Door panel: door panel is made of stainless steel 304 with no frame. Core materials are paper honeycomb, aluminum honeycomb, PU, EPS and etc. The installation sites of door lock, door closer and hinge are reinforced with square tubes of more than1.5mmthickness which are compression moulded by special technology.
Door frame: it is made of completely stainless steel 304. The connection types with wallboards are double-clip type and aluminum connection. The former is applied mostly to machine made wallboard and the latter hand made wallboard. The accessories are double window and lift type sweeping bar. The lock can be famous door lock or the owners can select lock brands themselves.
Specification: common sizes 800X2100, 900X2100, 1500X2100 or1800X2100, can customize to customers` requirements, the materials can be selected according to customers` requirements such as306Lor other special materials.
Features: the stainless steel 304 door we produced are of elegant appearance, sturdy and durable, acid and rotting resistance and thermal insulation. It is the first choice for high-end projects at home and engineering concerning foreign affairs that requires for anticorrosion and high quality such as electronics factory and food factory
Hospital Sliding Door,Hospital Automatic Sliding Door,Hospital Sliding Glass Door,Hospital Sliding Ward Door Shenzhen Hongfa Automatic Door Co., Ltd. , https://www.pvchighspeeddoor.com
Third, steel drum screen printing method
Screen printing plate making is the basis of screen printing. If the plate making quality is not good, it is difficult to print a good quality product. The failures in printing are often related to the improper selection of materials in plate making process technology and plate making. Therefore, if you want to make a good quality screen printing plate, you must correctly master the plate making technology according to the requirements of the plate making process, and strictly select plate making materials for plate making. The issues involved in the platemaking work include: how to correctly use the materials used in plate making, such as screens, frames, and photosensitive materials, and how to master the bottom plate making, stretching, coating, printing, developing, and light source.
(a) Screen
The screen is the skeleton of the screen, and it is the substrate that supports the photosensitive film. The commonly used wire mesh screen printing for steel drums is monofilament nylon mesh, thin nylon mesh, and stainless steel mesh.
1, nylon mesh
It is a nylon monofilament weaved and heat-treated and dimensionally stable after weaving. Plain weave can reach 380 mesh and twill weave is larger than 330 mesh. Nylon mesh has the following characteristics:
(1) The nylon mesh has a smooth surface and good ink permeability, and can use inks with large viscosity and large particles, so that a fine print pattern can be obtained;
(2) Use fine mesh woven mesh nets, suitable for very fine line drawing patterns and dot printing;
(3) Large elasticity, appropriate flexibility, good adaptability to the surface of steel drum, suitable for printing curved surface of steel drum;
(4) The tensile strength, nodule fastness, elasticity and friction resistance are good, and the service life is long;
(5) Good resistance to acids, chemicals, and organic solvents. Recycling is easy, especially for alkalis.
Use nylon mesh should pay attention to the following points:
(1) Compared with polyester silk and silkworm silk screens, nylon silk screens have high elongation. In order not to cause a printing failure, it is necessary to increase the tension of the stretching net, and at this time, the contraction force also becomes large. Therefore, it is required to use a strong frame and a stretching machine.
(2) Because of its low heat resistance, if the mesh is fixed to the frame by the hot melt method, the operation is difficult;
(3) It is not resistant to erosion by strong acids, phenols, cresols, formic acid, etc.;
(4) Poor light fastness, easy to degrade under ultraviolet light, avoid light when storing.
2, polyester mesh
Polyester mesh has the following features:
(1) It has small elongation and strong elasticity when it is under tension, and single-line screen is suitable for high-precision printing;
(2) The tensile strength, structural strength, resilience, and print resistance are all good;
(3) It has sufficient chemical resistance, especially acid resistance and organic solvent resistance, and can be recycled and utilized like nylon.
(4) Low hygroscopicity, hardly affected by humidity;
(5) Heat resistance is higher than that of nylon, and is less affected by ultraviolet rays than nylon.
Polyester mesh should pay attention to the following points:
(1) It needs more stretched net tension than nylon net, and it requires stronger frame, stretcher and firmer bonding method;
(2) Due to the hydrophobicity of polyester, it is difficult to adhere to the plate, and care must be taken to wash and degrease the plate before plate making.
(3) The ink is poorer than nylon, and is not resistant to alkali corrosion.
3, stainless steel wire mesh
Stainless steel wire mesh has the following characteristics:
(1) excellent plane stability, stable dimensionality of the produced graphics, suitable for printing high-precision steel drum products;
(2) excellent ink passability;
(3) Good alkali resistance and tensile strength, excellent chemical resistance;
(4) Strong heat resistance, suitable for the printing of hot melt printing materials.
