need advice (sourcing manufacturer US/EU) & casting method!

[JóneK]

firstly - before i begin - i should make clear i have no experience in metal casting. i used to be a welder about 20 years ago - but that's about it. no foundry experience.

so - i have a design that needs casting. i have been told that my design cannot be sand casted and that it was recommended that i consider lost-wax casting instead.

there are a couple issues with this. i live in iceland - there are only 2 foundries - and both only offer sand-casting. so i am having to now out-source elsewhere. i am looking at either a US manufacturer or the EU.

i am needing to know & understand what casting options work best for me and my design. the design will eventually be sold in the icelandic marketplace - a country of about 360 thousand.

for the year 2021 - i am hoping for 1st round to produce somewhere between 1000 to maybe 3500, 5000. and it 2021 proves to be successful - i will amp up much higher numbers for 2022.

i was told even with lost wax casting - machining will be needed. please review the attached images regarding part of the design - small radius(s).

sooooo
- i need to source a manufacture first .
- then i need an approximate quote (including machining, if needed) for either 1000, 3500 or 5000.

can you help me?

jón

[ThomasPowers]

So WHAT do you want these cast in Inconel, cast iron, brass, aluminum?  You would probably need to go to the far east to get a reasonable price per piece and have to hunt down a custom house that will do such small runs.

[Deimos]

Just looking at the design I wonder how those radiuses could be done by machining. Clamping it down would be a nightmare (any action on the arms would send vibrations everywhere and maybe break something), and for each action it needs to be repositioned.

Almost makes me wonder if just machining the entire piece would be that much more expensive. Shaving a bit of the "arms" so that the .025mm radius is level instead of sloped would help, I wonder if it is even possible to do with a machine (if someone would want something like that I would rather grab a file).

 

 

[SLAG]

Mr. J. K.,

Have you considered a suitable casting method and subsequent electrical discharge machining. (EDM).

That might be suitable for "Inconel ", metal and probably the other alloy that Mr. Powers mentioned.

Just a stray thought.

Also, welcome to the forum.

SLAG. 

[Scott NC]

  Cnc can do wonders.  Probably cheaper.  I can't see the whole part in those photos.

[ThomasPowers]

Method depends a lot on the material and the price point; both of which are not provided in the original post.

[Scott NC]

  True.  Also missing are complete pictures and all dimensions as well as what it is.  That may be proprietary information though.  Who knows.  It looks like a heavy duty cheese slicer to me....

[JóneK]

On 3/24/2021 at 10:27 AM, ThomasPowers said:

So WHAT do you want these cast in Inconel, cast iron, brass, aluminum?  You would probably need to go to the far east to get a reasonable price per piece and have to hunt down a custom house that will do such small runs.

i would prefer cast iron.

22 hours ago, Deimos said:

Just looking at the design I wonder how those radiuses could be done by machining. Clamping it down would be a nightmare (any action on the arms would send vibrations everywhere and maybe break something), and for each action it needs to be repositioned.

indeed - i am now considering that maybe the piece doesn't need the machining altogether.

however, if i am going to provide the manufacture my design part - so that they can create the mold - i am assuming the design itself would need a minimum radius on the edges, correct? and if that's the case - would you know what those minimums would be?

22 hours ago, SLAG said:

Mr. J. K.,

Have you considered a suitable casting method and subsequent electrical discharge machining. (EDM).

i haven't sorted the actual casting process as of yet - which is why i joined this forum - hoping to discover.

what exactly is (inconel)?

the piece will not be used under heavy duress, fyi. and nodebt correct - for proprietary reasons, thanks.

21 hours ago, ThomasPowers said:

Method depends a lot on the material and the price point; both of which are not provided in the original post.

the goal is high volume production - and a clean design. cast iron / stainless steel? i don't have a price point persay - it is my goal to naturally make this in good quality and find a process that is the most affordable.

i am sharing a photo of the fastener that will be used to fit the piece - quite small.

with that mention - concerning softening the edges for the cast mould - what would the minimum radius need to be?

is there a process where i can make a cast - and then have the finished cast tumbled - in softening the edges? rather than any deburring?

[Deimos]

Since the part is so small, I think that if it is tumbled, all the sharp edges will be gone. You could just tell the manufacturer that all edged need to be around 0.1mm. The more precise you want that, the more expensive it gets. Normal tolerances are around +/- 0.2mm (which gives you about 0.4mm of play).

Just curious, the part that is places between the screws, does it need to move or rotate?

Another thing that just popped into my head, you say you want to make it from cast iron. Have you any idea what you want to do to make it not rust? And have you thought about the thickness of said rust protection / time it takes to remove any exces coating? (as an example, zinc coating leaves holes covered and is a nightmare in recessed holes.)

[ThomasPowers]

Far east will be cheapest; though it's common for your supplier to morph into your competitor!  You have to pick a metal to get the ball rolling!

Inconel is a very high Nickel alloy good for high temps and corrosive environments---also *VERY* expensive!  Only use it when nothing else will work!

[Deimos]

Or that the quality/tolerances are terrible. Even cheap local suppliers can give you absolute garbage. (I remember us getting hydraulic pistons that where just tossed into a crate after machining, scratches almost 0.5mm deep and some even covered in rust.) The further you go from home the harder it is to do any form of quality control or claim warranty. 

