Bridgeport Manual to CNC conversion...

[Chaz]

The Yaskawa stuff looks very similar to Panasonic. Look at the front panel, very similar if not the same layout. Wouldnt be surprised if there is some commonality here.

For what its worth, my Father In Law used to be in charge of one of the largest ports in the world, running all their electrical systems. Think of moving millions of tons of goods per month. They used Yaskawa variable speed drives extensively, a serious outfit.

[Colin Barron]

I have a Denford Easiturn 3 which had old electronics which did not work and i have removed them. I then thought i would reuse the steppers and drivers or steppers and the likes of the Leadshine 882 or if new servos are a direct replacement (mechanically) then the BST servos at about £250 each looks a decent bet.
On the controller front the Chinese controllers look a better bet than the mach3 bits and pieces which look like a project in themselves. A decision must be made before the controller is purchased as i believe i must specify incremental or absolute type (whatever that means?).
I was looking at the GSK clones such as Newker http://newker-cnc.com/index.php?m=co...=166&l=3&id=91

[JAZZCNC]

A decision must be made before the controller is purchased as i believe i must specify incremental or absolute type (whatever that means?).
I was looking at the GSK clones such as Newker http://newker-cnc.com/index.php?m=co...=166&l=3&id=91

Yes, it's a bit of a mind field with these controllers so be careful, I've been looking for Mill controllers. Make sure you read all the tech spec because some have limited memory amongst other differences like how many simultaneous axis can be used at one time.

Regards Absolute and Incremental then it relates to the Encoder type used on the Servo. The BST uses incremental encoders as do most other types of servos unless you state you want Absolute.

The difference being that with incremental when you shut down the machine, the controller has no idea where the position of the machine is when it starts back up so you have to home the machine at the start of each day. (or if the servos are powered down) Just like you do with the stepper system.

Absolute Encoders retain the position of the servo even after shutdown, they do this by having a battery attached to the cable to power the memory of the encoder. This means you don't need to home the machine on startup and the drives/encoders know at all times where the machine is located, even if after power down someone manually moves an axis. (provided the battery power doesn't fail or the encoder cable is unplugged from the motor)
There is some setup I believe to be done when first installing because the drives/motors/encoders need to be told where Zero is located etc and the controller needs to support Absolute type but after that they work just like Incremental but without the need to home on startup.

[Muzzer]

I've not seen the "absolute bus type" (990MDCb) version of the Newker in the flesh but it sounds as if it uses some sort of serial bus to pass absolute motor positional data back to the controller and presumably also does away with the conventional step/dir signals in the process.

Must admit I'd prefer not to have to home the machine each time at power on but the feature comes at a cost. I just accept that both the Newker and the Acorn need homing each time but I'd be interested to hear how the costs for the 2 alternatives compare if you enquire with Newker. Presumably you would need to buy their motors as well as the controller itself for the system to work.

[JAZZCNC]

I've not seen the "absolute bus type" (990MDCb) version of the Newker in the flesh but it sounds as if it uses some sort of serial bus to pass absolute motor positional data back to the controller and presumably also does away with the conventional step/dir signals in the process.

I've been in touch with Newker about Bus type Absolute setup for my VMC and the absolute controller is NEW1000 MiCb-4 series. The absolute drives are dual axis so for a lathe you'll only need one drive.

I've got the manual if anyone wants to see it but it's too large to upload to Forum so contact me directly thru PM.

[Colin Barron]

How good are the BST servos and drives? Have you tried any other cheap servo motors/drives. Do the incremental controllers operate with stepper drives, for example the Leadshine am882?

[JAZZCNC]

How good are the BST servos and drives? Have you tried any other cheap servo motors/drives. Do the incremental controllers operate with stepper drives, for example the Leadshine am882?

The BST servos are very good for the money they cost and well worth the price but don't be under any illusions that they are in the same league as Yaskawa or any of the leading brands because they are not. You really do get what you pay for when it comes to Servos.

Regards the controller then if it outputs Step/Dir then it doesn't matter what's on the other end ie: Steppers or Servos. it knows nothing about what's attached. All it does is send out pulses and receive feedback if your using encoders and fully closing the loop.

If you are unsure about Servos and don't need the speed they allow have you considered Closed loop stepper systems? I only use Closed steppers now on all the machines I build now and I can tell you they are much better than standard steppers. They are simple and accurate if sized correctly for the machine. They don't come with any of the issues that AC brushless servos have in that you need to tune the motors to the drives and controller etc. They also don't require the same high-frequency controller that servos need to get best from them.

The difference between servos and steppers in technical terms is quite large and much more costly. I would seriously ask my self if you need to take this route when in all probabilty Closed-loop steppers will serve you just as good with a lot less hassle and cost.!

[pippin88]

New Yaskawa servos seem to be about two to three times the price of Delta servos.

Delta servos seem to be 1.5 to 2 times the price of the generic Chinese (e.g. BST).

I am considering 750w Delta servos for a new mill build. Possibly the newer B3 drives, a bit more expensive but look to have good features. I am encouraged by the manual in comprehensible English.

[Boyan Silyavski]

Check DMM servos

[JAZZCNC]

New Yaskawa servos seem to be about two to three times the price of Delta servos.

Delta servos seem to be 1.5 to 2 times the price of the generic Chinese (e.g. BST).

Not really £400 for B3 Delta's on Ebay £525 for Yaskawa and can be found cheaper. While half decent the Delta's don't compare to Yaskawa and I'd gladly pay £100 more for Yaskawa.