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[Metrology] Mill Spindle Mounted Microscope (aka Cheap Optical Comparator)

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RJSakowski

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#1
I had thought about building a spindle mounted microscope for the Tormach for some time. The idea was to cannibalize and old phone or adapt a webcam camera but the optics was rather daunting some the project was shelved.

About a month ago, I saw an ad for a USB 50 - 500X microscope on eBay for $13.99 , including shipping. For the cost of lunch for two at McD's, it was worth a shot. The microscope came in a week ago and, after checking it out, I began designing the adapter.

The microscope would have two primary functions. 1. With the use of the DRO in Mach 3, it would in fact create a low cost optical comparator. and 2. If the microscope were concentric with the spindle axis, it would provide a means for optically locating a part feature prior to machining.

The idea was to dedicate an R8 1/2" end mill holder to the microscope. Since the R8 adapter is keyed to the spindle, the microscope will always install with the same orientation. The adapter would be adjustable to allow centering the microscope axis with the spindle axis. A clamping mechanism was first designed . An L shaped bracket was attached to the clamp and a flange with a 1/2" shaft attached to it by means of three oversized holes to allow for adjustment. Aluminum was used for all but the shaft which was made from stainless (OMC outboard motor drive shaft).

The microscope was assembled and mounted in the Tormach spindle. An old laptop provided the user interface. By rotating the spindle, the image would rotate and a feature was moved to be at the center of the rotation. That feature would then be directly in line with the spindle axis. The camera adapter was then adjusted to bring that feature to the approximate center of the screen and the adjustments locked down. This was done on the highest magnification setting. For alignment, virtual crosshairs would be ideal but the provided software did not have a feature like that for real time images so initially, the plan is to print a set of crosshairs on a transparency and tape the overlay on the screen.

In the lowest magnification setting, the field of view is 8.8 x 6.5 mm. On a 15" monitor, this is equivalent to a magnification of 35. On the highest magnification, the field of view is .97 x .72mm, which is equivalent to a magnification of 300. I am able to resolve movements of .0001" (2.5 microns) at the highest setting, which is the smallest incremental movement that I can make in Mach 3. The bubbles in the hi res. image are imperfections in the comparator supplied with the microscope for calibration.

Edited to correct the price from $123.99 to $13.99. 8/30/2015 22:31

Bob
Microscope.JPG Microscope 1 .JPG Microscope 2 .JPG Lo Res Image .JPG Hi Res. Image.jpg
 
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brino

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#2
Beautifully simple design, well executed and definitely very useful!
Thanks for sharing!
-brino
 

JimDawson

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#3
I like yours much better than mine. Nice job. I may have to get one of those to play with. I have some software that will put the crosshairs on the screen and it MAY work with that web cam. If it does, you or anybody else are welcome to a copy. (no copyright problems, I'm the author). It will be a couple of weeks before I have time to play with it.
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RJSakowski

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I like yours much better than mine. Nice job. I may have to get one of those to play with. I have some software that will put the crosshairs on the screen and it MAY work with that web cam. If it does, you or anybody else are welcome to a copy. (no copyright problems, I'm the author). It will be a couple of weeks before I have time to play with it.
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Thank you for the offer Jim. It would definitely be better than an overlay transparency. We need those yellow lines they put on the first down line. ;)

Bob
 

Ken_Shea

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#5
Very interesting and a superb job,
Amazing what a small investment, some imagination and todays electronics can do.

Ken
 

brino

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#6
Bob,

okay, you made me look, I went off to ebay.....two things:
1) your $123 above must be a typo right? or you are looking at very different cameras than I see ($20-30 range) (_and_ your local burger joint is ripping you off ;))
2) what mega-pixel is yours? I see 2 and 5 (although they seem to have similar image size specs.....hmmmm)

Thanks,
-brino
 
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RJSakowski

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Bob,

okay, you made me look, I went off to ebay.....two things:
1) your $123 above must be a typo right? or you are looking at very different cameras than I see ($20-30 range) (_and_ and your local burger joint is ripping you off ;))
2) what mega-pixel is yours? I see 2 and 5 (although they seem to have similar image size specs.....hmmmm)

Thanks,
-brino
Wow, thanks for the catch, brino! The microscope was actually $13.99 from Bang Good. About a week later, I saw they went up to about $20.00. It is a 2 mega-pixel camera.

Bob
 

JimDawson

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#9
Looks like $16.88 today. I'll order one tonight. A new toy to play with! :grin:

EDIT: Microscope camera inbound!
 
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Holescreek

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#10
We use those in the lab at work daily for quick measurements so I bought one off Ebay for my home shop too. If you got the good software package you can actually calibrate them to take accurate measurements at various magnifications. Isn't it funny how cheap technology has gotten? I bought a 6' long 5mm endoscope a few weeks ago for $8 shipped.
 

Hawkeye

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#11
Just ordered one. Under $20Ca. Free shipping. Jim, I'd be interested in your crosshair software when you have it ready for this application.

