To distort the image, click and drag the corner handles until it fits in the laptop screen. Advanced Photoshop Distortion Tools to Get Creative With. If you want to get creative, you can use one of the more advanced Photoshop distortion tools. Here are a few examples. Using the Warp Tool to Curve Objects. The warp tool is an excellent option to. The distortion is then measured using the following formula: where H. is the distance of the dot from the image center H is the nominal distance of the dot from the image center based on the expanded regular grid The maximum Distortion measured for any of the geometric structures in the image is the one that is reported.

Jim Throne Consultant, in, 2011 Publisher SummaryThermoforming is a generic term that refers to a process that begins with an extruded sheet of plastic. The process involves heating the plastic sheet to a temperature range where it is soft or malleable. Thermoforming represents a group of sheet-forming processes that includes vacuum forming, drape forming, billow of free bubble forming, mechanical bending, matched mold forming, billet molding, pressure forming, and twinsheet forming. The thermoforming process is usually segmented into thin-gauge and thick-gauge markets.

Thin-gauge markets tend toward disposable products such as rigid packaging. Thick-gauge markets tend toward permanent or industrial products.

Thermoforming is a low-temperature, low-pressure process in which the sheet is handled as a rubbery solid or elastic liquid. Molds are usually single-surfaced. Mold materials are relatively inexpensive and are often fabricated in relatively short times. Thick-gauge thermoforming produces a limited number of products at production costs below those produced by other processes such as injection molding. In contrast the advantages thermoforming has several disadvantages.

The incoming material is an extruded sheet, with the extrusion process adding 50% or more to the cost of the formed product. Thermoforming generates substantially more trim than other processes and that trim must be ground and re-extruded at additional cost. Jim Throne, in, 2017 16.3 Thermoformed Product CharacteristicsThermoforming is a low-temperature, low-pressure process in which the sheet is handled as a rubbery solid or elastic liquid. Molds are usually single-surfaced. Mold materials are relatively inexpensive and are often fabricated in relatively short times. Thick-gauge thermoforming produces a limited number of products at production costs below those produced by other processes, such as injection molding. Thin-gauge thermoforming produces millions of products at production costs below those produced by other processes.

Thin-gauge products traditionally have surface area-to-thickness ratios as large as 100,000:1. No other process can produce similar results.In contrast to these advantages, thermoforming has several disadvantages.

The incoming material is an extruded sheet, with the extrusion process adding 50% or more to the cost of the formed product. Thermoforming generates substantially more trim than other processes and that trim must be ground and reextruded at additional cost. Thermoforming is a differential stretching process, meaning that as the sheet is stretched, only that portion of the sheet that is free of the mold is stretched. As a result, the wall thickness of the formed product is nonuniform ( Fig. 16.1) 4.

Although some improvement in wall thickness is achieved by mechanical or pneumatic stretching of the hot sheet prior to pulling it against the mold surface, wall thickness tolerance is typically 10–20%. As local areas of formed products are designed to minimum critical thickness, many portions of the formed products contain more plastic than necessary to meet the design criteria. Regarding product surface quality, only one side of the product contacts and replicates the mold surface.

As noted, the thermoformed sheet is in a rubbery solid or nearly solid state when it is stretched at relatively low pressures. Nearly all applications use unfilled or unreinforced sheet.

As the sheet is usually stretched in its solid, rubbery elastic state, the thermoformed products are under substantial residual stress. As a result, substantial distortion can occur if formed products are subsequently heated to near-forming temperatures.

This is discussed later. Erik Tempelman. Bruno Ninaber van Eyben, in, 2014 Cost breakdown: some additional commentsIn thermoforming, the materials tend to be responsible for a considerable part of the total production cost: typically 30% to 50% for thin-gauge products and 45% to 70% for heavy-gauge ones. In economically developed countries, the costs of operating the forming machines themselves range between 100 to 300 euro/hour.

