I'd agree with Robert, waaaay too much spindle extension on the tool. Plus the work isn't really clamped tightly enough for running a face mill. Lastly 2 thou depth of cut is not really making the inserts work properly. Combining any two of the three is probably enough to induce chatter. This is the ideal for face milling, rigid tooling and everything clamped down:

Andrew

Is there a reason the stock is so high in the vice? It looks like you were only intending to skim off about 1/8".

I would especially want stock as large as that is in relation to the vice to sit as low as possible to maximize the surface area doing the clamping and being clamped.

Hope not! 60 passes @2 thou a time – that should wear out the edges rather more than a good cut!

I can’t see much that is right with that set up. One parallel (why even one?. A hard rod (at least why not in the jaw groove, as well?). Excess hang-out of the quill. Did ways include the quill? Conventional cutting direction? Origin of the face mill?

Movement of the part under cut. Cut point forced the part up to hit the inserts behind that point. I have a GH Universal and have a 50mm face mill on a R8 holder and use a depth of cut of at least 0.5mm at 1000rpm and hand feed. Rather than cutting along the vice jaw, x-axis, try cutting across into the fixed jaw, y-axis. That said I do think the part would be helped with putting more support under the part.

Looks at the lower part of the photo like the saw cut has eased away to nothing before the edge of the cast block, leaving the rough cast surface intact just on the edge half inch or so. Or perhaps that is rough corrosion since it was cut? Looks more like the cast surface, but hard to tell from pics of course. That would leave some depth of hard "skin" perhaps even on the saw cut area as the saw cut looks to have been only a few thou deep in that area.

But a stouter set up and deeper cut should help, either way.

I would like to point out that the difference between a fly cutter at this diameter and a 5 insert face cutter is that the rate of feed for a given RPM needs to be 5 times faster. These multi insert cutters are designed for rapid material removal and require a suitable feed rate to get the best use out of them. They need to be worked reasonably hard.

So as stated above you probably need to have a bigger depth of cut, an RPM in the region of 425RPM and a feed rate in the region of 65mm/min. I don't know what your lead screw pitch is but if it is 5mm then you are looking at a handwheel being turned close to once every 4 seconds. You should be seeing obvious chips coming off rather than dust.

Martin C

Work holding.

Differing heights of insert in the head = duff face mill

Bad inserts.

You don't need parallels for the first cut.

PS hard spots are all shiney.

Your machine should be quite capable of a 1mm depth of cut using the whole width of the cutter if needed, My lighter X3 can do it so yours should be able to as well.

I think we can rule out poor inserts.

What sort of speed and feed were you using.? I have a 50mm 4 insert face mill and run that between 100 and 125m/min surface speed so that is 600-800rpm. feed about 100 per min, yours could be feed 25% faster. This gives a chip load of 0.02-0.03mm (approx 1thou) and that is a true load as you are using over 50% cutter width so no chip thinning to ease things.

Here it is taking 1mm depth off a 45mm wide bit of poor quality CI then steel then ali with ali inserts. Cheap holder, decent inserts

Edited By JasonB on 07/04/2022 18:58:49

Edited By JasonB on 07/04/2022 18:59:39

Would stall my mill dead and can't be faffed doing loads of shallower passes

Feels like a combination problem to me – bit of work-holding, shallow cuts, the material and maybe the inserts.

What do the team make of this table from the 1204 datasheet?

I read the table as describing an insert optimised for wet cutting Stainless Steel and Titanium at moderate feed rates, that can also cut steel when run fast and hard. Could it be the rake and edge angles are completely wrong for cast-iron?

Forum friends occasionally blame poor quality Chinese insets for a new tool's disappointing performance. Possibly nothing wrong with the inserts, the problem being they're the wrong specification for hobby machines cutting hobby metals. The same inserts might be brilliant fitted to a machine correctly set-up to plough efficiently through Titanium!

Dave

I'd be inclined to try different inserts too. Your set up may not be the stiffest possible, but it's not unreasonable either. The mill isn't a weed, chilled cast-iron isn't likely, and others get on ok with that type of cutter. It ought to do better than it is.

I'd try faster deeper cutting first though. Might be that simple, and inserts aren't cheap!

Dave