[Beezle]

PCNC 1100 3 here.

I make a lot of parts that have contoured surfaces. Or angles, elipsoids, etc. And I tend to simply use SprutCAM's waterline operations and a relatively fine depth of cut with square end end mills. Even as fine as .005. I've even done .001 steps.

The results are okay, especially in wood, but in aluminum of course it can be a mess. If the end mill isn't particularly sharp, etc. And I tumble my aluminum parts in ceramic media in rotary tumblers. And that works well.

But I keep wondering if there isn't a better way? I'll see photos of parts made on the Tormachs that honestly look a lot nicer fresh off of the machine than mine do.

Any tips on better ways to do this appreciated. CAM wise I plan on sticking with SprutCAM for now. I upgraded to 10 and whoa, no bugs. Woo. But if Fusion happened to have some kickbutt operation for such things, I'd be happy to give it a whirl.

Thanks in advance.

[pickled]

I don't quite understand your dilemma, but it sounds like you are talking about machining 3D surfaces using a 2.5D milling approach? Pardon me if I interpreted your statements wrong, but this is what I think you are looking for. Mind you I still use SprutCam7 here so your version should be able to do everything and more that I reference. When machining parts like you describe I typically will use the roughing waterline or plane operation with a 3/8" end mill (square end) to remove the bulk of material in an ugly fashion with as high of a material removal rate as I can get away with. Then finish everything off to the desired 3D contours via adding one or more finishing operations using ball end mills of appropriate diameters. Sprut will allow you to set the scallop height desired that is to be left behind for 3D surfacing.

Getting a nice looking surface is typically nothing more than a balance between the amount of machining time that you are willing to tolerate coupled with using the largest diameter ball mill that will still remove the bulk of material while satisfying the geometry of your design. Basically you can 3D surface with a 1/2" ball mill, but it would be hard to make a 1/8" pocket or half sphere with one :-). A lot of times my process would be something like run the initial waterline with a 3/8" EM employing a generous DOC or WOC depending on the geometry to get a good material removal rate (using HSM when it makes sense). I would then follow that up with a ball mill roughing/finishing waterline or complex operation with a scallop of say 2 thou. If necessary then I perform the same operation with a smaller diameter ball mill and the parts typically look almost there. If you are real picky you can run with a smaller scallop height initially or perform a "rest machining" operation and go further. Most of the time I am pretty happy after 1 or 2 ball mill passes run at opposing angles. At that point a little time in the polisher will yield some sweet looking parts that resemble what you drew in the CAD program :-). As a general rule the simulation in Sprut shows gouges and residual material pretty well matching real life. Trust me though it won't show you the problems induced by the user (dumb stuff I do like poor fixture design, pushing the tool too hard or not noticing when an end mill has a small chip in a flute :-(.

[popspipes]

I use ball mills for contour type work, I have a contoured transition hole that I use a .25 ball mill with a .010 stepover, very acceptable finish off the machine.

edit:
I use a roughing waterline first leaving .007 stock, then finish with a finish waterline 20 ipm .010 stepover, the finish can be better but the time goes up. I use a 4 flute .25 ball cutter 5140 rpm. I like the 4 flute as it produces a better finish in my opinion.

[pickled]

Hope that this makes sense. Sprut and the Tormach mills work quite well together for true 3 axis machining operations...I have been happy with the combo for many years. I didn't like the Sprut Bugs and version issues, but once you have a stable version to work with it sure is nice!

[Beezle]

Thanks for the replies.

Here is a typical example. So how smooth the angled surface is is what I am thinking about.

Attachment 326524

I will give ball mills a try. I do have some that I almost never use.

[Beezle]

And here are the actual parts. This is after tumbling. They will be powder coated and the surface is fine for that, but I wouldn't want to anodize them like this. I would probably tumble them for a few days.

And again, thanks for the help. I think ball mills are what I am looking for.

[keen]

Hi - You can buy Ball nose end mills and Hog Nose or Bull Nose for that type of work also - they are like a half way between a end mill and a ball nose .

Look at the cutter supplier web sites.

Keen

[SCzEngrgGroup]

And here are the actual parts. This is after tumbling. They will be powder coated and the surface is fine for that, but I wouldn't want to anodize them like this. I would probably tumble them for a few days.

And again, thanks for the help. I think ball mills are what I am looking for.

Get a vibratory finisher - it will deburr and smooth the parts FAR faster than a tumber (about one hour with "green pyramids" will remove machining marks, and completely deburr most parts), using the same plastic or ceramic media. Even the cheap 18-pound unit from Harbor Freight works well.

Regards,
Ray L.

[Beezle]

Get a vibratory finisher - it will deburr and smooth the parts FAR faster than a tumber (about one hour with "green pyramids" will remove machining marks, and completely deburr most parts), using the same plastic or ceramic media. Even the cheap 18-pound unit from Harbor Freight works well.

Regards,
Ray L.

No thanks. Tumblers are much more quiet. Maybe slower, but I'm okay with that.

