Well a bit of time has gone by and I have made a decision about the VMC-760 machining centre. I decided not to go ahead at the last minute. The supplier was adamant that I use their 3 phase spindle, which would have necessitated buying what they called a variator. Unfortunately, despite numerous e-mails they were unable to give me any clear information as to what a variator was. I assume that it is a phase converter, but whether it's mechanical or electronic I don't know. To this day I am perplexed. I think they just didn't understand my questions; I would say "I believe a variator is a type of phase converter, could you please tell me if it is a mechanical or solid state device" and they would say something like "The spindle need 3 phase power you need variator to operate it with single phase". We just kept going in circles until I gave up. Once I had given up they sent me this link in an attempt to resurrect the sale but they couldn't tell me what model the one they were quoting was.
http://www.shinhsing.com.tw/index.php?option=com_content&task=view&id=46&Itemid=45In the end I lost confidence and decided it was too much money to spend, when I didn't really know what I was going to end up with and how expensive and time consuming it was going to be to sort out the inevitable problems. I probably should have just bought the basic machine frame and then sourced the remaining electrical components after it arrived, but by this stage I was worn down and was getting impatient.
One day I will go to Taiwan and China and have a look at the factories over there it should be fascinating.
Having put the import business to bed I turned around and ordered a convention knee mill from a local Melbourne supplier, since I had just sold my existing mill being sure that I was going ahead with the VMC-760.
The mill I have bought is a King Rich KR-V3000, which is set up already for CNC conversion with ground C5 ballscrews on the X and Y and precast brackets for the servos. I just need to supply and fit the motors, put a ballscrew on the quill and do the wiring.
There are a couple of conversion threads on CNCZone for this mill:
http://www.cnczone.com/forums/knee_vertical_mills/117112-conversion_king_rich_3000_a.htmlhttp://www.cnczone.com/forums/knee_vertical_mills/105668-king_rich_krv-2000_knee_mill.htmlI had already ordered the 1 kw servos from GSK, after they confirmed that their 1kw servo is fine on 240v single phase, GSK was a bit concerned that I may be under powering the mill, but the guys on CncZone who have converted these mills have used 400watt and 750watt motors in their conversions, so hopefully I will be Ok.
Since I had saved some money by not buying the machining centre I went ahead and ordered some more servos for the lathe as well. I found a single phase 2.5kw one with 2500rpm and a 5000line encoder and drive from Adtech that runs on single phase. I intend to put this on the spindle, and two 500watt servos for the X and Z drives, which should put the lost steps from my steppers to bed.
The mill should arrive in the next week or so so I think I might document the conversion on CncZone, since it seems to be the in thing.
Cheers
Dave
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what do you think of the idea?