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Thread: Chinese laser purchase/Shenui/Laserworks tips and tricks thread

  1. #61
    The other thing with this estimate in the simulator is that the "idle" time which is when the laser is not firing is calculated on the basis of the "work" rate and if there is a lot of white space it can grossly overestimate. For example, we were doing a few small cuts in a large sheet of acrylic and the travel time between them was grossly overestimated based on a speed of something like 10mm/s which means it thinks it needs a few minutes to cross the table. So I go off the work time and add a bit for white space.

    Quote Originally Posted by Rich Harman View Post
    Here's an issue that I discovered today. Laserworks has a nice feature (preview) that will tell you how long the work will take. It is very useful when working up a quote. The problem comes when there are different speeds.

    If you have two identical items, one above the other with the top one set to 5mm/sec and the other 10mm/sec, the estimated time that it reports will be as if both pieces are cut at 5mm/sec. If you swap them around then the total time will be reported at 10mm/sec.

    The workaround is to make sure that you get the times on each speed setting separately.
    Shenhui 1280 100W RECI

  2. #62
    Join Date
    Mar 2011
    Location
    Olalla, WA
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    I've noticed some problems with the preview estimate.

    I cut out several things yesterday ranging from under a minute to about 15 minutes. In every case the Preview estimate was considerably more than the actual time required to cut.

    Here are some times that I wrote down;

    :25 - preview
    :09 - actual

    3:35 - preview
    2:42 - actual

    6:07 - preview
    5:23 - actual

    7:02 - preview
    5:35 - actual

    In every case the cut speed was 16mm/sec, only one color was used.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

  3. #63
    Join Date
    Mar 2011
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    Olalla, WA
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    1,532
    Quote Originally Posted by john banks View Post
    The other thing with this estimate in the simulator is that the "idle" time which is when the laser is not firing is calculated on the basis of the "work" rate and if there is a lot of white space it can grossly overestimate. For example, we were doing a few small cuts in a large sheet of acrylic and the travel time between them was grossly overestimated based on a speed of something like 10mm/s which means it thinks it needs a few minutes to cross the table. So I go off the work time and add a bit for white space.
    I had been using "Total Time", not realizing that it did not account for rapids. The "Light Time" estimate (5:23) works out to be just 12 seconds under the actual time on the piece that estimated 7:02 for the total time.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

  4. #64
    Sorry I mangled the terminology

    Total = light + idle

    I think I labelled them differently:

    Total = work + idle

    To calculate the idle periods correctly it would have to look at the accel/decel stuff which the machine does if you do a worktime preview, but it takes a little while. Hopefully a PC would be able to do it much faster, saving the effort of having to send the job to the laser just to do "worktime preview".
    Last edited by john banks; 06-11-2012 at 2:29 PM.
    Shenhui 1280 100W RECI

  5. #65
    Join Date
    Jun 2012
    Location
    Bellevue (Seattle), Washington, USA
    Posts
    16
    This was very helpful. Thanks. I had exactly the same issue and went and bought those little connectors today.
    100W 24"x36" Morntech laser, 4"x5" Betterlight digital scanback camera
    Corel X5, Macs, PCs, Illustrator CS5, PS CS5, more software than we care to mention here.
    Two Epson 9900 giclee printers - Bellevue, WA

  6. #66
    Join Date
    Jul 2004
    Location
    Victor, NY
    Posts
    1,288
    Hi Gang;
    My Shenhui is pretty big-the bed is almost 4 ft x 3 ft. As a result, the normal exhaust system has a bit of trouble clearing the smoke (I cut alotta wood) quickly. To assist the process I installed three 4" computer fans in the small removable front panel (removable for long projects) and power them with a 12 volt power supply from an old HP printer which died. Fans like these are readily available and inexpensive-check Ebayfans3.jpgfans2.jpg
    *twin 80 watt Shenhui 1280
    *60 watt Laserpro Mercury -42ips
    *(2) 30 watt Laserpro Venus-42 ips
    *whole bunch of woodworking/metalworking machines
    *128 screwdrivers (all needed)
    *wonderful wife (1st) of 53 years who allows me to collect screwdrivers

  7. #67
    Join Date
    Mar 2011
    Location
    Olalla, WA
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    Twice in the last week LaseWorks has crashed. That alone is not much of a problem but what is a real pain is that all of my settings vanish and have to be re-entered. Is there a way to save the configuration and reload it after a crash?
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

  8. #68
    You could take a copy of the laserworks folder and restore it if necessary. There are various config files that get their dates changed (config and pfile I think), so you could just copy those if you prefer.
    Shenhui 1280 100W RECI

  9. #69

    No power to the tube.

