PM-728VT CNC Conversion Instructions

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chipinator

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Hello all...I hope everyone is staying well. I would like to convert my PM-728VT to CNC. I've searched around on the interwebs, YouTube, etc..., and I can't seem to find detailed instructions on how to do this, from the electrical to the mechanical, everything. Going into it blind is not something that I relish doing. Would anyone happen to know where I might find detailed instructions on this conversion? Thanks.
 
With no answers, apparently there aren't any instructions for this conversion. That's too bad. I'm sure there is a market for instructions such as this. There are likely a lot of people that would like to know how.

Maybe someone can answer this question associated with this post then. I was sourcing AC servo motors for my PM-728VT mill and I was asked how much torque was needed. Seeing I'm no CNC machinist, yet, would anyone be able to provide a torque value I would need? Any suggestions would be helpful. Thanks.
 
There are no step by step instructions, as what every individual wants/needs/budget is different.

There are pleanty of "guides" on youtube and the web to wire and set up individual components. Its up to you to research and decide what components to use.

Your AC servos is a perfect example. With non ground ball screws and the typical support bearing quality/housing design that most of these machines use, AC servos provide little advantage except fast rapids. And I question the "need" for fast rapids in such a small machine and the detriment to the plain ways that they can cause. But some feel that they need them, and thats ok. Life would be dull if everyone did the same thing.

Steppers, especially the closed loop ones with encoders provide higher slow speed torque and can provide more accuracy than the mechanical components can provide.
 
@chipinator I don't mean to be rude but aren't you the guy that did not want to fix the one shot oiler system? I believe you said you weren't a milling machine mechanic. As @Firebrick43 just pointed out it is a large process to convert a mill and there are no step by step instructions to my knowledge. You will have to completely disassemble the mill for the most part to put in ball screws etc etc.
 
@Firebrick43 Thank you for taking time out to respond. I appreciate it. AC servos vs. steppers is noted. A nice bit of information to have.

@7milesup I'm not a milling machine mechanic which is why I didn't want to disassemble my mill to try and find a leak that was an issue from the point of purchase. Why should I be responsible for an issue that I didn't cause on a brand new item and why should I be the person to have to fix it when it's under warranty? Just like my car analogy...I'm not a car mechanic so when something happens to it I take it to the stealership to get it fixed, and I'm willing to pay. Maybe not your cup of tea but it's mine just fine. As @Firebrick43 stated above, "Life would be dull if everyone did the same thing." Cheers!
 
@sunrise305 I haven't started yet. I've been sourcing all of the components at a snails pace it seems. For instance, I'm interested in DMM AC servo motors but I just found out a few days ago that the mounting holes in the NEMA23 motors are not straight through, they are oblong. DMM does have an 8mm thick mounting bracket in case the mounting holes of the motor don't align with the holes in the mounting bracket for the motors that attach to the mill. I want to make sure I'm purchasing correctly the first time as these are high dollar items. As well, I'm trying to find all of the companies that produce/market/sell AC servo motors so I can make comparisons. I called Precision Matthews and asked if their precision ball screws were ground as @Firebrick43 mentioned above and they are not ground. I haven't found any precision ball screws for this machine that are ground. If anyone finds precision ground ball screws for this machine, I would be interested in receiving that information. That's kind of where I'm at. Once I find really good AC servo motors, I can move forward a little further.
 
chipinator said:
@sunrise305 I haven't started yet. I've been sourcing all of the components at a snails pace it seems. For instance, I'm interested in DMM AC servo motors but I just found out a few days ago that the mounting holes in the NEMA23 motors are not straight through, they are oblong. DMM does have an 8mm thick mounting bracket in case the mounting holes of the motor don't align with the holes in the mounting bracket for the motors that attach to the mill. I want to make sure I'm purchasing correctly the first time as these are high dollar items. As well, I'm trying to find all of the companies that produce/market/sell AC servo motors so I can make comparisons. I called Precision Matthews and asked if their precision ball screws were ground as @Firebrick43 mentioned above and they are not ground. I haven't found any precision ball screws for this machine that are ground. If anyone finds precision ground ball screws for this machine, I would be interested in receiving that information. That's kind of where I'm at. Once I find really good AC servo motors, I can move forward a little further.
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Thanks for your response. I have seen numerous threads about PM-728VT owners heading down this path, a conversion that is of interest to me and many others, but never any reports of the final outcome. I posted a question on this forum months ago asking for feedback on how those conversions turned out but received rzero response.
 
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