Sheet thickness is usually specified by the manufacture […]
Sheet thickness is usually specified by the manufacturer, or it can be measured using a micrometer, because for such small sizes, using a ruler would be impractical. It is necessary to know the thickness of a sheet material such as a plastic sheet, as it will affect characteristics such as the stiffness of the sheet, ie how easily the sheet bends.
This is relevant to designers who need to designate plastic plates, such as in the sign industry. The correct thickness of the plastic cover for the snap frame is different from the thickness required for a hinged door poster box or a stand-alone printing stand. The former needs to be flexible, the latter needs to be strict. Communicating the right specifications requires understanding of potentially ambiguous terminology, such as U.S. companies that want to trade outside North America.
In the metric measurement system used in the United Kingdom, millimeters (mm) are convenient small units for measuring the thickness of thin plates. However, for thicknesses less than 1 mm, it is often convenient to divide 1 mm into 1000 parts, these units are called micrometers. Therefore, 0.5mm is 500 microns.
In the United States, the 'mil' measurement is equal to 1/1000 of an inch. Mil is the same as the old empire unit Thou (thousandths of an inch). Americans often express plural forms as mils. For metric users, this can be very confusing because it sounds the same as spoken millimeters-although expressed in millimeters, it is expressed in mils. Crossing the Atlantic Ocean, meaning changes.
For example, here are some examples of flexible plastic covers for many poster frames, such as snap frames:
400 microns or 0.4 mm \u003d 15 mils (15.75 mils to be precise). Americans may also write a thickness of 015 inches. This thickness applies only to small poster frames.
500 microns or 0.5 mm \u003d 20 mils. It might be written in North America. The thickness is 020 inches. This is a very common thickness for poster protectors for medium-sized poster frames, such as snap frames. If a spare cover is needed, the board can be rolled up for easy transportation.
1000 microns or 1mm \u003d 39 mils (39.37 mils to be precise). At this thickness, plastic sheets are quite hard and difficult to roll up, so transporting a single sheet becomes a challenge.
Rigid plastic board
When the application requires a harder plastic sheet, the typical thickness is 3mm (about 1/8 inch). This will apply to plastic 'glass' used in poster boxes or hinged doors with covered notice boards. In this case, the plastic acts like a window instead of a protective film. Plastic plates with a thickness of 2mm or 3mm, such as acrylic or polycarbonate, will also be used for projects such as self-supporting stand-alone plastic desktop printing stands.
Definition by weight per unit area
For thin plates, the weight of the plate can be expressed, not the thickness-in Europe it is expressed as g / m2, often abbreviated as gsm. Depending on the density of the particular material, the weight of g / m2 and the thickness of the micrometer may happen to be very close in quantity and may be confusing.
Possible measurement systems
Metal is also available in sheet form, in which case the thickness is often called a 'gauge'. The scale may be confusing for those who have not started, as it appears to be a 'backward' scale. The higher the number, the thinner the paper. For example, a 1.5 mm thick sheet of metal is 16 gauge (16 SWG), and a thinner 0.5 mm sheet of metal is 24 SWG-SWG is the abbreviation of the standard wire gauge, which is a standard inch size unit. It is not usually used for plastic boards.
The ISO (International Standards Organization) nomenclature for measuring paper size can also appeal to people because it also seems to tilt backwards: A8 paper is very small, A4 paper is closest to US letter size, and A0 is used for large posters. Most European users are very familiar with the A size, but are confused by the term 'letter size'. In the United States and Canada, the situation may be reversed.
By understanding these points, you can reduce or eliminate the confusion of measurement units in transatlantic trade related to thin plastic sheets.