[elmettaro]

Hi from italy people:

After some reading on the net and on this forum, we decided to start a new thread since it looks like no one has the problem we have (hope we're mistaking).

We bought a K40 maschine with moshidraw and for the first two weeks it worked just fine. We did some cool engravings , cut some circles perfectly until yesterday.

The machine quit cutting circles the way it did. While it does still engrave and cut other shapes just fine, it has problems cutting circles well. It warps top and bottom parts of it:




We tried to reinstall the software, used a different pc, used a different usb cable...but nothing seems to work.

Any help would be GREATLY APPRECIATED!
Thanks a ton!

Fulvio

[Things]

Unlikely a software issue, my first guess would be you have some slip or backlash in your belt. Check the belts and make sure they aren't hitting anything, and that they are still reasonably tight.

[elmettaro]

That's what I was thinking. Looks like the problem gets worse close to the starting point on the left. The more it gets far from the left bar, the more the circles are drawn better.

How would I know if the belt is tight enough though?
Thanks!

[Things]

Belts should be tight enough that they don't sag, but not so tight that they don't have any springyness to them.

Also maybe check your bearings and see if they still move smoothly. You could have gunk built up in your rails/bearings adding resistance.

[elmettaro]

How would I tighten my belt up?
also, gunk? sorry man, i'm italian, lived 2 years in the states but gunk sound very new to me

Also, thanks so much for your help!

[Things]

Never had one of the K40 machines, so not actually sure how you tighten the belts. Have a look around the ends where the pulleys are, and see if there are any screws attached to the pulley bearing block.

Gunk/Burnt material/scrap/hair, you know, the kind of stuff that builds up around spinning things

[elmettaro]

Ok, we found the screws that control the tightness of the belt.
We're gonna try to tight that now.

Let's see how it works.
Thanks

[elmettaro]

Ok, we found that the tightness of the belt does effect performance.
tried different degrees of tightness but it still has some problems tracing perfect circles. Thing it did not do only few days ago.

Any idea about the vertical axis ? It seems like the problem comes up with the top and bottom arcs of the circle.

Fulvio

[Things]

I'd just go over the entire belt/pulley/bearing system and make sure everything is still tightened up. Also have a look and make sure the couplers on the pulleys and stepper motors are tightened up and not slipping around. It doesn't appear you're losing steps, as the ends do still match up.

[elmettaro]

Everything looks good. Looks like it's lazy on curves though...we'll see what they guy that sold it to us will tell us. We've sent him a video of the problem

Thanks for your help man. Greatly appreciated!

[mondo50m]

I had a similiar problem on my unit. Under the front metal cover (black, I believe) is one of the shafts that are attached to the stepper. I found that the grub screws that hold the shaft onto the stepper were loose. I put some loctite on the screw and then tightened same. No problem after that..you might want to check the connection on both of the steppers.

Milt

[elmettaro]

we tighten the screws of the belt and the others.
Problem remains.

is this what you're talkign about?



the screws seen inside this hole?

[elmettaro]

So I found the other screws of the other shaft (the vertical one).
I've been playing around with that for the past hour, but the outline always comes out a little warped.

It's impossible to get the proper tightness for both axis just screwing and unscrewing. This is nuts.

Carving work well, but outlining really isn't accurate at all.
Guess there's nothing much to do, but sending it back.

[mondo50m]

If you are looking at the machine from the front, the metal panel is right in the front and is held in place by two screws. In your picture it is on the left hand side. Takethat panel off and you will see the shaft underneath it. There are two set screws, (grub screws) holding the rod onto the shaft of the stepper. Mine got loose and caused the shaft to have backlash in it. Looking at the pictures of the parts you cut out, it looks to me like backlash is the problem. Correction, there are 4 set screws holding the long shaft to the stepper.



Milt

[elmettaro]

So I got the black metal piece out, and I found at least 6 very tiny screws on the shaft. I tightened all of them and now the shaft doesn't move front back anymore. This didn't affect the rotatory movement of the stepper.

Going to try now...

IT WORKSSS!!!Milt, you'r my hero!!!
Thanks guys, really really saved my day! WOW! Thanks again!
if you ever wanna buy an iron man helmet or some movie props let me know...i'll treat you well

[mondo50m]

Glad to be of help. I have had my machine for about 9 months and am very happy with my "cheap Chinese laser". Where in Italy are you? I spent 3 years in a small town called San Vito when I was in the Air Force.

Milt

[elmettaro]

live in Rome
my parents live in tuscany and my brother in milan.

Where's was san vito? What region?

[mondo50m]

Way down on the heal of the boot. The base is no longer there. It got decommissioned after VietNam....yes, I am an old fart!!

Milt

[Things]

Yeah, stepper motors love vibrating every nut, bolt and screw loose that they can. If you take them all the way out and put some loctite (Thread glue) on them, it'll stop them from vibrating out again and causing issues

[elmettaro]

Put loctite and right now is a beast

Also guys, I have a friend who has problems with the calibration of the lenses. His machine got to him with a sucky calibration and now he had to redo it from zero.

Is there anything that can help him in the process other than hands and eyes? Thanks!