Newbie- Questions about retrofiting a series one BP.

[tomoracle290]

I am looking at getting one of these = http://i48.tinypic.com/hvs6t0.jpg
My intention will then be to retrofit allowing the use of mach3.
Will one of these do the job?
http://home.icx.net/~ashburn/index.html
Also its called a "Interact 1 series 1" I noticed similar posts on here always talk about BOSS X... is that just the controller?
Thanks!

[Hood]

That is a servo system on that one, you will either need to get new servo drives or use one of the digital to analogue setups if you intend to use with Mach.
Most of the normal servo drives used by people that do DIY retrofits (Geckos etc) will not handle the voltage that these motors require so speed would be limited. There is however the Dugong from http://cncdrive.com that seems to be a perfect candidate for 80's period DC Motors. I have never tried them myself but they do seem to get good reviews.

The other option would be to keep the amplifiers that are there and use something like the DSPMC http://www.vitalsystem.com/ or KFlop http://dynomotion.com/ to convert the Step/Dir from Mach to analogue for the amplifiers.

Hood

[tomoracle290]

Think I might look for a machine using steppers instead seams like its a more simple set-up.

[Hood]

Much better with servos in my opinion for a mill that size. I have a Series 1 that I have steppers on and its great but I also have a bigger mill with AC Servos and a lathe with AC Servos and its much better.

Suppose it all depends on what you intend to do with the mill, if its hobby stuff where time is of no importance then steppers will do, problem is once you have had it for a while it will seem slow I am talking from experience.

Hood

[tomoracle290]

What are steppers like for accuracy in comparison to servos?

Main reason why I don't really want to go with servos was there seams to be a lot more cost, and no "single" board that you can basically put a pc in one end and the motors in the other, like the steppers.

Just looks more complicated...

[Hood]

Originally Posted by tomoracle290 What are steppers like for accuracy in comparison to servos? Main reason why I don't really want to go with servos was there seams to be a lot more cost, and no "single" board that you can basically put a pc in one end and the motors in the other, like the steppers. Just looks more complicated...

With steppers you will still need drives unless you decide to keep the original Bridgeport drives and motors. Many people have and are happy but from what I have heard the Bridgeports old electronics are tempremental but I must stress this is just from hearing about it and not from experience. I stripped mine before I could try as I figured I could do without the aggravation.
Servos versus steppers is usually an emotive topic but for me there is a place for steppers and a place for servos, I have steppers on a coil winder I made recently and servos would just have been a waste for this application and steppers are perfect. On a lathe or a mill or for that matter a router I think acceleration is king and for that servos are the choice.

As for accuracy, well steppers are reasonably accurate to a full step, the drive usually has microstepping (not sure about the earlier BOSS ones though) which sort of increases accuracy but the accuracy of the microsteps is not a precise thing and you can be nearer one microstep than another then vice versa, but I should say that is only my understanding of things and I am not an expert

Servos can be very inaccurate or very accurate, the tuning has a big affect on that, a well tuned servo system is very accurate. The servos on my lathe will fault if they are out by more than 20 counts and 20 mS. There are 8000 counts per rev on my lathe and the ballscrew is 5mm pitch, so that is 0.0125mm or 0.00049 inch and that is at full rapid speed of 15m/min with an acceleration of 10m/s/s.

Hood

[Hood]

Where about in the UK are you? If you are anywhere near me (Carnoustie, Scotland) you are more than welcome to come and see the Bridgeport and the other machines.

Hood

[Sparky_NY]

I have a series 1 manual machine I retrofitted with steppers and gecko drives. It works very nice, runs about 130 IPM rapid speeds and can position within 1/2 thou anywhere in its travels. The steppers are quite noisey, they sound like a organ playing a song.

I just recently got a bridgeport series one cnc, a V2e3, which is a servo machine, proablably using the same motors as the one earlier in this thread. I am in the process of retrofitting it now with dugong drives and mach control. I can tell you the machine is far smoother, quieter, more accurate, much faster. This machine rapids at 250 IPM and is extremely quiet.

As for cost and complexity, the servo drives cost about the same as stepper drives. I reused the original power supply. (steppers would have needed a supply also). Servos require tuning, so do steppers but far far less and easier. Still, I found the servos very easy to tune.

Having done both I would never consider steppers over servos if the choice was available. On a bridgeport, you are right at the upper end of the limits a stepper can power, on larger machines servos are far superior.

PS for hood : the dugong drives are working out fantastic. Extremely easy to tune. They run the V2E3 like a dream. I am running AMD capacitive encoders at 2048 counts/rev. Balazs, at cncdrives.com has been outstanding at support, any questions have been answered in extreme detail within a day. The drives are also less expensive than the alternatives.

[tomoracle290]

I am on the rock (Isle of Man) so your a bit out of my reach.
So if I was to get a servo based machine how much £$£$ are we looking at to retro fit?
I take it bascially it would require new ecoders and drivers?
What parts would be recommended. It is more of a hobby and learning machine therefore I wouldn't really want to break the bank doing it.

[tomoracle290]

Just been doing some more reading... would three Dugong (http://cncdrive.com) and one of their BOB's do the job? or would I also have to look into replacing the encoders?

[Hood]

Not sure exactly how much it would cost. A mill with a heidenhain on it would cost more than one with a Boss control I would think, how much all depends, you may be lucky.
3 Dugong drives would set you back €360 plus postage, you would really need a breakout board, I like the PMDX 122 but there are plenty about including the one in your first post. Then you would probably need encoders as the Heidenhain are likely not to be TTL, so that would likely be about $150 to $200 for the US Digital ones. Then I would add a SmoothStepper ($150) into the equation, that would allow you to use high resolution encoders but if you preferred to use the parallel port then that would save that cost but you would need to get lower res encoders.

You could however offset some of the cost by selling the Heidenhain control and drives, I sold the ones I had on the Beaver mill and got nearly £500 for them. Mine only had a 145 control which is not nearly so saleable but that was also including the motors and drives, think I got about £300 for the control, the screen and the handwheel.

Hood

[Sparky_NY]

I used the AMD capacitive encoders, they are programmable via dip switch from 48-2048 line resolution. I am running at 2048 on the bridgeport nicely.

The amd encoders are only $30 !!!!!!!! There are posts about these encoders by Marris (of geckodrives) here in the forum with more detail.