    Running a generic laser - Reci 100w tube. Now getting no power to the tube when the laser is test fired. Tube appears to be fine. All the spots in the electrical appear to be getting juice using a sensor to test. Everything else works, chiller working, water flowing, no obvious shorts or damage anywhere.

    Any suggestions? I tried the search function and didn't come up with any threads that matched my problem so if there has been one and you have a link I would appreciate it.

    Thanks in advance,

    John
    Running Chinese 100w - Glass Tube - in China
    Also have - Universal 660 - in USA

  10. #70
    Join Date
    Mar 2011
    Location
    Olalla, WA
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    I think to properly diagnose we need more details.

    I have had the problem of no laser when hitting the "laser" button on the control panel. It was a setting issue. You can specify the length of time that the laser is on when hitting the button. If there has been a change to that the laser may not appear to be firing when it really is. If it is set to zero then it will fire for as long as the button is held.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

  11. #71

    The story:

    Until 11:30pm two days ago the laser was working fine. We had replaced the water in the chiller at 9am and the laser ran fine until 11:30. After that it would not fire at all, either when trying to run a job or from the laser button on the control panel. I noticed that the wall plugs had burned up so I replaced them, checked the sockets on the laser and everything is fine with power going into the unit. All the boards appear to be lit up properly, the transformers appear to be working with no signs of shorts or arcing anywhere.

    The tube appears to be fully intact. The red wire connected to the tube was a touch frayed so I disconnected it, shaved off some insulation and hooked it back up to the tube. So there is a good connection at that point.

    Everything else works, the jobs will run but no beam is firing.

    I don't think it's a control panel issue. I get the beep when I try to test fire it. I also looked up into the backside of the control panel to see if there was any visible short or loose wires.

    We did replace the transformers about a month ago after one of them shorted out. I am stumped as to what the problem is here.





    UPDATE: FIXED - when my staff changed the water they pulled the alarm cable out from the back of the transformer. So the laser correctly assumed that there was no water and wouldn't fire. I am so stupid that I didn't notice this all day yesterday. I now have taken a picture of how everything is supposed to be connected for everyone to check off when doing anything. Sorry for bothering you all.
    Last edited by John Barton; 07-31-2012 at 11:54 PM.
    Running Chinese 100w - Glass Tube - in China
    Also have - Universal 660 - in USA

  12. #72
    I got my new Shenhui 600 x 900 mm with 80W RECI tube. I'm cutting the plexi of 3 mm with speed 12mm/sec and 90% power and I think that this must go faster. Am I wrong?
    Epilog Mini 24/35W, Shenhui 600x900/80W RECI, CNC WK1325, Galvo Fiber 10W

  13. #73
    Join Date
    Mar 2011
    Location
    Olalla, WA
    Posts
    1,532
    Dou you have an ammeter? If so, what is the mA when firing at 90% power?

    The power setting is somewhat irrelevant if the laser power supply is not tuned. I run my 80 Watt Reci at 85% - which is 24 mA on the ammeter. Reci states a max of 29 mA but recommends limiting to 26 mA for long life. I run at 24 mA only because I do not notice a significant improvement with a couple more milliamps.

    I cut 3mm smoked cast acrylic at 18mm/sec when placed in the upper left quadrant of the table.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

  14. #74
    Join Date
    Oct 2011
    Location
    Vancouver BC
    Posts
    97
    Hi Rich,

    On the topic of Ammeter, any thoughts on what type and/or specs for a unit to add on, and where to have the leads connect. I think I know that it is between the low voltage side and the power supply, but I don't know if it's a run of the mill ammeter or something higher voltage.

    The machines we ordered didn't come with ammeters, an oversight in the ordering process my myself. I think our working machine might need that exact tuning you describe.

    Thanks, Greg
    80 watt RECI 1290 Shenhui laser.
    Chinese Quick CNC 5x10 toolchange
    Unofficial record holder of 6 tubes shipped for one machine. 2 defective and 4 broken. Recommend Coletech for replacement tube!

  15. #75
    Join Date
    Mar 2011
    Location
    Olalla, WA
    Posts
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    The ammeter connects in series on the low side like you said, the voltage on the low side will be near zero. I would think that any ammeter with the appropriate range scale would work well - but I have never had to source one.

    Best thing would be to get Shenhui to send you a couple.

    Aside from that I would try to find one with a very low resistance. The ammeters that I have experience with use a milli-ohm shunt in series with the the circuit. The resistance of the shunt is extremely low but very precise. When you measure the voltage drop across the shunt you can calculate the current using Ohm's law. The milliammeters that I have found on Mouser have resistances of 1k Ohms or higher. I do not know how it will affect the laser by putting a 1K (or whatever) resistor in the circuit.
    Last edited by Rich Harman; 09-10-2012 at 6:37 PM.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

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