[ThomasPowers]

Yes, I remember when a company I worked for moved their cable making factory outside the USA; they had to go to 100% test and still had to ship 2 complete sets of cables for an update we were doing to make sure we could do it (On a computer system that was *netting* 3-7 billion US$ a year----downtime was not looked favorably on!)

[Deimos]

When I worked as a hydraulic mechanic I checked everything we used, even items that where made in house. In those 4 years I cannot recall a single batch being "perfect". Drove a lot of people insane by doing that, but then again, my machines never got their proportional valves damaged (things break when they do a one night stand with a 2um or bigger piece of anything, at $2000 a piece that is an expensive repair).

Why do I get the idea those cables where at least a few hundred meters in length? Downtime is the worst, it costs you double...

[ThomasPowers]

Nope fairly short but a bunch of wires had to be in exact order in the various plugs.  Old school computers that did a lot of stuff with the wires, the upgrade had 640 wiring changes; and was not easy.  I got to do it on a Lab Machine and realized that when I had a problem and called the support team and off the cuff he could tell me "that error means that this wire is one pin off..."  out of 640 wiring changes!  Must have been infernal in the field to have memorized all the possible errors!   I was on the support team for software updates, the "maintenance window" was between 2 am and 6 am and I was expected to cover that and work my regular hours as well.   (Most errors were "you have to do step 6 before you can do step 7, I have backed out the mess from doing otherwise please do step 6 now."  "But I did step 6!"  "I have the system logs in front of me and no you did not do step 6..."  at 3am.

[Deimos]

That sounds like fun . At least you had system logs that told you what the user had done. I remember this one time I had to drive about 5 hours because a machine was not even turning on and the manager was 100% sure it was started up the correct way. All I had to do was walk around the machine and turn on the main switch (can't recall what you call it in English, you have those big 400VAC 5 pole wall sockets with a on/off switch on them) , the "not so smart man" had just looked at the wrong one. And instead of admitting his mistake he starts complaining about the bill I had to write the work I did.

Another fun one, we where in Russia for some maintenance and the operators show us print-screens of the error log, in Russian, expecting us to just do something with it. Had to explain them again that they could just click the huge (and I mean HUGE) SAVE ERROR LOG button next to the RESET ERROR LOG so that the machine would save the error log in Dutch so we could actually do something with it.

Last one, spending 4 hours trying to find a very weird error about a sensor not sending correct data (it just added a random number to the measurement). First thing I wanted to try was change out the PCB because I already rules out the sensor and cables. But like my boss said "those PCB's are never broken. Guess what was broken when I finally convinced everyone that it could only be the PCB.... 4 hours wasted.

[ThomasPowers]

International field support was always fun, especially dealing with the time differences.  I did however get to spend 89 days in Germany one summer and 30 days in Indonesia doing installations and a week in the UK, (one day on site with a protocol analyzer showing that our system was doing exactly what it was supposed to and the error was on *their* side---took a flight from the middle of the USA to London to do that...)

[Glenn]

Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys. Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected to pressure and heat.

[JóneK]

On 3/25/2021 at 5:03 AM, Deimos said:

Another thing that just popped into my head, you say you want to make it from cast iron. Have you any idea what you want to do to make it not rust?

ah interesting - i hadn't thought about rust with regards to iron. would brass or bronze be a better choice? but in doing so - would i left with a finish that typifies brass/bronze (a golden hue)? or am i completely ignorant of this process? i would prefer a more neutral tone in finish.

regarding tumbling - is this suitable for high volume? and if not - then maybe it would be best that i revise my design and apply the +/- 0.2mm  tolerance?

On 3/25/2021 at 10:17 AM, ThomasPowers said:

Inconel is a very high Nickel alloy good for high temps and corrosive environments---also *VERY* expensive!  Only use it when nothing else will work!

good to learn about Inconel - but i think i'll try to avoid that as an option.

Edited March 26, 2021 by Mod30
Trim quote.

[Deimos]

Tumbling is designed for high volumes, deburring by hand is only fun with single piece production.

If you do not want any coating on your product then any type of material that does not oxidize is good I guess. Without knowing where you want to use it, or what for it is really hard to give advice. Cast metal will not be as shiny as you think, it needs to be polished first. 

[JóneK]

ok - good to know.

firstly - it doesn't need to be shiny. with regards to choosing a metal that doesn not oxidize - what do you suggest is the most affordable? the metal doesn'r need to be ductile - and will not be used under any stress - if that helps.

and lastly - can you personally recommend a manufacture for such a service?

 

Edited March 26, 2021 by Mod30
Excessive quoting

[Deimos]

If it is not used under any stress, why not just make it from some hard type of plastic? 

[JóneK]

simply put - it comes down to the design and the aesthetic. 

[Deimos]

Well, then Aluminum would be the cheapest option, still not really sure why you would want the part cast and not just machined.

[JóneK]

well interestingly enough - i was under the impression that casting would be cheaper? i would think my design would require at least a 5-axis.

Edited March 26, 2021 by Mod30
Excessive quoting

[Deimos]

That depends, re-clamping the piece in another orientation could mean it can be done on a more simple machine. From what I know it is mostly the time it takes to let the machine do its job that determines the price. I would not rule it out as an option.

For casting, maybe you can give RAM Mounts a call, I have worked with their products in the past and everything they have is (or at least was) cast aluminum with a black coating. Maybe they can tell you who does their work for them.