The disadvantages of stainless steel wire mesh are:
(1) susceptible to damage caused by external forces;
(2) In the printing process, it is easy to loosen the mesh due to pressure and affect the resistance to printing force;
(3) The price is high and the cost is high.
The thickness of the screen should be compatible with the fineness of the pattern on the surface of the drum. The rough pattern can be used with a coarse mesh below 200 meshes, the general pattern is a screen with 200-300 meshes, and the fine pattern is a fine mesh with a mesh size of 300 mesh or more.
Nylon mesh, polyester mesh and stainless steel mesh are commonly used screen printing materials. Nylon mesh has good resilience, good ink permeability, less static electricity than polyester mesh, good wear resistance, moderate cost, and is generally The preferred screen for drum printing. However, due to the high elongation of nylon mesh, it is not suitable for printing high-precision patterns. For screen printing, such as multicolor printing, polyester screens are preferred; when printing patterns require particularly high precision, stainless steel screens should be used. Because stainless steel screens have major drawbacks of poor flexibility and high price, they are generally used less frequently in screen printing of steel drums.
(b) Frames and stretch nets
1, the net frame
The frame is a frame used to support the screen. It is made of metal, wood or other materials and is divided into two types, fixed and adjustable. The most commonly used is the frame made of aluminum. The materials used to make the frame will meet the tension requirements, and will be strong, durable, lightweight and inexpensive.
Square and rectangular frames are generally used for printing on the top surface of a drum. However, when printing on the circular surface of the barrel body, a frame adapted to its shape is generally used.
The cross-sectional thickness and shape of the frame material are also different due to the different methods of fixing the screen, its use, and strength. For example, when fixing a screen with an adhesive, angle members and corners are generally used; when performing physical fixing, a slotted frame is generally used. In the case of higher strength requirements, strengthen the ribs on the inside of the tube and use a certain thickness of the tube. In addition, some special frames themselves are equipped with stretching nets, which can be stretched without stretching the net. FIG. 2 is a cross-sectional schematic view of various shapes of the frame.
In order to ensure plate making, printing quality and other requirements, the frame can be selected based on the following conditions.
(1) Strong resistance to strain. The material of the frame should have enough strength to resist the tension of the mesh, because when the mesh is stretched, the mesh will produce a certain pulling force on the frame, and if the strength is not enough, the frame will flex and deform, so that no good print will be printed.
(2) It should be prestressed. After the netting, the bending deformation of the frame will affect the tension stability of the screen. To reduce this effect, the network box can be pre-processed. There are two methods for handling: First, according to the strength principle of the arched structure, the mesh frame is made into a convex shape, its deflection is about 4 mm/meter, each internal angle is slightly larger than 90°, or the metal frame that has been made, With a special tool to stretch this shape, this pre-deformation treatment can resist the impact of the screen tension. Another method is to do a pre-stress treatment while doing pneumatic pulling, that is, the front end of the drawer is tight against the outside of the frame, the net frame is bent by the top force, and when the net is fixed, the frame is subjected to force. Although the surface is moved from the outside to the top, the force direction and size are basically the same, so no more bending is added. Due to these advantages, the pneumatic stretching machine has become the most popular one at home and abroad.
(3) Suitable size. The production of different specifications of the network box configuration, when used according to the size of the print size to determine the appropriate frame, can reduce waste, but also easy to operate.
The size of the frame should be larger than that of the printing plate. If the plate pattern is a × b, the inside size of the frame is 2a × 2b, which can be fully printed. The selection of the frame size is based not only on the printing area, but also on the need for the squeegee and the starting and ending positions of the ink return plate during printing; the need for printing ink on the plate; and ensuring uniform screen tension at the plate version. The need for silk screen printing in the squeegee printing stroke.
2, stretch net
The stretch net stretches the wire mesh to the frame, which is manually operated and mechanically operated. Manual stretch nets are simple and easy to use and are commonly used methods, while mechanical stretch nets are of good quality. Whether it is hand-stretched or mechanical stretched nets have to pay attention to the tension of the screen. It is not easy to stretch the tension of the screen too much. If it is too small, the screen tends to be loose (the stainless steel screen will also appear premature relaxation); if it is too large, the screen will break easily. In the actual stretching operation, the tension of the stretching net can be determined empirically, and while the screen is stretched, the screen is pressed with a finger until the screen has a feeling of elasticity. Commonly used stretching methods are:
(1) Manual stretch nets The manual stretch net steps are as follows:
1 Cut a screen larger than the size of the outer net frame. Generally, the length and width of the screen are 40~60mm larger than the size of the outer net frame.
2 soak the screen in water.
