Test Print for silver...

Hi everyone. I only print in silver but I would like to do a test print in another material first. Does anyone know what is the best analog befor I have it made in silver? For this test print, inexpensive would be best since this is only a test print...

I used White detail in the past. Probably a little higher detail, but right around the same rules.

Thank you. I like this about Shapeways, everyone is helpful.

And here I come to maybe be not so helpful.

Over the last four months, I have an on going saga about an item I designed for a customer. The test prints in FUD were fine and the customer gave me the go-ahead. Sadly now after several redesigns, the item is not printable due to the fragility of the wax print and because the silver would not fill all of the mould, so there can be a few hurdles going from 3D printed plastic direct from the printer, to Silver models a step or two after the print.

Having said that, the model in your image looks like there would be no issues with silver production (imho)

Paul

Any advice is good advice. I will be getting test prints for 2 different rings. The second ring is not finished yet, but I have attached what I have completed so far. Can you give me more information on what type of issue you had? Pictures possibly? Maybe it will help me avoid same issues. I try to sday within the silver tolerances, but if there are other things I can keep in mind while creating my designs, it would help a lot.

Thanks

The design was 34 little wheel type shapes on a circular bar. Sorry no images as it is for a customer.

To start with I was told multiple parts can't be printed - the model was one complete mesh.
Next was that the regeion where the wheels joined the bar was too thin and that the wax print broke, so I beefed it up a bit.
Then the model was rejected because multiple parts aren't allowed - again the model was one complete mesh. After re-submitting the reason was the wax print broke.
I changed the design slightly to allow for more joining points for the little wheels. This too was rejected for multiple parts.
And then finally the print was rejected because the wax print was too delicate and that due to the design, silver wouldn't flow to all areas of the model.

But the good news is that a similar model with just 4 wheels can be done.

I'm thinking that mainly my issues had to do with funnels, vents and handling for the casting proces.

The problem with plastic models is they give no indication of how metal flows while being cast. If I was making a casting pattern for your ring, I would put a sprue vertically across the inside so that enough metal can flow into the heavier top before the sides freeze. If this isn't done then the sides of the rind can become porous. (The metal stays molten in both the head and the sprue and as they both cool and shrink they put a tension on the sides of the ring. I've seen designs break at this point when the sides have been too thin.)
For your design I would suggest the following:-
Make the head hollow and as thin as you can make it.
Make the sides at least as thick as the head, and any modelling on the sides should be added to the surface rather than cut in.
The transition between the head and the sides should be as smooth as you can make it, the metal needs to flow smoothly and without turbulence.
Put a flat pad on the back of the ring so that the caster knows where to sprue to. This is always a good idea if you are not going to do your own finishing.
I would do any engraving on the inside of the ring after it has been finished. You will get a much sharper and brighter finish that way.

Thanks for the advice. I will have my first rings made here and will post the end result as soon as they arrive. I do appreciate stop4stuff's and your advice. I took this into consideration while finalizing my designs...