Messages

11

Show"N"Tell ( What you have made with your CNC machine.) / Re: Ummm Art

« on: February 21, 2008, 03:09:56 AM »

Yep I must agree. Very cool.

Chad

12

Mach3 and G-Rex / Re: G100 and VFD`s

« on: February 15, 2008, 01:06:04 AM »

My vfd would not let me scale the analog input that high. What I did instead was double the max drive frequency.

Chad

13

Show"N"Tell ( Your Machines) / Re: Parker OEM750 stepper and mach3

« on: February 15, 2008, 12:57:46 AM »

That link is bad.

I will take a look when i can.

Chad

14

SmoothStepper USB / Re: Updates?

« on: January 30, 2008, 01:18:09 AM »

Cool! What is the material you are cutting??

Chad

15

Show"N"Tell ( What you have made with your CNC machine.) / Re: Helicopter Rotor Head

« on: December 13, 2007, 08:17:42 AM »

Yea that is awesome! looks really nice..

How long did it take you?

16

General Mach Discussion / Re: Power Supply Voltage Too High

« on: December 01, 2007, 06:41:24 AM »

HI, sorry I have been really busy, and needed to take a little break from forums, not just here but on the other 6 I regularly visit also.

As for the 5 axis guy, I have the new head designed but haven't been working on it much lately. We are probably going to get a new haas VF-3 and the new head will probably be one of the first projects for it. 

I have been working on making 1/5 scale motorcycle rims. That is a huge pain in the butt. I had to build a 5 axis trunnion table for the mach bp clone. I will post some stuff in a couple of days. Ask Brian, he was in town and he stopped by the shop and we went out and had some beers

chad

17

General Mach Discussion / Re: Power Supply Voltage Too High

« on: November 28, 2007, 10:13:44 PM »

Unfortunately I am going to interject a little reality here. Everything mentioned will work, sorta.  A resistor will limit current, and that will cause the voltage to drop but it would have to be a huge, really, a big one, to handle the current for servo drives. A proper one would probably cost more than a new power supply.

Voltage regulators: Linear, (linear technology) does make "linear" voltage regulators, like the 7805 (a positive 5 volt regulator).
I think He is confusing the term linear (as in the technology of linear regulators) with the company Linear Technology, oof- confusing.

Ok now to the point. There is really not a good way to do what you would like to do. The suggestion of unwinding some of the secondary is in my opinion the best advice. This is what I would do. It will not change the current at all, that is based on the wire gauge and not the length. Unfortunately this is not a really easy thing to do.

A resistor just isn't an option (sorry Chaoticone

Linear regulators just are not good with high current things like servo drives. It could be done but it would cost much more than the correct power supply.

So I guess the bottom line is put that supply up on ebay and go get yourself the proper supply. I would look for a multi output switching supply that does what you want. Double the max current that you think you will need and you chould be good to go. Power supplys are not the place to cheap out for servo drives.

Chad

18

General Mach Discussion / Re: Running 4th axis independently from xyz

« on: October 18, 2007, 11:47:06 PM »

Here is a great page on the 555.

It has more that you would ever want to know about the 555. Look at the Astable oscillator calculator.

http://home.cogeco.ca/~rpaisley4/LM555.html#3

chad

19

Show"N"Tell ( Your Machines) / Re: Chads new machine

« on: October 12, 2007, 03:55:01 PM »

I have never had any problems with "self resonance", in other words just running up to any spindle speed in free air. If you are having that problem I would suspect you have some sort of spindle balance problem. Try running it up with out any tooling in it and see if it does the same thing. If it does i would send the spindle back and have them re balance it. If it only does it with a tool in it, look for better tools.
Resonances are harmonics based if you get a bad one around 10k have you tried just pushing through it and going to 20k? also make sure your linear rails are solid and beefy and you have enough of a separation (on the yz mount) to make a sturdy z. There is no slop in my machine at all. I can grab the z and push in any direction with all i am worth and nothing clunks. I can flex things a couple of hundredths (my poor design in the y) but everything is tight.

If none of that helps then remember the old adage 'mass is your friend'.  I was having a problem with cutting at about 250 ipm .750 deep in mdf. This is I found was the about the right feed for what i was doing but I was getting a oscillation while cutting (slip stick). My solution was to add 4 25lb blocks of lead to the end just above the spindle mount inside of the z tube. This got rid of almost all of the problem.

Please start a thread with lots of pictures. I would love to see your machine. There are not many BIG mach machines that i have seen pictures of..

Chad

20

Mach3 and G-Rex / Re: Driving a galvo head with Grex possible?

« on: August 30, 2007, 03:16:34 AM »

Hi, I have not done much with high speed marking or machining but I have lots of laser display knowledge.

I suppose you could do it but there are probably better alternatives. What kind of head do you have? I have never seen a head that does not have feedback. If they are open loop you will have to wait a long time for them to settle down. If they are general scanning they have a torsion bar and will oscillate like crazy with those big mirrors on a step. If thy are Cambridge they cannot work with out feedback, they do not have any kind of physical centering.

chad