Drawing the Same Mold Using OnShape CAD

I will make a classic Medalta beer bottle case-mold for 3D printing (just pour in plaster and you have a mold to slip cast bottles). I will highlight the differences between it and Fusion 360 as we go.

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More coming soon. I am super excited by the prospect of using OnShape 3D CAD that is free for hobby makers (vs. $750/year I have been paying for Fusion 360).

Links

URLs

https://www.onshape.com
OnShape parametric cloud-native CAD software
This is looking like my new favorite 3D CAD package. It is free for hobby makers, runs in a browser so it works on almost any computer. And it works on iPad. If you have Fusion 360 experience you will hit the ground running, most of the tools and functionality needed for mold making are very similar.

3D Printed Pour Spout Forms a Rounded Lip

Slipcasting mold and spout made using OnShape

This picture has its own page with more detail, click here to see it.

This 3D-printed PLA pour spout potentially increases the utility of this one-piece plaster mold. As can be seen on the upper section analysis, the spout is designed to form the lip of this small Medalta Potteries bowl (and provide a guide for cutting its inside edge). It has lugs that extend outward to enable holding it down using rubber bands. I intend that it will be cleanly removable after the piece begins to pull away from the mold, leaving a high-quality lip that only needs a little trimming. This spout also permits precise monitoring of when to pour out the slip and it prevents most of the mess made using traditional molds having a spare.

This is the first piece I have made wholly using OnShape CAD. Experience with Fusion 360 gives me expectations of how this should work and those expectations are generally being met. Cost is no longer an obstacle to adopting professional 3D CAD for mold making. I am using OnShape on my 2014 Mac Mini running Ubuntu Linux (on 16gb RAM). And Prusa Slicer, OctoPrint, GIMP, Kdenlive, InkScape and productivity software are all running smoothly on it.

3D mechanical design software 2025:

Which is the best for mold making in ceramics?

This picture has its own page with more detail, click here to see it.

CAD software and 3D printing are a potential revolution in vessel mold-making for ceramics (3D modelling is another topic). But there are two big problems: There is no way a potter, hobbyist or even small manufacturer can afford the typical software cost. While it is true most have free or low-cost trial or hobby versions, the strings attached are deal breakers. The second problem is the complexity of learning - that can be a bigger obstacle than cost.

Until the recent price increase, Fusion 360 seemed to be exactly what was needed. A great way to on-board the CAD world, using the free version and its great learning resources and best-in-class user interface. It is new and modern, a YouTube star. It is fully parametric supporting constraints and a timeline. True, it can choke on more complex drawings on consumer computers, but we don’t need to do those. But, for commercial use, it costs $680/yr. But that is cheap compared to some others! Upon discovery of the capability, the cost might be doable for you.

Here are the ones you likely cannot afford (and maybe don't want):
-OnShape runs in your browser, in our testing it looks really good. Free-version drawings are public (but no other restrictions). Going private costs $1500/yr!
-Rhino is usable for CAD but is polygonal and targeted at modelling. It is not fully parametric and does not have a traditional timeline (however Rhino+Grasshopper is life-changing for geeks, both for CAD and modelling). $1000 to buy but upgrading is $500+.
-Solidworks is a long-time proven product, it is fully parametric with editable history. Runs on Windows only (or the xDesign product runs in a browser like OnShape). It is low cost for hobby use (but the restriction of not being able to save or open the commercial SolidWorks file format is a potential deal-breaker for hobbyists). For commercial use: $2600/yr in 2025.

Some upcoming possibilities:
-FreeCAD is becoming more viable. It is parametric, has constraints and exports and imports popular formats (but with lots of issues). Its model tree is equivalent to the Fusion 360 timeline, but more clunky and depends on careful setting of constraints. The learning curve right now puts it out of practical reach of most. But a capital injection, like Blender got, is coming.
-Shapr 3D costs $299/yr, also works on iPad (which Fusion 360 does not), and uses the Parasolid engine like OnShape and SolidWorks. But it seems to be targeted at being intuitive for conceptual modeling and quick prototyping for drawings that are finalized in other products (limited support for accurate feature placement, constraints, parametrics and boolean operations).

By Tony Hansen
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