So designing your parts to be as thin as possible gives a double benefit: lower material costs and, through faster cycle times, lower machine costs. Transport of thermoformed products is relatively expensive, as the products tend to be light or even contain a lot of air. For this reason, thermoforming companies limit their market to clients within a 750-km radius around their location. For stretch blow-molded bottles, the preform parisons are relatively compact, so it pays in transport terms to blow the bottles to full size in the same facility as they will be filled. Note that when production volumes get really large, as they are for coffee cups, the extruder that produces the sheet or foil is usually placed in line with the thermoforming machine, together forming a single production line. This has two major cost benefits: (1) it saves energy, as the plastic only needs to be heated once, and (2) it allows easy in-house recycling of production scrap (the material that is trimmed off can simply be reground and put back into the extruder, without the potentially costly transport step that is involved if the extruder and thermoforming machine are in different locations).

Rosato, in, 2004 Twin Sheet FormingTwin sheet forming, also called dual sheet forming and clamshell, is a special thermoforming technique. The process resembles blow molding ( Chapter 6), except that twin heated sheets are used instead of a tubular extruded parison or injection molded preform. Like a blow molding, the twin sheet forming mold usually consists of matched female mold halves.

Molds can include pinch-off zones at the periphery of the cavities. Air pressure through a blowing needle is introduced at a suitable point between the heated sheets, then the mold halves are closed under pressure, welding the sheets into a closed body at the pinch-off zones. Air under pressure forces each sheet into conformity with the corresponding mold cavity face.

Thermoforming does not provide the accuracy and tighter measurement tolerance of blow molding but for products not requiring such performance, they provide significant cost advantages. Syed Ali Ashter, in, 2014Thermoforming is a primary polymer conversion process in which a plastics sheet is heated to its rubbery state and by either mechanical or pneumatic means formed into a three-dimensional object. Chances of getting black ice skin.

Today, it is one of the fastest growing segments of the plastics industry. This has been brought on by the development of new materials and techniques, coupled with innovative production and specialized equipment capable of providing manufacturing efficiency for the industry. The major advantages of thermoforming are its cost-effective thermoforming tools, reasonably priced thermoforming machines, the possibility for processing even multilayered materials, foams and preprinted forming materials. This chapter primarily gives an overview of the history of thermoforming, thermoforming markets and applications. Syed Ali Ashter, in, 2014Thermoforming is a high-deformation rate process in which polymeric material is deformed by heating to a temperature above its glass transition. The main source of concern is uneven heating, which directly relates to thinning of parts.

This leads to a decrease in the mechanical properties of formed parts. In the current thermoforming process, the optimization of the final part thickness is done by trial and error, by changing the design of the component, polymer material and processing conditions such as heating temperature, mold temperature, applied pressure and plug design. Any such inappropriate change in the conditions leads to non-uniform thickness distribution of the part.

Modeling heating of plastic sheet is the starting point in simulating the thermoforming process.In this chapter, a complete literature review is provided to model the thermoforming process. Each step of the thermoforming process is identified and different models are studied. Thermoforming is a process for converting thermoplastics into shell forms, using sheet material as a preform.

At its most basic, thermoforming is performed by clamping a heated thermoplastic sheet over a mold cavity and drawing a vacuum in the cavity. This causes atmospheric air pressure to press and plastically deform the sheet into the mold cavity, where it is cooled to retain the formed shape. This is known as vacuum forming, a term that is less comprehensive than thermoforming, although the two are often erroneously treated as interchangeable and synonymous. In practice, the key factors in thermoforming all have two to three optional forms (see Table 4.33). For example, the forming force can be supplied by vacuum, by positive air pressure, or by power press. These options can be assembled in many different permutations to create a very wide variety of thermoforming processes.

