Clarifying Confusion Over The Thickness of Thin Plastic Sheets

Sheet thickness is commonly said by the producer or it may be measured utilizing a micrometer, as utilizing a ruler could be impractical for such small sizes. The thickness of skinny sheet materials comparable to plastic sheets must be often called it’s going to affect properties such because the sheet stiffness – i.e. how simply the sheet can flex.

That is related to designers who must specify plastic sheeting – for instance within the signal trade. The right thickness of a plastic cowl sheet for a snap body is totally different to that required for a hinged-door poster case or free-standing print holder. The previous must be versatile, the latter must be inflexible. Speaking the proper specification requires an understanding of probably ambiguous terminology – as an example for US corporations wishing to commerce exterior North America.

The Mils Muddle

Within the metric system of measurement, comparable to used within the UK, the millimetre (mm) is a handy small unit of measurement of sheet thickness. Nevertheless for thicknesses beneath 1 mm it’s usually handy to divide 1 mm into 1000 elements and these items are known as microns. Thus 0.5 mm is 500 microns.

In USA ‘mil’ is a measurement equal to 1/a thousandth of an inch. Mil is similar because the previous imperial unit Thou (one thousandth of an inch). Individuals often state the plural model as mils. That is probably very complicated to metric customers because it sounds an identical to the colloquial for millimetres – spoken as mils although all the time written as mm. The that means adjustments as one crosses the Atlantic.

To present some examples relevant, for instance, to versatile plastic cowl sheets of many poster frames (comparable to snap frames):


  • 400 micron or 0.4 mm = 15 mils (to be exact 15.75 mils). Individuals may additionally write.015″ thickness. This thickness would solely be appropriate for small poster frames.
  • 500 micron or 0.5 mm = 20 mils. In North America it is perhaps written.020″ thickness. This can be a quite common thickness for a poster protector sheet for medium measurement poster frames comparable to snap frames. This sheet may very well be rolled up for handy delivery if spare covers are required.
  • 1000 micron or 1mm = 39 mils (to be exact 39.37 mils). At this thickness plastic sheets are pretty inflexible and couldn’t be rolled up simply, so delivery single sheets turns into problematic.


Stiff plastic sheets

When the appliance requires stiffer plastic sheet a typical thickness is 3mm (approx 1/eighth inch). This might apply to the plastic ‘glazing’ used within the hinged door of a poster case or coated discover board. On this case the plastic features like a window relatively than a protecting movie. Plastic sheeting, comparable to acrylic solid surface manufacturer or polycarbonate, with thickness 2mm or 3mm would even be specified for gadgets comparable to free-standing plastic table-top print holders which have to be self-supporting.

Defining by weight per unit space

For skinny sheets the burden of the sheet could also be said, relatively than the thickness – in Europe said as g/m2, often abbreviated to gsm. Relying on the density of the actual materials the g/m2 weight and micron thickness can coincidentally be fairly shut in quantity and could also be confused.

Measurement methods which can seem back-to-front

Metals are additionally provided in skinny sheets and on this case the thickness is also known as the ‘gauge’. Gauge could be a little complicated to the uninitiated because it seems to be a ‘backwards’ scale. The upper the quantity the thinner the sheet. For instance, 1.5 mm thick steel sheet is 16 gauge (16 SWG) whereas the a lot thinner 0.5 mm steel sheet is 24 SWG – SWG is the abbreviation for traditional wire gauge, a long-established imperial unit of measure. It’s not typically used for plastic sheets.

The ISO (Worldwide Requirements Organisation) metric paper measurement nomenclature also can catch folks out as a result of it can also appear to be a backwards scale: A8 paper may be very small, A4 is closest to US letter measurement, and A0 is used for big posters. Most European customers will probably be very conversant in A sizes while being baffled by the time period ‘letter measurement’. In US and Canada the reverse could also be true.

By appreciating these factors confusion over measurement items will be decreased or eradicated in transatlantic commerce referring to skinny plastic sheet supplies.

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