ZBrushCentral

Using CNC for moulds

Community
#1

So I’ve been thinking about going into figurine making on a scale shown here but think it might be a waste to have a 3D print done just to make moulds that would only give detail in one direction.

So I’m pondering a different method where I make the moulds in Zbrush and have their positives made using a CNC Machine. I’m blindly assuming that CNC services are cheaper but if it worked, Making the actual moulds would be a lot easier then with a full 3D model. Just pour in some plaster or other such material and hopefully keep the positive for later.

I’m still looking at the best and fastest way to make the models. So far i have a base plane that i sculpt to meet the model’s parting line, Some Zsphere tools for feeding lines and the model it self. Up the document res, copy the base plane and go at it with Zproject. after one side is done, I placed some shapes and a border for alignment and hopefuly containment. I make the other side with the first half visible instead of the base.

It’s not perfect and no matter how high res the mesh is, the edges of the mould are a bit jagged. I haven’t found any CNC machines around to test it but I’m hoping for some advice on the moulding side of things and weither i’m on the right track.

Attachments

zbrushmould.jpg

#2

If you want to make multiple castings like hiroshi’s resin models, you need to have a durable mold. Silicone rubber (many different grades available) is probably the best bet. I have worked with companies that have cnc’d the “molds” but only for larger objects for single use only. Even rubber molds break down after a number of castings (varies with shape and materials cast) and you will get degrading after 15-20 in resin casts around edges. Simple shapes maybe up to 50 before slight tears etc. We have gotten up to a hundred very simple shapes. I don’t know of any printable material that would be suitable for the mold.

#3

Well, The idea is to have the positive version of the mold milled out by one of those robotic drills, so most materials are possible. Stone would be a bit overkill but it could definitely be tougher then plaster or wax.

After it’s made the positives, I would wall them in with cardboard and start brushing in the material that would make the real mold. Hopefully the material of the positive could survive the process to be reused to make replace molds.

If CNC-ing in tough materials costs too much, I could just have the negative made in wax and create the positive from that. It might be the better option because I could use a material that could stand up to abuse from Silicone molds for far longer.

#4

Good luck, maybe some will have other ideas. :slight_smile:

#5

make the molds for the machining in a router using foam, mdf or wood.

Later you have to cover all the sculpt.

Is a interest process but yes you can.

Take care

#6

I Was also thinking of doing this, as it takes the work out of making molds.
But another negative of doing this would be that your model needs to be cleaned up and polished after its printed. So I think even if molds were printed, they wouldn’t be as good as taking mold from perfectly polished print.

#7

Maybe Maximus is a solution :slight_smile:

We produce from small to large.

Davy

#8

I recommend you go to a Jeweler and talk to to him. He will tell you how to do it. There are not many choices none of which are cheap. A good mold is difficult to make and is an expensive piece of work in itself. Only while making larger quantities of products the cost for a mold can be justified. Usually a mold is a ‘one off’ piece and costs accordingly.
Rainer

#9

Try contacting a rapid prototyping shop. They can also offer up to date advice.

#10

This is certainly possible, I use zbrush models in cad/cam applications all the time. Depending on how much you want spend on the mould you can get a very detailed piece indeed.

2 ways:

  • Make a mould as shown above in your post. (obviously making sure there are no undercuts, but zproject handles this quite well)
  • Cut a master to mould/cast from. Depending on what you want to achieve this can be done on a 3,4 or 5 axis machine.

3D printing is great for the price but lacks the resolution of a cnc (although it has a great advantage of being able to print even hard to reach places that a cnc would not be able to get to). I have no doubt that the technology will get there in a couple of years. You can now 3d print in metal alloys which is pretty amazing.

Let me know if you need any help on the project.

Cheers,