Maintenance of heat transfer printing machines

1. The base plate of the tablet machine
This is mainly for low-end flatbed machines. In order to reduce costs, the thick aluminum plate that should be used for the bottom plate has been changed to a thin steel iron plate welded into a cavity. Due to the easy deformation of the plate, after using it for a period of time, one side or one corner tilts, resulting in uneven pressure, resulting in light colors in these areas after transfer printing. When using pure cotton transfer paper, it is not pressed tightly, resulting in clothes being scrapped.
2. Relay
The temperature of the heat transfer equipment is maintained to a certain extent. The principle is that when the temperature rises to the allowable upper limit, the power supply to the development heat plate is cut off, and the heating is stopped. When the temperature drops below the allowable lower limit, the power supply to the heat plate is turned on to heat it up. Repeated control is used to make the temperature fluctuate above and below the set value.
The disconnection and connection are achieved by relying on relays, and the attached figure shows the commonly used relays in thermal transfer equipment. Small power relays are generally used for small power equipment such as toasters and baking pans.
3. Temperature and time control devices:
Whether it is a baking cup machine, a baking tray machine, or various tablet machines, temperature and time must be controlled. Therefore, a temperature controller and a time controller are needed, which can be divided into two types: one is digital setting digital control. Another type is analog control (using a knob to rotate to the position specified by the scale).
The function of both is the same, with the difference being that the setting of the digital display can be very accurate without the need to rely on the eyes to estimate the scale. At the same time, digital control can display the temperature (or time) of the heat transfer equipment in real-time, which is very intuitive and accurate. This is a superficial result, but there are actually internal differences.
Time controller: The scale indicates the charging and discharging time of the capacitor, and the charging and discharging of the capacitor is a differential and integral transformation curve. The function curve is not a straight line, so the indication of the dial is not uniform. However, even if the dial imitates the differential and integral curves of the capacitor, due to differences in components, the scale indication error is often large. For someone who is very familiar with heat transfer printing, it is determined by testing a few times and scrapping a few products, so that there will be no problems with transfer printing in the future. But for a novice or transfer printed product, the timing often varies, which may be a nightmare.
Temperature controller: For temperature controllers with scale indication, the control temperature is generally 20 degrees above or below the set temperature, while for digital control, it is generally 5 degrees above or below. Don't underestimate this error. For products that only take 25 seconds for transfer printing, an additional 10 degrees above or below can cause some temperatures to be too high and scrapped, and some temperatures to be too low and the image to be blurry. This type of product can only be suitable for products with longer transfer time and lower temperature requirements. For surface transfer printing of metals, ceramics, and other materials, the results of continuous transfer printing of products result in varying shades of color, making it difficult to control the effect.
4. Heating plate/pad
This component is the core of heat transfer printing equipment, and its importance and value are like that of a nozzle to a printer. The picture tube is for the display. The value accounts for about 1/4 or even half of the total machine value.
The most critical requirement is that the heating plate/pad as a whole should heat evenly. In the heating plate/pad, heating relies on the electric heating wire inside.
For baking cup machines and baking tray machines, due to the direct laying of electric heating wires and S-shaped electric heating wires on silicone, the spacing can be made very small, so even heating can be achieved by relying on oneself.
For cap baking machines and flatbed machines, due to their large area and high surface flatness requirements, metal plates must be used to meet the requirements. Metal is conductive, so the electric heating wire must run inside insulated conduits. In this way, it is necessary to rely on the simultaneous thermal conductivity of the metal plate to achieve overall temperature balance. For large format flatbed machines, such as 80cm * 120cm flat plates, electric heating devices are generally used to heat the oil, relying on the flow of high-temperature oil to achieve the average heating of the entire heating plate.
Next is power. If the power is low, the edges of the heating plate/pad emit more heat due to radiation, conduction, and convection, while the heat generated by the low-power electric heating wire cannot supplement the dissipated heat, resulting in insufficient temperature near the edges. Thus, defective or even scrap products can be transferred and printed.
If the heating plate has poor manufacturing process, poor materials used, or low power, it will directly lead to uneven transfer color, or the intermediate transfer temperature is too high or too long and blurry.