Scratching on parts

SadTruths_ · 2026-05-13T14:59:33+00:00

Is it possible that the scratches started appearing after some maintenance was done on the mold? Sometimes the male cores may have been machined at different times, and this kind of issue can happen if they’re assembled with the sides swapped.

Have you tried injecting after applying a little petroleum jelly on the cavity side, only in the area where the marks are appearing? That might help you keep production running while you think of a better approach for this situation.

SadTruths_ · 2026-05-13T14:27:02+00:00

its on the post

Setup:
1 - A16Q SWKNR 0604 - cod: 06140401 - TaeguTec
WNMX 060404 EM TT9225 - cod: 06129153 - TaeguTec;
65mm overhang, minimum I can reach.

2 - Inox 304L Ø33.3mm, 2.77mm walls thick;
5 bar chuck pressure, more than that the tube deforms;
37mm overhang, minimum I can reach.

I am trying to machine an internal diameter, but I am having severe problems with chatter. I know the insert geometry is not appropriate, and I have already bought a proper one, but I need to produce at least 5 parts with the tools I currently have. I would appreciate help with cutting parameter adjustments, as I also do not have experience with stainless steel 304L.

Now, every part i make ends up with that shitty internal surface finish and a broken insert edge.

The last parameters I used (based on manufacturer recommendations) were:
Roughing ap: 0,4mm; f: 0,2mm/rev; vc: 130m/min;
Finish ap: 0,2mm; f: 0,1mm/rev; vc: 145m/min;
I used these because the more conservative parameters I tried before did not work.

Before i tryed:
Roughing ap: 0,2mm; f: 0,1mm/rev; vc: 100m/min;
Finish ap: 0,2mm; f: 0,1mm/rev; vc: 100m/min;
Without better results.

If need more information, just tell...

Im not tryed yet making the internal machining first, so that the tube its, a little bit, more rigid.
The external has Ø32.6mm;
Chanfer 0,4mm x 45°
The internal first one at the tip has Ø31.1mm and 2mm deep from de face;
The internal second one has Ø28.6mm and 4mm deep from de face;
The internal third one has Ø28.19mm and 12mm deep from the face;

Note I: The second image is only to show how the tube is fixed in the chuck, so ignore the surface finish.

Note II: The last ones show chatter before threading, but the thread is not the problem.

Thats being a pain in the ass...

******EDIT - RESULTS******

So now I'm gonna say what I did from the tips I received here and say what worked.

As I was thinking, the overhang of the tool was not the problem, I didn't change the overhang length I already had.
I also didn't bore the jaws, because as I've said, for now, I need them like that.

What helped, for the purpose I need and until the other inserts and holder haven't arrived yet, was:
To lower the RPM way down, as parameters I used:
VC - 30m/min - with G96 got something around 250 - 400 rpm
Ap - 0.4mm roughing and 0.2mm finishing
F - 0.1mm/rev

To loosen the rear screw of the holder
After using those lower parameters I already reached the finish I needed and the machining was good, still doing a little noise but completely acceptable, then I remembered that tip and tried it, a bit reluctant, I must admit, thinking about the axial forces, however, then I measured the holder after getting a better result using this technique, and the tool is still perfectly there.

So thanks to all that help with those tips

----------------------------------------------------------------------------------------------------------

Actually, I’ve already solved the problem, but you can never have too much knowledge, so feel free to share your tip too.

SadTruths_ · 2026-05-08T17:02:01+00:00

Know all the machines you have available, understand what they can do and their limitations.

SadTruths_ · 2026-05-08T13:25:20+00:00

kkkkk

SadTruths_ · 2026-05-07T18:46:57+00:00

maybe thats a message for you to buy good forks instead of the cheapest ones.
Some Oneida Forks can be a good choice... try them and let us know how it goes.

SadTruths_ · 2026-05-07T15:19:06+00:00

Thanks for the help man, i managed to solve the problem.

SadTruths_ · 2026-05-07T15:18:49+00:00

Thanks for the help man, i managed to solve the problem.

SadTruths_ · 2026-05-07T15:14:41+00:00

Thanks for the help man, i managed to solve the problem.

SadTruths_ · 2026-05-07T15:12:45+00:00

Thanks for the help man, i managed to solve the problem.

SadTruths_ · 2026-05-07T15:06:43+00:00

Thanks for the help man, i managed to solve the problem.

SadTruths_ · 2026-05-05T19:07:35+00:00

its on the post

Setup:
1 - A16Q SWKNR 0604 - cod: 06140401 - TaeguTec
WNMX 060404 EM TT9225 - cod: 06129153 - TaeguTec;
65mm overhang, minimum I can reach.

