Making Silicone Molds without Air Bubbles

One of the most common methods for chocolatiers to make their own molds is to use food grade, liquid silicone rubber.  The problem is that liquid silicone rubber is very expensive and can take a long time to set.  If your silicone inadvertently gets air in it while mixing or pouring, you may very well go through the whole process only to find that your mold did not turn out right because of one unsightly placed air bubble.

There are several things that can be done.  The simplest form is not over-mixing and brushing a small layer of the silicone on the model before pouring the whole mold.  This way you get into the detail and have less air bubbles on the surface where it matters most.  The next best thing you can do is use a vacuum degasser.  To use a vacuum degasser, the mixed liquid silicone is put in a chamber before it is poured.  This process will break up most of the air bubbles before casting.  This is very effective, but not all the way as air can be brought back during the pouring.

The best way to ensure a bubble free mold is to use a pressure casting method.  A pressure pot is a metal chamber that uses a compressor to cure the mold under pressure.  The liquid silicone is poured over the model then placed in the chamber.  The pressure, max 60 psi, eliminates the bubbles during the cure process.  You can buy pressure pots at Smoot On, or I have seen them used for the paint industry which can be bought at many places, even Amazon (link will take you right to the pressure pots).

Word of caution:  do not attempt to make your own pressure pot as they can explode.

To read more about mold making see our in depth instructions on The Chocolate Mold Factory's Main Site under "Personalized Molds".  There are tutorials about designing molds and how to make them.  Though the site is geared towards chocolate molds, these instructions are the same as would be for any other type of non food grade mold.

Making Custom Chocolates Using Logo Plates that fit into Master Molds

I was just reading an article about how some companies make mass custom chocolates from a company called Gourmet Gift Food People.  Apparently they sell customized chocolate products.  At any rate, they described the process of making custom chocolates and the reasoning behind set-up fees as follows:

" One of the questions we often hear is if the customer can keep the logo or company message chocolate mold when purchasing corporate logo chocolates, since they paid for the set up fee.

Answer: When you order a piece of chocolate from a catalog or website, the actual chocolate molds have already been created by the factory and the master plates are already made. When you add your logo or text message, a tiny plate, the size of the logo or text is created to fit snugly in to the master plate and this is how your logo or message is added to the chocolate. The chocolate mold plate created with your logo or message would not be useful for any other purpose as it was only created to fit in to the master chocolate plate for the item you are ordering this time. If you re-order again later in the year or even next year, the exact same chocolate item, your plate should be made available to use again without paying an additional set up fee.

However, if you choose to go with a different piece of chocolate, - something that would require your logo to be larger or smaller than the piece already created or shaped differently than the original to fit in a master mold, you more than likely will be required to pay a new set up fee."

Read more: http://www.articlesbase.com/food-and-beverage-articles/combined-pricing-for-corporate-logo-chocolate-gifts-2830984.html#ixzz0u5vaDxuM


Under Creative Commons License: Attribution

I have tried to do this before and you must be precise about getting the logo plate to fit very snugly into the master mold.  If anyone has information about this process, I am interested in learning more.

CAD/CAM Software for Making Chocolate Molds - Delcam Case Study

Delcam software gives chocolate mould manufacturer a taste of success

Since 1999, Kaupert, a leading German manufacturer of chocolate moulds, has used Delcam software for the design of all its polycarbonate tooling. These moulds are produced using injection moulding or stamping tools, which are also developed with Delcam systems. Today Kaupert’s customers can expect delivery of their moulds in as little as six to eight weeks after confirmation of their chosen design – and so make an early start with the production of their own special chocolate creation.

Large-scale confectionery manufacturers like Lindt, Bahlsen, Storck, Kraft Foods and Master Foods are responsible for the greater part of Kaupert’s turnover. Its customers also include some traditional craft firms – confectioners, patisseries and chocolate-makers. For both sets of customers, particularly demanding standards of accuracy and surface quality must be met by those tool components that will later form the cavities in the chocolate moulds, and so have a decisive effect on the appearance of the chocolate wares that will be the end result.

Previously, the modellers created their artistic forms – Easter bunnies, Father Christmasses, hearts, flowers, animals, stars and a great variety of other designs – in the form of plaster models. Some 20,000 of these sculptures are stored as an archive resource. For most of them, injection moulding or stamping tools have already been created, making it possible for the designs to be reused.

When the tools are not available or when the design requires some modification, Kaupert’s designers and modellers use Delcam’s CopyCAD reverse engineering program to capture a computer model from the plaster original. The sculpting tools within the software then enable the user to add material to the CAD model or to pare it down to generate the final design.

The designers also use Delcam’s ArtCAM Pro engraving package to create new decorations for ornamental engraving and for writing on surfaces, usually for single-bar products. Data from CopyCAD and ArtCAM Pro can be combined with more engineering shapes developed with the PowerSHAPE CAD modeller through Delcam’s unique Total Modelling. With this unique approach, the user can process complicated 3-D reliefs, solid models and free-form surface models in a single system and on an equal footing.

PowerSHAPE also calculates both the shrinkage of the synthetic material and the effects of hardening on the chocolate shape, and so ensures that the confectionery that will be produced matches exactly to the designer’s intentions.

The toolmaker then generates programs for the company’s Micron and Röders milling machines with the PowerMILL CAM system. One of the strengths of the system is that it warns of possible sources of error in advance: collision checks, analyses of rest material, and machine tool simulations work together to ensure that in the subsequent machining process nothing is left to chance.

Artwork Guidelines for Custom Chocolate Molds

If you have ever tried to order a custom chocolate mold with a logo or graphics, you may have wondered what the artwork requirements are all about and why people are not willing to bend when it comes to them. Most mold makers require very clean, black and white line art. No fine lines; no small letters; alot of space between characters. Photos are generally not acceptable unless they can be easily converted into line art.

The reason is related to the method in which the mold, or the model for the mold, will be made. For example, if the mold maker will be making vacuum formed plastic molds, characters must be adequately spaced and sized to allow the plastic to form properly. Silicone molds are a bit more forgiving, but still have limitations. If the mold maker will be using photo-sensitive materials such as photopolymer printing plates or magnesium hot stamping dies to make the model, the blank spaces within and between the letters must be large enough to wash away. If the lines are too fine, there is a danger that the line itself will actually wash away. If the mold maker is going to be using CNC machinery, the fonts will have to be large enough for the cutting to be done.

In an effort to avoid these problems in the first place look at the letters "a", "o", and "e" for clues. These are often the hardest letters because the spaces are so small. Unfortunately, there are no hard and fast rules about what size font to use, or how much spacing is needing. It depends on the font. However, I would really recommend not using anything under a 36 pt. Arial for comparison purposes. Generally, the larger the font the better.

While on the subject of fonts, you must pay particular attention to the font you use. The best fonts will be bold and simple, without serif (which is the little decorative lines at the ends of the letters). These fonts may be labeled "sans serif". Script and cursive fonts can be used as long as the font is large enough and the lines are not too fine.

The requirements will also be different if you are going to have the text recessed, rather than raised, on the chocolate bar. To accomplish this, you will need an even larger font to ensure that the desired area is washed away completely and deeply.

For more information about making custom molds, see the Learn section of The Chocolate Mold Factory.