How to manufacture this Iron Sleeve 1

[valmeidan]

ok so this is a small part for a little pump. It is an iron sleeve with about 5.5mm outer dia. it's very similar to an iron bearing sleeve, but I was wondering if its possible to manufacture one with an endcap on it. The surface finish etc must be quite smooth along with the dimensional tolerance. How could this be done? the pic shows a section through half the part, it is a cylinder.

 

[MintJulep]

Depending on what "quite smooth" means to you, and how badly you really need the sharp corner at the inside bottom, yes it is possible.

 

[Compositepro]

This type of part is often made cheaply in large quantities by pressing from powdered metal.

 

[valmeidan]

talking .05mm tolerance, and a 63 micro inch surface finish

 

[byrdj]

could you use and existing sleeve bearing and press in a plug?

 

[MintJulep]

Seems like it could be machined from bar stock.

Either conventional machining or EDM.

If it doesn't need to be homogeneous it could be made from a tube, with the end closed in any number of ways.

 

[arunmrao]

If the quantities are large, P/M route is desirable, else machine a bar stock.

I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)

 

[valmeidan]

pressing in an end cap might not be the most desirable way as it would also have to be water tight. Machined maybe from barstock but it is a pretty small piece @5.5mm dia and about the same for height

 

[valmeidan]

Plus can you machine such a small part?

 

[ctopher]

Another option in addition to above suggestions. Grind OD of bar. Cut to lengths. Mill ID, repeated on CNC mill.
I have done this for similar sizes.

A shop with a turning center can spit out a lot of them in short time.

Chris, CSWA
SolidWorks 14
ctopher's home
SolidWorks Legion

 

[MikeHalloran]

It looks like a natural for a Meehanite bar in a screw machine. You may need a secondary to remove the tip left by the parting tool on the flat exterior face.

As mentioned, the intersection of bore and internal face needs some consideration re relief, radius, or chamfer on mating parts if any.



Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

I agree with MikeHalloran, you could make this part from continuous cast iron bar stock using a screw machine. Holding the .05mm bore tolerance and 63 microinch surface finish should not be a problem, but it would be helpful to provide some tolerance relief where the bore meets the flat floor of the bushing.

 

[valmeidan]

what would you suggest for fillet around the outer bottom surface and the inner bottom surface floor? I have used 0.2 and 0.6 respectively

 

[MikeHalloran]

The fillets look reasonable, BUT we are unaware of how they interact with the mating parts, or do or do not satisfy the functional requirements. Even a part as simple appearing as your little cup/sleeve cannot be designed in isolation.

In particular, a fillet that's perfectly tangent to a cylindrical surface and a planar surface at all points is very difficult to produce.

We often see external fillets of a slightly larger radius, or double internal fillets of a smaller radius, as generated by the cutting tools, with the fillet edges only loosely controlled.

If the cup is inserted into a tight fitting bore, it's common to see an asymmetrical chamfer rather than a fillet, so the cup will align itself as it's pushed into the bore.

Similarly, if there's a piston or similar to be inserted into the cup, then the cup is missing a chamfer at the ID of its open end.

Only you know the details of the assembly into which the subject cup fits, and how the assembly is intended to work, so we are not in a position to advise you further.




Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

I would suggest using a larger fillet at the bottom of the inner bore if possible. If it is not possible, I would suggest using a radius dimension that provides as much tolerance as possible, like "R.02 MAX". Very small radius fillets like this can be very hard to inspect.

At the outer corner I would suggest using a chamfer rather than a radius if possible. A chamfer is much easier to machine. Or even better, simply use a note that states "CORNER TO CLEAR R.XX MAX FILLET". This would allow any corner profile that provides sufficient clearance, regardless of shape.