Messages

581

General Mach Discussion / Re: power supply

« on: September 05, 2013, 08:05:22 PM »

I would agree with Ray about the high inductance.  Also since your gantry has about 3 times the mass of mine I'd go with the 1200 oz./in steppers not the the 906.  Even then, that is a lot of mass to be moving around, don't expect stellar performance.

582

General Mach Discussion / Re: When touching off X Y

« on: September 05, 2013, 07:58:23 PM »

Hood,
I have always wanted to try one of those.  Do they work well?

583

General Mach Discussion / Re: When touching off X Y

« on: September 05, 2013, 01:47:26 PM »

Yes, you always have to take into account the radius of whatever you are measuring with, just like a manual mill.  CNCs are really really dumb. They only know three moves, straight, left turn, right turn.  If you say go from point A to point B and it happens to go through the part, the table or a clamp, well that is where it is going!

584

General Mach Discussion / Re: When touching off X Y

« on: September 04, 2013, 08:35:48 PM »

I use an edge finder with a 0.200" tip, then when it trips I select the DRO and enter + or - 0.1" as the current location. Edge finders are part friendly, they don't gouge like the tool will in an oops.I have a Starrett and a $10 chinese edge finder. The Starrett is worth every penny, it works so much better. I am amazed that it repeats to a couple of tenths! I like to pick up the top of a part using a 1/2" guage pin rolled under the tool. No accidental crashes when you are that far away. Enter 0.5" in the Z DRO as the current position.

585

General Mach Discussion / Re: stepper size

« on: September 04, 2013, 04:18:48 PM »

My power supply is a 120 vac x 24/48 vac transformer rated at 750 va. It feeds a full wave bridge rectifier and a large capacitor (don't recall the size) at 48 volt ac so that the unregulated DC voltage is about 68 volts. My drives are rated for 80 vdc input. If all the axis were slowing down at the same time putting power back into the supply the voltage might rise well above the drives maximum rating, so I have a large zener diode across the output to keep that from happening.

586

General Mach Discussion / Re: stepper size

« on: September 03, 2013, 08:24:08 PM »

Okay,
My machine is half the size of yours, has 20mm x 5mm pitch ball screws driven by 800 in/oz. steppers at 68 vdc.  The steppers are also low impedence.  No problem with power and it is very quick, up to 3000mm/min. I can cut steel with no problem. I don't think this helps you much.

587

Third party software and hardware support forums. / Re: Just got BOBCAD and here are my initial thoughts.

« on: September 03, 2013, 01:54:53 PM »

Hood,
I used to turn rollers like those all the time. I mounted them on an arbor in a collet on my mill spindle and mounted the cutter on the table. One thing that worked really well. I had a shop vac with a large tank and the suction through the lid not the side.  I'd put a garbage bag in the tank. Once you started the plastic chip into the vacuum hose off to one side it would continue the whole time you were cutting.  No mess and the chips were already in the bag for disposal.  One word of warning, do NOT reach in the chip bag, the static charge REALLY hurts!

588

General Mach Discussion / Re: stepper size

« on: September 03, 2013, 09:11:12 AM »

You need to provide a whole lot more information in order to even guess at the answer!
Are you:
Drawing, knife cutting, 3d printing, cutting wood, cutting aluminum, cutting steel?
Ball screw, belt drive, acme screw, acme with anti-backlash?
Air bearing, ball slides, wheels, plastic bearings, metal on metal?
Plastic frame, aluminum frame, steel frame, cast iron frame?
Slow, faster, very fast, extremely fast?
Wood accuracy, metal accuracy, extreme accuracy?
On a tight budget, have money, price is no object?

I ordered the questions by increasing cost or difficulty from left to right.

589

General Mach Discussion / Re: USB Breakout board for Mach3

« on: September 02, 2013, 04:11:14 PM »

I believe this is the xulifeng board that I am currently using. The only problem I had was the issue with axis jog locking up with the shift key, and it turned out the ESS board has the same issue. I bought the ESS board and a breakout card to replace this one, which has worked just fine. If you can wait a bit I'll give you a great "student" discount on it. It has never glitched even once, other than the shift key jog issue.

590

Screen designer tips and tutorials / Re: Small changes to jog flyout

« on: August 29, 2013, 09:31:18 PM »

Gerry,
Thanks, I'll give that a try!

Gary H. Lucas