Pressing and finishing technologies has gone through many innovative advances in the last decade. Beginning with irons, the new developments advanced through ironing tables, claddings, specialized bucks, form finishers and tunnel finishers. However, hand-held irons still remain the most used finishing equipment on the shop floor. Team StitchWorld surveys different ironing options in the market and reviews them based on their end use.
The end use of an iron influences its characteristics such as size, shape, wattages and steam consumption. Man-made fibres like polyester, viscose and their blends can be finished with electrically heated sole plates. However, for wrinkle resistant fabrics steam is used in combination with electricity. Fabrics like cotton require only steam at high temperatures for their finishing. Likewise, the choice of size of the iron plate depends on the size and type of garments. A large sized plate won’t be suitable to iron infant clothes as most of the time substantial portions of the plate will be out of the garment area and thus waste energy. Also as an example, inline pressing needs irons of small width whereas finish or final pressing needs an iron with a bigger surface area to reduce the time on ironing. The shape of the iron is very critical in ironing as sometimes there are points in a garment which can never be reached by an iron. The shape depends on the application – a narrow iron for seam opening and a wide base when pressing a panel. For example with a new pointed soleplate, complicated ironing of tucks or pleats is no longer a problem and a slightly arched soleplate point enables improved sliding features. The low weight of iron facilitates smooth gliding over the garments.
Considering power consumption, the reheating time is inversely proportional to the wattage of the iron, i.e. more the wattage, less is the reheating time and vice versa. Due to this probability of maintaining a constant temperature increases with the increase in wattage. But, in many cases high power consumption by an iron indicates poor energy efficiency as well. The wattage to be used depends upon the work load and of course the fabric types being handled.
Based on the consumption of electricity and steam, industrial irons can be Electric, All Steam and Electric Steam.
Electric irons, also called dry irons comprise of an electrically heated sole and its temperature is regulated using a thermostat. A thermostat is a device for regulating and maintaining the temperature of a system near to a desired “set point” and is typically maintained within ±1.5°C. Electric irons like this use no steam and so they have problems in ironing wrinkle prone fabrics especially made up of natural fibres. This is because garments made from natural fibres tend to get wrinkled faster and steam is very helpful in relaxing the fabric wrinkles. Electrical irons are good to use on interlinings and fabrics which don’t crush much.
A major problem with the electrical irons is the development of shine on the fabric surface being ironed. During ironing the small invisible protruding fibres in the fabric surface are aligned in uni-direction, resulting in uniform light reflection thus shine. Also, electric irons have a polished smooth ironing surface which has an increased area of contact and thus results in greater heat transfer thereby leading to burning of the protruding fibres, ultimately resulting in shine on the fabric surface. Moreover, while ironing with electric irons the surface (warps and wefts) of a fabric flattens out and develops the characteristic undesirable glaze.
It is better to use an electric iron with Teflon® [polytetrafluoroethylene (PTFE)] coated plate to avoid much of shine. Teflon coating gives the surface matte finish, which decreases the area of contact between iron surface and cloth and also rearranges the protruding fibres in an irregular manner. These are energy efficient and are available in wattages starting from 800 W.
Steam irons also known as heatless irons, as they operate on relatively lower temperatures 125ºC-145ºC, though high enough to burn the skin. These irons use only steam to heat up their sole plates which comes from a steam generating assembly. It has two pipes one for inlet and other for the outlet of steam; new models have come up with a single pipe for both incoming and outgoing steam. Here the condensation drain tube is built into the steam feeding hose. This is achieved by two concentric hoses (pipes carrying steam) with each (the inner and the outer) employed separately for inlet and outlet of steam.
Typically working on a lower temperature, steam irons provide higher crease recovery as compared to an electric iron running at same temperature because of steam use instead of electricity. It is suitable for use in final pressing, under-pressing, seam opening, and giving touch-ups. It is also good for flat-knit finishing.