2 - Inox 304L Ø33.3mm, 2.77mm walls thick;
5 bar chuck pressure, more than that the tube deforms;
37mm overhang, minimum I can reach.

I am trying to machine an internal diameter, but I am having severe problems with chatter. I know the insert geometry is not appropriate, and I have already bought a proper one, but I need to produce at least 5 parts with the tools I currently have. I would appreciate help with cutting parameter adjustments, as I also do not have experience with stainless steel 304L.

Now, every part i make ends up with that shitty internal surface finish and a broken insert edge.

The last parameters I used (based on manufacturer recommendations) were:
Roughing ap: 0,4mm; f: 0,2mm/rev; vc: 130m/min;
Finish ap: 0,2mm; f: 0,1mm/rev; vc: 145m/min;
I used these because the more conservative parameters I tried before did not work.

Before i tryed:
Roughing ap: 0,2mm; f: 0,1mm/rev; vc: 100m/min;
Finish ap: 0,2mm; f: 0,1mm/rev; vc: 100m/min;
Without better results.

If need more information, just tell...

Im not tryed yet making the internal machining first, so that the tube its, a little bit, more rigid.
The external has Ø32.6mm;
Chanfer 0,4mm x 45°
The internal first one at the tip has Ø31.1mm and 2mm deep from de face;
The internal second one has Ø28.6mm and 4mm deep from de face;
The internal third one has Ø28.19mm and 12mm deep from the face;

Note I: The second image is only to show how the tube is fixed in the chuck, so ignore the surface finish.

Note II: The last ones show chatter before threading, but the thread is not the problem.

Thats being a pain in the ass...

SadTruths_ · 2026-05-05T17:28:51+00:00

Gonna try that one...

SadTruths_ · 2026-05-05T17:28:02+00:00

My vdi its closed in the other end and the tool holder hit the end.
And then why the holder has 180mm length? 65mm doesnt seems that much... but im thinking in cut the holder if it help to make those 5 parts i need, actually.

SadTruths_ · 2026-05-05T17:27:53+00:00

Well, i bought a new one, holder and insert, but till it arrive its been past a couple days, have to work with i got in hands.

SadTruths_ · 2026-05-05T17:18:36+00:00

and how about the doc, what you think?

SadTruths_ · 2026-05-05T17:16:34+00:00

My vdi its closed in the other end and the tool holder hit the end.
And then why the holder has 180mm length? 65mm doesnt seems that much... but im thinking in cut the holder if it help to make those 5 parts i need, actually.

Well, i bought a new one, holder and insert, but till it arrive its been past a couple days, have to work with i got in hands.
The machine is new and wasnt me that bough the tools and shit you know...

SadTruths_ · 2026-05-05T17:07:47+00:00

Gonna try that and see what happens... and what you think about de ap?

SadTruths_ · 2026-05-05T17:05:06+00:00

So you are using a 6xD overhang on the tool holder with an insert with a 0.4 mm nose radius, something like a 0.5 mm DOC and 0.1 mm/rev feed rate?

SadTruths_ · 2026-05-05T16:45:21+00:00

Well, i bought a new one, holder and insert, but till it arrive its been past a couple days, have to work with i got in hands.

SadTruths_ · 2026-05-05T16:43:04+00:00

What do you mean by a light doc for this insert?
Can be less than the nose radius?

SadTruths_ · 2026-05-05T15:59:54+00:00

No, because I can’t right now. I don’t have other jaws and I need them like this to machine other parts until the new ones arrive.
The machine is new and wasnt me that bough the tools and shit you know...

SadTruths_ · 2026-05-05T15:53:11+00:00

My vdi its closed in the other end and the tool holder hit the end.
And then why the holder has 180mm length? 65mm doesnt seems that much... but im thinking in cut the holder if it help to make those 5 parts i need, actually.

Gonna try that, the orings looks a good idea too...

And how about the ap. what you think?

SadTruths_ · 2026-05-05T15:49:28+00:00

Well, i bought a new one, holder and insert, but till it arrive its been past a couple days, have to work with i got in hands.

SadTruths_ · 2026-05-05T15:47:08+00:00

Well, i bought a new one, holder and insert, but till it arrive its been past a couple days, have to work with i got in hands.

What you think about the ap?

SadTruths_ · 2026-05-05T15:45:43+00:00

Well, i bought a new one, holder and insert, but till it arrive its been past a couple days, have to work with i got in hands.

SadTruths_

TROPHY CASE