Homing process

qa

#1

Now that so many people have pre-release units I’m curious to know a little more about the homing process. There was some discussion early this year about homing but since there weren’t any pre-release units at the time nobody had any real idea what it would look like.

So: when does the machine home itself and how long does it take? Is it performed every time the lid is opened or only on power up?

Apologies if I’ve missed an end-to-end demonstration video that shows this - I didn’t find anything while searching but that doesn’t mean a lot!


#2

The process has gotten significantly shorter since the first Pre-release units shipped. It does it at power up and if it feels like it needs to. (I have no idea what that criteria is)
It does not home every time the door is opened. Most of the time the process is less than 30 sec. but I’ve seen it take longer.

Bottom line, homing will not eat up a lot of your time.


#3

When you turn on the machine the head kind of be-bops around for less than a minute (and I’ve got the slowest connection known to man).

It moves to the upper lefthand corner, establishes itself, moves the mark on the head under the lens camera, takes 3 pictures and sends them to the cloud and receives a signal back each time, straightens itself out, and it’s ready to go.

Total time is about a minute.


#4

Unless it gets lost, then it does a dance for quite a while. I get rather tired of watching it try to home itself once its gotten lost, so I just move it under the camera manually and then let it finish its business. If you dont, youre going to get quite the show, and not a short one I may add.


#5

The longest homing stint for me has been 35 mins. Hunt, hunt, hunt, big move, big move, hunt, hunt…


#6

A couple times it has gotten confused during the homing process. I’ve only seen it do that after I manually moved the gantry or head to a weird location while the power was off. For example, to clean the rails or lens. So I just kill the power again, move the gantry/head slightly and power it back up. It usually does a normal sequence after that. Homing on the Glowforge is a process that gets the head to a precise point under the overhead camera so that the camera and head are aligned to each other.

Edit: that was supposed to be a general reply. Not one to you.


#7

I hope that when I finally get mine it bee-bops too. :grin:


#8

Ah. Clever. That sounds like it’s re-calibrating the bed size and head camera offset. Bet it’s counting steps on the trip from the corner to the lens camera. Cool.


#9

The motion is representative of the average homing routine from cold start for me. One minute to one and half minutes is what happens today. This video represents three months ago when average time was longer.

As @takitus confirms, sometimes you can cut it short by moving the gantry and head to be under the lid cam. I had some initial issues and when things got reset, this is how I got it to work. Now it does the whole routine starting from the back left each time. I can’t recall when the last time I had to turn off power and do a manual align assist.


#10

So checking for logo was when it looks for the Proofgrade ® code?


#11

Yours says homing? Mine always says calibrating…


#12

If I understand right, it’s looking for the GF logo on the head (from the lid camera) That’s how it sets it’s initial position.


#13

yes, calibrating. Most of the time I don’t see that because I turn the laser on when I get into the room and it’s homing while I’m getting the computer plugged in and booted up.


#14

I hope that someone at GF is working on a solution to that. Even 30 seconds seems like forever when you are waiting for something to happen and have nothing else to distract you.


#16

Same here. About three or four times I’ve had the head get lost. Each time it was because I moved the head from the ending home position, (from loading or cleaning or whatever). Turn off the machine, fire it back up again, and it does the normal thing.


#17

Usually only goes into calibration mode when first powered on for the day. Certainly a lot less time than it takes my computer to boot.


#18

Thanks @marmak3261, that’s a video of what I was looking for. I should have just searched YouTube :slight_smile:

Since opening the lid doesn’t cause it to re-home, I wonder whether it’s actually de-energising the gantry steppers? I had assumed it would for safety (since there’s no actual e-stop, I would have expected opening the lid to perform the same effect) but maybe not. Though the stepper drives could be monitoring for any movement while they are de-energised and re-home if any movement is detected.

Does it ever bump into the sides? I’m not sure how they could avoid that without soft limit detection.

If they are using the lid cam to home then theoretically it should be able to determine a rough position of the head no matter where it is currently located. Maybe a slightly more sophisticated future version of the homing process won’t need to do any random hunting.

It already sounds pretty workable though - just turn it on before you start getting your materials and design ready and it will be ready before you are


#19

Maybe that’s what the speaker is for… it can play some elevator music while you wait!


#20

Yes, and repeatedly when it thinks it’s somewhere where it’s not. That’s why as soon as I see it’s lost, just push it back under the camera. Collisions give me anxiety


#21

Right, that makes sense. Hopefully in the future it will be able to detect the head position and move close to the center in one crash-free step.

Then again, if there’s one thing I am confident of in this world, it is that technology (and software in particular) will always fall short of its potential. Often laughably so :slight_smile: So I guess we will just have to wait and see!

Still very excited for my Glowforge!