[stryco_moco]

Hello, I have this part (photo included). I would like to know approximately how long it would take to machine such a part from a solid rod (300 mm length, 180 mm diameter). The material is corrosion-resistant steel 316 LSi. I don't have much experience with this type of machining or access to software that could simulate it. A precise estimate would be very helpful. Wall height 50 mm, width 6 mm.

[ralfg]

Such a part can only be produced with at least a 5-axis milling machine. There are undercuts on the helix. CamBam cannot create the G-code for such parts and for 5-axis machines.

[Bob La Londe]

Such a part can only be produced with at least a 5-axis milling machine. There are undercuts on the helix. CamBam cannot create the G-code for such parts and for 5-axis machines.

Why? I could rough the entire thing with a 3 axis machine and manual indexing. I see no reason it couldn't be done in s a single setup with a 4th axis. CamBam does not lend itself well to more than 3 axis machining, but its capable of it. Since there does not appear to be an undercut to deal with it seems like this could even be manually coded if you can't make your CAM software do the job.

I have a 4th axis, and I have manually indexing hardware.

I would probably 3D rough machine it with either manual or 4th axis indexing, and then manually program the cleanup passes on my 4th axis.

depending on exactly what this part is and what the tolerances are I might use an all manual machining, and fabrication approach. (grain or chip auger for example). For something a little more precise like a plastic injector screw I might use a manual lathe and a taper attachment, but I could use the 3D roughing and indexing, with a 4th axis cleanup for that too.

The image attached was 3D roughed, indexed, roughed again, run a simple series of profile cutes with indexing, and then manually polished on a manual lathe. Letting the robots do all the work isn't always the most efficient approach. I made about a 100 of these if I recall correctly.

[Bob La Londe]

As the OP's request about time. You are basically asking somebody to do all the work and simulate it to give you the time to machine.

1. The limitations of your machine only you can know.
2. I don't know what 316LS is, but 316L is supposedly more machinable than 316. My experience doesn't agree, but that's the claim. I would run it like 316.
3. 316 is very easily work hardened, so some experimentation to see how heavy you can cut on your machine will be required.
4. For a starting point, use FS Wizard or HSM Adviser to help you get suitable feeds and speeds, and then adjust for your machine.
5. Setup the job and generate the code.
6. Download Mach 3 and create a machine profile with the same rapid and acceleration as your machine.
7. Load the code in Mach 3.
8. Use the Toolpath screen to "simulate program run."
9. Read the time from the display. It's usually within a few percent.
10. Add time for stock prep and setup or setups.

[metalmayhem]

the helix looks angled to me , so if milling it would require a 5th axis as previously mentioned or a rotary axis mounted on an angle plate .
good luck cutting that manually it's far different than the simple part you posted

[Bob La Londe]

the helix looks angled to me , so if milling it would require a 5th axis as previously mentioned or a rotary axis mounted on an angle plate .
good luck cutting that manually it's far different than the simple part you posted

The part I posted "appears" simpler, but I have to ask. "Have you ever used a lathe?" I could cut the OPs entire part on a manual lathe even if the "plane" of the helix is not perpendicular. In a lot of ways it's simpler than the part I posted, because it's all easily defined "square flat" geometry. The only feature that I might have some issue cutting with a simple engine lathe is the perpendicular flat at the end of the helix. I've cut floating barley twists out of maple. His part is easier, because at least the helix remains attached, and there is no grain to break unpredictably.

It's not that complex of a part. It just looks that way.

Really, the biggest issue is that he want to cut it out of 316. 316 generally likes heavy cuts with sharp tools or it can become difficult.

[Bob La Londe]

And you may have confused manual indexing or manual programming with manual machining.

[metalmayhem]

Why? I could rough the entire thing with a 3 axis machine and manual indexing. I see no reason it couldn't be done in s a single setup with a 4th axis.
I have a 4th axis, and I have manually indexing hardware.


depending on exactly what this part is and what the tolerances are I might use an all manual machining, and fabrication approach. .

Have you ever used a lathe

no confusion manual indexing is still working manually

You stated your part was done on an indexer then polished on a lathe . I can assure you that letting "robots" do all the work is far more efficient than cutting a part like that manually .
As for your question , I've used manual and cnc lathes many times while I was in the industry and I have 3 of my own running running cnc , I ditched my manuals years ago .

A guy could look at it as simple as machining a 3 start thread but I have my doubts that any unmodified manual lathe will handle the pitch .

As far as time estimates go which is what the op asked for - there is a huge difference between a proper proper set up and a mickey mouse approach .

[Bob La Londe]

So your ego is the problem here then.

Fair enough. You go right on ranting about how you're right, and i'm wrong.

Why don't you go ahead and answer his question. Note the lack of a question mark. That's on purpose.

If you go back and read my post you'll not see anywhere where I said I manually indexed that part. I said I roughed it by indexing. I mentioned manual indexing because I've made other similar parts by manually indexing them and to let the op know that it's not absolutely necessary to have an automated fourth axis.

Modified? You mean picking up or making some extra gears and doing some very basic math? Really?

The absolute hardest part of making something like this for most people is getting out of their own head and tackling the job. For me, I would struggle with machining it out of 316 because I don't do it every day.

I work in a subspecialty of mold making where I've had.maybe a dozen people in the last year tell me that they had several other machinists tell them the part they wanted wasn't possible to make. I made the part for them. Don't get me wrong. I don't have the ability to violate the laws of physics. I do have a different mindset of finding a solution, and I often find one.