Thanks, guys. Always need some new toys.
 

brino

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#12
If you got the good software package you can actually calibrate them to take accurate measurements at various magnifications.
Any recommendations for good software packages with calibration and measurement functions?
-brino
 

RJSakowski

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#13
The software that came with the microscope has a calibration feature with additional features like drawing lines and shapes, annotating the image ,and the ability to measure angles and calculate areas of circles and rectangles. The calibration is in mm/pixel and seemed to be accurate. I haven't used it much, just a look-see. The software apparently only works with captured images, not the real time, and can be used with various image formats although the camera must be plugged in to open the software.

It works with a provided calibration grid with the crossed scales that I imaged, a series of different sized circles ranging from 100 microns to 1000 microns, a pattern of crossed lines on a 1 mm mesh size, line widths from .o3 to 1mm, inch and metric scales with .05 mm and .05in. divisions.

I am not really concerned about the calibration as both of my mills have a DRO and I intend to use the DRO to move the object under the crosshairs and obtain my coordinates from the DRO.

I have also used AutoCAD and SolidWorks for image analysis and I expect that other CAD packages offer similar capability.

Bob
 

RJSakowski

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#14
Since it appears that a number of you have ordered or are planning to order the same microscope I have, here are the drawings of the clamping arrangement that I used. Microscope Clamp.JPG Microscope Clamp.JPG

Bob

Microscope Carrier.JPG
 

Holescreek

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#15
Unless you're using it to pick up scribed lines there isn't any real reason it needs to be centered under the mill spindle is there? You could stick it to the side of the spindle with a magnet if you just want to use it for measurement.

Also, for those buying them from Ebay, make sure the model you get works with your computer. There are both newer and older models on EBay. The one I bought works on my old XP system in the work shop but won't run on my W8 computer in the office.
 

RJSakowski

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#16
Unless you're using it to pick up scribed lines there isn't any real reason it needs to be centered under the mill spindle is there? You could stick it to the side of the spindle with a magnet if you just want to use it for measurement.

Also, for those buying them from Ebay, make sure the model you get works with your computer. There are both newer and older models on EBay. The one I bought works on my old XP system in the work shop but won't run on my W8 computer in the office.
You are correct. You can mount the camera anywhere on the head for use as an optical comparator. Mounting on the spindle axis enables locating a feature prior to a machining operation. For example , a while back, some wanted to locate the center of an irregular boss on a casting prior to drilling. This would be a good use.
 

JimDawson

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#17
I'll see what I can do to write a measuring function into my software. It already edge finds and will measure in the X and Y axis, actually Z also if you use a laser as a light source. But it's geared for high speed wood processing (+/- 1mm at 600 FPM) not high precision metal work, I'll play with it a bit and see what I can do.

This assumes that I can get my software to work at all with this camera.

I'll post a link in this thread if I can get it working, so watch this thread. It will be maybe a month before it's ready for test.
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Holescreek

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#18
I just happened upon this thread again at lunch (I work nights) and checked out our little digital microscope to see if it had a crosshair setting. It doesn't, but I found that it allowed me to make my own by drawing two perpendicular lines in the live viewing screen which worked the same as having a dedicated crosshair. The scopes we get here in the lab are very expensive versions of the $16 scopes on Ebay. These cost the company about $500 each for the same kind of scope. The brand name is DINO LITE (http://www.dinolite.us/).

The cool thing (maybe?) is that the software is available online for free download from the site. I haven't tried it but can't think of a reason it shouldn't work with another brand of scope.
 

RJSakowski

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Will it work with windows 10?
The user manual does not list Windows 8 or 10 but the manual was written in 2009. I am running the software on a Windows 7 Ultimate, 64 bit system and on a laptop with Windows XP.

Bob
 

RJSakowski

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#26
Hi All,

I just found this web article on the same topic.
He uses a different camera, but it has lots of good pictures and write-up.

http://www.technitoys.com/milling-machine-spindle-camera/

It also contains a link to a free Mach3 plugin to provide cross hairs.
I have never used it, but thought it might be useful to someone here.

-brino
Hey brino, Thanks for the lead! I took a brief look at the link and I will give it a try.

The great thing about the internet is hardly anything is really new. Anything that you can think of has been thought of by someone else and more than likely, they have come up with a solution.Linking millions of people together makes the sharing possible.

Bob
 

KMoffett

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#30
I decided I'd take a whack at adding video to my ENCO(?) centering microscope. To adjust scope cross-hairs you have to repeatedly swing the scope 90° to the left and 90° to the right while adjusting the lens tilt and the table's X axis. To many bumps on the head from the CNC display and other stuff hanging there.
I looked for a small, cheap webcam and settled on this one: http://www.amazon.com/gp/product/B000Q3VECE?psc=1&redirect=true&ref_=od_aui_detailpages00
Pulled the base and bail off to reduce the size. Used scrap PVC pipe for the mount. 1/2" Schedule 80 bored through to slip fit over the centering scope. 10-32 drilled and tapped on the side for a nylon thumb screw. 3/4" Schedule 40 bored through to slip fit over the 1/2" PVC and bored 0.16" deep to press fit the camera's lens collar. I glued the 3/4" PVC on the end of the 1/2" PVC. Because the camera lens collar was a bit wobbly, once I had the cross-hairs focused and centered in the video display, I hot melt glued the body to the collar. The optics are not the greatest, but are OK for my purpose. The attached laptop display is a 0.020" hole in an aluminum plate.

Ken

Scope1.jpg
Scope2.jpg
Scope3.jpg
 
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