Kev Williams
01-23-2014, 12:01 PM
What's the consensus on how tight the belts should be? My main focus of this question concerns the very long X-axis belt on my 1300x900 Triumph. FWIW, I've always kept the belts on my other 2 lasers quite tight. Not quite guitar-string tight mind you, but I CAN "strum" the X-axis belt on my LS900. I can tell when it needs tightening because some letters, near the point of deceleration on the sweep, start getting a bit thicker than others. My ULS-Optima has a smallish belt so it's not REAL tight but it's not loose. I've never messed with the Y-axis belts on either machine, but they're snug.
As for short belts, the Y-axis motor-to-shaft belt on my LS900 is extremely tight. In contrast, my IS7000 engraving machine uses a short belt from the stepper to the X-axis lead screw, and to me, that belt feels fairly loose. Yet the machine's 'slack' is virtually zero, even when machining aluminum.
Back to the Triumph... I'm thinking I need to cinch up the X-axis belt, as I'm having trouble with backlash alignment and producing lettering with smooth edges. Compared to my LS900 the belt isn't tight at all. I have played with the tension a few times. First time I snugged it up a bit, the belt (to me) still wasn't all that tight, but as the machine was running a 24" back and forth pass at 500mm/s (full speed for this machine), it seemed to produce a high frequency vibration harmonic that caused the machine's steel housing to 'hum'. Not real bad or loud, just noticeable. Could be I was just hearing something it always does, I'm not sure?
Anyway- If I keep the tension a little on the loose side, the long-side of the belt will wobble as it rasters. Pretty sure I don't want that because I've noticed very little movement of the belt causes the lens head to move quite noticeably. Also, I've created my own 'alignment test' which is simply a bunch of vertical lines .010 wide, about 1/8" apart that spans about 4" wide. I use a .3mm gap to run the test. Regardless of how close I can get the backlash to zero in the middle of the lines, the end lines will have around .010" or more 'zig-zag'. Tightening the belt helps reduce the end slack. Right now, I have the belt as tight as possible as the adjustment screws are bottomed out. Not a problem for me to move the belt in the adjuster a tooth so I can cinch it up tighter. As is, it still seems relatively loose to me by feel, and the belt still wobbles slightly during rastering. For what it's worth, the Y belts are MUCH tighter than the X belt..
Side question on the adjusters- there's 2 lock nuts on the adjuster's screws, which can be cinched up either against the lens head, or the belt clamp. I notice if they're cinched against the head, the belt clamp is free to "rock" a bit. If cinched against the belt clamp, the clamp won't rock. Which is correct?
Thanks in advance! :)
As for short belts, the Y-axis motor-to-shaft belt on my LS900 is extremely tight. In contrast, my IS7000 engraving machine uses a short belt from the stepper to the X-axis lead screw, and to me, that belt feels fairly loose. Yet the machine's 'slack' is virtually zero, even when machining aluminum.
Back to the Triumph... I'm thinking I need to cinch up the X-axis belt, as I'm having trouble with backlash alignment and producing lettering with smooth edges. Compared to my LS900 the belt isn't tight at all. I have played with the tension a few times. First time I snugged it up a bit, the belt (to me) still wasn't all that tight, but as the machine was running a 24" back and forth pass at 500mm/s (full speed for this machine), it seemed to produce a high frequency vibration harmonic that caused the machine's steel housing to 'hum'. Not real bad or loud, just noticeable. Could be I was just hearing something it always does, I'm not sure?
Anyway- If I keep the tension a little on the loose side, the long-side of the belt will wobble as it rasters. Pretty sure I don't want that because I've noticed very little movement of the belt causes the lens head to move quite noticeably. Also, I've created my own 'alignment test' which is simply a bunch of vertical lines .010 wide, about 1/8" apart that spans about 4" wide. I use a .3mm gap to run the test. Regardless of how close I can get the backlash to zero in the middle of the lines, the end lines will have around .010" or more 'zig-zag'. Tightening the belt helps reduce the end slack. Right now, I have the belt as tight as possible as the adjustment screws are bottomed out. Not a problem for me to move the belt in the adjuster a tooth so I can cinch it up tighter. As is, it still seems relatively loose to me by feel, and the belt still wobbles slightly during rastering. For what it's worth, the Y belts are MUCH tighter than the X belt..
Side question on the adjusters- there's 2 lock nuts on the adjuster's screws, which can be cinched up either against the lens head, or the belt clamp. I notice if they're cinched against the head, the belt clamp is free to "rock" a bit. If cinched against the belt clamp, the clamp won't rock. Which is correct?
Thanks in advance! :)