will say there machine runs fine with cheap components which maybe they think it does.? But often that is because they have never experienced a machine that uses quality parts and is setup correctly.!! . . . . . Many times i've visited machines which the owner never even knew they had issues with resonance etc and just accepted that was the Max performance the machine was capable off. When infact it was running like can of marbles and capable of much more with far smoother running motors.!

[bogstandard]

Jazz,
Not one bit of animosity felt at all.

It is fine going down your route, but in all honesty, even though it will produce a much finer machine, can everyone afford to go down that route?

It has been worked out (and not just by me) that by going down the route I am, I should be able to produce an acceptable working machine for less than £1600, and that includes the cost for mill and 4 axis RT.
I am fairly new to this electronic sort of work in the shop, except for building a Divisionmaster for my large mill, that is why I called in help from a very good friend who designs machines for the average model engineers we have now, in fact he designed and made the protos for the hobby CNC machines produced by Sieg, which although based on old technology, are doing sterling service in many thousands of home workshops.
Well we are on the same road again, making two of the same machines, just that one is geared towards the self assembler as a bolt on kit and mine, which will use a better engineeredand machined unit, takes a little more time and effort, but in the end works much better mechanically

It is the old addage about a Mini and a Rolls, they both get you there in the end, just that one costs 5 times as much to cover the same distance.


OK going for all the latest and most expensive pieces, and I am sure that yours would be a much superior machine, but for what I need, and most probably what another 95% of modell engineers require as well, going down the route I am will be perfectly acceptable.

I remember in the mid 80's having a new CNC Bridgeport delivered to our model shop. Except for size of work it could do, these small home built machines would knock spots off what the Bridgy could do.
It is all about progress. In 10 years, your stuff will most probably totally out of date. Some of us are just a little behind the times, but we do still have a little bit of cash left in our wallets.

John

[JAZZCNC]

I am fairly new to this electronic sort of work in the shop, except for building a Divisionmaster for my large mill, that is why I called in help from a very good friend who designs machines for the average model engineers we have now, in fact he designed and made the protos for the hobby CNC machines produced by Sieg

Would that be my Old mate and partner in crime John Stevenson your refering to . ?

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.

[komatias]

Would that be my Old mate and partner in crime John Stevenson your refering to . ?

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.
i

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 mind

[Fatoftheland]

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.
Regards
Jon

Also sent you a message to your website.

[komatias]

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.
Regards
Jon

Also sent you a message to your website.

Hi Jon,

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.


Regards

George

[Fatoftheland]

Thanks gents.
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?

[JAZZCNC]

Thanks gents.
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?

Well depends on your lathe and your abilty's really. You'll need Collet chuck to hold the screws as 3 or 4 jaw won't be good enough. How hard depends on the screw quality. Often chinese screws are only case hardened and not very deep so can be turned with correct tooling.
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.

[fifa]

Good day Jon

Leadshine is far to expensive for hobby machine like that. Machine spindle is not capable to do HSC, limit yourself for federates up to 2m/min >>ballnut drive = 400 rpm. More than enough.
Any step motor driver with at least 64 steps can do approx sine curve, means you are on the safe side against resonance. Chose the motor which has enough torque also at highest speed, otherwise you will loose the steps.
Backlash do not depend on the "C" class. It depends on the nut. For "diy" variants it is much cheaper to instal 2 nuts per axis (additional costs ca 30-60 GBP ) and pre-stress them for ca 10% of nominal load. Prestress ration can easily be checked with compactor and spring scale.

regards