3 The screen is placed on the frame. The latitude line of the screen is parallel to the frame (vertical). However, when used for high-precision printing or level printing, the latitude line is at an angle to the frame. It is 20°~45°.
4 Place the strip a, nail the frame A, and then pull the screen toward the direction of E (see Figure 3). Then all the strips a nailed, fixed AB side.
5 Tighten the screen in the direction of F, put the molding c, and then screw the C end. Then, while pulling the screen toward the direction of G, tighten the molding c so that the side of the CD is fixed.
6 In the same way, nail the bars b and d and fix the BC and AD sides. At this point, the stretching operation is completed.
(2) The device stretches the net? The stretch net of the device is also called self-expanding net. This kind of stretch net method uses more simple equipment to assist manual stretch nets, and its net frame is called self-tension net frame. This kind of frame is mostly made of metal. Its outstanding feature is that it can be pulled at any time. After the stencil is loose, it does not have to be replaced and it can be used again. In recent years, roll-type self-expanding nets have been successfully used for precision printing, and the market has expanded rapidly. Among them, the rolling frame has the best performance. It is composed of four aluminum tubes. The tube has a simple fastening device to clamp the screen. The two ends of each frame tube can be twisted with a wrench to complete the stretching.
(3) Motorized stretch nets The mechanical stretch nets are used in motorized stretch nets. The mechanical stretcher has a buckle type, a screw type and a gear type. Large-scale stretch nets are generally motorized, while medium- and small-size stretch nets are mainly manual.
The biggest feature of the manual mechanical stretching machine is that it does not require electricity and gas. The quality of the stretching net is significantly higher than that of manual stretching, and it is close to the quality of the pneumatic stretching net.
(4) Pneumatic stretching nets Pneumatic stretching nets use compressed air as the air source to drive multiple cylinder pistons to synchronously push the net clamps to perform relative contraction movements in both vertical and horizontal directions, resulting in uniform and consistent tension on the screen. Generally, the net pressure of the nylon mesh can be controlled at 0.8-1.0 MPa; the stretch net pressure of the polyester mesh can be controlled at 0.8-1.0 MPa; and the stretch net pressure of the stainless steel mesh can be controlled at 1.0-1.3 MPa.
When using the pneumatic stretching method, the net frame is first placed on the stretching net, and then the net is fixed on the chuck after the net horizontally is laid flat on the net frame. Tension is applied according to the required tension, and then the adhesive is applied on the contact surface between the frame and the screen. This method gives uniform tension.
3, the fixed screen
There are two methods for fixing the screen to the frame, namely the clamping method and the bonding method.
(1) The clamping method The clamping method is to clamp the screen between two objects and fix it with friction. The fixing method of the screen is not easy to loosen, but the tension of the stretching net is not easy to control, and the manual stretching net is commonly used.
(2) Bonding method The bonding method uses an adhesive to fix the screen. The screen tension of this fixing method is easy to control, but after a period of use, the screen will loosen. Commonly used adhesives are the following.
1 photosensitive adhesive
The formulation of the photosensitive adhesive is as follows: epoxy phenolic methacrylic resin 300 mL; benzoin butyl ether 10-12 mL; anhydrous ethanol 150 mL.
How to use: Apply the adhesive on the adhesive surface of the mesh frame so that the taut mesh adheres tightly to the adhesive surface. Apply a layer of adhesive to the joint between the mesh and the mesh frame. After being coated, it is cured with ultraviolet rays, that is, irradiated with a 1000 W ultraviolet high-pressure mercury lamp, with a distance of 500 mm, a time of 5-8 minutes, and cooling with a fan.
2 Polyvinyl acetal glue Diluted 4 parts of JSF-4 glue with 1 part absolute ethanol, brush on the adhesive surface of the mesh frame, tightly touch the tight mesh and then brush once, naturally dry or use Infrared drying. This adhesive is often used for the bonding of wooden net frames and metal net frame stretch nets.
3 Shellac? Dissolve 1 part of insect film in 3 parts of anhydrous ethanol to make a shellac solution. In order to facilitate the bonding, the surface of the frame can be pre-coated with shellac, dried and used. When sticking the net, a sufficient amount of absolute ethanol is directly applied on the screen of the adhesive layer to dissolve the shellac. After being dried, it can be used.
In addition, there are phenolic-neoprene, nitrile rubber, nitrile rubber, nitrocellulose gum, vinyl chloride rubber and so on.
It is usually purchased from the market. The commonly used imported adhesive nets are Japanese-made W-18 and Italian-made UG-3 adhesive, which makes the operation very easy. The tension of the stretch net is easy to control, and the net and frame are sticky. Firmly.