Extron machining centre

peter35

Peter35
I have an extron machining centre with panasonic motors and drives, these have been giving me grief and am now looking to replace them. Drive and encoder errors however motors appear to be ok.

l am looking on ebay at the chinese motors and drives, 1.8kw 6nm ac motors, has anyone had any experience with these? At around $600.00 per axis these are still a lot more affordable than genuine panasonic.
 

peter35

Peter35
G'day Don

I came across this youtube clip last night, good information on the open, closed steppers and the servo motors.
Franco CNC.

I have nema34 1070 oz motors on my KingRich (bridgeport copy) mill. Did this conversion about 10 years ago, have been happy with it but it has lossed steps in the middle of a job a few times. I was considering the hybrid steppers but after watching video would prefer to spend the extra money on such a big machine. Steppers work fine on the smaller machines
 

meri

Meri
Hi Peter,

Maybe the problem you had was because they were open loop?

The original stepper motors on my Dyna Myte 4400 are only 140 in. oz. closed loop and worked well for many years. They are belt driving the ball screws at a 5:1 ratio.

The video accurately portrays just some facts but not all the details. Read this: https://www.kollmorgen.com/en-us/se...pper-motor-or-servo-motor-which-should-it-be/

I am going to stick with hybrid closed loop stepper motors for the x,y,z and ATC.

Here are the prices I got last night directly from China so I will upgrade to 8NM motors and drivers which are 8 x more powerful than originals. Eventually I will probably just eliminate the belt drives. Much cheaper than going through eBay. These are Nema 34 motor frames. https://www.alibaba.com/product-det...l?spm=a2700.7724838.2017115.23.734e22f1p1dfpT

1. 4N is USD 98.(566 oz. in.)


2. 8N is USD 104 (1133 oz. in.)


3. 12N is USD 118 (1699 oz. in.)


Also shipping cost is USD 120 by Fedex.

Cheers
Don
 

peter35

Peter35
Don, you are correct, my motors are open loop, didn't know any better 10 years ago, that is if there was an option. Also at the time it cost over $2k to purchase motor, drives etc.

Have just read the article on steppers and servo motors, very interesting. will have to give this more thought.

At the moment machine is running 1kw 4nm ac servo motors. l am more familiar with stepper than servo motors. Steppers are easier to setup, it may be possible to run a bigger stepper motor for the same result.
 

peter35

Peter35
So l have had a mate come in and spend the time to help with electronics. At the moment l have all existing Panasonic drives and motors running. X, Y and Z axis running, calibrated and homing switches working.

I have another spindle drive on order which should be here sometime this week, Whilst waiting for drive have got existing display cabinet updated. Have fitted a 22" color screen, emergency stop, over travel switch and homing switches fitted and running.

Once spindle is sorted, will then be the 16 tool umbrella changer to sort out, lubricator, coolant pump and spindle clamp, these are working on previous board just need to be sorted on the Masso.
 

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