1. Some parts of my new stainless steel press plate become colored after using for some time, why?
There are two possible reasons.
a. The temperature of press plate is not in accordance with the curing temperature of paper, and the high temperature of steel plate leads to an undesired chemical reaction, thus causing the color change. In addition, the steel plate is able to endure 1000°C.
b. If the glue content of melamine paper is low and there is too much urea resin, this phenomenon may occur as well.
2. How to avoid platen sticking during initial use?
When the boiler starts to work, put a thin raw board in the hot press, and the heated platen moves down onto the unlacquered board. This is intended to raise the temperature to a desired value without pressurizing though the platen is closed. The temperature should be increased at a low speed at this time, and the recommended value is within 20-30°C/h. For initial use, the hot platen should press the unlacquered board for five times, and then you can bond melamine paper onto the substrate.
The implementation of raw board is to realize fully contact between hot platen and press plate, thereby ensuring uniform heat transfer. Moreover, the temperature and closing time for the raw board are the same as those for melamine paper.
You should contact with the paper supplier to get the curing temperature range of the glue. Usually, we start testing process using the maximum temperature, and slow down the temperature gradually to a middle value. Here are the recommended values for some typical materials.
a. For common embossed board, the test temperature is set at 190°C, and closing time is 18 seconds.
b. For flooring, the temperature should be increased to 210°C because of the existence of abrasion resistant paper.
c. For ordinary flat board, the test temperature and closing time are 150°C and 15 seconds, respectively.
After this step, melamine paper is applied to determine the working temperature. Please be noted that the temperature should be set at a high value at first, and then it decreases step by step to find out the best value by checking the quality of end product.
3. For power connection, what should I pay attention to?
First of all, the power cord must be able to withstand the load.
Second, the power switch must be connected to the live wire rather than the neutral wire. If the power switch is connected to the neutral wire, there will be a flow of electrical current in the live wire of our equipment even though the switch is opened. Thus, the electrical components would break down due to the unbalanced voltage. In particular, the PLC controller may be damaged as a result of misoperation.
4. How to prolong the service life of oil cylinder?
When the hot press stops, please remember to release the pressure to set the press under unpressurized status.
a. For hot press whose oil cylinder is placed at the bottom, the oil cylinder shall be lowered to the bottom so as to open all the platens.
b. For top-mounted type, the upper and lower platens shall contact with each other, but a clean and smooth unlacquered board must be inserted between them to avoid damages to the mould or stainless steel press plate.
5. How to decide the boiler capacity?
a. For a 5-layer 1200T door skin hot press (3×7 feet), the boiler capacity should be 400,000 kilocalories if the fuel is coal, while the number is changed into 500,000 for diesel oil.
b. If the boiler uses coal to generate heat, its capacity needs to be 200,000 kilocalories for 1200-1400T double side hot press (4×8 feet), while 150,000 kilocalories is enough for 1200-1600T single side type (4×8 feet).
6. Is it proper to use a 6×9 hot press to make 6×8 or 4×8 boards?
6×8 is OK because it is only slightly smaller, but 4×8 is not allowed. For 4×8 boards, the oil cylinder’s center of gravity will deviate from the board edge, and the finished board will have a thinner edge. What is worse, the hot platen will deform after long-term use.
7. I don’t have any manufacturing experience in this field, and I am not familiar with the production process. What should I do?
You can turn to us for help, and we can provide some simple production instructions. If professional technique is needed, we strongly recommend you to send your engineers to receive training courses in China, and we can help to arrange this. The cost depends on the requirements of the factory that your engineers are going to learn in, but it is usually affordable. Otherwise, it is very expensive to invite Chinese engineers to your factory to give out lessons.
8. Why the finished board is partially white?
The single side hot press is usually used to process thin board with thickness between 2 and 5mm. The thin board has low elasticity, resulting in uneven pressure distribution. Given this, you can place a raw board on the lower worktable to realize uniform pressure distribution, and its thickness could be adjusted according to actual performance.
9. Why there are blisters on the finished board?
When the furniture board is heated up, the moisture inside will change into gas via vaporization process, leading to this phenomenon. So, you can lower the temperature properly to solve this problem. However, if high temperature is a must for the pressing step, you can use furniture board with less moisture content.