What's new
What's new
By:
Advanced search…

Please school me on having small cast iron parts made

Luke Rickert

Luke Rickert

Hot Rolled
Joined
Oct 24, 2007
Location
OSLO
Hi I am prototyping some small cast iron parts and would like to send out the RFQ's. My background is in aerospace so cast iron is not something I have much experience with and I need some pointers for what I should send to the foundries to communicate most effectively.

First what process should I be using for a small number of small (1 to 10 kg) ductile iron castings. I would like the best surface finish possible. On a small scale is lost wax/foam a good option or crazy expensive? Should I stick with green sand or something else.

Would it be helpful to a small foundry to send them 3D printed (drafted) versions of the parts I would like cast?

Should I send drawings and 3D models of the finished parts, 3D models of parts as cast etc?

Does anyone have a foundry in Europe they can recommend? There don't appear to be any small places left in Norway that work with cast iron (off shore industry only) so I am guessing the UK or maybe Sweden. I have lists of places contact but could use help reducing that list. Actually if there are any good places near New Jersey in the States that could work as well, shipping from there to Norway by sea is cheap.

thanks

Luke
 
Before writing an RFQ, contact the prospective foundries.

TALK with them, get their limitations, make changes to the design to accommodate
the casting process. I went so far as drawing in the parting line after consulting the foundry (on the casting drawing which you should be making), and thereby eliminated a core.
 
I'd be machining from durabar if possible before I sunk the cost into a casting pattern. For your initial order cost probably won't be a lot different. depends if you can get durabar that size of course.
 
Luke,
I'm with Willie, make the prototypes from cast bar stock if
possible. I have made many parts that patterns were no longer in
existence and saved my customer time and money. Small casting are
sometimes more difficult to finish than machining from solid and may require a special fixture.
spaeth
 
spaeth said:
Luke,
I'm with Willie, make the prototypes from cast bar stock if
possible. I have made many parts that patterns were no longer in
existence and saved my customer time and money. Small casting are
sometimes more difficult to finish than machining from solid and may require a special fixture.
spaeth
Click to expand...

....and here I thought you were going to suggest "Powdered Metal" instead....:D
 
Agree with machining from bar stock.. Might hand, manual machine,or CNC wood patterns if a casting shop advises that for sand pouring. Yes you would need size advice ..

Making patterns can be a huge cost part of a few-up job. We have a number of casting shops here around Detroit.

Never did this but likely one could CNC a few wax parts and save dollars rather than making an aluminum wax mold..still CNC a wax mold is easy enough.

Here is one.
International Casting Corp. - New Baltimore, MI 4847 - Castings

That might be a good product.. rough size cast iron ingots for your machining finishing. Yes much for sizes where bar stock cut-off would be more costly.

*It would seem Germany would have small foundries..and a better choice than USA.
 
Here is a reference for a place that offers "custom" iron castings.

Tomahawk Foundry

I've no affiliation nor experience with them, but off the link as an example of how they proceed with customs.

Best is to provide a green sand ready mold. (shrinkage allowance included)

Buying mold making service is a separate item. But talking with the foundry will be the only useful reply.
 
thanks for the replies, durabar really isn't an option given the shapes I am working with but for sure in many cases it would make sense. These are parts that would be more or less straightforward to cast but rather difficult (complicated CNC work) and inefficient to machine from block or bar with probably 30% utilization and lots of curved non-critical surfaces.

I will just pick a few foundry's, talk to them and go from there.

L
 
ductile iron castings often do not come as good 100% all the time. i often see some fail at pressure testing or have metal defects like slag or hard spots that give considerable trouble machining.
.
most times you get 10 castings from a foundry as a sample and machine them and see what quality is like. even if you got 10 good castings it can vary on the next batch of castings.
.
just saying ductile iron has advantages and disadvantages. i have see ductile machining jobs that literally always were much harder to do successfully compared to regular cast iron.
 
DMF_TomB said:
ductile iron castings often do not come as good 100% all the time..
Click to expand...

Thanks, that is good info to get. If it weren't for the massive difference in tensile strength I would go with gray iron. Maybe I should see if I can change the design work with it, that is something to keep in mind anyway. Any idea what it is about ductile iron that makes it harder to cast, different temperature of the melt or something?

L
 
Thanks Peter, it is nodular cast iron I am looking at. No one can agree what this stuff is called but in English anyway the family of materials called ductile iron is also known as nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron and SG iron to borrow a bit of text from Wikipeia. The exact materials obviously have official names such as the one you mentioned or EN-GJS-700-2 which avoids this issue :)

Do you know of any small foundries in your part of the world that might be good to talk to? The Netherlands is not so far from Norway.

Luke
 
I have had my own backyard foundry And did have excellent results if I may say so
But commercial there are no foundries here that I know of which are intrested in one offs or small quantities

Peter
 
Its important to understand there will be no castings without some sort of pattern tooling - from which molds are made

This generally involves some substantial expense as compared to a casting's "cost"

This is the reason for the general impracticality of a few castings

But it can be done - it just takes large investments of time or money or both - and of course has suitable skills involved

Example:

https://www.google.com/url?sa=t&rct...fZAI8rgV9rTrz71Yg&sig2=MIyST8iagoQvxO0xH8HoDw
 
3d printing work just fine. They cast from 3d pattern all the time at Matrix industries .if using pla they can also dip your pattern in ceramic coating much like lost wax process.

They deal world wide.

Also you can send 3d model to them and they will confirm if doable with quote.
 
Hi Luke,

My name is Dylan from Jingle-metal, and as for ductile iron casting parts, also with small qty order, I can arrange it and of course, now it is too late to reply you, for I just see it today.
I have been in this field for 10 years' experience and if you need any help, do not hesitate to let me know.

Good day.
Mr. Dylan
 
some foundries doing grey cast iron have relatively crude equipment but make ok castings.
.
ductile iron requires much might tighter control of metal alloys percentage, temperatures, etc. shape of casting matters much more with ductile iron. often section thickness cannot vary much other wise thinner sections are much harder and extra thick sections might have internal voids or cracks. if they experiment casting, a temporary chill block put in mold can make thicker section void or internal crack free but might be so hard as to be unmachinable or 10x harder to machine.
.
just saying be careful what you ask for. ductile iron takes alot more experience and expertise to cast and machine. sure if you make 1000 to 10,000 you eventually find out what works best. its the small quantity stuff you might have more problems with.
 
You must log in or register to reply here.

Similar threads

hierholzer
Drilling a hole into cast Aluminum while Avoiding Part Deformation
Replies
5
Views
234
challenger
challenger
J
Painting & refinishing iron castings
Replies
2
Views
344
SteveM
S
I
Custom Cast Iron castings - any rec’s?
2 3
Replies
42
Views
3K
John Madarasz
John Madarasz
S
small batch casings, cost effective?
Replies
11
Views
1K
spaeth
S
L
Any suggestions on cutting small and thin parts from 304
2
Replies
25
Views
2K
Rob F.
R








 

ABOUT PRACTICAL MACHINIST

With more than 10.6 million unique visitors over the last year, Practical Machinist is the most visited site for metalworking professionals. Practical Machinist is the easiest way to learn new techniques, get answers quickly and discuss common challenges with your peers. Register for the world’s largest manufacturing technology forum for free today to stay in the know.

Learn more about us.

STAY CONNECTED

Facebook Instagram YouTube LinkedIn Pinterest Twitter Tiktok

Register Become a forum member. Register today.

Sign Up Sign up for our e-newsletter.

© 2024 Copyright Practicalmachinist.com. All Rights reserved.

Back
Top