Powder Coating Curing Oven

How to choose the suitable powder coating cure oven ?Choosing the suitable oven for the applications depends on all sorts of variables, including the product size, shape, thickness, material composition, and production throughput, operating cost and type of energy to be used must be considered.Curing Ovens should be designed to ensure efficient use of production labour and minimum maintenance is required.Temperature should be exactingly controlled, if possible within 3 degrees of the specified curing temperature, temperature indicating heads should be situated as near as possible to the path of the workpiece in the oven.Convection ovens is most popular method where gas or oil-fired heaters are used to heat air. This is circuilated through an enclosed space where it provides the requiremd temperature. The powder coated pieces are carried in to oven, reach the surrounding temperature and keep this temperature for the set time.In a direct fired oven, the products of burner combustion are carried directly in to the heat holding zone, in an indirectly fired oven the burner products pass through a heat exchanger so that only clean air enters the heat holding zone.Infrared ovens Generally, infrared heat energy is emitted by a hot body and transferred in straight lines untill it makes contact with another body when the heat is absorbed by the latter causing it to rise in temperature.

How many type of heating method of the curing oven?Powder coating curing is the final step in the paint process, the cure oven raises the products and coated material to a specified temperature and holds this temperature for a set time. Typically, 20-30 mins at a set temperature is need to achieve a minimum curing for 20 minutes. There are two types heating method.Direct heating: like electric oven,powerd by heating pipe, and infrared powerd oven, by infrared burners.Indirect heating: like Gas powered oven and LPG/DIESEL powered oven, generally will install a combustion chamber, the advantage of this one is make the oven inner more clean and the heating more well-distributed, longer time operation life time.Choose which one all depends on your situation just at that moment.

A convection oven has five major components.Oven enclosure (shell):contains the environment necessary for the curing process, including a support structure, insulated panels, and product opening seals.Heater unit: the second system at work in an oven is the heater unit.The heater generates the energy for curing and beings the distribution of energy.The most of the heater are the burner, supply fan and filters.Supply air system.Recirculated air system, the recirculating system returns oven air to the heater unit so that energy is continually added to the oven. Exhaust air system, every oven must be exhausted, Exhausts create a negative environment so that air seals operate properly  .

                                     You do not know how to build your curing oven? what is cheaper?  what are the costs?We will answer your questions.Electric heating curing oven uses heating elements heat, less investment disposable equipment, high degree of automation, simple structure, easy maintenance, the disadvantage is consuming large use. Heating with electricity as energy, cost a little high.oil fuel heating curing oven :heating curing oven rapid heating, the furnace temperature uniformity, consistency of good quality finished products. Disadvantages: 1. one-time investment is relatively large; 2, with the gradual increase in oil prices, the cost advantage compared with electricity becoming Gas heating curing oven :In high-volume continuous industrial processes, gas curing oven in production costs than electric heating can save 60% ​​-70%, non-polluting, and the power supply system requirements are very low, generally the size of a curing oven just 3 to 5kw the power supply will be able to workGas powder coating oven  advantages: lower consumption costs, rapid heating, the furnace temperature uniformity, high degree of automation, environmental pollution, the quality of the finished product consistency well; both adaptation intermittent work, but also to adapt to continuous work; fuel choice or canned liquefied natural gas pipelines, natural gas cans   Disadvantages: one-time investment much higher than electric heating system

                                    curing oven types , A curing oven must heat a part repidly to the desired metal temperature,without disturbing the powder on the part ,and exhaust the by-products of cure and combustion.There are three ways to heat parts to the metal temperature required to cure the powder coating , Convection ,which transmits energy by air circulation to heat the part . Radiation,which transmits energy directly to the part without heating the air between the part and the radiation source. Conduction ,which transmits energy to heat the part by coming into contact with the heat source.The physics principles above are more identifiable by the actual ovens that employ them. For example ,conduction heating systems are mostly used to preheat parts for fusion-bonded epoxy applications asuh as those used in pipe and concrete rebar powder coating systems. Because these types of ovens have limited applications in the powder coating undustry Gas -and electric -fired infrared ovens use radiation in high or low intensities to heat parts. Although IR systems sometimes are used to boost the temperature of the part as it enters a  convection oven ,they normally are used to cure powder on parts of simple construction and symmetrical shape. Even though IR systems can efficiently cure powder in a very short time (as little as 30 seconds),they have line -of -sie limitations that prevent them from curing all areas of complex parts. An IR emitter can only provide energy to part surfaces that it sees ,Some heat transfer occurs along the part surface ,however,these is a risk of overbaking exposed surfaces before full cure takes place on hidden surfaces.A sufficient array of IR emitters must be used to cure the entire part.Convections systems are the most popular type of oven used to cure powder coatings. They are available in drect-fired gas ,indirect-fired gas and electric styles .electric and indirect-fired gas styles are good choices if the by-products of combustion cause discoloration of light-colored powders .Electric can be used when gas is unavaible. The most prevalent oven design in powder coating systmes , direct-fired gas convection ovens circulate the spend combustion air throughout the oven interior to heat a part to the desired metal temerature.

