Split case machining

[DCORDENG]

I am an engineer at a pump manufacturing company. We are thinking about developing and eventually mass producing horizontal split case pumps (HSC). We currently do not manufacture these and are asking around for advice to establish if it is a worthwhile investment to upgrade our facilities to produce such a pump. We would want to mass produce them as well, possibly at a rate of 2/day.

My main question for any of you who are familiar with these pumps is….. what machinery would be required to machine the castings for these pumps? We will be farming out the castings and machining them ourselves. The castings which would require machining include; top casing, lower casing, bearing housing and impeller.
The general, overall dimensions of the pieces are as follows:
Top Casing: L: W: H:
Bottom Casing: L: W: H: 40”
Bearing Housing: OD: 17”
Impeller: OD: 21”

If you are not familiar with these types of pumps than you probably do not know what these components even look like.
I apologize for the lack of information but at this point we are just fishing for information.

 

[DCORDENG]

EDIT: DID NOT ADD ALL DIMENSIONS

Here they are.

Top Casing: L:50" W:47" H:29"
Bottom Casing: L:50" W:47" H:40 40"
Bearing Housing: OD: 17"
Impeller: OD: 21"

 

[MikeHalloran]

You need a big-ass mill or planer/mill to machine the housing halves.

Bearing housings can probably be done on a generic CNC mill of modest capacity. Same machine might be used to do the impeller, though a lathe is more traditional.

Once the housing halves are joined, you need to bore surfaces for the shafts, seals, and/or bearings, or to hold the bearing housings. I.e. some kind of long stroke boring machine.

Big machines are very expensive to buy new. Look at surplus machinery sources for sturdy old stuff to repurpose.
Also ask them to help you find a cranky old machinist for hire or rent to help you figure out what combination of machinery will get you started.



Mike Halloran
Pembroke Pines, FL, USA

 

[TenPenny]

And don't forget that when you put the top and bottom casings together, to bore for the bearings and stuffing box bores, you have to use a spacer to compensate for the casing gasket.

 

[1gibson]

What material? Cast iron you can't really repair, stainless or other materials with high shrink can have issues with that casting geometry at the corners. Make sure you have a plan for casting repair cost sharing if voids open up during machining, NDE responsibility (hydro at minimum.) 2/day might be optimistic, these can be tricky to build, you'll have to dowel the bearing housings... Check into start to finish assembly procedure before you jump in.

A lot of that applies to any pump type, but especially with HSC you are really putting all your eggs in one basket (upper/lower case castings.) If you are mass producing and won't suffer delays while repairing or remachining castings then it might work out, just make sure you have plenty of physical space and weld/machine time to make the repairs.

 

[DubMac]

Your milling machine for the two case faces and horizontal boring mill will be the most expensive machines, you may have to sub this out initially.

Are you in the U.S.?? If so, I sure hope you have these pumps dedicated to a captive market, or a very rich owner that doesn't care about losing money. Without either of these it is hard to imagine kicking off a new "homebuilt" line of competitive splitcases. The pumps currently coming out of India, China, Mexico, etc. are incredibly cheaper than anything built here. DOn't know where you are located, but in my town we can't find machinists worth their while for less than $60/hr.

 

[DCORDENG]

The material is class 35 cast iron for all castings excluding the impeller. The impeller is to be 316 SS. We are located in the U.S. and have a decent size work force. We would probably need to take on more people if we were to complete the machining all in house.
We do have a dedicated customer for these pumps.
Thanks for all the info everyone!