In this chapter, the principal processes ( Table 4.34) and the main factors are discussed. Process FactorOptionsForming forceVacuumPositive air pressurePower pressMold typeFemaleMaleMatched male/femaleSheet pre-stretchVacuumPositive air pressure (billow)Mechanical plugMaterial inputExtruder (in-line, hot forming)Reel (reheat, cold forming)Cut sheet (reheat, cold forming)Process phaseSolid phaseMelt phaseHeating modeOne side of sheetBoth sides of sheet (sandwich)Heating meansRadiation: rod, ceramic, quartz, or infrared heatersConvection: hot roller, contact panel, or hot oil bathMaier C, Calafut T. Polypropylene: the definitive user's guide and databook.

Norwich (NY): Plastics Design Library; 1998. ProcessForming ForceMold TypeSheet Pre-stretchBasic vacuumVacuumFemaleNoneBasic pressurePositive air pressureFemaleNoneDrapeVacuumMaleNoneSnap backVacuumMaleVacuumBillowVacuumMalePositive air pressurePlug assistVacuumFemaleMechanical plugBillow plug assistVacuumFemalePositive air pressure and mechanical plugAir slipVacuumMalePositive air pressureAir slip plug assistVacuumMalePositive air pressure and mechanical plugMatched moldPower pressMatched male/femaleNoneTwin sheetPositive air pressureMatched male/femaleNoneMaier C, Calafut T.

Polypropylene: the definitive user's guide and databook. Norwich (NY): Plastics Design Library; 1998. Packaging (75-80% of Total Thermoforming Resin VolumeBarrier Food ContainersPortion (Creamers, Syrup, etc.); Unit Dose DrugsConvenience and Carry-outBlister and Bubble Packs (Hardware, Batteries, etc.)Containers, Deli and Dairy ContainersMeat and Poultry Trays, EggElectronics. The most common polymer materials that are converted in thermoforming processes are: ABS, PMMA, Cellulosics, LDPE, HDPE, PET, PP, PS, PVC. The advantages of thermoforming over injection molding are lower equipment costs, ability to make thinner walls, ability to make large surface area parts, shorter possible lead time from conception to production, and less costly model changes due to less expensive tolling.

The disadvantages compared to injection molding are first - it is a two-step process (extrusion plus thermoforming); more scrap and regrind is generated; there tends to be more part to part variation; wall thickness is less adjustable and more variable; lower surface gloss; less part complexity. Figures 1 and 2 illustrate some key features of thermoforming. Figure 1 illustrates a sheet fed rotary thermoformer. Figure 2 shows a roll fed continuous thermoformer. Refer also to Sheet Extrusion. (Sources: Throne, J.

L., Thermoforming, Hanser Publishers, 1987; Gruenwald, G, Thermoforming: A Plastics Processing Guide, Technomic Publishing Co, 1987). Ain, in, 2013 ThermoformingThermoforming is a manufacturing process in which a composite sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or ‘film’ when referring to thinner gauges and certain material types, is heated in an oven to a temperature that makes it possible to be stretched into or onto a mold and cooled to a finished shape.Bhattacharyya et al. Processed wood fiber–PP composites sheets by the thermoforming process 52 and wood fiber–biopole composites studying the thermoforming performance and biodegradability of the composites 53. 54, 55 investigated the liquid composites molding process for wood plastic composite materials. Syed Ali Ashter, in, 2014The thermoforming process largely involves reciprocating mechanical motions both in the forming process and in the trimming of formed articles using sharp instruments, which provide many opportunities for accidents. Therefore, it is important to have awareness of safety and safe working conditions.

Proper training in handling of thermoforming equipment should be provided to employees of corporations directly involved in thermoforming. In addition, warning signs, built-in-safety measures and recurring hazard evaluations help in mitigating, minimizing and sometimes eliminating the risk of an accident. Major accidents with thermoforming machines are caused primarily by inadequate safeguarding, safeguarding that has been removed and safeguarding that has been overridden.This chapter provides insight on the causes of accidents in the thermoforming industry and different ways to prevent these accidents. In addition, this chapter also covers recycling and its economics, and the environmental impact of scrap.