DIY Laser levelling using webcam and laser level

[devmonkey]

Joe,
That's beginning to sound as fiddly as using the traditional West Systems 105/209 epoxy leveling method with more potential for errors. Gravity never makes mistakes. What do you see as the advantages to your proposed method?

Hi Kit,

I do have a pack of 105/209 here for this machine, trouble is the temperature in the UK in my unheated uninsulated garage is about 6 degrees, so would have to wait until summer.

I was also hoping we could improve upon the accuracy of epoxy, from the measurements taken in this thread:
http://www.mycncuk.com/threads/8197-...5194#post65194
and Jonathon's build here:
http://www.mycncuk.com/threads/6484-...8616#post48616
It appears with epoxy 60um (0.06mm) peak-peak error is possible, I think we can do better than this with the laser and also not have to wait 2 weeks for the epoxy to cure. It might be possible to perform the process I described above in a couple of hours. 0.06mm is 20 pixels on the image sensor to give an idea of comparable resolution.

Cheers, Joe

[Kitwn]

Hi Kit,

I do have a pack of 105/209 here for this machine, trouble is the temperature in the UK in my unheated uninsulated garage is about 6 degrees, so would have to wait until summer.

I was also hoping we could improve upon the accuracy of epoxy, from the measurements taken in this thread:
http://www.mycncuk.com/threads/8197-...5194#post65194

It appears with epoxy 100um (0.1mm) peak-peak error is possible, I think we can do better than this with the laser and also not have to wait 2 weeks for the epoxy to cure. It might be possible to perform the process I described above in a couple of hours.

Cheers, Joe

We're having the opposite problem here. Last night's overnight low was 29C and the days have been up to 46C recently. I'm keeping our epoxy resin (wife and I are making some fancy stuff to sell in the local gift shop) in what used to be a wine fridge.
Maybe you could pour the resin and then come over to us for a fortnight's tropical snorkeling with whale sharks and manta rays while it cures? Then take your enviable winter tan home and use the laser to guide you hand-scraping the last 100 microns of errors out? Hand scraping resin shouldn't be to hard.

[devmonkey]

Hmm, so I now have another problem.

I set laser on the milling machine head, just needs to be attached to something solid, then levelled the laser to the machine frame which is sat on a sturdy bench. The problem is that walking near the laser causes microscopic deflections in the concrete floor, sufficiently large to show up as 10-20um of error 3m away on the machine frame. These are probably amplified by the height of the laser from the floor, about 1.5m as the same doesn't occur walking near the bench.

I think I will need to move everything directly onto the concrete to stand any hope of getting things stable enough to do any frame levelling. Problem will then be not kicking it during the process.

[JAZZCNC]

It appears with epoxy 60um (0.06mm) peak-peak error is possible, I think we can do better than this with the laser and also not have to wait 2 weeks for the epoxy to cure.

Question.!... Why do you need better than 0.06 for a router..? . . . . Answer.! . . . You don't.

With all the watts of brainpower you've invested in this, you could have heated the garage and built the bloody thing.! . . . Just get on with it and stop overthinking is my suggestion.

[devmonkey]

Question.!... Why do you need better than 0.06 for a router..? . . . . Answer.! . . . You don't.

With all the watts of brainpower you've invested in this, you could have heated the garage and built the bloody thing.! . . . Just get on with it and stop overthinking is my suggestion.

Yes I could have done, using maths I even worked out it would cost £84 in electricity ;-)

I may still use the epoxy if this doesn't work out but this thread is about developing a open source optical metrology system using very cheap components for the benefit of anyone who wants to measure anything accurately to few microns. I thought you'd be well up for that given your pet hate of people quoting accuracy figures they cannot measure.

Some projects do require better than 60um accuracy, or at least calibration of that level of error. For example I want to use the machine currently under construction or one of its offspring to position high power magnets into a halbach array for a coreless axial flux PMDC EV motor I'm developing, this needs 10um accuracy under quite significant magnetic load.