[ihavenofish]

so, sieg has a new X4 machine up on their site. its basically their version of the short travel RF45. has 550mm x travel (21.5"), 200mm y travel (8"), and something around 17"-19" of possible head movement. i assume the price will be in like with other rf45's - $1500 to $2000 range.

ill be getting shop space soon, and can do with something much bigger than my novakon kx1. theres several premade machines i can get, but the x4 is looking very appealing for both price and "fun".

so, for anyone thats done an rf45 or variant, whats possible here?

1st step is a ball screw conversion. ive heard good things about the chinese rolled c7 grade screws on ebay. price is super cheap, like $500 or so for all axes including bearing supports. they are quite adequate for my needs at under .001" repeatability and .0015" precision. the question is, what size? they have 16mm, 20mm, and 25mm. i know the table is very heavy compared to my little kx1 which has 12mm screws, but is 25mm wasted money and overkill?

anyhow, second step is the motors. i have a whole pile of parker nema23 brushless servos, and the granite devices drives ($1000 for the set) will happily run them from mach. to save costs and power, i can run them with a 48v psu. they will go 2250rpm with 73oz-in and have a peak usable torque of about 150oz-in.

so obviously thats not much torque, but alot of speed. realistically i think 150ipm is tops for this machine, which means i can gear down to 3:1, and get 450oz-in peak and 150oz-in at top speed..

so the question to people who've got similar machines, is this enough? i CAN spend a chunk more money on a psu and simply run the motors at 96v and get 2x the torque with a 6:1 belt drive. obviously thats better all around, but do i HAVE to? Z will be pushing it maybe, but i do plan to counter balance the head.

ill also be messing with the spindle, putting an oiler in, and some other stuff, but i think i know what ill be doing there... maybe.

thoughts?

[ihavenofish]

no thoughts? lazy bums!



i had some. i did some math, and found that with a 4 to 1 ratio on my little parker servos, i will have ample torque for the x and y, though its a stretch for the Z even with a counterweight. at 48v ill get 100ipm, and at 96v ill get 200ipm. so now i have to decide whether the complexity and flaws of a high ratio belt drive outweigh the cost of just buying 3 larger motors.

in any case, looking deeper into RF45 type mills, i think im leaning to the bigger IH sized ones - bigger than the X4. 30" of travel opens up alot of possibilities for me and for the mere $1000 extra, i think its justified since the cost of retrofitting doesnt change much. theres no x4 dealers in north america yet either, but there is an IH sized rf45 dealer near me.

[slashmaster]

My thought is, now that there is an X4 which is the one you're talking about and an X4 which is basically a turnkey cnc X3, it's going to create confusion on this forum from now on.

[arizonavideo]

The RF clones have 1" leadscrews. It looks like Sieg is just buying the unit from someone else. The low RPM gearbox and other things look like the standard ZAY-45 machines.

The table will be fine with 16mm screws but you might go to 20mm for the head. It is about 175 to 200 LB and likes to stick.

One new servo for the head wont be too much, I would get a larger one. For the price of a gas shock you can get a larger servo.

I do hope that Sieg does the finish work like the Quill and ways.

[ihavenofish]

The RF clones have 1" leadscrews. It looks like Sieg is just buying the unit from someone else. The low RPM gearbox and other things look like the standard ZAY-45 machines.

The table will be fine with 16mm screws but you might go to 20mm for the head. It is about 175 to 200 LB and likes to stick.

One new servo for the head wont be too much, I would get a larger one. For the price of a gas shock you can get a larger servo.

I do hope that Sieg does the finish work like the Quill and ways.

well, sieg says its $1250us plus freights and import costs. so it will basically cost the same as most other rf45's.. about $1500ish. the "big" rf45 is $2400cdn ($2200us) and local.

im thinking 20mm screws for the x and y and 25mm for the z in either case.
im still searching for info and pondering options.