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How do I grind this?

P

Puddington

Plastic
Joined
Jan 31, 2019
Hi forumers,
I'm quite new here in this forum, been lurking around for awhile now and finally posting my first thread. I do freelance grinding and recently I was given a task which I honestly could not figure out how to solve.

This is the drawing on it. Imgur: The magic of the Internet

Anyone have any idea on how I could grind out the taper radius from a grinding machine? Couldn't figure out how to proceed other than using a sinker EDM(have to source it from an EDM shop if that's the case). If anyone have any idea, your help is very much appreciated.
 
Radial travel to the R1.5 would make it a time-consuming part and need a special point mounted wheel. Perhaps a special fixture if a production part. For a one-up one would slash the 1.600, roll the 11.40 - 12.40 with the same dress, and hand or fixture the R1.5 with a special dress point.
A tough job on the SG as one would not likely have the wheel mount or RPM to run a small point. , likely take me 4 hours or so with making a dressing form for 15* and R.3 and using my manual grinders. No, I don't want the job. Yes a CNC grinder would do better and make the job much easier.
What is the material? What is the length? Why do you choose grinding is that for surface finish needs?
A CNC mill could make easier this job...but even there if a production part a special cutter would best serve the part.
 
Maybe a CNC Jig grinder with a wheel dressed on a taper if the part isn't too long. It would be a lot of wheel contact. Step down with a ball shaped wheel? Inches or MM?
 
Or, if the shaft is short and could beheld vertically, it could be a jig grinder (or jig grinding spindle mounted on a mill, depending upon the precision required) job, using a conical stone.
In the case of a long shaft, it could still be done, but likely requiring the construction of a sort of "clamp-on jig grinder".

Paolo
 
Sorry guys I guess I should provide more information regarding the work. I was thinking of ways to use a surface grinder for this is because EDM would likely cost me much more than my customer is willing to pay. The material is carbide and it is in MM. Also, because of the material, I think I might have to rule milling out.
 
You wont do that with a surface grinder (maybe the tapered OD with a diamond wheel on a sine chuck)
The inside features also appear to be tapered. Correct?
Looks like a face detail for a powdered metal punch.

2 options to do that. Sink EDM, or hardmill.
To sink EDM you'll need copper tungsten electrodes
To hardmill (I'd do this) You need PVD diamond cutters and a TIGHT machine that can maintain a very specific chip load
 
I would not EDM sink this in carbide but if your machine is a surface grinder or a manual tool and cutter grinder. ......walk away.
If tolerances allow the best bet is a VMC with custom diamond grinding bits.
This is very slow, roughing out some of the stock on other machines would help.
I'd slash out the center, rough the OD .010 over and then go at it with custom plated grinding pins that would have my angle and top rad built in.
Bob
 
You could mill that electrode easily enough, but will require diamond coated endmills to cut the electrodes from copper tungsten.
Then you will need an EDM that will support carbide burn parameters. You will see heavy wear on the electrode.

Best to mill it, if you have the capability.

The 16mm dia should come finished from your carbide supplier, so you are only concerned about the end form.

This is a standard job in the powdered metal industry.
 
Burning would cost an upward of 120USD, not something my client would pay for. Thanks everyone for your input. Since VMC/EDM is probably the only choices I have, I guess I will walk away from this project. Again, thank you all very much for your input!
 
In carbide a one up would be a very expensive part to grind.
If to become a production part that form could be pressed and sintered to that ...but this would/may not lend to a long part. The form would be like a carbide insert so might be silver soldered to a shank. likely/perhaps the shank would need be ground after the braze. location and likely be perhaps .001 to .003 close.

Perhaps modern talents could press and sinter the whole part(?)
Modern CNC EDM should make that an easy part..

but for a one-up or few-up expensive.

Back in the day I had connections with Carboloy and Valenite both now gone so you will have to search if it may become a production part.

Perhaps Ultra Met, Quality Carbide,PSM Brown or the like. .. ..again for a production part.

QT [Burning would cost an upward of 120USD,] likely that or more to buy special wheels to grind it.
 
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