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I got started on a project early January. The job was to model silicon baby products using reference images he sent and make them look like they were professionally taken in a studio.

I completed the job successfully, but now he wants to use the models I made and have them manufactured and turned into real silicon products and have them mass produced. He asked if I thought my models would meet the technical specifications to use them produced at a factory.

He wasn't sure if Blender was something like CAD software and I'm not sure either, but I have read that you can create the products in Blender to have them 3D printed, but I'm not too sure this is the same thing.

How is this done? Is Blender enough, do I need some plug-in that will help meet all the specifications, or is this something more suited for CAD software? He's talking about mass production, so I don't want to mess this up! If more specialized CAD software is needed, is it easy to pick up for a Blender user, and is there an easy one to start of with?

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    $\begingroup$ Do you know the specifications that your model has to meet? If not, this can't be answered! Obviously CAD software is designed for this purpose, but as long as you can make a valid model using any software, the factory doesn't care what software you used to create it. $\endgroup$
    – Criticizing Israel not allowed
    Commented Feb 28, 2021 at 13:45
  • $\begingroup$ Well, I use Blender to manufacture parts as described in this thread here: blender.stackexchange.com/questions/212949/…. These are exported as stl files and printed through a process called laser sintering in a PA12 material. So this works just fine for me. $\endgroup$
    – Strawberry
    Commented Feb 28, 2021 at 19:02
  • $\begingroup$ Wow, everyone had a lot of good answers here! I will have to think of which one is the best answer. I can't thank you guys enough! @joojaa I feel, may have brought up a good point. From what I gather this will need to be mass production ready. But these products are very simple. I will refer this information back to my client to discuss our future plans. $\endgroup$
    – Jeremy McCloud
    Commented Mar 1, 2021 at 4:03
  • $\begingroup$ The one important thing to check that nobody has mentioned so far is the absolute dimensions - a visual model is great if all of the dimensions in the view are correctly proportioned but if your dummy is 5 units long by 3 wide it is important to know is that 5 cm, 5 inches, 5 m, 5 km, 5 mm, etc. This is the one area where CAD tool tend to score over blender. You can also use companies like Shapeways, (who will accept blender files) to make single test items at a reasonable cost. they will even 3D print in wax so that you could use lost wax moulding. $\endgroup$
    – Steve Barnes
    Commented Mar 4, 2021 at 21:30

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AFAIK, CAD software and blender are not that different, especially for 3D printing. The main difference would be operation, and maybe some tools to make sure the object could be made with a mold. Just do some checks:

  1. Make sure the geometry is watertight, commonly referred to as being manifold. You don’t want any holes!
  2. Double check that all the normals are pointing the right way.
  3. Make sure the mesh is high poly enough that the resulting product won’t look polygonal like a low-res video game object.

If you have already printed a few things with this model and they are totally fine, I’d say you’re good to go. :-)

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    $\begingroup$ Just a side note for the third point, it may be helpful to use flat shading instead of smooth shading to ensure you’re viewing the object as it will appear when produced (since, of course, you can’t use fake normals on a real object). $\endgroup$
    – TheTrueJard
    Commented Feb 26, 2021 at 22:12
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    $\begingroup$ Your first sentence is not really correct. There is a huge difference between how geometry is represented for graphics and manufacturing. In Blender a model is a collection of vertices/edges/faces. In CAD a model is a parametric body, i.e. a series of features (extrude, cut, revolve, sweep, etc.). While you can ensure a model in Blender is manifold and thus can be used to represent a solid, it is still a collection of flat faces so truly curved surfaces are not possible. All manufacturers I have worked with (including for 3D printing) want STEP or parasolid files which are of the latter type. $\endgroup$
    – PGmath
    Commented Mar 11, 2021 at 17:49
  • $\begingroup$ OK well, my bad. But Blender does export to STL, right? $\endgroup$
    – TheLabCat
    Commented Mar 11, 2021 at 17:51
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    $\begingroup$ Blender does export to STL. But STL is a mesh format, not a parametric solid. This hugely depends on how OP intends to manufacture the parts and what volumes are meant by "mass production", but I don't know of any manufacturers which would take a mesh as reference. $\endgroup$
    – PGmath
    Commented Mar 11, 2021 at 18:12
  • $\begingroup$ I guess I don’t really either, but 3-D systems used to accept STL files before they went down. And no, they didn’t go down because of what format they accepted. Really, honest. $\endgroup$
    – TheLabCat
    Commented Mar 11, 2021 at 18:13
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Zargul is correct about what is needed for the model. There is more to it than just making sure a model is manifold. A molded product must meet certain restrictions of not having deep recesses that may keep the product from releasing from the mold. Save out an STL file and send it to the mold manufacturer. They will be able to tell you if your model meets specs and will probably have suggestions for fixes or even someone on staff who can fix it up for you. There will likely be a good bit of going back and forth with the manufacturer to get the design in shape for manufacturing, so make sure you charge for multiple iterations or make it clear to your customer that iterations will cost more.

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There are two kinds of 3D file formats in common usage:

Mesh formats: The model consists of flat triangles or polygons. This is the native format of Blender, and can be exported as .STL which is widely supported.

Surface formats: The model consists of curved NURBS surfaces. This is the format preferred by CAD applications, as it gives better precision and surface quality. Blender has some modeling tools for NURBS surfaces described here. It does not support direct export to .STEP or .IGES, which are the preferred formats in CAD world. It can export surfaces to .OBJ, which should be possible to convert to .STEP without loss of accuracy, perhaps with FreeCAD.

In mass production they take your 3D model and design a mold based on it. Whoever does this would definitely prefer to receive a surface-based model. But almost all CAD packages have a way to convert mesh formats to surface formats with a small loss of accuracy. Most critically, the accuracy of all round holes is lost: a 20.00 mm hole might become a 19.99 mm hole. The accuracy of conversion depends on the size of the triangles in the mesh.

If your object is more of artistic quality than having precise 0.01 mm dimensions, you should be fine providing .STL export from Blender. You may want to specify that it is ok if the conversions result in some dimensional inaccuracy, as long as the general shape is preserved and smooth. Ask also to verify the model after conversion, and make sure that there are no remaining triangles or they are small enough - otherwise it could show up in final product.

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In addition you can activate the "3d-print toolbox" in the plugin section to get some information about your model. As it is not clear what type of model and what specification for production would be needed its difficult to give proper feedback.

Blender is not CAD software which uses primarely nurbs, as those have perfect surface information and thus is well suited for production. But as described in the other answers, enough density and clean, manifold geometry will certainly work.

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For 3D printing meshes are fine. But 3d printing is not exactly mass production ready.**

However, if you need your object made with a CNC machine like say you need aluminum or steel injection molds made then the CAM operator is not going to be happy with a mesh. Why because its really problematic for the path planning to have a angular surface*. So be prepared to pay for your own work again in the engineering department and time to market as they will be calling you on the phone a lot.

While the CAD can sometimes approximate surfaces out of a mesh this isn't entirely ideal for the mass production team for several reasons. When I have had to do this we have been charging the same as if we would have designed the piece to begin with. But it depends on the company.

The thing is you don't want to have to redo a 50,000 tooling cost because of a auto conversion error. Though you can probably live with a lot less than that for vacuum/rotary casting of silicone.

* the fact that it looks right in rendering is irrelevant its all well to approximate a surface for rendering with something that has no bearing on physical truth. But for the CNC it is physical truth or no dice.

** Well, you can make a casting master in a resin printer then spend time post processing it to become a master and mold it in platinum silicone which can then be used as molds for processing. But this all depends on do you need a 100, a thousand, ten thousand or hundred thousand units.

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