Vacuum Forming

About Vacuum Forming and Vacuum Forming Services Including Blister Packs, Clamshells, Pressure Forming, Thermoforming & Vacuum Formed Plastics.

Vacuum forming is a plastic thermoforming process that involves forming thermoplastic sheets into three-dimensional shapes through the application of heat and pressure. In general terms, vacuum forming services are all sheet forming methods, including drape forming, which is one of the most popular services. Basically during the vacuum forming process, plastic material is heated until it becomes pliable, and then it is placed over a mold and drawn in by a vacuum until it takes on the desired shape. Vacuum thermoforming is a great method for producing plastic parts that have sharp details and fit nicely to specific products.
 
During the vacuum forming process, a sheet of heated plastic material is placed over a male or female mold. The mold then moves towards the sheet and presses against it to create a seal. Next, the application of a vacuum draws out the air between the mold and the sheet so that the plastic conforms to the mold exactly. This is accomplished through venting holes in the mold that are joined to vacuum lines. The mold also has a water cooling system integrated into it that brings the temperature of the plastic to the set temperature needed. When the curing temperature is reached and the piece is formed, air blows back into the mold and separates the new part from the mold.
 
Vacuum forming services produce plastic parts for various industries, such as the food, cosmetic, medical, electronics, entertainment, household products, toys, athletic equipment, appliance, automotive, office supplies and clothing industries. One of the most important industries that thermoforming serves, however, is packaging. Products like blister packs, inserts, trays and clamshells are used to house other products and are important for both preservation of the items they hold and the aesthetic designs they can provide. Consumer product manufacturers often use vacuum forming to produce plastic trays and glasses. Another interesting use for vacuum formed plastic is the creation of signs for gas stations and convenience stores.
 
The greatest advantage to vacuum forming services is that it involves less parts and tooling than injection molding, and therefore is more cost-effective. It is an economical choice that can be used for small and medium production runs, with low cost tool modifications. There is great design flexibility available, from a variety of prototypes to custom made designs that can be used to cover almost any product. Most manufacturers also offer a wide variety of trim and other decoration options that can prove quite a visual advantage. Time of production is generally short, which frees up time to do more detail-oriented aspects of production. Sharp, precise detail is available for many products, which makes vacuum formed plastics an attractive alternative to other molding processes.

Vacuum Forming and Vacuum Forming Services Images Provided by Kintz Plastics Incorporated

Types of Vacuum Forming and Vacuum Forming Manufacturers

• Blister packs are clear plastic, nonresealable packaging used for products that could be tampered with.
  
• Clamshells are plastic packages that have hinges to open and close like a clam’s shell.
  
• Drape vacuum forming is like snapback forming except that the thermoplastic sheet is stretched to the base of the mold. In both cases, the use of air to stretch the material prior to vacuum sealing and application to the mold permits the material to thin uniformly.
  
• Plug forming is a thermoforming procedure that uses a plug or male mold to press the heated thermoplastic material into the female mold prior to the application of a vacuum. This method helps uniformly distribute the sheet.
  
• Pressure forming is a thermoforming procedure that involves applying pressure to the top of the plastic sheeting while the vacuum force pulls downward. Pressure forming is done through air pressure or mechanical means, and provides greater precision because the plastic is able to attain a greater definition of shape in the mold.
  
• Snapback vacuum forming is the process of pre-stretching the sheet material with a vacuum box. A partial vacuum is then applied to the box, just enough for the necessary stretching, and the mold is pushed into the material where the box is vented to atmospheric pressure that draws on a vacuum.
  
• Straight vacuum forming is vacuum thermoforming using only female molds that produce a material distribution that is the opposite of the results obtained from male molds.
  
• Thermoforming involves heating and stretching plastics.
  
• Vacuum formed plastics are created by a thermoforming process that uses a vacuum to suck the plastic sheet into a mold.

Vacuum Forming Vacuum Forming Manufacturers Terms

Black Points – The dark particles that appear in plastic film during thermoforming processes because of contamination.
 
Bleed – The characteristic of some plastics of losing their colors when coming into contact with water or certain solvents. Also, this is the undesirable movement of materials to the surface of plastic or into an adjacent material.
 
Blister – Thermoformed semi-rigid plastic shells, typically made to conform to the shape of the product being packaged.
 
Boss – A protrusion on a plastic part that adds strength, assists with alignment in assembly and allows for fastenings.
 
Burn Holes – Portions of thermoformed plastic where vacuum and heat produce an opening in weak or thin points.
 
Degradation – A change in the structure of a plastic material.
 
Denest – The detachment of thermoformed parts, like blisters, from one another for the next phase of the packaging procedure.
 
Destaticization – The process of removing static electricity from plastic so that less dust clings to it.
 
Die Cutting (http://www.iqsdirectory.com/die-cutting/) – The use of a steel rule die to cut finished sheets of blisters or blister cards to create individual pieces.
 
Draft Angle – The degree to which the sidewall of a blister or clamshell is tapered to smooth the progress of the removal from the thermoforming mold and denesting of the blister.
 
Embossing – A technique that creates depressions in a specific pattern on plastic film and sheeting.
 
Environmental Stress Cracking – The tendency of thermoformed plastic to crack under the influences of certain chemicals.
 
Fold-Over Blister Card – A blister card that is scored and die cut, permitting entrapment of the blister between the two halves of the card. This supplies a seal between two boards or between a board and a blister flange, especially useful when blister packaging heavy items.
 
Heat-Sealing – The process of joining two or more plastics together with the application of heat and pressure.
 
Pock Marks – The result of inadequate contact of the plastic material with the surface of the mold due to trapped air, moisture on the surface of the mold or low pressure in irregular indentations on the material’s surface.
 
Prototype – A model of an intended part. Prototypes show the final size as well as the design.
 
Reprocessed Plastic – Thermoplastic material derived from industrial plastic scrap from a different processor.
 
Sag – The flow of heated plastic sheeting in a thermoforming procedure in which molten plastic sheets sag before forming. The distance of the sag is determined by an electric eye and is good for determining the forming readiness of the material.
 
Sandwich Heating – A heating procedure before forming a thermoplastic sheet that involves heating both sides.
 
Scrap – Any plastic material, which is not part of the product, that results from a molding procedure. This material is typically tip scrap and can be reused.
 
Sheet Train – The construction required to create plastic sheeting, comprised of an extruder, die, polish rolls, conveyor, draw rolls, cutter and a stacker.
 
Thermal Expansion – The minute change in length or volume of a material when subjected to heat.
 
Two Piece Blister – A double blister for encapsulating a product for product visibility on two sides.
 
Undercut – An indentation or protrusion that hinders the removal from a mold.