Laser centre finder

[bernard towersParticipant @bernardtowers37738]

Typo should read magnifier, blxxxy predictive text and it’s the same as the one on eBay.

[JAParticipant @ja]

I bought one with the attachments many years ago and found it very difficult to use. The main problem was that the laser dot was too large.

I have tried most of the suggested methods to find an edge but all are difficult. The simple rotating edge finder gives the easiest consistent results while a centring microscope (I made the one described in the Model Engineer in September 1999) is near ideal but one has to be a limbo dancer to use it. I think the ideal would be a Renishaw type touch probe.

At present I am putting a camera on my microscope.

JA

[bernard towers]

On bernard towers Said:

… and it’s the same as the one on eBay.

By trawling back through this topic, I have deduced that the object of my desires must be here:

Home

Now to work-out why theirs is better than the rest.

MichaelG.

[Clive FosterParticipant @clivefoster55965]

Back in the day I built several pieces of lab equipment requiring a high quality beam from laser diodes. Both focused to a point and expanded to a foot or so diameter with a respectably uniform intensity across the beam.

Starting with professional quality units already fitted with internal polarising filters and beam shaping optics, £1,000 up in the day, a spatial filter before my optics was essential to get any form of acceptable beam or focus quality. A spatial filter for a visible laser is a pinhole around 15 to 25 µm diameter so some pretty effective beam shaping and quality focusing is needed to get most of the laser power through it whilst stripping out the noise.

Even then, whatever you do there will be some speckle effects. Much less than a proper gas laser, which is why we went laser diode, but still there.

The modern cheap import laser diode units perform remarkably well given the price point but, objectively not that good. Given lab facilities I’d like to get my hands on modern high end devices with diffractive or holographic optics inside to see how good they are compared to 2 or 3 decade old school devices.

Clive

[Michael Gilligan]

On Michael Gilligan Said:

Now to work-out why theirs is better than the rest.

With a little help from AI

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US Patent No. 7,464,478: Granted on 16 December 2008 for a “Workpiece center and edge finder having visual light indicator”.
US Patent No. 7,137,208: Granted in November/December 2006 covering the core operational components of the alignment tool. [1, 2, 3, 4]
Both patents were filed by inventor Merle “Skip” Adrian, the founder of SDA Manufacturing, LLC based out of Piedra, California.

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MichaelG.

🙂

[Michael GilliganParticipant @michaelgilligan61133]

[ UPDATE ]

We all know that AI can make mistakes …

Here are the patent references, as per Espacenet

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MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

Well they are not cheap at ~$200 each and they do not have any formal specification. In their FAQ they mention it as estimated at 1 thou.

Robert.

[Michael Gilligan]

On Michael Gilligan Said:

On bernard towers Said:

Having used one for a considerable no of years I fail to understand Michaels comment on their suitability for model engineering.

I wold be interested to see the size and shape of the laser-spot that you are using, Bernard.

Perhaps we are thinking about different use-cases, but a fuzzy rectangular spot seems like a poor “finder” to me.

MichaelG.

The size and shape of the spot can be altered. I did this myself with a rotating laser pointer I knocked up some years ago. I don’t know where it is now. If I can find it I’ll post some details. Admittedly it was a prototype but I do remember I wasn’t overly impressed with the results.

Edit: the inspiration for my laser pointer came from here.

 

https://youtu.be/otSjut1iGGk?is=NDfdoewW2uxtYXeH

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