                                    Choosing the oven  suited for a particular application depends on all sorts of variables, including the product size, shape, thickness, material composition, production throughput, operating cost and type of powder to be used must be considered.As powders are cured or hardened, time and temperatures are critical considerations.  Within certain limits a period at a lower temperature may be equivalent to a shorter exposure period at a higher temperature.  However it must be emphasized that the curing temperature specified by the powder supplier refers to the article temperature itself and not to the air or panel temperature of an emitter.Ovens should be designed to ensure efficient use of production labour and minimum maintenance is required.  Maximum use should be made of fuel and the efficient recycle of hot air maintained where possible.Temperature should be exactingly controlled, if possible within ±3oC of the specified curing temperature..  Temperature indicating heads should be situated as near as possible to the path of the workpiece in the oven.Due allowance should be made for possible extension of the oven and/or possible changes in the type and flow of workpieces being processed.Care should be taken that air velocities within a forced convection oven should not be so strong as to blow powder off or to move workpieces so that they come into contact with each other during stoving.  Air velocities which are acceptable lie in the 1-2 metres/second range.If the oven has relatively small openings normal exhaust seals will be adequate, but with larger openings seals that re-circulate to minimise heat loss are effective.Ovens available to cure powders differ widely using a variety of heating methods.Convection ovensThis is by far the most popular method where gas or oil-fired heaters are used to heat air. This is then circulated through an enclosed space where it provides the required temperature.  The powder coated pieces are then carried into this space where they absorb heat, reach the surrounding temperature and are held at this temperature for the specified time.In a direct fired oven, the products of burner combustion are carried directly into the heat holding zone, whilst in an indirectly fired oven the burner products pass through a heat exchanger so that only clean air enters the heat holding zone.  In the latter case, the hot air is free of combustion products which can in some instances interfere detrimentally with the powder during the curing cycle.The quantity of air exhausted from a convection oven must be sufficient to keep the atmosphere within the oven below the lower explosion limit of the gases being released in the oven.Care must be taken, especially in the case of direct fired ovens, to regularly inspect and clean the oven interior as foreign material can build up on the inner oven sections, which can from time to time flake off and adhere to the workpieces which in turn can lead to rejection.Infra-red ovensBasically, infra-red heat energy is emitted by a hot body and transferred in straight lines until it makes contact with another body when the heat is absorbed by the latter causing it to rise in temperature.  The main advantage of radiant heating is that it produces a rapid rise in object temperature.  As the temperature of the heating source is increased, so the proportion of heat transferred by radiation as opposed to convection increases appreciably.  The amount of heat energy radiated from any source depends upon its area, its temperature and its emissivity.Medium temperature radiation offers the most effective source of radiant heat for curing thermosetting powder.  Usually the emitter panels are gas-fired giving a panel surface temperature of 850-950oC, or alternatively sheathed electric panels of a surface temperature of 750-850oC.  The workpiece is maintained at about 30cm from the emitter panel surface with a minimum distance of 15cm.The color of the powder is an important consideration – light colors can reflect (depending on powder composition) proportionately more infra-red radiation and do not heat up as quickly as the darker colors.  This means that each and every powder must be evaluated to determine the optimum curing conditions.As radiant heat tracks in straight lines, coated articles of intricate design, or having sections shielded from the radiation source cannot be processed using this method.  Ideally infra-red radiation is used for simple workpieces such as relatively flat surfaces.