X2 working annealed 4140 and 304

[corgano]

I'm building my first CNC steel mill and have been looking at getting an X2. I've got a few concerns and ideas. I'll do this in list format for easy quoting of responses (thanks in advance)

1. The mills I've worked with 4140 and 304 on are typically 2hp-10hp. Given the X2 is 3/4th hp, is that enough? What about chip load and welding of debris to work? Can't really use a flood due to the layout of the machine.

2. Is the weight of this machine enough? 150lbs doesn't provide much stability, even when bolted into my ~800lb shop bench.

3. If I get an X2, I don't really want to invest more than $600 in the CNC retrofit. Can anyone recommend a conversion kit that has doesn't use aluminum mount plates and acme screws? I'm looking to put nema 34's on it as I've got 3 ~700oz/in'ers laying around.

Thanks,
-Corgano

[MrWild]

1. Sure, 3/4hp is more than enough... if you understand you can't use the same size tooling, or speeds and feeds. Welding of debris to the work??? Have you seen an X2 up close? it's a TOY! Sure, it's a toy that does real work, but you are NOT going ro be welding debris to the work piece through the sheer awesome power of an X2. For cutting 4140 and stainless with an X2, if you can't use flood, you have to use mist.

2. It's an X2. It's a toy. Why would you need to bolt it to a 800# bench? A 4" kurt vise dwarfs this machine. How large are the parts you want to machine? How heavy are they? How far will they hang off the table?

3. You want to machine difficult material but you don't want to spend much money? Cannot be done without disappointing you. it can be done, but not for $600 with good results for 4140 and stainless. IF you do ALL the work yourself... Here are somem costs.

1. Ballscrews. $180 and they need to have their ends machined. Don't forget the ball nut mounts.
2. Electronics.
a. A drive(s) $200-$350 Make sure you have the needed BOB, cabling, E-stop and limit switches
b. A power supply $30-$70 Cheap cheap don't cut it.
c. An old computer and monitor $free to $? Don't forget the PP cable $8-$15
d. motors $38 ea x 3 27s minimum price for what you want. 34s are a waste and actually give less performance. Te 27s you want are $49 ea x 3.

Hardware. If you can get aluminum scrap at work, you have your mounts. If you can't, oy $50 in al at least. Thrust bearings, motor couplings, etc. $100.

Say a total if you do all the work, of $750. For a kit? NWIH

[corgano]

Well I guess I made the assumption I couldn't mist or flood due to the lack of structure to support a catch pan. Also having drive components directly underneath the work piece. I may buy one since they're $500 and play with it in manual mode to decide if I want to keep it.

The 800lb bench is already in my garage. I built the frame out of 2" square tube 1/4" wall structural steel after coming across a large pile of ~10' sections at a local scrap yard.

The largest parts I'm currently machining is approximately 12" x 4" x 2". The $600 wasn't inclusive of the mill itself. I figured ~$1100 for a mini-mill conversion.

I've been modeling out a larger table in the mean time in Solidworks trying to reuse some of the spare parts I can pick up cheap from a local yard.

Currently the parts list of things I have earmarked are:
6 THK block & rail assemblies
3 NSK ballscrew assemblies (with mounts)

For the spindle I was thinking of 2:1 pulley reducing a 2HP grizzly 3450 RPM motor. I can either buy servos or steppers, was planning on NEMA 34 in the 750-900 oz/in range.

My day job is computers/electronics and if I'm building a mill from scratch I'd make my own controller, drivers, and power supplies. Primarily so I can have one board for the controller that uses a single FPGA instead of half a dozen MCU's and interface via USB instead of PP. Was thinking this might be a fun project to open source as well as servo drivers are pretty pricey and with little reason.

Out of curiosity, why aluminum for the mounts? I was thinking steel since I've got lots more steel scrap than aluminum. I'd probably make the frame out of 2" square tube like my bench as I still have a dozen or so 10' pieces.

If I'm building it myself I don't mind spending $3k or so knowing the machine will do the job.

Thanks for the reply.

[MrWild]

If you have steel scrap, use that. if your parts are 4 x 12, the cheap HF X2 is too small. The $500 X2 has less than 4" total Y travel. The $650 before shipping X2 from LMS has a larger base and 5.5" of travel. You need the extra travel to machine the sides of your 4" wide part. if I were to do it again, I'd go with the LMS big X2 as it also has a more powerful BLDC motor.

Figure more like $1,400 to be up and running. I didn't include CAD/CAM programs or the cost of Mach 3. I use EMC2 which is free and works well. What will you use for a vise, hold downs, and cutters/collets? More $$$.... $1,600 As you are doing 4140/stainless, I'd suggest indexible carbide end mills. Mist won't require a drip pan so you save there, and you can build a mist rig... oops, pressure regulator, valves, etc... It isn't cheap.

I just read you want to build your own controllers and comm using your USB port. I think maybe before you buy the mill, buy your motors and work out your control. Unless you are a electron and programming god, you may find this part of your task will take over a year of your time. Do some research on the "smooth stepper." Not saying you can't. I know I can't but I don't have your day job. Rolling your own is such a lot of work, that doing it all on your own including the drives will be a hobby all in itself

[corgano]

I was planning on using ECM2 and I've got an old copy of Solidworks/Camworks my sister bought while going to university.

As far as tooling goes (collets, bits, etc), I've got a separate budget for that as I figured it would be fixed no matter which route I went. Yup, carbide isn't cheap and tools break, figured it would be an ongoing thing.

For misting and/or flooding, would using a controllable volume/pressure DC pump to a Loc-line coolant hose be appropriate?

Thanks again,
-Corgano