Messages

111

Show"N"Tell ( Your Machines) / Re: Warco VMc /Chester 626 knee mill CNC conversion

« on: July 20, 2008, 10:54:10 AM »

Thanks. I'll give them a google.

112

Show"N"Tell ( Your Machines) / Re: Warco VMc /Chester 626 knee mill CNC conversion

« on: July 20, 2008, 07:36:08 AM »

has anyone got any suggestions as to a good gearing system to get the 3:1 mentioned above ? I'm thinking of timing belts and pulleys, Where would I get suitable ones in the UK ?
Thanks

113

General Mach Discussion / Re: Spindle RPM

« on: July 20, 2008, 06:44:08 AM »

Anything above about 3 hp would start to give me problems with my supply. Still I may give it a go once everything else is up and running. I've got my eye on a small three phase motor already that I may be able to get for a very reasonable price as it's in a mates garage and he isn't doing anything with it. I work in a power station so you'd have thought there would be plenty getting scrapped here and there but unfortunately most of them you'd also need a power station to run.

114

General Mach Discussion / Re: Spindle RPM

« on: July 20, 2008, 06:19:19 AM »

Hood you put your weak points in the CNC and now you've got a box full of strong ones. :-)
Very good point about selling the single phase motors they do go for more than three phase and would off set the costs of getting the converter I think I would still have to use the gears though unless upgrading to a 3hp motor would give me enough torque at the bottom end.

115

Mach3 under Vista / Re: mach 3 and vista

« on: July 20, 2008, 06:13:07 AM »

It's all working now. Downloaded the software again went through all the steps again and didn't expect any difference but hmmm..there it was working. The pulse train isn't very healthy though but that shouldn't be a problem once I get my smoothstepper :-) . Thanks for all your input.

116

Show"N"Tell ( What you have made with your CNC machine.) / Re: RC scale airplane propeller blades.

« on: July 20, 2008, 06:09:50 AM »

The video wasn't working for me yesterday but works good today. I can see now it's all done from a flat piece of wood. The finished articles are pretty splendid. The blades don't appear to have a twist in them as a lot do and thus that's why I was thinking a 4th axis would be needed but I suppose even with a twist is can still be done with the same method (3 axis) only would probably require a bit more sanding on the leading edges. Is it called plasma due to it primarily being used for plasma cutters? Interesting to see how you'd make one of these with a plasma cutter.  Good stuff.

117

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 01:02:38 PM »

I looked at that one Hood yep it looks like it would do the job but $525 plus tax plus shipping...hmmm it may just end up a would like for the future.
Jim I've had a thought about your over speed problem and I'm thinking it would be unlikely to be the supply voltage to the box as it's a digital signal it's not easy to see how supply fluctuations can give you a multiplier effect.  I would tend to think you are getting multi pulses from somewhere these things are quite fast enough to trigger a couple or more times on the same target. Is the target as small as possible and completely flat i.e. no bent corners ?If you use reflective material such as the reflective strips on clothing they contain a number of miniscule reflective surfaces to maximise the chance of getting a reflection no matter where the light source is and thus something like this could give you multiple triggers. The other thing that can effect IR receivers is back ground light. I know it's not meant to but there is a fair bit of IR in normal light so maybe something is being reflected off something else? I would think a small blob of Tipex would give you a good enough target to try in case the multi trigger is your problem. I'm thinking aloud here so please feel free to ignore me if (no doubted) you've already thought of all this. The only other thing I suppose is noise pick up on the cable it it’s long enough or goes near enough to an electrically noisy thing.

118

Show"N"Tell ( What you have made with your CNC machine.) / Re: some mach3 inlay work

« on: July 19, 2008, 12:02:41 PM »

Nice work. I'm not sure what v carving means I must be honest. I'm in the process of converting a mill and this is the kind of work I'd love to be able to do particularly copper/brass inlays in furniture and seeing your work mean at least I know it is possible to acheive the kind of results I'm after.

119

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 11:36:40 AM »

As far as I know the common single phase motor runs at a speed slightly behind the circulating stator field, as you apply load the 'slip' or difference between the applied field and rotor field increases and draws more current trying to catch up. so in essence all you have to do is provide it with a sort of sin wave at whatever frequency you want (within reason) and the motor will try and match it ( I may be completely wrong of course). Problem being it is a lot harder to produce a good variable frequency controller than some sort of chopper controller that basically turns the power off for part of the cycle and thus gives you poor low speed torque . Handy you only need one converter and just switch it to one machine or the other but it would mean swapping the motors on the lathe and miller which I suppose isn't a huge problem as they have the same foot print and shaft size but is extra hassle and extra cost as well as the cost of the converter. So I may have to leave it as it is for now unless I come up with a cheap set up for either. Hood if the VFD thing requires 0 to 10v to set the speed, what does Mach3 give out to try and control it? Is a frequency control or a pulse width controller? either one is fairly easy to get 0 to 10v out of especially if it can be set up as part of a feed back loop and thus any inaccuracies in the drive circuit get noticed by the once per rev and will auto compensate. The sticky reflective pad is also a good idea as I could mount this in the pulley housing on the spindle pulley and thus keep it out of the way of danger though I suppose I could also mount a slot plate up there so both are possible.

120

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 09:54:29 AM »

It's a 1.5HP single phase. I suspected the low speed torque would be a problem if left on the high gearing. Still it's not a problem to change belt pulleys before a job and thus will give me a band of speeds available with some sort of variable frequency motor control. As I'm trying to do as least invention as possible to get it up and running have you any experience of a variable frequency controller that will work on Mach 3 for 1.5 hp single phase ?  I've also got a lathe that I may be converting (if this one goes well) and hopefully building a large 8' X 4 ' router in the future and the good thing is all the drivers, speed controller and most of the CNC kit except for the steppers will be able to be used on all of them and thus will cut the cost of the conversion somewhat. Thanks again.