Thermoforming is the process of heating huge plastic sheets into a very high temperature and cooling them in the required format. Vacuum forming is a sub process or a type of thermoforming where vacuum is applied in between the molds and the plastic to create various shapes. Thermoforming has several advantages and disadvantages compared to the other plastic molding methods like injection molding. In addition to vacuum forming, several other methods like drape forming, twin sheet forming and pressure forming can be incorporated along with thermoforming to produce different kind of products. Several types of plastic can be molded in the method.
Disadvantages of thermoforming
1. Thermoforming is quite costly. Compared to other methods like injection molding, this method can cost up to 50% more.
2. Large plastic sheets are used in the method. They have to be fed into the rollers again and again. This leads to lots of extrusion.
3. The plastic street is stretched in the under pressure in this method. Hence the products formed using thermoforming break at a certain temperature.
4. Thermoforming uses more plastic than other methods. Nearly 10 to 20% more plastic is used to make any product in this method. This adds to cost and creates extensive wastage too.
5. Vacuum forming process done along with thermoforming does not give the required shapes sometimes. The whole process has to be repeated which is expensive as well as time-consuming.
Advantages of thermoforming
There are several advantages in using this method in spite of all these disadvantages.
1. Thermoforming is the only method in which huge plastic sheets can be molded into huge objects. All other methods are used for making small objects only.
2. Though the process is costly, the tools required for the trade or quite cheap. Injection molding machinery is nearly 33% costlier than the Thermoforming machinery tools.
3. Several different products can be prepared in the thermoforming machines. Only certain products can be prepared in other machines. Nearly all types of plastic can be used for the plastic. Other methods use only specific plastic for production.
4. Skilled labor to operate the thermoforming machineries are available in abundant. But, laborers capable of operating machineries of injection molding or vacuum forming are quite less.
5. Superior quality products using more plastic are formed in the method. Hence, they are more durable than the objects created through other local methods.
There are many more advantages in the method. Though costly and a bit time-consuming thermoformed products are preferred by most of the packaging industries due to their high quality.
In vacuum forming or thermoforming fabrication, the material is just as important as the mold. If a lower-quality plastic sheet is used, the end product could be compromised. The color of the sheet could be uneven and inconsistent. Unpredictable melting could occur, causing irregular gauge thickness. Longer curing and drying could add operation time and cost to the fabrication process. In other words, having the best vacuum formable plastic sheet will always yield the best-finished product.
In short, vacuum forming is a stripped down, simpler adaptation of thermoforming. With vacuum forming, a heated, pliant plastic sheet is stretched on top or inside of a mold. The formable sheet then conforms to the shape of the mold with the application of a vacuum to ensure the plastic fills the mold, tightly and neatly. Once the sheet is formed, the vacuum is released, along with the now-formed plastic sheet.
Vacuum forming is ideal for prototyping and manufacturing parts with a shorter-run production output due to being an easy and economical operation. It is also an outstanding way to fabricate more shallow molds without the higher operational costs associated with thermoforming. Newer, technological advances have allowed vacuum forming with deeper molds, as long as the formable sheet is of higher quality and is mechanically stretched before application to the mold.
When selecting the material for your project, forming plastic is an ideal option. Vacuum formable plastic sheets, usually made of PVC (Polyvinyl Chloride) are designed especially for the vacuum forming or thermoforming process. They can withstand heat application without melting or breaking down. They are also highly regarded for their ease of processing and are inexpensive in comparison to other sheets. Be sure to choose a plastic or PVC sheet that meets your specific requirements, such as thickness, color, surface texture, and overall size. Look for a product that offers precise gauge control and consistent color with lot-to-lot traceability. This way, there will be no differences between manufacturing runs.
There are a variety of applications that benefit from both vacuum/thermoforming and formable plastic sheets. The production of kiosks and automated teller machines include external plastic structures that accommodate delicate, internal mechanisms securely and with branded aesthetics. Since the formable sheets are highly customizable, medical device housing and electronic equipment cases can be properly fitted for a precise fit and appropriate protection. On a smaller scale, electrical components are a perfect application because of the inherent flame retardance of the formable plastic sheet material.
If you are considering your options for a small run of manufactured molded parts or experimenting with a prototype, vacuum forming/thermoforming with vacuum formable plastic sheets is an excellent choice. While the manufacturing process itself is straightforward, the selection of an industry-proven formable sheet will provide high-performance durability without cutting into your bottom line. Be sure to choose a high-quality formable plastic sheet that will hold up to the demands of your next project; you will have a consistent, reliable end product every time.