How to make these parts?

[alexccmeister]

Hi All,

I had these parts milled by a company. As the cost is high when someone is doing it. I thought I will do it myself. So currently in the process of getting myself a cnc mill.

I have a few questions as to how some of the parts are milled? If you look at the photos, circled red are the recess and protruding parts that I am curious as to how they actually milled it. Its 90 degrees so I don't see how they can use an endmill to mill it without having some curve chamfers. Can anyone advised?




Thanks in advance.

[turmite]

Broach or edm and I don't think you can broach a blind hole. I am not a machinist but have been around a lot of it. You have your work cut out making these with just one machine. I'd be willing to wager that the price you paid for them will not look nearly so high when you get through with the process of making them yourself! Ask me how I know!!!!


Mike

[alexccmeister]

Originally Posted by turmite Broach or edm and I don't think you can broach a blind hole. I am not a machinist but have been around a lot of it. You have your work cut out making these with just one machine. I'd be willing to wager that the price you paid for them will not look nearly so high when you get through with the process of making them yourself! Ask me how I know!!!! Mike

Hi Mike, Thanks for the quick response. I know its not going to be easy to do this after reading some of the threads here. When you say the part may need to be milled with a few machines, what are the other machineries that the fabricator may have used to do this?

I might not be bothered to mill this out eventually and let the expert do it but knowing how its done would really help me to understand more about milling.

Its so funny that the fabricator informed me before fabricating the part that they couldn't do a perfect rectangular hole for me as shown in the model. So what they ended up doing was giving me a rectangular hole with curve chamfer on all four corners. Now I know how they made that. By using an endmill right? So if they can't do a perfect rectangle or square, how come they could do a perfect 90 degree recess and a protrusion?

I will probably ask them personally but if anyone can offer me an answer here. that will be great. I doubt very much if they would want to tell me so mcuh info on this seeing its their business.

Here is the picture I mentioned about the square hole.



They ended up giving me this instead.



Thanks

[JerryFlyGuy]

So your building a cnc mill to make this part? I'd think you should have looked at EDM, I don't think you'll find that you can make these on a mill, that is unless they are huge, and you have a teeny 5 axis head to reach inside there and cut them. 90deg corners on a milled part like that is pretty much outta the question..

Jerry

[matsuura]

They probably did this in many pieces and then welded them.

[DareBee]

Mill then EDM

[turmite]

Originally Posted by alexccmeister Hi Mike, Thanks for the quick response. I know its not going to be easy to do this after reading some of the threads here. When you say the part may need to be milled with a few machines, what are the other machineries that the fabricator may have used to do this? I might not be bothered to mill this out eventually and let the expert do it but knowing how its done would really help me to understand more about milling. Its so funny that the fabricator informed me before fabricating the part that they couldn't do a perfect rectangular hole for me as shown in the model. So what they ended up doing was giving me a rectangular hole with curve chamfer on all four corners. Now I know how they made that. By using an endmill right? So if they can't do a perfect rectangle or square, how come they could do a perfect 90 degree recess and a protrusion? I will probably ask them personally but if anyone can offer me an answer here. that will be great. I doubt very much if they would want to tell me so mcuh info on this seeing its their business. Thanks

I forgot to ask and made an assumption that this was metal. Is it metal or plastic? If plastic it would be injection molded, but the additional machines would still be needed.

If the "square" hole had radiused corners it was milled. I would approach it by lathe and edm, for the part and a mill to make the electrode for the edm, so there is three machines.


Now where is HU when you need him?

Mike

[precisiontork]

This part could be made on a mazak integrex and you could do internal hobbing or broaching to make internal parts but this is a expensive machine around 300,000.00 for a small one

[alexccmeister]

Hi All,

Thanks for all your replies. The part is aluminium and the internal diameter is 70mm exactly. The thickness of the wall is 3mm. Well, the person informed me that the whole thing will be milled. She didn't mentioned anything about any other type of machine to do the job.

So your building a cnc mill to make this part? I'd think you should have looked at EDM, I don't think you'll find that you can make these on a mill, that is unless they are huge, and you have a teeny 5 axis head to reach inside there and cut them. 90deg corners on a milled part like that is pretty much outta the question..

I would love to do this with a CNC machine of my own, but if its too difficult, I may need to redesign the parts taking account of the limitation of the cnc mill. Can a six axis machine do this part? I am sure their equipment is expensive, but unless their chuck or what evre is holding the endmill is small enough to get into a 70mm round space, I dont see how they can do it. I think EDM method may be the answer.

If the "square" hole had radiused corners it was milled. I would approach it by lathe and edm, for the part and a mill to make the electrode for the edm, so there is three machines.

I am pretty sure this is milled as well. But that begs the question why they didn't do EDM on this part when they could do it on the most difficult part. I don't get it. They specifically told me they can't do it when I ask if they can give me sharp corners. Not that they won't do it as the square corner isn't that critical and I can live with round corners. They just can't.

They probably did this in many pieces and then welded them.

I am not so sure as the part is really smooth and nicely done, no indication of any welded joints. I am convinced it is milled from a solid block of aluminium.

Thanks guys. I will put in an email to the fabricator and see if they can offer an answer. If they do, I will post the answer here. Thanks.

[fyffe555]

Interesting looking part - what does it do?

I have to ask; Does the function of the part *need* the difficult to machine elements as designed? Could you make the part easier to machine by including radius to allow simple milling?

Too often a part gets designed by people without much machine room experience and the part is unnecessarily hard or expensive to produce...

[holbieone]

to make this part you will need to

mill ,broach and or scrape

or cast then finish with machining process

or forged then finish with machining process

or precision cast to finish

[alexccmeister]

I have just emailed the fabricator regarding this issue. Will see what they have to say.

Interesting looking part - what does it do? I have to ask; Does the function of the part *need* the difficult to machine elements as designed? Could you make the part easier to machine by including radius to allow simple milling? Too often a part gets designed by people without much machine room experience and the part is unnecessarily hard or expensive to produce... Reply With Quote

Its part of an imaging device I am working on. The prototype is already done by the fabricator. real; professional. Cost me a bomb having it made by a third party. So planning on getting some of the parts done myself. Here's the part after it was made, polished and anodised.



I could probably just have the mill cut the piece out but with the curve chamfer instead of a 90 degree corner. Probably a very small end mill will do the job to finish off the corner portion?