Kev Williams
03-25-2017, 4:00 PM
I've mentioned several times that my 13 year old LS900 is still on the original everything and aside from q-tipping the lens & mirrors occasionally, the only 'actual' maintenance I ever do is grease the table's lead screws.
So last night I was doing a rush job, very small .06"/1.5mm tall Century Gothic lettering. They looked fine to the naked eye, but a little raggely magnified. But lately I've noticed at certain areas on the table, lettering tends to get thicker, which indicates it IS time to change the belt. So I did.
Took some pics and made a few wear observations.
First, note the loop on the left, this is the 'home position' loop, where the machine always parks, and the belt takes a 'set' there.
After all these years, the belt has hardened up some, especially the exposed length. about 1/3 of the length has never seen the light of day,
and looks like new, but it's noticeably stiffer than the new belt...
356876
in this pic, the lower portion, from the right edge of the 'loop' to the end, this part of the belt
has virgin teeth as they've never touched a cog wheel. the portion of the belt directly above
represents the first 8" of travel, and these teeth have likely seen the most passes around cog teeth...
356877
So I meshed the teeth together and took some pics...
In this pic the upper teeth are the worn teeth--
356878
This is the same exact pic, only upside down ;)
356879
Notice the virgin teeth have relatively straight sides and a relatively straight flat point-edge,
whereas the used teeth are worn down to half circles... These half circles just don't fit the cog teeth well!
First thing I noticed after the new belt is when slewing the X or when it goes home, it's dead silent now.
The old belt was making quite a bit more noise when moving, some of it I assume from the teeth not
fitting the cog teeth well, and some due to the belt's stiffness. Now all I hear is the stepper motor!
The thickerspots issue has pretty much vanished thankfully, and the overall engraving quality picked up a bit on the tiny letters,
but not a whole lot.. it really wasn't that bad before. (Found my lens mirror wasn't tight, which sure won't help! ;) )
After all this time, that says something about the quality of this machine,I have nothing but good to say about it.
And once I had the belt off, I fully expected that some of the old noise I was hearing was dry, worn-out bearings
on the guide rail, since I've never touched it- or even seen it till last night!
...... Nope. The laser head glides along the guide rail as easily as rolling a marble across a table, with no slop
or bearing-feel whatsoever. I was so amazed I took a video of it :D
https://youtu.be/shX4EkXLxeU
So last night I was doing a rush job, very small .06"/1.5mm tall Century Gothic lettering. They looked fine to the naked eye, but a little raggely magnified. But lately I've noticed at certain areas on the table, lettering tends to get thicker, which indicates it IS time to change the belt. So I did.
Took some pics and made a few wear observations.
First, note the loop on the left, this is the 'home position' loop, where the machine always parks, and the belt takes a 'set' there.
After all these years, the belt has hardened up some, especially the exposed length. about 1/3 of the length has never seen the light of day,
and looks like new, but it's noticeably stiffer than the new belt...
356876
in this pic, the lower portion, from the right edge of the 'loop' to the end, this part of the belt
has virgin teeth as they've never touched a cog wheel. the portion of the belt directly above
represents the first 8" of travel, and these teeth have likely seen the most passes around cog teeth...
356877
So I meshed the teeth together and took some pics...
In this pic the upper teeth are the worn teeth--
356878
This is the same exact pic, only upside down ;)
356879
Notice the virgin teeth have relatively straight sides and a relatively straight flat point-edge,
whereas the used teeth are worn down to half circles... These half circles just don't fit the cog teeth well!
First thing I noticed after the new belt is when slewing the X or when it goes home, it's dead silent now.
The old belt was making quite a bit more noise when moving, some of it I assume from the teeth not
fitting the cog teeth well, and some due to the belt's stiffness. Now all I hear is the stepper motor!
The thickerspots issue has pretty much vanished thankfully, and the overall engraving quality picked up a bit on the tiny letters,
but not a whole lot.. it really wasn't that bad before. (Found my lens mirror wasn't tight, which sure won't help! ;) )
After all this time, that says something about the quality of this machine,I have nothing but good to say about it.
And once I had the belt off, I fully expected that some of the old noise I was hearing was dry, worn-out bearings
on the guide rail, since I've never touched it- or even seen it till last night!
...... Nope. The laser head glides along the guide rail as easily as rolling a marble across a table, with no slop
or bearing-feel whatsoever. I was so amazed I took a video of it :D
https://youtu.be/shX4EkXLxeU