Since the 1980s, plastic doors and windows have started to rise in our country. The manufacturing methods and technical conditions of plastic doors and windows have been basically developed and mature. With the development of the society, China is constantly improving the production standards and requirements of plastic doors and windows, among which are the six physical performance indicators: air tightness, water tightness, wind pressure resistance, sound insulation, thermal insulation, day lighting. They are the life of doors and windows. Whether the doors and windows can meet these six requirements is the most important in the manufacturing. In order to improve the performance of doors and windows, each link of the manufacturing process is the key factor. The following is a discussion on the relevant technical requirements and process improvement of the manufacturing process of doors and windows according to the relevant requirements of national standards.
Step1. PVC profile blanking, milling "V" port
The quality requirements shall pay attention to the following three aspects.
1. Allowable deviation of "V" opening depth is within ±0. 3mm
2. Angle deviation of saw cut shall be controlled within ±0. 5mm
3. It is required that the sawing flatness is ≤0. 5mm
At present, some door and window manufacturers don't use "V" port welding to connect the plastic section mullions, but use rigid corner welding. The latter is a better connection method than "V" port welding. Because the lining steel of "V" welded joint is in an empty state. No matter what, the difficulty of angle cleaning is increased. The problem is solved by using corner bolt connection, which makes the joint more beautiful and the wind pressure resistance strength is further improved. This method is worthy of further promotion.
Step 2. Drain hole Vent hole (also called air pressure balance hole)
Drainage holes have been widely used in the production of doors and windows at present. There are a series of relevant technical standards, which depends on the profile design in recent years to improve the technical content. Multi-chamber profiles have been continuously put on the market. The three-chamber profile structure design is a good option from the practical, thermal insulation and economic aspects. Therefore it is most widely used. It has separated the steel lining cavity, the drainage cavity and the thermal insulation cavity. The cavity has its own use. The drainage function of doors and windows has come into being since then. It has become a great progress in the development of plastic doors and windows. With the development of the times, the plastic door and window profiles are still constantly improved. Color co-extrusion and color laminated profiles have come out one after another, providing more choices for the vast number of users and being widely favored by users. At the same time, another problem is to drill vent holes.
The material of plastic section is "UPVC "and its softening point is relatively low, generally about 80℃, close to softening.
According to relevant technical data, the surface temperature of PVC profiles of various colors in direct sunlight at 30°C corresponds to the following table:
|Profile surface temperature(℃)
After the plastic profile is made into a door or a window, the temperature of the outer chamber of the profile in a completely closed state rises sharply under direct sunlight. The air in the chamber will further expand, so that the surface of the door and window will bubble, form and swell under long-term direct sunlight, and the strength of the door or window will be greatly reduced. We have to pay attention to this problem. In order to achieve the air pressure balance, the solution to this problem is to blow the vent hole. The completion of this process is not complicated. The vent hole and the drain hole can be completed in the same process. Under the condition that the appearance is not affected, blow the vent hole on the corresponding upper inner side of the drain hole. Generally, according to the length interval ≤300mm, blow the vent hole with the diameter of 5-8mm (if the long hole can be selected as 5×30mm) can solve this problem.
Step3. Sealing strips (Rubber gaskets or brush)
There are two methods for embedding the adhesive tape. The following describes its precautions:
1. Manual penetration method
(1) The rubber gaskets shall not be stretched during installation;
(2) Length shrinkage allowance shall be reserved during shearing;
(3) Only one rubber strip can be installed on each profile without joint;
2. Roller rolling method (this method shall be carried out after welding)
(1) The sealing strip at the corner of the window can not be cut off. A bit of connection shall be left on the edge of 45 degrees of shearing. Only one joint shall be left at the corner.
(2) An additional section shall be embedded during assembly to prevent end shrinkage, so as to avoid potential water leakage.
Step 4. Steel reinforcement
(1) Selection of steel reinforcement: it shall meet the wall thickness standard and shall not be less than 1.5mm, and the surface shall be subject to anti-corrosion treatment.
(2) Conditions for assembling steel lining for profiles:when the length of profiles is more than 450mm and the hardware must be assembled with steel lining.
(3) Assembly method:the steel reinforcement shall be fully inserted into the inner cavity of the profile and shall not affect the welding.