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Cutting tool for as-cast, Aluminum, dowel pin?

uncleho

Plastic
Joined
Feb 13, 2024
Location
Motown
Hello,

I'm not a machinist so pardon my ignorance for asking this. I am looking for advice on what type/style of cutting tool can be used to create a 'Dowel Pin' of sorts in a die cast, aluminum (A380 for example) part.

SCENARIO: We want to cast a protrusion in a die cast part (actual die cast part is not important) that requires further machining that results in (2) Dowel Pins that are integral to the die cast part. Said Pins will function to locate a mating part. Machining would be done with 3 axis CNC mill machining center.

OPPORTUNITY: We want to reduce mass and assembly process of pressing in typical, steel Dowel Pins.

PROBLEM: I don't know if there is a style of tool that can be made in order to cut custom profile for the Pins. We basically want the Pins to have a bullet nose with the following, general geometry:
1) ~10mm OD
2) ~15mm height
3) ~45deg x ~5-7mm lead chamfer
4) The critical, machined features are the finished 10mm OD and the chamfer. The upper bullet tip can be as-cast (uncut).

I know we can mill/interpolate cut such a thing, but I was wondering if there was a style of cutting tool that could just plunge downward and cut the OD & chamfer without the interpolation.
 
The bullet nose would be interpolated with a roundover or maybe plunged with a custom form tool.

The cast pin would be turned using a boring head that's been set up for pin turning - essentially an insert head flipped around and a counterbalance.

 
This sound's like you are way overthinking it. Drill a hole, use a reamer, press in a real dowel pin. Probably will decrease the cost of your casting removing that boss if you haven't had molds made yet. If the chamfer being that big is really mandatory then some mild or stainless pins could be made for pretty cheap. If you insist on it being cast in then interpolating it with an endmill really is a great way to do it. With proper tools and a machine with say 10K rpm that feature can be cut in probably 20 seconds or less including the needed tool change to chamfer. Unless you plan on doing many many thousands of parts the cost of a tool like you are looking for will be very impractical.
 
What you're describing is a tenon cutter, but those are generally for wood. You could get this custom made, probably with a bore bar with a second insert at the correct height to cut the chamfer and height. But, that option would be expensive. If you're just looking for a prototype or short run. Cutting the diameter and height on a mill should be no problem. Tolerances at +-.0001 should be achievable (although hard to measure, and probably not necessary in AL.)
 
There was recently a discussion in another thread about hollow mills, which are intended for this sort of application. If you want the cylinder and the end profiled all-in-one, you'd need a custom, but you could cut the cylinder with a hollow mill, then CNC profile the end, or you could use an old-school knee tool with a cheap shop-made custom flat blade. Knee tools are asymmetric in shape and are intended for use on the lathe turret or tailstock, so please do not try to spin one on your 10K mill spindle.
 
This sound's like you are way overthinking it. Drill a hole, use a reamer, press in a real dowel pin. Probably will decrease the cost of your casting removing that boss if you haven't had molds made yet. If the chamfer being that big is really mandatory then some mild or stainless pins could be made for pretty cheap. If you insist on it being cast in then interpolating it with an endmill really is a great way to do it. With proper tools and a machine with say 10K rpm that feature can be cut in probably 20 seconds or less including the needed tool change to chamfer. Unless you plan on doing many many thousands of parts the cost of a tool like you are looking for will be very impractical.
That's the thing I forgot to mention. Volume = 100,000k/year so short cycle time.

Also, the die cast part cannot be turned on a lathe. It's prismatic blob in shape (i.e. Not symmetric)... and there are (2) dowels per each casting.
 
There was recently a discussion in another thread about hollow mills, which are intended for this sort of application. If you want the cylinder and the end profiled all-in-one, you'd need a custom, but you could cut the cylinder with a hollow mill, then CNC profile the end, or you could use an old-school knee tool with a cheap shop-made custom flat blade. Knee tools are asymmetric in shape and are intended for use on the lathe turret or tailstock, so please do not try to spin one on your 10K mill spindle.
Hollow mill, huh? Thanks. I was looking for the naming convention of the style of cutting tool.

Due to the higher volumes, we don't mind paying more. This is automotive grade parts.

I'm just trying to save on subsequent process (i.e. Pressing the Pins if they were the typical, steel dowels.).

Thanks, guys!
 








 
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