Phonographic Flange Finish: ANSI B16.5
I am working on how to get a phonographic finish onto the flanges of a customers casting we machine. The issue is the flange is only accessibly via a Mill operation. We have been running a small endmill at high RPMs which is both hurting spindle life and takes well over an hour to do the face.
Specs:
Depth: .002"
Bottom Radius: Max .031
GPI: 30-50 Groves per Inch
Material: CA6NM (Stainless Steel)
The faces range from:
2.0 ID to 4.0 OD
3.0 ID to 5.25 OD
8.0 ID to 11.0 OD
Option #1
I have been looking at using a #1 Carbide Center Drill at <2000 rpm and basically drag it across the face, .002" wont put too much stress on the tool. Will run a spiral from center out to OD of the grove feature
Option #2
Build a tool with two 32 TPI carbide thread mill inserts, bring to the face and allow to rotate on the face for a few revolutions enough to clean up the groves, then back off.
Option #3
Similar to Option #2 however this tool allows the bar holding the inserts to move freely a within a few degrees off center. The principal idea is that when the tool makes contact since there are two contact points they will even out pressure and equally put force on the face. This should take care of any issues Option #2 might of had with uneven inserts.
Option #???
If anyone has done this and has any input or how they did it I would be very appreciated.
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The problem I see with your proposed tool is the torque (horsepower) that it will take to drive it. I have only done this on a boring mill with boring head attachment that can feed Z(W) axis while cutting that moves the tool in or out at a specified feed rate to get the spiral effect desired. D'Andrea used to make an add-on boring head to do this. I do not know if it is still available.
One of my coworkers brought to my attention a company called Wohlhaupter who makes a triple feed facing boring bar. It would be a matter of calculating the number of revolutions it takes to do the feature then back off the part and reverse the spindle the number of initial rotations. I'll have to look into the company you specified.Originally Posted by txcncman
Now I did have another coworker show me we do have a 1.5" long 32 TPI thread mill and from what I'm seeing it covers the area that gets the phonographic finish, if thats true I can make a simple bar that will do the feature in one sweep with one insert.
Looks like a strong contender for face threading on a lathe.
A rugged CNC would give you the ability to use a rougher and finishing tool, and control the pitch/depth-cut increment accurately.
I can see where tool wear would be a problem with the 'engraving' approach.
The problem with a multi-thread tool is that the diameter varies considerably between the inner and outer grooves, leading to problems of side relief and potential dragging. Not what you want.
If you are going to use an engraver type tool, have you considered something really rugged, or CBN? I don't know how you're going to get around the spindle-on time, unless you mount a dedicated motor or speed doubler.
I've been involved with making similar grooves in a laquer coated aluminum disc in a vertical lathe, but we were making the cutting tool jiggle a lot, and using a ruby that didn't rotate. Chip control was actually a big problem... Ultimately, the biggest problem was making QC happy, because the measurements were translated into acoustic energy, and every QC guy had a subjective opinion. The lathes we used were Scully and Neumann.
We already run the other two faces through OP10 & OP20, they are opposing faces and easily done on there with the photographic finish. This is a flange that comes off the casting at a 90* and therefore due to the unique shape and size of the part we are unable to load them into our lathes or even VTL.
Would there really be that much of an issue with dragging with a .002" depth of cut? I was going to have the thread insert mounted at a back angle of 10* to create a clearance behind the front most edge of each of the thread points.
The engraving tool method was more for using a lower RPM to save our spindles over time, it would be great to cut down on production time but if it works to save the spindle that's what we are after right now. I havent' seen much for CBN or anything else outside of carbide for the engraving/center drill method. You know of any?
Basically, dragging is what's happening on a lathe anyway... ?
With the nature of this job I wouldn't be shy about talking to application engineers at say, Sandvik for example, because you're in the region of specialty tooling. What you have is a most interesting problem!
Re: Phonographic Flange Finish: ANSI B16.5
Hello,
I'm faced with exactly the same challenge and was wondering about your final solution.
Thank you
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