Colin Fox explains how soap moulds are designed and produced at The Soap Kitchen
It is not widely known that all of the soap moulds sold by The Soap Kitchen are designed and produced on site here in Devon. I produce two types of moulds: silicone rubber and vacuum formed-plastic. Both types of moulds produce excellent melt-and-pour soap bars, and numerous different bath bomb shapes. There is a huge range to choose from and all are listed on our website. Check them out here.
There are two processes involved in the making of the models from which to form the moulds. What’s know as 2.5 dimensional models are produced using a desktop CNC milling machine. Full 3D models are produced on a 3D printer
The first part of the process is for the design of the mould to be drawn. Given an idea I will draw from scratch, or use a logo or artwork design submitted by a client. I use either of two software packages to achieve this: Iron Cad Innovate, and Adobe In Design. Once the design is finalised, the software will convert the code to that read by either our 3D Printer, or our CNC milling machine.
The CNC will produce 2.5 dimensional models which are cut from blocks of porous modelling board. A 2.5 D model is actually 3 dimensional but because it can only be cut form the top there is no side or underside detail. The printer produces complete 3D models with detail on all sides.
Usually, models from the CNC machine will be used to produce the vacuum-formed plastic moulds. Models from the 3D printer, are used to produce full-enclosing silicone moulds.
Designs that use the CNC may have multiple files, as different cutting tool heads may have to be used to complete the image. This means that a cutting tool may have to be changed two or three times to produce one model, depending on the size of cut required.
Once complete, the model is extracted from its base, cleaned using a paint brush and lightly sanded to erase any sharp edges. When free of any dust, I then coat the model with a clear lacquer. After this has dried, the model is ready for vacuum forming. So you can see there is a lot of preliminary work carried out before the model is ready.
The plastic mould is produced using a Formech vacuum forming machine. The model is placed on the platform of the machine, and lowered away from the top level. A sheet of PET or PVC plastic is then tightly framed into place and heated. The model is then forced back up and the vacuum pump is activated. The hot plastic envelopes the model and the pump then sucks it firmly into place. The vacuum pressure is then released and once cool, the model is ejected from the newly-formed plastic mould. Any excess plastic around the mould is then trimmed.
A model which is produced on the 3D printer, when complete is positioned inside a container. Silicone is then mixed and poured around and over the model completely enclosing it, except for a small base area. Once the silicone has cured, usually overnight, the model is extracted from the silicone and the mould is ready for use. Silicone 3D moulds allow for a great deal more detail in the final soap bar.
To view our full range of moulds, please click here.