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The standard process steps can be identified as clamping, heating with sheet level activated, pre-stretch, forming with plug aid, cooling with air and spray mist, release and trimming they’re examined more closely under the following sub headings ;

Clamping
The clamp frame should be satisfactorily dynamic enough to guarantee the plastic sheet is firmly held in the forming process. It should be in a position to handle the thickest material certain to be formed on the machine up to 6mm with a single heater model and up to 1Omm with the twin heater machines. If an automatic process is employed the operation of the moving parts must be guarded and interlocked to avoid random damage.

Heating
Heaters are usually infra-red elements mounted inside an aluminium reflector plate. In order to obtain the best vacuum forming results, using any material, it is important that the sheet is heated regularly over its entire surface area and throughout its thickness. So as to achieve this it is necessary to have a sequence of sections which are managed by energy regulators. Ceramics do have some d rawback in that their high thermal mass makes them slow to warm up ( approx fifteen mins ) and slow in their reply time when adjustments are made.

Sheet Level
A photo-electric beam is incorporated in the machine to scan between the bottom heater and the sheet of plastic. If the sheet of plastic sags down and breaks the beam then a small amount of air is injected into the bottom chamber, so lifting the sheet to prevent it from sagg ing.

Pre-stretch ( Bubble )
Once the plastic has reached it’s forming temperature or “plastic” state it can be pre- stretched to ensure even wall thickness when the vacuum is applied. Pre-stretch is an invaluable feature when forming deep draw parts with minimum draft angles and high mold surface detail. The technique of controlling the bubble height should be such that consistent results are obtainable.

Vacuum
Once the material is suitably pre-stretched a vacuum can be applied to assist in forming the sheet. With larger machines a vacuum reservoir is used in conjunction with a high volume capacity vacuum pump. This enables a two stage vacuum to be applied making certain quick moulding of the heated sheet.

Plug aid
Plug-assist forming is the term used to describe the use of a male plug tool, mounted on a pneumatic or hydraulic cylinder situated over the forming area of the machine, to force the material into a female cavity within the moulding area. It enables complex and deep-draw moulds to be produced without webbing and with even thickness distribution. The idea behind the process is to feed as much material into the hole prior to the vacuum being applied to avoid thinning in that area. Plug moulds are typically made of wood or metal and a smooth surface permits the sheet to slip whilst stretching into the mould. A felt or leather lining guarantees that the danger of premature chilling on contact is seriously reduced. Resin plugs supply a reasonable alternative as being good insulators they don’t affect the temperature of the sheet.

Plug assist is also an essential feature when forming multiple impression male moulds as they can be placed awfully close together without the fear of the material webbing between the formed parts.

Cooling and Release
Once formed the plastic must be permitted to cool down then was released. If released too soon then deformation of the moulding will end up in a reject part. To hurry up the cooling cycle high speed fans are fitted and turned on once the part is created. A spray mist option is available whereby nozzles are attached to the fans and a fine mist of chilled water is directed onto the sheet. This, together with the fans can improve the cooling cycle by almost 30%.

Mildew temperature control units are also available which control the temperature in the mould ensuring accurate and consistent cooling instances when cooling crystal-like and crystallising polymers like PP, HDPE and PET.

Once cooled adequately the sheet can be released by a reverse pressure activated through the vacuum system. The part is then stripped from the mould and moved to the trimming station.

Trimming and Finishing
In vacuum forming once the formed part has cooled and been removed from the machine the surplus material is removed. Holes, slots and cut-outs are then drilled into the part. Other post-forming processes include decoration, printing, bracing, reinforcing and assembly.

I saw this guy, Richard Jacobsen, demonstrate how to make a vacu-form mold using parts in total that all costs less than 0. He was a super nice guy, and his demonstration was perfectly clear. All you need is a heat source, plywood frames to hold the styrene (plastic), a rubber mat with a hole in it, and a shop vac. It worked brilliantly.
Video Rating: 4 / 5

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It’s time to participate in saving our planet by decreasing plastic trash and recycled them into functional materials. As we know, plastic trash becomes a big problem for all countries. This plastic material can’t be diminished just like other materials; in fact, many people still depends with plastic bags and dump it everywhere.

Nowadays, there is one way to recycle plastic trash into other functional materials. Vacuum Forming is plastic recycle process that includes concrete shaping techniques. It is fun, easy learning that simply can applied at home or at school activity, since the process is simple and full of knowledge.

As a simpler way of thermo forming, all you need is thin plastic; including perspex, thermoplast, or polythene, plastic frame and the mould. There are some recommended plastic types for Vacuum Forming; they are including:

Styrene plastic; which has matte color and it’s easy to drape. In fact, it’s a bit hard to be shaped. It’s highly recommended for beginners, because it heats up slowly, and save money also.

ABS plastic; It is easy to form, and easily heat up.

There are some steps that you need to do in Vacuum Forming.

Put the plastic in the frame, by stretching it. You need to make it as stretch as possible so the heating process might form good soft plastic.
Put it in heater, or might your oven, then heat it in forming temperature. You will see that the plastic is getting soften and ready to form.
Switch off the heater, the use vacuum to suck the soft plastic and form it based on the mould.
Let the formed plastic get cooled and eject the plastic from the mould.
The process is done, and you will get shaped plastic form based on your creation.

These steps are easy; yet, you can use many materials around your house to recycle your plastic trash into functional things. You can also show this process to your student, and this will be a long lasting fun recycling project.

Basically, smallest industries until the biggest plastic industries use this process to form many kinds of plastic trashes into thousand of plastic things around you. Chair, plastic bowl, plastic cup, or even airplanes plastic parts.

So, how about you? Let’s start to do it at home.
Vacuum Forming at home need few things to consider.

The main problem is about space range to do Vacuum Forming equipment. So you need to prepare vacuum former that fits in your house and estimate the plastic width so you’ll not get difficulties in doing this.

You also need to consider your vacuum cleaner power. Since it has limited power, it is better for you to use thin plastic so you don’t need to buy or hardly find stronger vacuum to make Vacuum Forming process run well.

So, it is your chances to decrease plastic trash and re-cycle the plastic into an artistic things or functional materials. So let’s help our environment with your knowledge!  

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