5 AXIS UNDERCUT THREAD HELP

[CDurbin]

Hello all,

 

I'm new to the forum and have been looking around for quite sometime and have found some post here that are very helpful!

 

With that being said, i have a part that is giving me trouble. this part has to be milled because of other features on the part.

 

I've attached a file that has the feature in it.

 

can anyone point me in the right direction as to what tool path would be needed for the undercut section of the threads?

 

Thanks in advance,

Cody

5 AXIS THREAD.SLDPRT

[crazy^millman]

Sorry, but I am not understanding what is 5 Axis. Maybe 3+1 or 3+2, but that is just moving an axis to position to cut a basic thread shape. Mind giving some more detail as to what machine you are trying to machine these features on?

 

Welcome to the forum.

[CDurbin]

Thanks for the quick reply! The machine we will be running this on will be a Mazak VCU 400A. The thread has a dovetail profile to it instead of a V like a typical thread would have. I'm assuming your saying i can rotate indexer to that angle and just use the rotary? i think that's exactly what i'm trying to do, just cant seem to make it happen!

 

Also the hole for the minor Ø is .319

 

Thanks again for the help,

Cody

[mkd]

 If you could get a lathe (custom brazed) tool made, there is no relief area to retract the tool. (edit: which also wouldn't do any good in trying to step in with a canned cycle)

I guess you could take a min of 3 passes with a woodruff type cutter using a 3+2 method.

 I'm really questioning the engineer on this one. What is the point of having a reverse acme profile????? thread like this don't exist...for a good reason. There is a "B!tch slap the engineer day" thread on Practical Machinist. might be a good one to submit.

[BenK]

What type of thread is it? It sounds like a buttress, they make a thread mill for that and many other thread profiles. Just get the correct tool for the job and it will make your life much easier. 

[mkd]

What type of thread is it? It sounds like a buttress, they make a thread mill for that and many other thread profiles. Just get the correct tool for the job and it will make your life much easier. 

i thought buttress from his description too. It's not.

 take an ACME profile and reverse the angles.

nutty

[BenK]

mkd,

I didn't download the file so I'm only going off the description. That's why I asked what the call out was. Sounds like a custom tool is best.

[CDurbin]

Thanks Guys, y'all are the best! 

 

So this is just a job i'm trying to quote right now, so all i have is a model to go by. As far as tolerances go, i imagine it doesn't have to be perfect, as long as it looks right and functions with the screws they have sent me.

 

I have already purchased a custom tool to try this with, i just can't get the right motion out of it now. i actually have a tool that will drive the bottom surface of the thread, but the undercut is being a pain...

 

 

 

 I'm really questioning the engineer on this one. What is the point of having a reverse acme profile????? thread like this don't exist...for a good reason. There is a "B!tch slap the engineer day" thread on Practical Machinist. might be a good one to submit.

I completely agree with you, but you know how it goes...