Plastic mould design and production at The Soap Kitchen

Meet Colin Fox the mould designer (aka Clive)

In this article Colin talks us through and describes the way vacuum-formed moulds are designed and produced for sale at The Soap Kitchen. These moulds are suitable for melt-and-pour soap production.

Our “in-house” mould designs, are identified by a number of influences: these can be current and future trends, seasonal items, development of previous moulds, ideas that come from “brainstorming” meetings from Creative Suite design team, or indeed suggestions from any of the Soap Kitchen staff.

This is how the moulds are designed and made


Initially, I will draw the image, my preferred software being Adobe InDesign, but I also use IronCad by Inovate and Blender. In some cases I will draw a design freehand using a pen.

Once happy with the image, it is loaded into 3d imaging software which will give a clear representation of how the mould model will appear. The model size and scale can be adjusted at this stage. The software will give indication of how long the model will take to print and how much material will be used.

The model is then set to print.

I also produce 2d models which are more basic in form. These are drawn a similar way but put through a different software package, which will, in turn drive a desktop CNC machine. The CNC mills the model by cutting into a block of plastic-based composite material.

Once the 3d model has been printed, it needs to be re-produced in resin. This is because the heat used on the forming machine is higher than the 3d plastic can tolerate and it would begin to melt during the vacuum process.

So, a silicone mould is made from the 3d model. Once cured, the plastic model is extracted from the silicone and after trimming, resin can be mixed and poured into the cavity. Once the resin has cured, which is usually within 10-15 minutes, the model is extracted from the silicone, and cleaned off using sandpaper or a Dremil to give it a fine smooth finish.

Models which are produced using the CNC, do not need the silicone/resin procedure. The model is ready for the vacuum-forming machine once it has been sprayed with a clear laquer.

The model is then placed on the vacuum-forming machine bed. When heated, the plastic sheet is vacuumed around the shape of the model. After cooling, the model is popped out and the mould is trimmed ready for sale.

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