Excellent rapid manufacturing resource to produce numerically limited series items using polyurethane material. You can produce parts with rigid , semi-rigid or soft plastic and materials are available with V0 certification and FDA certification
Silicone mould replicas are an excellent Rapid Manufacturing solution for realizing a limited number of pieces in plastic. The methodology is similar to that of injection moulding. We create a prototype that will serve as master, generally by stereolithography, and surround it with a hard shell that is then filled with silicone. Once solidified, an operator manually dissected the block of silicon into two or more parts to extract the master and leave a hollow in the shape of the prototype. Production takes place in vacuum casting machines and daily production yield depends on the exact material to be used due to setting speed and safety requirements.
Each mould has a production capacity of approximately 25 pieces in polyurethane material, with different degrees of hardness and colour, that is also suitable for co-moulding with metal inserts and other plastic parts. Since this is a process without automatized mechanics, forms cannot have undercuts and must have minimum wall thicknesses to allow the material to flow. It is a technology suited to many industries and needs.
For example, silicone mould replicas can be used for a pre-series of test prototypes, because the material used can be very similar to that of the final product, or for a first production of components usable as final parts, even in the case where the products require food, FAR 25 or medical certifications.
Silicone mould replicas are also extremely useful for start-ups building their businesses with innovative hardware products as they can produce parts in very little time (approximately three weeks) without onerous investment and with great customizability in terms of finishes and colours, precisely because the pieces are produced individually.
Frequently Asked Questions
What materials can be used to make the objects?
The materials that may be used are soft (rubbers), rigid or transparent polyurethane resins that simulate the characteristics of definitive product materials.
In what format should I send the files?
You can send files in various formats: -.stl, -.stp, -.iges, -.x_t, -.model, -.sat, -.prt, -.par or native SolidWorks, Catia V5 (r15) or Cimatron -.step. In some cases, for CNC machining, for example, a 2D drawing may be enough, though this can only be confirmed by our technical department on quotation. Once the order has been made, for all machining operations the 3D files will be used. The 2D files will only be used to check dimensional tolerances. In case of any discrepancy between the 2D and 3D files, Coesum will use the 3D files in its possession.
Can I co-mould plastic parts with metal inserts?
If the master of the assembled object is created, the insert can be placed in its final position in the cavity and co-moulded. The insert can be sent by the customer or made by us via CNC. During the mould casting process, the polyurethane material will adhere to the metal and thus create the final assembled object.
How many objects can be made from a single mould?
In general, the silicone mould is good for approximately 25 reproductions, but it depends on the specific geometry of the object and on how much the mould is stressed when the replica is extracted manually.
Can I make objects of any shape and thickness?
Geometric limits are similar to those of prototypes, except for undercuts. Automatic movements that allow the extraction of these areas are not used with silicone moulds. Criticalities can often be resolved with ad-hoc metal inserts but only after an analysis performed on vision of the 3D file.
Can the objects be painted?
Yes, silicone replicas can be painted with acrylic spray paint or industrial paint from specialist suppliers.
Can V0 Flame retardant materials be used?
Yes, we have materials for silicone moulding that have V0 certification, widely used in transport and military sectors.
Can materials certified safe for food products be used?
Yes, 9012 resin is certified for use with both wet and dry solid or liquid food products.
How quickly will ready the objects be ready?
The standard time for the production of a first batch is about 2 weeks. Evaluation of the timeframes of each specific project is performed on analysis of 3D files. Partial deliveries may be agreed in accordance with customer needs.
How big can the objects be?
We can produce whole parts of a maximum size of 1800x800x800 mm.
How many pieces a silicone mould produce?
Each mould can produce approximately 25 pieces. To obtain a greater yield various moulds may be made at once (where possible). Evaluation of the exact number of pieces that the mould can produce is made from analysis of the 3D files. It is possible that the mould may still be usable for production beyond its estimated life-cycle, however, this can only be evaluated at the time of production and not at the quotation stage.
Can objects subsequently be machined for threads or holes?
Yes, silicone mould replicas can be machined with CNC machines and lathes to make holes and threads corresponding to 2D machining drawings that the customer must provide when requesting this.
Do I have to immediately produce all the pieces?
Following production of the mould, you can decide to produce one or all of the required pieces. If you did not need to make several separate reproductions, Coesum can keep the mould for processing until the conclusion of the casting.
What is intended by “silicone mould” and how many pieces can I get from one silicone mould?
The yield of a silicone mould (number of parts produced), is expressed in terms of individual products deriving from the mould. Coesum guarantees for each silicone mould an average yield of at least 20 products. A guarantee of yield greater or less than 20 individual products may be specified on a case by case basis as part of the commercial offer. Silicone moulds that have residual yield potential at the end of the requested production will be kept at Coesum for six successive months. After this period the silicone moulds will be disposed of by Coesum without further notice to the customer.