Evening folks! A little more pedestrian than some of our more crazy products and processes but I wanted to share our workflow on producing production soft tooling molds for clients, we've recently had a job come in to produce 150 units initially for a client on a job that is likely to extend to 500-600 pcs count, these numbers are typically well below the threshold of the ROI of Injection Molding tooling, so soft tooling can bridge the gap from small run 3D printing to Mass production quite well!

It's quite a small piece (we have three variants to produce)

We begin our process by arraying the source part, after modifying the dimensions of the part to accommodate and include an allowance for paint thickness, as the client wants to keep a reasonably tight OD on the part, we've factored 100 micron offset on OD for paint thickness based on 30-50 microns per coat typically on a 2k automotive clear coat, once all the walls and supports are designed we fabricate the masters and walls in house with our Formlabs Form 3 and our Bambu labs X1C (and the H2D which we JUST purchased yesterday!!)

Step 1:

With the masters printed and cleaned up we apply a layer of clear coat laquer to seal the parts, the silicone we use is Smooth-on Moldstar 30T as a platinum cure silicone it can be prone to mold inhibition in the presence of certain chemicals, SLA prints are known to have issues on this front so a clear coat as a barrier layer is always recommended, also as the print quality is so good it just adds an extra high grade gloss to the part which will both reduce wear on the soft tool as we are lowering the co-efficient of friction when remoting the parts, but also just looks cooler haha!! Experience tells us we should reasonably be able to get at the very least 40-50 cycles, which, with some drop out for the odd failure, means this mold can produce somewhere between 2,000 and 2500 parts!

So with that said, 

we take our master's 

Once sprayed, we individually key them onto the 3d printed mold base

Step 2:

Mixing up our silicone and degassing, we pour our silicone in a thin continuous stream over the parts to fill the mold box, followed by placing the mold into a pressure pot at 60 PSI to ensure a 100% bubble-free mold.

Step 3: 

Once the Silicone is cured, we can remove the mold box, leaving the masters in the silicone wherever possible, and inspect and clean the silicone. We can now see the embedded mold text telling us how much resin is required when the production team comes to run the mold in this case, 16 grams! (That's right; they are truly tiny parts!!)

Step 4: 

Next, we slide a mold wall (FDM printed) over the mold and apply a generous coat of mold release to the silicone. This stops the silicone from bonding to itself when we pour the second half!

Step 5:

As with the first half, we mix and degass the silicone and pour in a thin continuous stream, followed by placing the mold into a pressure pot at 60 PSI to ensure a 100% bubble-free mold

Step 6:

After removing the wall and taking out the masters (and storing them safely for next time!), We have our mold ready to run! The mold is dusted with gold mica powder before we run the parts, giving them a lustrous gold finish without using a drop of paint! (I'll share their results in a few weeks once the mold is up and running! but I wanted to share how we plan out and use solidworks to price our work, as this lets us know exactly how much material spend we need, how much the prints will cost and gives us a very accurate look technically on how the molds will run, so we can discuss internally and modify based on our expertise with these small but complex interlocking molds :) 

hope this was of some use to someone somewhere ^^