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putnik
01-28-2012, 04:27 AM
Hello there,
I have a simple CAD model (~40mm x ~20mm x ~4mm), destined for injection molding. Before that I would like to obtain a prototype.

A. Would like a simple aluminum mold to be designed and cut. Here is one possibility I see: Blank (http://www.injectionmolder.net/mold%20blank-01.jpg) , with something like This (http://www.injectionmolder.net/ASTM%20-%20test%20bar%20mold-03.jpg) being an expected result.

B. I am thinking to use simple Benchtop Injection molder with the mold cut. If you have an access to one, please let me know, and I 'll be glad to use your service as well.

C. Let me know if you could put together a more complex mold (slides?) for a model with undercuts.

Thank you for your time,
Alex

CaptainVee
01-28-2012, 05:13 AM
If it is about the prototype, why not 3D print it?
Costs next to nothing compared with having a mould made and then have that injected...

If that is not the look you need, have it printed and then use vacuum casting to get it in different looking material. Can be done with silicone mould, still likely to be cheaper than moulding in Alu and then custom injecting it.

Just a thought.

putnik
01-28-2012, 05:22 AM
If it is about the prototype, why not 3D print it?
Costs next to nothing compared with having a mould made and then have that injected...

Sven,
Thank you for your input. I've already obtained 3D printed prototypes to verify general appearance. It's more of a fit test now. It will be two prototypes that would need to fit together, if that makes sense. It's the matter of 0.01mm precision that is not possible to achieve/verify with 3D printers.

txcncman
01-28-2012, 07:28 AM
While it is reasonable to maintain 0.01mm repeatability in injection molding, getting to that first part that has 0.01mm precision usually takes trial and error on the part of the mold builder and the injection molder. Even a small mold is likely to cost 1000's of dollars. Are you prepared to pay 1000's of dollars at this point in your project?

mactec54
01-28-2012, 11:23 AM
putnik

Slides for undercuts can be done for these small molds,with no problem .010mm .0005 is not so easy to achieve,A Bench top machine this .01mm would be impossible, unless it is computer controlled machine, In a real molding machine you can mold parts with this kind of tolerance only if they have good control (Computer control) on there machines



Sent a PM

txcncman
01-28-2012, 11:41 AM
putnik

Slides for undercuts can be done for these small molds,with no problem .010 is easy to achieve, in a real molding machine you can mold parts to .001 & less if they have good controls (Computer control) on there machines

Bench top machines are hard to achieve part tolerance even the .010 because you don't have much control over the shot size, hold pressure Etc

Sent a PM

"in a real molding machine you can mold parts to .001 and less." Precision to +/-0.00003937" and less. Amazing! I would like to know how most people measure 0.00003937". None of my tools read smaller than 0.0001"

mactec54
01-28-2012, 01:13 PM
txcncman
"in a real molding machine you can mold parts to .001 and less." Precision to
+/-0.00003937" and less. Amazing! I would like to know how most people measure 0.00003937". None of my tools read smaller than 0.0001"

Not sure why you have a problem with .001 this is a big number to me I work with .0001 all the time every day

As you can see the numbers I used before I changed the post were inch not metric I changed the numbers once I saw he was using metric

Smertrios
01-28-2012, 02:05 PM
I believe I have seen both of those pics on another website as something you can already buy but there is no tolerance callout. Will look now for a URL as I don't recall where it was. Or... your part is different?

EDIT: your links show the website I was looking for http://www.injectionmolder.net
EDIT: nevermind I see now your part is a different size

putnik
01-28-2012, 05:09 PM
While it is reasonable to maintain 0.01mm repeatability in injection molding, getting to that first part that has 0.01mm precision usually takes trial and error on the part of the mold builder and the injection molder. Even a small mold is likely to cost 1000's of dollars. Are you prepared to pay 1000's of dollars at this point in your project?

Thank you for your input. Based on the quotes for production mold, I know a steel family mold of 8 items will run me anywhere from 5 to 10K. I was hoping that an aluminum mold for single item will be less. But that's why I posted this request to get a realistic prototyp equote. Would you care to look into it?
Regards,
Alex

txcncman
01-28-2012, 08:50 PM
Mold engineering is just that - engineering. Engineering is just one piece of the cost puzzle. If you do all of your own mold engineering, and just post the drawings of the mold you want to have machined as an RFQ, I am sure several people will bid on it. If you want someone else to do the mold engineering, assuming you have already engineered your part, I am sure you can pay someone to do that too. To keep cost down, the more of the work you do for yourself, the cheaper it will be. I seriously doubt you even have your part engineering correct at this point. You probably have not allowed for draft angles and material shrinkage.

In W.A.G. terms, I would venture up to 20 hours for mold engineering and another 20 hours to machine the mold. If someone was working for $50.00 per hour, that would be $1000.00 for the mold engineering and another $1000.00 plus material plus shipping for the machining of the mold.

I hope that helps.