Recently I had a fellow show me a part that I thought could probably only be made by EDM. I knew he wouldn't be able to afford what most shops would charge to do it that way, so I looked into it. It turns out I was wrong. Oh, he couldn't afford it, but it also wasn't a good candidate for EDM. it could have also been done with a five axis head, very very tiny cutters, add a very high speed spindle. Also, probably outside of his price range. I solved this problem in two setups, and by making a special cutter on the tool and cutter grinder.

Unlike you, I didn't make a bunch of assumptions. I didn't assume the OP had a tool and cutter grinder on his back bench. You assumed an observational bias about the shape of the helix. You could be right, but you don't know that. Even if you were right, I could machine the entire part on a simple fourth axis by just making some d-bits on the tool and cutter grinder. There is always (almost always) a way to do a job.

Mickey Mouse? Maybe, but it still works.

There, I gave you a whole bunch of things you can pick apart and tackle and feel better about yourself, but if you want to impress me with how smart you are answer the OPs original question.

[metalmayhem]

Ranting ?? Ego has nothing to do with anything I have said , If I hurt your feelings with my opinion then get over it .
the op asked for a " time estimate " at which you have provided how you would approach the job (not what he asked for) . You shot down the fact that the picture shows the helix at an angle or undercut as previously mentioned . Thats why I said if it's being done on a mill it would require either 5 axis or a 4th on an angle plate .
Tolerance and surface finish aside it would be difficult to machine that part with a manual indexer as you seem to think is so easy . And i stick by what I said "good luck"

As far as estimate goes I'd need to dig into it and I don't work for free . Since you have put far more thought into this than I have then what is your prediction

[Bob La Londe]

There is another limitation to this part. If the customer supplied exactly enough material to make the part, I probably wouldn't take the job. If I was supplying the material I would make the part over length to start with so that I could support both ends of the workpiece to reduce flex and chatter, then cut it to length as final operations. Maybe manually in the lathe.

[Bob La Londe]

Ranting ?? Ego has nothing to do with anything I have said , If I hurt your feelings with my opinion then get over it .
the op asked for a " time estimate " at which you have provided how you would approach the job (not what he asked for) . You shot down the fact that the picture shows the helix at an angle or undercut as previously mentioned . Thats why I said if it's being done on a mill it would require either 5 axis or a 4th on an angle plate .
Tolerance and surface finish aside it would be difficult to machine that part with a manual indexer as you seem to think is so easy . And i stick by what I said "good luck"

As far as estimate goes I'd need to dig into it and I don't work for free . Since you have put far more thought into this than I have then what is your prediction

I have no prediction. In fact, we agree that working for free is a bad idea. I did however provide the OP a rough outline of one way, 1 might approach calculating the time with what should be minimal resources available to somebody who thinks they can make that part. You did nothing to help the OP. I also didn't tell the op how I would make that part. I was responding to Ralf's claim that it could only be made on a 5 axis machines.

Even if you're a hundred percent right about the shape of the helix, i can think of a couple of ways. I would make that part without a five axis machine.

P.S. I added a little more to my previous post.

[Samshion]

Is this a three-start thread or a four-start thread?

[Bob La Londe]

Is this a three-start thread or a four-start thread?

The picture looks like a three start.

[metalmayhem]

P.S. I added a little more to my previous post.

There, I gave you a whole bunch of things you can pick apart and tackle and feel better about yourself, but if you want to impress me with how smart you are answer the OPs original question.


Unlike you, I didn't make a bunch of assumptions. I didn't assume the OP had a tool and cutter grinder on his back bench.

I went back and read it and it seems that you prefer to take a disagreement as a spoiled child that a man with a backbone . Getting back to egos unlike yourself I have nothing to prove to anyone or have a need to feel better about myself as you accuse . Maybe you can point out where I made such assumptions about what the op has on hand .
What is the maximum pitch your lathe capable of

[Bob La Londe]

Okay, rereading my first post to Ralf I can see how you might have thought I was saying I could finish the part manually with an indexer. That I could not. Maybe a spacer on a mill with a gear box connecting it to the lead screw, but a basic half decent 4th axis is m7ch cheaper if your are not stuck on a machine with a proprietary mfg setup and controller.

[Bob La Londe]

What is the maximum pitch your lathe capable of

Anything I want upto a few inches. Gears/math.

Okay I concede that you can't do it.

[Bob La Londe]

5th axis "might" be the way to mass produced the part.

I make a lot of one off parts. I can see some possible collision issues with THAT part with a 5 axis machining center if you are right about the shape. I don't have a 5 axis machining center. Tiny cutters and high speeds can reduce collision risk, but dramatically increases time and cost.

[metalmayhem]

Okay, rereading my first post to Ralf I can see how you might have thought I was saying I could finish the part manually with an indexer. That I could not. Maybe a spacer on a mill with a gear box connecting it to the lead screw, but a basic half decent 4th axis is m7ch cheaper if your are not stuck on a machine with a proprietary mfg setup and controller.

the attacks on my character and you finally see your reply as most people would .
it's not about you conceding , it was a simple question . all I was asking is what the max pitch is that is stated on the plate on your lathe , nothing else implied .

[Bob La Londe]

the attacks on my character and you finally see your reply as most people would .
it's not about you conceding , it was a simple question . all I was asking is what the max pitch is that is stated on the plate on your lathe , nothing else implied .

Reread your own posts. You're the one that started insulting. People like a schoolyard bully.

My original post does not say in it that I manually finished the part or that I would manually finish the original party's part.

You failed to comprehend what was actually written. I have cut injector screws on a manual lathe. All I did was some basic math and buy some gears.

While an injector screw typically doesn't have undercuts, it absolutely could, and it could be done with tools that any competent machinist could hand grind.

I concede. You are right. You couldn't make it without a fifth axis machine. I bet Ralf could.