Misalignment of print versus GFUI


#1

Hi all,

I seem to have a similar issue as others where my GF is printing in a different spot than what I see in the GFUI…

This is the design before printing (screenshot taken 2018-05-27 at 12.18.49 EST):

After the print, you can see that the print was done in the wrong spot (screenshot taken 2018-05-27 at 12.25.30 EST):

This was a print on PG medium draftboard that is not warped.

Please let me know if I’m doing something wrong or how I should troubleshoot this…

Thank you,
Bernard


#2

If that’s within 1/4" then it’s in spec.


#3

That looks to be just under 1/2" on the X-axis and right at 1/4" on the Y-axis.

Some things that you can do on your end:

You mentioned the wood was not warped. This is good. Sometimes it can be and it’s tough to tell; pushing down on the material at various places while it’s laying on the crumb tray can sometimes show warp that’s hard to see visually.

Remove the crumb tray, make very sure that nothing is below the feet/in the slot where the crumbtray sits and when you reinstall it, make sure that the feet are positively locked into the grooves. Anything under the feet, or not being put into the grooves has the same effect as warped wood; it changes the expected distance from the material to the camera.

The Glowforge case is susceptible to a certain amount of twist. This can impact the closing of the lid and since the lid camera is on the lid, this can impact the images from the camera. How does your lid close - any binding or spots where you can feel friction?


#4

Just did another test print - this time I marked the wood with an X (unfortunately after I did my screenshot :frowning:) and aligned my design in the GFUI to that.

Before screenshot (taken 2018-05-28 at 10.30.25 EST)

And after (2018-05-28 at 10.38.48):

Measured the deviation: it’s 10mm (0.3937008 inch) on both X and Y

@jbmanning5

Rechecked the wood - no warping when pushing it down on the crumb tray
Crumbtray is in perfect place - no dirt or anything under the feet
The lid closes without friction - I do however, not sure if that matters, see that the lid is perfectly aligned / level at the front and back of the printer however it feels like, in the middle (between front and back) ever so slightly higher than the sides of the printer - it’s difficult to see but to the touch it’s not level… if I had to guess (I don’t have any precision measurement instruments) I would say not even half a millimeter…


#5

This is normal. I believe every machine has the same design in this aspect.


#6

do you have the focal height set properly? the camera image seems pretty blurry. i’m sure it’s not enough to account for that much of a difference, but it could explain some of it.


#7

Just wanted to say, that’s one of the best descriptions of a problem I’ve seen on here. I get the feeling that support is going to need to run a few tests and check your metrics based on the times you provided and get back to you.

On the plus side - they can sometimes make magical adjustments on their end and correct that much variance…(I have no idea how they do it, but I’ve seen it a time or two), so until you hear back from them…nice job! :slightly_smiling_face::+1:


#8

It’s Med Draftboard - not sure if it auto identified or not, but the material height is set automatically. There could be some discrepancy between the actual material thickness and what it is inputting automatically. As for bluriness, the camera is fixed focus - changing the material thickness only changes the dewarping calcs; it doesn’t change the focus of the camera.

@Bernie:
Here is an official response from Glowforge (from a while back) regarding alignment issues:

https://community.glowforge.com/t/another-glowforge-with-alignment-issues/16840/25?u=jbmanning5

Turning it off and back on is a good suggestion because it forces a recalibration of the head position. Sometimes the head gets bumped when taking material in / out, or for whatever reason. Once it loses those steps, it loses those steps - meaning the head will not be physically in the location that it thinks it is.

I have no idea if this can impact alignment, but I suspect it could if bad enough… the Glowforge locates the head on calibration by moving the head under the camera and taking a picture of the Glowforge bug on top of the head and adjusting from there. You might wipe the top of the head off and wipe the lens of the lid camera just to ensure you’re getting the best possible image.


#9

right, but if you look at that image, it’s probably not in the center. and i’ve seen some pretty significant change in image quality by changing the material height. i can see it autoidentified in the original image, which has decent focus on prior cuts, but not in any of the subsequent crops, which look blurrier.

as i said, i don’t think it would account for all, but it’s always worth checking.


#10

Thanks all for the reponses - it’s reassuring to see the drive of the community to help one another!!!

