Bad curve cuts... Any suggestions

[powerfade]

So I am having a heck of a time with the curves. They are horrible to put it mildly. I ran this file at 30mm per sec. I have checked to make sure of all of my pulleys are tightened uo. It is kind of a bigger machine with approx 4 feet x 5 feet with xl belts and pulleys. I also have the laser mounted on the gantry. Even when I run the machine at 5mm per second it produces the same results. Especially on the Circle it looks like it is cutting then juts up at the top of the circle and then continues. I was wondering if there are any settings I may be missing, etc. I am have 3:1 reduction on Vexta 5 phase drives. 16 tooth drive pulleys. Any ideas??

Thanks.
Chris

[baccus61]

Run the same file a few times one after the other (4 or 5 times) with a very low power to just mark the material and see if it is repeatable. If it is then it is in the build of the machine. If it was lost steps then it won't follow the path exactly and the start point will be off.
Before you start engraving the file press the laser fire button on the HMI to show where the start/origin point is and see if it always comes back to that point. Use low power settings as it will be less likely to burn the spot too big and will make the adjustment a bit more accurate.
Rich.
Place a rule next to the work piece so we have a better idea how big things are too. It does help a bit to know how big some things are. Just being picky.

[maralb]

I had problems during motor reversal with these

[powerfade]

So I ran the file 5 times in a row and it went exactly to the same place everytime. So I guess it's not losing steps. The "S" and the circle are about .75 to 1.00 inches. Maybe it's binding somewhere??? I moved it to different portions of the table too, but still the same. Oh this is a bit frustrating... The straight lines and diagonal lines are great, so I guess that's a plus!! hahah

maralb I had those couplers on my larger scale router table before I changed it to rack and pinion. Maybe I should change this thing to rack and pinion...Oh the trials and tribulations..

[baccus61]

Okey dokey,
Are your mirrors fixed so they don't shake or wobble and is the laser also fixed really well so it doesn't shake around? As you know ANY movement will show up in the cut. How far is your Z axis lens from the mirror and would you get any movement from the lens or final mirror.
Do you have air assist. try without it on as maybe the air assist is moving the lens. (stab in the dark)
I really can't think of anything else other than belt stretch due to inertia.
Try REALLY slowing the thing down to 0.1"/sec and see how that goes and do the 4-5 cuts again. That should negate any stretch if at all in your belts.
Is the gantry really smooth when you push it without the belts on? I would think it is the way you have it set up.
Getting hard without looking at it working. Have you a video recorder and a STEADY hand.????
Rich.

[twehr]

You should be able to stop it from doing the letters in pieces by setting the route optimization when downloading the image.

See image for instructions.

[baccus61]

Hey Chris,
Any update on how your getting on with the laser and the many problems.?

[powerfade]

Hey Rich... I have been so backed up at work that I haven't even had time to touch it. I am hoping to get back at it in a couple of weeks. To much work, not enough play!!!! I do think I am going to go with wider belts though. I don't think my 1/2 wide XL belts are going to cut it, with my table size, which you told me a long time ago. I also think there may be some binding as well that I may need to deal with. Right now the table is a catch all for all of the stuff I don't have a place for in my shop. Thanks for checking in Rich. I will let you know how I progress here in a couple of weeks.

Take care..
Chris

[dwessels]

So I am having a heck of a time with the curves. They are horrible to put it mildly.

Chris,

I had some letter funkiness, but it was related to the speed at which I was trying to run the laser head. Anything above 500mm/s was too fast. Once I limited it to 500mm/s and below, cuts looked great.

[flybgair]

I just finished my machine and had the same problem. After checking settings on the drivers, mirror mounts and software settings I noticed a little play in the x axis of about 1mm. Turned out it was because the pulley on the motor was a little lose.