Plastic is everywhere you go. Have a look around you and you will see that is impossible to find something made of plastic. Our everyday tools are affected with this marvelous invention. The plastic technology world has improved rapidly and continues getting updated faster. In this articles you will be presented with 2 of the most popular techniques of plastic moulding. You will find how they work and then a comparison of both and their results.

Dip Moulding is a technique where metal (generally aluminum) moulds are dip into a liquid hot mix of PVC. Because the molds are cold and the mix isn’t a phenomenon happens when the liquid plastic sticks attached to the molds that are then retired and left to dry. The mix solidifies and the cools down and so the product is ready to be take out of the mold.

Injection Moulding is a technique where liquid resin is put into a machine using a hopper. Additives to give colour to the product are usually put into the machine directly after the hopper. The plastic mix enters an injection barrel using gravity. After entering to the barrel the mix is heated at a appropriate temperature. The mix is injected into the mould by a ram injector or a reciprocating screw. The ram injector usually injects 20% of the total shot while a screw injector injects more less 5% of the total shot. So basically the screw injector is better used for producing smaller products. The mould contains the mix until it cools down and solidifies. Then the moulds are open and the product is retired.

Dip Moulding is a cheaper alternative since all the material and equipment needed are much less expensive. When a prototype is needed at a lows cost and in a short period of time, Dip Moulding is the best alternative. It is also important to mention that because Dip Moulding materials and equipment are inexpensive then this technique allows you to produce small amounts of part at a relatively low cost price, which doesn’t happen with injection moulding. The finish of the product is naturally smooth, textured, glossy or matt and it doesn’t show split lines.

Dip Moulding has its limitations. It only works with the plastic resin called plastisol while injection moulding allows a more complex variety of engineered resin. This allows to obtain products with different textured and finish. Dip Moulding takes days and the products can go from soft so semi hard while injection moulding can take weeks or months but the products can also be as hard as a rock. The geometry of the product using Dip Moulding has to be kept simple while in injection moulding there is much more freedom to produce a highly customized product. Prototypes using injection moulding are very expensive.

Everything in the world has a process. There is a process for you and me to born to grow up, get old and die. That’s just part of the life. In the same way some PVC products have a process to be made. One of the processes CPL is experimented in, is the Dip Moulding process. The process is quite simple to explain and maybe not so easy to make. Dip Moulding is exactly what the very name suggest. This means it is a preheated dipped into the PVC plastisol and allowed to dwell. Then the mix has contact with a gelled coating of the plastisol. All of this is placed into a great oven where finally is cured. After the product is taken out, is cooled by different means and compressed by air. This process in known to be very simple among all the process to deal with PVC but it is also really effective and has a great advantage when talking about costs. This two qualities make the Dip Moulding process to have many applications in many if not all industries.

The process as you can see is very simple one. It can also be reducing to say: Pre heat, dwell, cure and cooling. However there are other factors than can have influence in the production and Dip Moulding Process. For tooling and certain material have certain effects that are not constant in the fabrication of the items. I’m talking about extern agents and the post Moulding operations that can or may be made on the resulting product.

In Dip Moulding process, several material can be used to produce different items according what is asked by the customers, however, among all of those items used in the dip process, the PVC highlight as the most outstanding and rentable one. Others companies have great experience using other materials with different results and obviously different qualities, however CPL has a great expertise working with PVC so they remain expecting about using other materials .The fascinating thing about PVC is them moulding capability it has to adapt to any condition. After be treated PVC results with a difference among other material used in the Dip Moulding Process, the Shore Hardness. The desired hardness expected in these kind of items can vary between 50 to 80 shore. PVC can easily satisfy this parameters when is finished, but not only this. It can also vary the hardness according special orders obtaining a different treatment giving ether softer or harder finished mouldings.

One of the properties well known and most desired about PVC is the insulation. This quality is extremely good. This allowed the material to be extensively used all over the country and the world in the electrical and related industries. PVC is so insulating that 1mm thickness of PVC can offer resistance to 40Kv, meanwhile other materials need a double value to achieve such resistance. PVC is also quite resistant to the contact to other substances. I mean things like acid and alkalis. The contact of these surfaces with other chemicals in a fabric or other place could diminish the resistance of the material, but no with PVC.

It is a very reliable material, precise for the Dip Moulding Process.