Zaphod,
    please be more specific, what size threads are you trying to detect.
    what is the specific end product

regards,
afterhrs

Hi,
The parts are almost exclusively carbon steel and are typically less than 20mm thick. The holes to be tapped are typically less than 10 mm in diameter and are thru-holes (Internal machine threads). The part if for a large engine and lays flat on conveyors through grinding/deburr, wash/corrosion inhibit etc.
I hope this helps.
Thanks

Zaphod1,
    check out General Inspection's web site

www.geninsp.com

regards,
afterhrs
 

I've heard of using Eddy Current to check threads but have never used them in an application myself.

Also see Thread404-21265...

There are several ways to do it.  The most recent way I have seen it done is with a vision system.  If you place the camera on an angle with a light.  The system will see the difference in the light and dark areas of the thread.  The other benifit of the vision system is once the image is aquired you can do many other inspections all in less than a second.  Check out Keyeance and Cognex.  Each one has their pluses and minuses.

We use Eddy Current sensors extensively, with substantial accuracy.  It is not cheap but it is the most consistent, predictable way of doing it.  We are currently using it, among other things, to probe a hole that is approximately .150" diameter.  Not only can we tell whether or not there is a thread, we can tell with some certainty the quality of the thread.  i.e. whether or not the tap ripped any threads, if the tap went deep enough or too deep as well as some other things.  

I believe that there are a few companies offering Eddy current inspection equipment in all different states of assembly from component to turn-key solutions.  We have been dealing with SE Systems in Califonia.

Here is his contact information:

Geoff King
SE Systems, Inc
(510) 723-6006 (V)
(510) 784-0810 (F)

I believe they have a website as well.

A.J.

Zaphod,

We currently have a Vision System running in a couple plants that detect threads very well.  We are using a Cognex InSight 1000, with LED Lighting.  If you have any questions, feel free to contact me.

Shawn Davidson
Radix Controls
(519) 737-1012 ext.335

Cognex, keyence,m LMI

Check out following:

http://www.eagledesigninc.com/etv.htm

David Baird
mrbaird@hotmail.com
 
Sr Controls Engineer

EET degree.

Journeyman Electrician.

Hello,
In the past I have used Pico Dot lasers from Banner for this. In the last 3 projects Ive done for thread detection I have used the new Keyence LV-H32 series laser with great results. At a 30 degree angle to the threaded hole Im able to adjust the spot beam to cover 6 to 8 threads and have a lot of ajustability in the amplifier.

http://www.keyence.com/products/sensors/lv/lv_h32.html?links=4:M:T

Bob

Bob1371,
    Are you running the same part all the time or different parts. I have had some issues with "teachability" factor and operators. This would not be an issue if you are running the same parts all the time.
    
Regards,
Afterhrs  

Each of the three products are only running one part with very tight tolerence on the machined surfaces so It probably makes it alot more reliable.
Bob

Bob,
   I am curious to see how you rate the Banner pico dot,
from a reliability and accuracy stand point. I am getting ready to replace an outdated unit and the pico dot has been
given some consideration for this application.

Thank you,
Afterhrs    

Only real problem I ever had with the pico dot was adjustability. I usually have to mount sensors in some tricky locations and getting to the little (read that as very, very tiny) adjustment screw on the back is a pain. (and forget the little plastic screwdriver they send with it)

I just like the adjustability control I have with the new Keyence amplifiers.
Bob

I have seen ads in Manufacturing Engineering magazine for a gizmo claiming to detect threads with a non-contact probe.  The ad says they give no-cost demonstrations.

NDT Technologies inc
1838 E. Highwood Rd
Pontiac  MI 48340
248-332-0709
www.ndttechinc.com

If you go this route, I'd be curious if it works.

Email is a stealth email to minimize spam.  Contact me & I'll get back in touch with you.

TygerDawg