One other thing I should probably have mentioned earlier: the GF is no longer recognising my materials (even though the QR codes are on each piece I have put in so far)… Perhaps that’s also an indicator something is wrong?

@shop - I have no idea how to set the “focal height” :frowning: Wouldn’t that be set at the time I choose the material (see above, have to set it myself)?

@Jules - thanks for the “nice job” - I had read in some other posts where the GF team was asking for those timestamps so decided to add the right off the bat :slight_smile:

@jbmanning5 - just had a look at that link - seems I followed all the steps there - it recalibrated when I started it up and again later on…


#11

well, if i’m noticing that your camera views seem blurry even when you have the right material height dialed in, and your camera isn’t picking up the QR codes, it may be that there’s a focus/alignment issue with the camera on the lid. that could also account for not being able to align cuts with camera view.


#12

I’m sorry you ran into trouble. Thanks for taking the time to provide those screenshots and details.

Most alignment problems come from the material being closer or farther from the camera than expected. The image is taken using a wide angle camera. We use software to correct the image so the image you see matches what’s in the bed. The software is still improving, and you may see an alignment error of about 1/4".

The lid camera uses a wide angle lens to take a photo of the entire bed. The software uses the height of the material to correct the image so what you see in the Workspace matches the print placement on the actual material. That said, it is important for the height to be correct and accurate.

I’d like you to try a few steps for me so we can look into this further. Could you please do the following?

  1. Turn off your Glowforge.
  2. Turn your Glowforge back on.
  3. We included an extra piece of Proofgrade Draftboard with your materials shipment for troubleshooting. Place the Proofgrade Draftboard in the center of the bed and print the Gift of Good Measure using the default settings.
  4. When the print finishes, leave the lid closed and wait until the fans stop and the picture updates. 5. Without moving your artwork or your material, take a screenshot of the Workspace to show us the difference between the artwork placement and the actual print placement. Make sure to include the rulers in your screenshot and show as much of the bed as possible.
    • Mac: Press Shift-Command-4 and click and drag a box around your image. You’ll find the screenshot file saved on your desktop.
    • Windows: Click on the Start Menu and type “snipping tool”. Open the Snipping Tool > New then click and drag a box around your image. Click the Save icon and name and save your file.
  1. Send us the screenshot along with the date and time of the print, and we’ll investigate.

Additionally, I extracted the logs to look into the issue, and it looks like on prints where Proofgrade wasn’t recognized, there was a very bright light shining into your Glowforge during that time. On prints where the light level was lower, the logs showed that the Glowforge recognized the Proofgrade. If the app has trouble recognizing your material again, would you try reducing the direct light overhead and see if that helps?

Thank you in advance!


#13

Hi Vee,

thank you for coming back to me this fast - much appreciated!

  I've just completed the test print - attached the files (before and after). Note that there is no additional overhead light on - the bright light seems to come from the right strip of led lights. Today, the GF recognised the wood I put in perhaps because it was quite high up on the tray (because I needed to put the print in the middle of the bed and I didn't have a fresh piece of draftboard readily available).

Please let me know if you need anything else!

Thank you,

  Bernard.


#14

Wait…that piece of wood wasn’t flat on the grid portion of the tray? That’s going to affect the results.


#15

I think he just moved the wood “up” (Y-direction).


#16

Mine has a slight lip…I hit it every time I try for passthrough work. It might not be quite level.


#17

Hi all,

I always make sure the wood is flat on the grid (even sometimes removing some of the masking as it sometimes prevents it from fitting) and also assure it isn’t on that little flat piece at the top of the grid…

I know that a little difference in level / deviation can impact the end result - I used to have a Shapeoko and the smallest of differences could cause an entire price of work to come out wrong…


#18

Cool! Just checking. :slightly_smiling_face:


#19

Is the right end of the board square? If so the camera view is very distorted. This seems typical of machines with poor alignment.


#20

Thank you for doing the test.

Unfortunately, it looks like your unit is experiencing an issue that we can’t resolve remotely. I want you to have a reliable unit, so I’m recommending we replace this one. I’ll be in touch via email to sort out the details. I’m so sorry about the bad news.