Steam Electric Irons
[bleft]A light weight, hand-held version of steam electric iron (called a Hand Finisher) is used for carrying out minor corrections during final inspection, for removing wrinkles, shine and marks as well as for smoothing and freshening of garments and improving the shape of all kinds of fabrics and leather[/bleft]
Steam electric irons utilize the power of both electricity and steam, and so have access to high temperatures as well as better crease recovery. Like electric irons these irons also provide a temperature control of ±1.5ºC. Also, as they can attain higher temperatures, Teflon sole plates are recommended if ironing fabrics like polyester which are prone to shine. These can be of two types chambered and chamber-less.
The chambered one has one electrical connection and a steam inlet. The steam comes and gets stored in the steam chamber(s) and is released with a steam button provided. This has a disadvantage that if the iron is not in use for some time steam condenses and water droplets may come out on ironing later. The chamber-less variety removes this deficiency by providing no storage chambers, putting in one steam outlet pipe; so now the steam is kept in continuous circulation through and back so that there is no condensate formation, but this requires more steam. However, it removes the possibility of any cracks in the iron body due to high steam pressure.
Steam electrical irons can be widely used, on almost every kind of fabric with the right setting of the thermostat and steam pressure. This is the most widely used variety in all finishing setups around the world.
Industrial Gravity Feed Steam Iron (IGFSI)
[bleft]Typically working on a lower temperature, steam irons provide higher crease recovery as compared to an electric iron running at same temperature because of steam use instead of electricity. It is suitable for use in final pressing, under-pressing, seam opening, and giving touch-ups. It is also good for flat-knit finishing [/bleft]
Discontinued by many big players in the iron manufacture, the steam electric ironing system, IGFSI does not require a boiler. It utilizes a separate water bottle that is suspended above the working surface. It operates similarly to a household iron but has the separate water storage for longer amounts of pressing and also uses a professional style iron. It uses distilled water the purpose, which can be obtained from a demineralizer (a type of water purifier). These have same usability as steam electric irons but they are useful in small setups which don’t have capital for a huge boiler and for those which don’t want to have fixed setups of steam lines.
However, using an IGFSI would compromise with the quality of finish to an extent. This is because the steam pressure is not enough to penetrate into the fabric structure to soften them for better wrinkle removal. The IGFSI irons are not suitable for mass production as the operators have to press for a long time for effective heat transfer, which in turn slows down the whole production process.
What to Consider when Buying a New Iron?
There are various industry standard tests which could be checked before buying irons, especially if you are going to buy in bulk. These check the durability as well as safety of the device.
- Drop test: The iron is dropped three feet onto an oak floor, once on each side, once on the point, once on the heel and once flat, while heated and unheated. Iron must continue to operate normally afterwards. There should be no such opening which is big enough to allow a finger to enter the iron and touch any live part.
- Endurance test: Tests the iron for continuous 500 hours.
- Flex test: It tests the cords integrity by flexing it 50,000 times, 20 cycles per minute.
- Temperature test: It determines that no surface of the iron ever gets hotter than 6620F, a condition that could cause a fire.
- Mold-stress test : Here iron is baked in an oven for seven hours at 180F higher than maximum operating temperature to check for its structural integrity.
- Moisture test: It conditions the iron in a humidity chamber for 24 hours at 85% humidity.
- Overfill test: In this, a steam iron is overfilled till water drips over the unit to check for a shock hazard.
- Strain relief test: Here, the cord is pulled for one minute by suspending a 20 pound weight from it to simulate the effect of yanking on the cord.
- Stability test: Tests if iron can stand stably, it is angled on an inclined plane at 100 to observe if it does tip over.
- Flame resistance test: The iron is applied with direct flame for 30 seconds to determine if it is combustible.
- Leakage test: It is checked for the presence of excessive current on the outside of the appliance.
- Power-input test: This determines that the iron draws no more than 105% of rated wattage.