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[Solved] Two laser troubles  

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jwalt
Posts: 6
(@jwalt)
Active Member
Joined: 9 months ago

Hi,

Today I added a second laser to my Fabscan Pi, and I am getting wrong results. The scan from the first laser is about 10% smaller in the X and Y dimension than the scan from the second laser. The error seems to be less pronounced in the Z direction. Both point clouds are also rotated relative to each other (about 1-2 degrees).

After making sure that the lasers cross the exact center of the turn table, the camera also points exactly at the center (both with less than 1mm offset), and making sure the lasers are exactly vertical, and recalibrating, I am at a loss what else I can try.

Additionally, for this model I always get points in thin air, always under the arm. I covered the model in blue spray chalk to eliminate any reflection and reduce indirect illumination, but it didn't help.

Many other parts look pretty decent, but due to these issues, the scan is ultimately unusable. I was unable to fix this up in meshlab.

It's really frustrating to have bought this device and not being able to produce a single successful scan in three years. Please help.

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17 Replies
Hamishi
Posts: 31
(@hamishi)
Eminent Member
Joined: 9 months ago

Dear Mario,

Thanks for the response.

I have to buy another green one I guess. Means another 30 days waiting for delivery from China.

Regards,

Hamishi

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Hamishi
Posts: 31
(@hamishi)
Eminent Member
Joined: 9 months ago

Besides that I still have a red and a green laser, I had some advancement in the scan results. I have my 3D printer kit up and running for a while and found some interesting FabScan Pi improvements on Thinginverse, the laser towers and a stand for the calibration sheet.

I printed two towers and installed them in the FabScan, realigned the lasers and did a calibration with the old calibration sheet holder. Scan results still poor.

After that I did a calibration with the new calibration sheet holder, same sheet but upside down mounted in the sheet holder. Scan results seem very good to me now. 

The two laser setup appears to be more sensitive to the placement of the calibration sheet then for a single laser setup.

green red laser scan of z axis symmetric object

 This is a low resolution scan with the first laser of red color, the second laser of green color, settings of scan: no color, auto threshold, low resolution

@mario, can you explain what the effect is of setting the (RGB) parameter? From this scan it doesn't seem to matter significantly.

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Hamishi
Posts: 31
(@hamishi)
Eminent Member
Joined: 9 months ago

I also installed a fan. No more CPU throttle warnings and crashes anymore.

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nerd
Posts: 1
 nerd
(@nerd)
New Member
Joined: 1 month ago

Hello I hope someone can help me. I am trying to get the second laser running but it never aligns with the first one. Also the first one usually has quite a bit of warp. 

Am I doing something wrong? What is the accuracy someone can expect? My current software version is v.0.9.3 and I ordered the kit from Watterott.

Many thanks
Nerd

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