[RickPflimlin]

It's not just 0's and O's but they are the most obvious.

They tilt to the left if the bit is traveling clockwise, and they tilt to the right if it traveling counterclockwise??? I first noticed the problem when I had a G and O together. One tilted one way and the other tilted the opposite way. The contrast made it more obvious.

I used several bits and moved the engravings from one end of the mills travel to the other with the same results. I recently adjusted all my gibes. My next best guess is worn ball screws? 3 year old 770 with no more than 3000 hours. 99% of the hours are light engraving, no major crashes ever.

I'm going to check the ballscrews for any obvious wear. I replaced the Z ball screw 6-8 months ago when metal specs were floating in the way oil. Of course we know this is not a Z problem.

I'm hoping someone has run into this and can suggest a quick fix? Great machine with very few problems.

[MFchief]

I don't have a real answer for you, but a couple of thoughts.

Did you do these with the PathPilot engraving conversational or some other program?
If it were me, I would first try the same engraving with different software, then you would know if it's hardware related or the software.
Good Luck
Terry

[tmarks11]

This doesn't look like a backlash/ball-screw wear problem to me. If it was, it seems like there would be a small disconnect where each "O" ended engraving. Also, when the letter is traveling directly vertically, it is still leaning; if this was ball-screw wear, during the vertical stroke the tip would make a straight line (just slight off in the X axis).

[LeeWay]

If it is Mach 3, then it may be the CV setting. I haven't messed with those too much. They are a bit confusing. Another thing pushing me toward Path Pilot.

[TXFred]

I see two possibilities.

1. X axis backlash. However, tmarks makes a good argument against that.

2. Slop in the spindle, causing the tool to move slightly under cutting forces. This could also explain why there's a divot at the end of each toolpath.

[Doubleoh9]

Are you using a drag engraver? Looks like where the drag engraver changes direction - since the cutting axis is off the axial center.

[popspipes]

spindle bearings wouldnt cause the character to "lean" if it wasnt programmed, It could cause the divot at the end though as suggested above as per Tx Fred. I dont think backlash would do that either at least not consistently. I would be suspect of a setting or the machine software as LeeWay suggested??

If its Mach 3, I have had problems with it, but nothing like what you are showing.

I am very interested to see what you find, keep us posted on the outcome, good luck!

[RickPflimlin]

Thanks for the suggestions.

This is Vectric VCarve Pro 6.5 program with Mach3 controller. The same program I've been running for three years. I have the upgraded version of VCarve Pro (V8) on a second computer. I did try re-writing it on that computer with the same results which still leave Mach3.

I do have a Path Pilot controller in the back room waiting for the switch. I have just been too busy to take the leap. If it's not broke don't fix it kind of mentality. It may be a good time to learn Path Pilot??

[RickPflimlin]

After checking my backlash I think my problem is in my X axis. It is about .008. My Y backlash is not even detectable.

New problem! I'm out of gib adjustment When tightened down the gib sticks out nearly 1/4 of an inch. I can't get the back side adjustment screw to catch it. even with the adjustment screw just inside the hole ment to hold it the gib pushes past it???

Any suggestions?

[TXFred]

The gibs don't adjust backlash. They shouldn't affect backlash unless you have them too tight, in which case they will induce backlash.

Try loosening up the gib and rechecking backlash.
Then adjust the ballscrew thrust bearings to reduce backlash.
Once this is done, tighten the gibs a bit at a time until they induce backlash, then back them off slightly.

[RickPflimlin]

Thanks Fred, I was just reading about that in the manual. It was my next move but hearing someone else say it helps.
I have replaced those bearings on my Z axis and have the spanner wrenches on hand.

[RickPflimlin]

I just adjusted the ballscrew thrust bearings. Made no difference at all. They were a little loose but sungging them until I could feel slight resistance made no difference in my backlash or tilted 0's.

[tmarks11]

1. What tool are you using to engrave with?

2. What is the height of the letters in your example?

[RickPflimlin]

Spring loaded diamond drag bit. The letters are 1/10 of an inch high.

[tmarks11]

So what does the letters look like when you make them an 1" tall?

How are you programming the g-code? Is it the PP conversational or are you using something else?

[RickPflimlin]

Probably would not be noticable 1 " high but my business doesn't call for 1" serial numbers. As covered in earlier post Vectric VCarve Pro 6.5 and V8 from different computers. Three years without any problems.

[RickPflimlin]

After the adjusting the gibs and the thrust bearings I'm thinking it has to be down to the ballscrew. Even with less than 3000 hours. I had to replace the Z ballscrew at 2000 hours. That was a little more obvious with little chrome bits in my way oil.

[LeeWay]

How many hours does the drag bit have on it?
Do you have a V bit, mill drill or some other tools that you can try this with?

Those sound like low mileage hours to have to replace the ball screws on the table if it is getting good oil.
Your Z is a harder working axis and I suspect you could have replaced the balls once if you wanted to. You should have plenty of time to look into doing that now as a spare since you installed a new one. Of course if you saw visible wear on the screw itself, it would not be worth it.

[RickPflimlin]

I have three drag bits from two different companies. I have my favorite (with the most hours) and my first thought was that it was getting sloppy, but the engravings with other two were just as bad.

I do plan on replacing the balls on the Z screw to have a spare. These things always happen when you're too busy to wait for repairs. Any suggestions as to where to get it repaired or where to get replacement balls are welcome.
When engraving small letters the Z does get a workout.

[LeeWay]

I have bought spare balls off Ebay, but here is where I usually get them now.
VXB Bearing Search Results | Search for Bearings Today
I keep spares from my THK linear trucks and my ball screws.
I do not know what size is on my mill or my lathe yet. I hope I never have to find out.
I have a screw sitting here from my old home made mill that is waiting for new balls.
I also had to replace the Y trucks on it and the old ones are waiting for new balls.
I probably won't do those repairs until I need them. It can be a tedious job. I find using a white towel laid out on the desk and a magnifying glass helps to get the job done and inspect parts. A loupe may be useful. Small tools, 3 in one oil and acetone may also be useful. Be by yourself with no distractions. And good luck with it.