2 Attachment(s)
parting off with a drill?
Attached is a pic of a linkage ball that i need to make hundreds of. Very small, ball diameter is 5.25mm, through hole is 2mm, diameter at base is 4mm. My machine does not have a sub spindle so im trying to come up with a parting strategy that will leave the part finished without a burr. I havent ran any yet, so the first thing ill try is just parting it off with a very thin sharp carbide parting insert that is biased to one side, front edge of parting insert has 7 degree angle so the point of it breaks through the part side first. This may still leave a ring of material around the 2mm through hole. Another idea i had was to run the parting op before the 2mm through hole. Parting op will run to a depth just a few thou beyond the edge of where the 2mm bore will be. After that i will drill the 2mm hole that will meet up with the parting feature and separate the part. At this point the part will be sitting on the drill, which can feed over to a fork, drop down over it, and back up to push the part off of the drill into a container.
so im wondering if this could possibly leave a cleaner part off line vs just doing the parting op last. When the drill breaks the part free, there will most likely be a ring of material there at the back corner, but the drill will continue to feed through into the bar stock behind the part. I would think the little ring of material left on the part would get sandwiched between the drill and bar stock, effectively removing it and leaving a nice clean part off. Has anyone tried using a drill for parting off like this?
https://www.cnczone.com/forums/attac...d=434018&stc=1
Re: parting off with a drill?
I think you would be best off doing the parting operation last. If you make sure the the 2mm drilling operation drills the hole to it's absolute minimum depth, then there should be no ring of material left on the part.
Re: parting off with a drill?
My best guess is that the part will pop off of the stock and move down the drill slightly and leave a small burr. Exactly how it reacts will depend on the exact OD of the nub left by the parting tool relative to the drilled hole diameter. I will be very interested to see if I'm correct.
Re: parting off with a drill?
Ok, thanks guys. Ill experiment and see what works best. Jim, you might be right. Also i think another possible scenario with the drill parting is the ring of material causing the drill to break since the link ball along with the bur is going to immediately stop spinning on the drill when breaking through, so the drill is just gonna be pushing into that stationary material as the bar stock is rubbing on the back side of it. Kinda like a drill trying to recut a chip. 2mm carbide drill is pretty fragile. We'll see what happens. Looks like i might need to order another tool for holding vbmt style insert to get at all the geometry.
Re: parting off with a drill?
Interesting way to do a Setup. would be a fun one to watch run for sure with Vending Machine Fork ejector....luv it. But, why add the extra op.... unless you need the finished sharp edge outward as opposed to inward on the 2mm dia. One more thing maybe to think about is 2mm (.0787) diameter would bend or break with any sideways force.
my2cents,
DJ
Re: parting off with a drill?
Hmmmmm….personally I wouldn't bother making parts like that, parts that are too hard to make and have problems don't pay well anyway......I learned that a long time ago, I would think you could put your time to better use on another job......time is money after all.....just my opinion.
Ian.
Re: parting off with a drill?
I did not catch the type of material. I used run a similar repeat job out of 303 stainless. With a 24 degree angled .030 wide parting tool feeding at .0005 IPR @ 2500 rpm, I could drop them with a very mininimal burr in the bore that you could easily clean up with a cordless drill and a chamfer tool or tumbling in small tacks and media. Even if you did not deburr them you could pass a gauge pin through that was only .001 under hole size.
Re: parting off with a drill?
Quote:
Originally Posted by
QuinnSjoblom
303 here as well. The through hole is not crucial, just needs an m2 cap screw to pass through so there's a few thou of room. Also the parts that these bolt onto will have a chamfered tapped hole, so even if a the burr ends up slightly on the face, that's probably ok as well. Sounds like a regular part off might be ok.
The smaller the stock the skinnier the part off tool must be.
Re: parting off with a drill?
When you're making a prototype the cost factor of a second op would not be something to think about, it's when you then go on to a production mode that the time becomes a critical cost factor, and in this case you're going to source your production parts from a better labour cost source like China etc...…..why are you stressing out on a prototype problem?
Ian.
Re: parting off with a drill?
Quote:
Originally Posted by
QuinnSjoblom
Yep, I'm gonna get a really tiny one. My Kaiser thinbit holder has been super handy for various odd applications. Thousands of insert options
I will have to look into that. I have an Iscar holder. I just use Thinbit for skinny grooves. Not sure what machine you have but I have a small overhead gang tooled Swiss that has very limited clearance between tool positions and the gap between the guide bushing and gang assembly. That eliminates a lot of insert tools.
Re: parting off with a drill?
Quote:
Originally Posted by
QuinnSjoblom
The product is a large performance RC helicopter. These models are commonly crashed and rebuilt so all replacement parts need to be available at all times..
Great business to be in. I had a friend who had a strange unjustified amount of confidence in his abilities yet he pretty much failed at any new task he tried. He had never even tried to use a remote control car or even a boat, yet he said he was going to buy a remote control helicopter. I told him to buy something easier and work his way up. He insisted it would be no problem. I swear that thing never got more than two feet off the ground before he crashed it. There was a hobby shop in town that sold parts for it, my friend who was on disability leave paid that shop daily visits. I think after about crash #50 he tossed that thing in the trash. I blame You Tube for his troubles. Too many people watch highly skilled people with a lot of experience do something and think "That looks easy, I can do that." They don't realize it is the operator's skill that makes it look easy, not that the task is easy.
Re: parting off with a drill?
We also don't have subspindles on our lathes so sometimes the cut off can be tricky especially on small parts.
We will program the cut off to almost cut it off then turn off the coolant for the last .010 or so and reduce the feed and the part will drop into the parts catcher. Almost always.
Like others have said, angled sharp thin cut off blade.