Messages

1331

General Mach Discussion / Re: Mach3 skips to subroutine, crashes Z, ruins part :(

« on: December 04, 2008, 05:54:26 AM »

Just a couple thoughts:

The thing that has caught me with subroutines is not having a hard carriage return after M99. Mach3's response to this seems unpredictable. Sometimes it will ignore the sub and sometimes it will just stop at the end of the sub.

On the issue of computers in general I have a lot of experience and my advise for any crititcal application is to have the computer running on a UPS. Spikes destroy things immeditately, but power sags, especially if the power company is doing rotating brown outs, can leave the computer running, but with the memory contents changed. I have traced many recurrant spooky problems to this phenonema.

Watch out for other probrams that may be running on a PC, especially if the PC is on a network, or the web. I am running Mach3 on a laptop (temporarily) and the power saver feature kicked in unexpectedly and slowed the CPU down which caused the probram to blow up. If I leave the laptop connected to my network (wireless), Mach runs, but is unreliable.

1332

Show"N"Tell ( Your Machines) / Re: 4th axis - show and tell - pictures

« on: November 24, 2008, 07:02:07 AM »

I got a chance to use the 4th axis. The external threads were single pointed on the rig and the flats were also cut for the nut.


These parts are cut from 1.5" OD steel bar stock. Threads are 3/4-16  . .  quite a feat for a little X2 

1333

General Mach Discussion / Re: GROUNDING - what is the correct way to ground a CNC machine?

« on: November 23, 2008, 08:37:33 AM »

Thanks Ray,

Based on the advice I got here, the metal plate that the electronics are mounted on now has a separate wire running directly to earth ground via the ground pin on the wall outlet.

The only shielded wire I have is to the indexer sensor and it's shield is connected to common on the controller board. It came wired that way.

So any boards that are grounded thru their mounting holes will be grounded. Everything is working fine, so I guess I'm good to go.

1334

Show"N"Tell ( Your Machines) / Re: 4th axis - show and tell - pictures

« on: November 23, 2008, 08:26:47 AM »

Looks like this is the spot for machine mods. I can't wait to look through this topic!


I put needle roller thrust bearings front and back so I could run it with zero play for grinding cutteres, but the 'bearing' is just cast iron to cast iron, as it was. I put Mobil ! synthetic in it thru the locking screw hole on top. It's low RPM so I think it will be OK as is.

I plan to use it for sharpening, grinding OD of hard stuff, making pulleys and gears and perhaps single point threading.

My rotary table (now sold) would have been more accurate, but would rotate too slowly for what I need.

1335

Show"N"Tell ( Your Machines) / Re: 4th axis - show and tell - pictures

« on: November 22, 2008, 10:17:13 AM »

Looks like this is the wrong place for hardware discussion.

I don't know my around this community yet, but I do recognize this is a software forum, so can someone please point me to the best place to discuss the actual machine modifications?

1336

General Mach Discussion / Re: Specific PC for Mach 3

« on: November 22, 2008, 10:11:17 AM »

Hood,

Impressive setup.

You might want to beef up that frame though . .   

1337

General Mach Discussion / Re: GROUNDING - what is the correct way to ground a CNC machine?

« on: November 22, 2008, 10:08:29 AM »

I appreciate the replies, but I still don;t think I have an answer.


I get the chassis grounding and protecting people from high voltage, etc.

I get that the DC common is 0v and should not be connected to earth ground. All of the 0v (common) wires from the Geckos go to com terminals on the BOB.

I have a 5v (to the BOB) and 12v (fans and relays) supply coming from an old PC power supply. Each is only two wires. I am not taking any power from the PC and it is connected by a shielded,  all wires connected parallel cable.

Here is the question as succinctly as I can put it:

Are there any earth (or otherwise) grounding requirements that must be done on the electronics side i.e BOB, indexer board, charge pump, spindle controller, PC, etc that I need to specifically address?

Sorry to be a pest, I just don't want to fry anything else due to my lack of electrical knowledge.

1338

General Mach Discussion / Re: Backlash - very slow movement with every change of direction - Normal?

« on: November 22, 2008, 09:52:18 AM »

My observation is that these setting in fact have no effect (using newest .20 version). I've played with it a bit more now and no matter what shuttle or backlash sleed is set to, there is still a large and very noticeable delay at each change of direction, both for jogging and during program execution.

The actual backlash takeup speed seems to be stuck at 20%. It will go slower if set lower, but it will not go any faster no matter what number is put in the box, including 100% with shuttle set to 0.

I noted that using backlash defeates the CV, which would not be a good tradoff, methinks.

My machine now has .005" backlash on each axis using rolled Thompson ball screws. AM I being too anal wanting to use the backlash function? What do most people do? What is a reasonable amout of backlash to accept?

Is this an undocumented unsupported feature in the demo verion?

Sorry for all the questions. Newebee here.

1339

General Mach Discussion / Re: Backlash - very slow movement with every change of direction - Normal?

« on: November 22, 2008, 08:22:29 AM »

RC, thanks!

Steppers. Two 495oz-in and a 900+ on the Z

20,000 steps X and Y

13,333 steps on Z

I didn't know the shuttle had anything to do with it. I'll check that out.

What is the speed setting in the backlash dialogue box for? It doesn't seem to have any effect.

1340

General Mach Discussion / Re: GROUNDING - what is the correct way to ground a CNC machine?

« on: November 22, 2008, 08:16:28 AM »

Thanks Ian,

I read all of the posts carefully. I have all the power grounds done and tested. I put a ohm meter between the machine frame and the ground in the actual wall outlet and got 100%. Did same for control box and spindle control box (both aluminum). So that's done.

The 0 volt thing is what I am still unclear on. There are no grounding terminals that I can find and no instructions on grounding for the electronics that I can find.

It occured to me that the BOB is probably already grounded as it is mounted via aluminum standoffs to an aluminum plate which is grounded to earth. But I don't know if the mounting pads on the board are connected to ground. There is no separte specific ground wire between any of the electronics boards that I know of.

As to the laptop, I already had the issue with power saver feature. On this particular laptop, it is defeatable in the bios. I've done that and also I run it off wall current thru the charger, so it is not succeptable to the battery going low. It is an el cheapo laptop that I bought only to use with tuning and diagnostic software for an '82 Vette and I don't particularly care if it gets ruined by chips and oil.

I'm just in the process of building my first CNC. I'll put a permanent PC in place one everything is final and I have appropriate protection (including proper grounding) for it.

The spindle controller is already connected and working. It just does not provide a very consistent speed and I have not looked into that yet.

As to 'isolation'. There was only passing mention of it in both the BOB and the DC drive docs. I had no idea what 'isolation' was and consequently fried two DC drives and the BOB. After I fried the first DC drive, I explained in detail to a Minaric rep what had happened and he sold me a replacement unisolated drive . . which of course also fried and again took the BOB with it. Minaric made good by selling me new isolated drives for only the difference in retail price, so I can't complain too much.

But now you see why I am a little paranoid now about grounding.