Vacuum Casting Low volume production and urethane casting in silicone mold

Compared to injection molding process, rapid vacuum casting process are no need to care about the part drafts, small undercuts and sliding directions. The silicone mold is easy to make by using a master patten, compared to the metal mold, the silicone mold is soft and flexble,  the products can be taken off the silicone mold easy by hand pulling. It is the best way for low volume production in the prototype way, and every silicone molds gets 15-20copies. There are two kinds  of brand PU materials we are  using for vacuum casting, the Axson from France and de-cast from Japan, material is good for end use.

 Rapid Vacuum casting silicone molding makes it all possible for many options

• Hard plastic products made by vacuum casting range from small electronic components to big parts like car doors, printer shells parts, air conditioner frames parts, medical machine enclosure parts

• Transparence plastic products made by vacuum casting are the follows, the show box, decorate parts, containers, touch pad screens, car lamps, and medical device windows.

• Soft rigid and flexible plastic products made by vacuum casting PU rubber like material, part hardness range from 20 Shore A to 90 Shore A, like product protected covers and corners, pipes, sealing gaskets.

• Metal Inserts like pins, Brass inserts, metal sheet can be insert in the silicone mold and get the part mold out together with the metal inserts by vacuum casting.

 Over molding, known as 2K molding is an important process for injection molding mass production, But there are many requirements in low volume production that no need to have a metal mold made, Hence, overmolding in Vaccum casting is the only option for one to dozens over molding prototype parts. The overmolding process is adding an additional layer of liquid material go over an existing part and curing around it as a combined single part. the two  materials inside and out are normally different in status or properties.

• Clear Plastic over opaque plastic overmolding process is normally applied for car lamps, which the existing opaque housing made by CNC or Vacuum casting with the fine post finish and get the clear PU liquid material  casting  over around and get cure, the final product is a single lamp combined with opaque hosing and water clear layer lamp cover.  

• Opaque plastic over clear plastic overmolding process is similar to the above process.

• Soft plastic over hard plastic overmolding  process is applied for all kinds of consumer products in required of water proof and drop test. the soft PU rubber liquid material casting over the existing hard plastic as the  water proof Gaskets on edge or protecting layer over around.  

• Soft Plastic and Hard plastic over Metal overmolding process something like insert molding in injection molding, which the brass inserts or  the steel sheet ribs are puting inside the mold, and casting the hard plastic over on top.  

Medical device housing and shells according to the size and demands, require different processing methods, such as CNC machining for the verify mockups, appearance prototype and metal components. Vacuum casting and Vacuum forming are two processes for low volume pre-marketing testing production.

 Vacuum casting and vacuum forming are  both the process for housings and  frame products, according to clients' requiement, Medical device housing and shells products are alternative produced whether from Vacuum casting or Vacuum forming process. These two process are the most cost effective methods for the housings parts as the mold design and structure details are much simple compared to Injection molding mass production mold. 

At the same time, the mold making process work for vacuum casting is less than Vacuum forming and a lot less than injection mold. so that the lead time will be faster and cost cheaper . Hence, in turns, Vacuum casting is the best way for the short run production and Vacuum Forming followes is an optinal way for both low volume production and big volume mass productions. 

Vacuum casting process is not able to get prefect color matching in material  compared to Vacuum forming and injection molding, so that the post painting process for vacuum casting parts is very necessary,  colors and textures are always  made by painting according to the pantone number and texture number.  for the end use purpose, the painting finish for medical device housing is required to go thru the painting adhesive test and  anti-alcohol test. In alternal, vacuum forming is OK for both painting and color in material way. 

 Silicone press molding is a supplement process for vacuum casting  process. As known, mold material for Vacuum Casting is silicone,  so the silicone parts are no possible to be made via a silicone mold from vacuum casting, Hence, silicone press molding comes as a addendum process for silicone prototypes.

The mold material for silicone press molding  is the ABS, it is no need to make any metal mold for the process as the quanties is normally less than 10 pieces.  For the silicone prototype products out from an ABS mold, this mold cavtity is made by CNC machining or SLA. This process is as simple as to put the fluxible silicone material with or without color into the mold cavity and press by force. The geometrical shape of the part will be formed soon as the silicone cured.

For silicone press molding process, the silicone material hardness is settled

around 45 shore A, this is the first disadvantage.  and the second disadvantage  of the process is that only simple structures like gasket,O rings or flat plates can be produce by this techniques. In other hand, besides the above, all the soft part prototype from vaccum casting,  material PU rubber will insteads almost all of the soft TPU, TPE, Rubber or silicone material request,  and this is a limited for material choice for soft part producing in rapid prototyping. 

If requires soft parts for low volume or production way, compression molding and Injection rapid tooling are the alternal processes for the manufacture, which not only Silicone has the options for hardness, but also soft parts have the material options like TPU, TPE, Rubber, PVC and So on .