Deckel FP4A Retrofit

Very nice!

There is indeed a belt drive, all the axes and the spindle are timing belt driven, I don't have the spec on the belt handy though and I haven't been able to track down a copy of the parts manual yet. I actually just took the X motor off today to get the dimensions and I think I'll see about figuring out the pulley, if I swap the motors I doubt I'll be so lucky as to have the original pulley fit the new shaft

So after a ton of research and talking to a few companies, it looks like I'm going with Lichuan servos and drivers, I figured this might be the most cost effective way to get the machine back into operation.

Maybe this has been discussed somewhere and I just haven't seen it, but maybe having a list of a vendors and offerings would be good for newbies like myself so we don't all end up duplicating research on what is available

I picked the 1.8KW, 6NM, 3000RPM motors for the X and Y and the 2.6KW, 10NM, 2500RPM motor with brake for the Z axis, I calculated my moment of inertia for the axes and these seemed like a good fit, they won't be quite as fast as the original motors on rapids, but should be as fast as stock on cutting moves, so I think they will be OK. The other reason I decided to go this route was to convert the machine to single phase 220V so that I won't need to go with a rotary phase converter, which should save several thousand bucks on the retrofit, I think that alone is worth the slower rapids.

As far as the spindle goes, I think I can reuse the existing motor and just operate it with a cheap VFD, I'm looking at the Vevor 5HP VFD. The stock motor is only 2HP, which I think is odd since the manual states that the FP4A should come with a 5HP spindle, but at least buying the 5HP VFD should make it easy enough to upgrade the spindle motor in the future if I decide it needs more power, and with a working CNC, I could have the machine make parts for itself, which is always fun

From my research, the other option for the axes I think would have been to go to 6000RPM GSK motors, but they all operate on 380V 3 phase drivers and are a fair bit more expensive than the Lichuans.

While I'm working on getting the motors ordered in, I need to figure out the rest of the machine as far as how much I/O I'm going to need to control all the various functions and what kind of Mesa card I will need to control everything, so that's my next area of focus.


I need to do more looking around on the machine to see what sensors I have to interface with, but just for the gearbox I'm going to need 9 inputs for the position switches alone, I'm sure there are other things I'll want to connect as well, but at this point I'm thinking the 7i77 card is probably what I'm going to need for interfacing, I'd love to hear input from the more experienced on this though! I understand the 7i77 should be able to read my Heidenhain scales as well through their 602 EXEs, so that's great!