[pickled]

I love my vibratory finishers! I have a large one that I use the green pyramids in and a couple of small ones with various corn and walnut mixes for more "delicate" work. I keep the little ones on the second floor of my building and turn them on before I leave. When I come in in the morning the buzzing noise reminds me to go upstairs and check on my parts. They make things idiot proof for me here and I need that!

[Beezle]

I have one. It sits on a shelf, being nice and quiet.

[popspipes]

And here are the actual parts. This is after tumbling. They will be powder coated and the surface is fine for that, but I wouldn't want to anodize them like this. I would probably tumble them for a few days.

And again, thanks for the help. I think ball mills are what I am looking for.

Please let us know how the ball mill worked out, I for one would be very interested to know if that fixes the problem or not.........

I have found that a relatively light cut .005 to .007 on the finish cut works better for my parts, any more and I get a touch of herringbone in the finish.

[pickled]

Please let us know how the ball mill worked out, I for one would be very interested to know if that fixes the problem or not.........

I have found that a relatively light cut .005 to .007 on the finish cut works better for my parts, any more and I get a touch of herringbone in the finish.

That sounded like a grey poupon description :-).

"Pardon me Sir? Would it be possible to have the serving spoon for my foie gras prepared with a touch of herringbone in the finish?".

Things have been way too serious in my world lately so thanks for giving me an opportunity to share something that may help while queuing up my awkward sense of humor. I too look forward to hearing about potential improvements to appearance and cycle time reduction via a different approach. Pulling those parts off with a square end mill had to take a while. Well back to making steel turn blue and chip!

[SCzEngrgGroup]

Maybe it's just the photos, lighting, etc., but the finish on those parts really doesn't look very good. After an hour in green pyramids, my parts would come out looking like they had been perfectly smoothed, all the edges just slightly broken, then bead-blasted. The finish would be absolutely consistent on all surfaces, with no hint of machining marks. In the photos, especially the angled surfaces, the surface looks more like it was roughly filed. What do the parts look like right off the mill?

Regards,
Ray L.

[coffeetek]

Maybe it's just the photos, lighting, etc., but the finish on those parts really doesn't look very good. After an hour in green pyramids, my parts would come out looking like they had been perfectly smoothed, all the edges just slightly broken, then bead-blasted. The finish would be absolutely consistent on all surfaces, with no hint of machining marks. In the photos, especially the angled surfaces, the surface looks more like it was roughly filed. What do the parts look like right off the mill?

Regards,
Ray L.

Ray which vibratory machine are you using now and which media (where do you get it)?

[SCzEngrgGroup]

Ray which vibratory machine are you using now and which media (where do you get it)?

I have two machines, though I don't recall who made either. The first is a probably 18" diameter bowl, and will handle parts up to about 10" long. I paid about $500 for it 6-7 years ago. It holds something like 20 pounds of media. The second I got for $150 from a machine shop that went out of business. It's probably a 24" bowl, with a 1HP motor - SERIOUSLY heavy duty. Id guess it probably holds 30-40 pounds of media. Both are setup with a water "flow-thru" to keep the media clean.

I use mostly "green pyramids", which are 1/4" plastic pyramids with embedded abrasive. They work great, the only headache is they get really wedged into holes. I use a little bit of SimpleGreen in the water to fight "sudsing", and keep the media clean.

I did do some aluminum polishing years ago. I'd start with green pyramids, then ceramic cylinders with a fine abrasive, followed by walnut shells with rouge. But, for the parts I was doing, I decided it made more sense to simply pay a local metal polisher to do the work. Dealing with all the media, and the mess, was a real hassle.

Regards,
Ray L.

[wildwhl]

Just a note on vibratory finishers and noise.

Build a hood, or enclosure, out of 1" foam. It's quick and easy - I use the foil backed variety and foil tape to hold the box together. Drop the box over the offending noise maker (I keep a few on hand) and cut the DB output substantially.

If you want it really quiet use 1/2" plywood with 1" foam and egg crate foam bonded to the inside.

WW

[pickled]

Just a note on vibratory finishers and noise.

Build a hood, or enclosure, out of 1" foam. It's quick and easy - I use the foil backed variety and foil tape to hold the box together. Drop the box over the offending noise maker (I keep a few on hand) and cut the DB output substantially.

If you want it really quiet use 1/2" plywood with 1" foam and egg crate foam bonded to the inside.

WW

Great tips! That foil backed 1" foam is a problem solver! It's great for shipping flat parts or blade stock, and now I know that I can quiet my loud vibe finisher down with it as well. I will appreciate it even more!

[Steve Seebold]

No thanks. Tumblers are much more quiet. Maybe slower, but I'm okay with that.

I have 2 Burr King vibratory tumblers. One is a 3 quart and the other is a 10 quart. The big one has ceramic media and does light deburring, the small one had walnut shells with jewelers rouge and is used for polishing.

Deburring takes about 2 hours, polishing can take a week.

If I keep the lids securely fastened down, the noise level is at least tolerable.