Yeah a log would be nice to see, I was looking at your build log the other day actually for the belt based machine you did for the guy in Ireland I think it was New Machine Build Belt Driven extrusion framed wee beasty!! - ...
It would be a nice thought to know you've got log(s) on here too...
Last edited by Lee Roberts; 07-11-2015 at 12:03 AM..Me
To be honest I often feel bad that I don't post build logs but to fair I haven't got time to record and photo all the nitty gritty stuff that matters or helps.
Also because I mostly use CNC machines to build CNC machines most of it won't help new builders because it's a little like comparing apples to oranges. What I do they can't easily without a machine to help them and to do it manually would be completley different approach and often would be designed different to suit manual methods better.
Mill on the other hand is more retro-fit so will be easier to show so i'll maybe do this.!
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Subscribed to Mr Crispin, Lee... that loco seems pretty hardcore :D
Weekend, themed "chicken and egg". Could of done a far better job of the Z stepper bracket, if the machine was working...
but its done nevertheless, even if its just for now
As mentioned previously, the spindle has two mechanical systems to control spindle speed. The "vari-drive" pulley arrangement, and also a back-gear which halves the rev output from the selected speed range from the vari-belt system. As Im unwilling to spend a fortune on the variable drive pulley I need for the motor, I intend to drive the spindle with a single ratio, then rely on the VFD and back-gear for speed change.
In order to get adequate torque at the spindle head, I need to start off with too much power, that way if Ive reduced the revs with the vfd, there is still ample power by ratio.
I was kindly given a main spindle motor for the machine, Its a brand new 8hp siemens 4 pole, it runs at 380v in star, so, il only achieve 4hp at 240v, If I run this at 100hz Il get approx 3000rpm at the spindle, and if I gear that 3:4 my top spindle speed will be around 4000rpm
only problem is,said motor was dropped (hence its free) the rear casing is shattered, It is also foot mouted, I need it face mounted. Therefore, I intend to replace the broken rear face plate with the existing front plate, then re-make the front plate, building in a face-mount
so, spent fifty notes on a nice slab of ali
then armed with my new found qualifications after a 18months of channel updates from the likes of doubleboost and keith fenner, off I set
what could possibly go wrong? ...
er, the "brake" setting on the vfd could be a bit optimistic for that amount of momentum.... and you could sheer a gear in the lathe gearbox !!!
stripped a cog...
so now need to fix the lathe. god knows how..... I figure if I get really oily and look like I know what Im doing, inspiration will hit me....So have that in bits everywhere
Busy week at work, and in wales next weekend, so sulking with beer tonight.
anybody tooled up to make gears?
Last edited by kingcreaky; 08-11-2015 at 10:09 PM.
Following this, I was left with little choice but to bypass the feed gearbox, by hanging the motor directly off the main lathe input pulley, and put up with the lack of torque.
This enabled me to produce a new motor front
however, despite my best efforts, its clearly not aligned perfectly, as I can feel the stata grind when turning the shaft manually, either that or the actual shaft or casing was bent when it dropped? Disappointing but I learnt alot, managed to brake my lathe, and lightened my wallet to the tune for £65 on ali. Nevermind
so... I bought a "new" motor (£22 off the bay, 2.2kw)
havent yet fitted it, but it is face mounted, and has a long shaft, so I dont think it will be too difficult.
As for the machine, with thanks for the Dean, I got the servos working.
The servos have 10,000 steps per revoloution, as im driving the ballscrews via 2:1 ratio, and they are 5mm pitch, I make that 4000 steps per mm.
My old faithful parrelel port, cant keep up with that kind of resolution so komatias kindly sold me a ethernet smooth stepper.
I mounted the control box to the side of the machine, using rubber mounts, and made a bracket to mount the monitor keyboard and mouse.
and albeit, not yet including home switches, limit switches, a spindle motor or coolant, the machine is moving
listen how quite those servos are compared to the z stepper!
Last edited by kingcreaky; 01-12-2015 at 09:47 PM.
Sounding Good Matt but get them Limits on ASAP because if those servos throw a fit or you mistakenly type X1500 instead of X150 they won't stall like steppers and just keeping pumping in juice until something breaks or goes up in smoke.!!!
Also just be careful for while with how fast you run and accelerate/deccelerate that big heavy table because you may need a Braking resistor if you push too hard. The drive will give an Alarm if higher than the internal Regen resistor can handle or Heat sink Temp rises due to internal Resistor getting hot.
You can also monitor the Regenerative Load and Heat sink Temp on the drive panel to get an idea of how close to the edge your pushing. Set DN013 to monitor the Load percentage.
Then write to some back n forth G-code moves and watch the drives when accel or Deccel to see how close to 100% you come.
Next video better see some cutting going down. . . Lol
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