Cutting Angle Measuring Instrument

frikiati:

Have you considered using an optical goniometer?

Try searching GlobalSpec. You may find just what you are looking for...

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Just my $0.02...

Hello frikiati,

Welcome to CR4. It is a great place with some pretty clever members, good luck here OK.

Is the item being measured still or moving? Have you tried something which is harder than the work it touches or measures like Tungsten or if measuring a still object have the end of the measurer made from diamond? Just a thought.

You seem to be doing something done all the time across the world, IE. Measuring the thread angle, is that correct? Or are you measuring the pointed tip of the end of the screw? Can you give me a little more detail of what you are measuring and how you do it now?

Hi Babybear,

Thanks for your enquiries. Well, as I wrote we produce taps, for different threads for example: M, MF, UNC, UNF, G, W. The type of the core hole can be: through or blind.

The taps are made of HSS, HSSE or PM basic material. Our tools have got 2-3-4-5-6 flutes (it depends on the size of the given tap and the material that we have to machine) Just in the case of twist drills. The hardness of our taps is appr. 800-900 HV10. There is a prescribed cutting angle in the flutes that we have to measure. We have to put the tool between two centering male of female centers in the measuring instrument. The cutting angle measuring unit is perpendicular to the tool. While we measure the cutting angle we have to put the toucher in the flute and with the help of an eccentric we have to pull the toucher to the outside diameter of the tap because this is the starting point of the angle measurement. Then we have to twist the tap in the axis of rotation. After it we move the toucher in the flute. There is a dial indicator on the equipment which shows the measured angle. The cutting angle can be from -5 to +16 grades (it depends on the type of the tap). The way of the toucher depends on the pitch of the thread (from 0,1mm to 1,6mm). It is appr. half of the pitch. Now we use heavy metal toucher, it is quite strong but very vulnerable too.

It is very difficult to write it down, however the whole measurement process is very simple. I hope you can understand it. In two weeks I shall take a picture of the measuring equipment itself and send you it.

Bye,

Ati

Hello frikiati,

I must say congratulations on your complete explanation of the detail needed!

I almost understand but, a picture will be extremely helpful.

I look forward to getting it.

=

My initial thoughts are to use a 'distance' type measure using lasers. If, as it seems you test these dies in the same place a laser could be set up on the desk?

It is what I would choose.

I will search more after seeing your photo.

Thank you very much for the great description.

Hello again BB,

I like your approach of a laser. But as you point out, a picture is certainly needed to ascertain methodology and feasibility.

The method that comes to my mind is a combination of a laser and the original responser's proposal of a goniometer. In this approach, the collimated beam of laser light would intersect the measured edge. With the beam being wider than the tip of the edge, two reflections off of either side of the cutting edge would indicate the angle. A camera and some geometry calculations would then permit calculating back to the cutting angle. If this process is possible then full scale automation might permit rapid measurement of every production piece. My only concerns for this approach is that this maybe too precise; the scoring from cutting may appear like a diffraction grating instead of a simple smooth surface, coherent light may produce unanticipated peaking and cancellations of the laser light. (Is it a particle or a wave? Only her hairdresser knows for sure. Now I'm really dating myself. )

hello redfred,

To start at the end,....................I doubt it will ever make any difference whether 'wave' or 'particle', I just accept it as it is, something we can see by and use as a sensor.

Last time we had a similar question I read and researched of different coloured light, lasers and other light sources. There may be a place for Fibre Optics? As you say the interference type thing may happen but should be stopped with either dimming or changing the light colour.

I have not looked too hard so do not know precisely what the shape of a sensor will be, but, I did have in mind of a fixed unit on a test bench or perhaps as you say used as part of the machine?

Take care, OK?

Hi Baby bear,

Thanks, for your thoughts. There are some important factors in connection with the cutting angle measurement. Fisrt of all it shouldn't be too expensive (our factory is not too large, and we also suffer from the economics crisis). On the other hand the measuring equipment should be easy to handle, because it is next to the flute grinding machine and the worker uses it regularly. (not to mention the oil filled air in the department). I'll take a picture and send you in two weeks.

Once again, I would like to thank you for your efforts.

Bye,

Ati

I don't know about Taps

But Comparators have been used in machine shops for hundreds of years:

http://en.wikipedia.org/wiki/Optical_comparator

I've seen em used for cutting tools & threaded parts

The only electronics involved are the light source

Hello frikiati,

I enclose some laser and other measuring devices. You will have to decide which suites you, if any, and get in touch with the Manufacturer for cost etc.=

http://www.ferret.com.au/t/Sensors

You will have to read through this search page below to find what you want. Quite a lot of the listed sites are for hand held measurement devices. But there is also a whole lot of devices for industry as well. Good luck.

http://www.google.com/search?client=safari&rls=en-gb&q=industry+laser+measuring&ie=UTF-8&oe=UTF-8 =

Take care

There are inspection products that use a video camera to look at the part then compare the image to a reference image. It is fully automated and can keep the image for documentation.

Hello Pineapple,

Yes I could see that working!

Take care.

I have an obvious suggestion that might slip into a missed opportunity, save a few of your failed taps to test your new potential inspection system.

I think a simple video camera, microscopic lens and display monitor though maybe your simplest (aka lowest cost) approach. Also this would permit future refinement by allowing a computer to later examine the video signal instead of the subjective human eye.

Hello redfred,

This suggestion is diffinately worth a try! ;=) Take care