What should we pay attention to when choosing the spring of vibrating screen? The following four points will be used to make a simple analysis for you:
1. The suitable rubber material should be selected according to the sieving material, environment and conditions, as well as the specific gravity and static electricity of the material itself.
2. Attention must be paid to the bonding degree between rubber and metal to avoid stress concentration at the bonding surface.
3. Technically, in order to improve the service life of shear deformation isolators, Alide machines usually give proper pre-compression in the vertical shear direction, which hardens the stiffness in the compression direction and softens the stiffness in the shear direction.
4. If there is resistance, energy must be consumed. This part of lost energy is converted into heat energy. Rubber is a bad conductor of heat. In order to prevent excessive temperature rise from affecting the performance of rubber isolators, rubber isolators should not be too large. Structurally, measures should be taken that are easy to dissipate heat, or natural rubber materials with less heat generation should be selected. Because rubber isolator can convert part of energy into heat energy, reduce vibration energy and achieve the purpose of vibration reduction, so rubber isolator is often called shock absorber.
There are many kinds of hooks, there are very standard plastic hooks, there are some strange shapes. Generally speaking, no matter what kind of accessories, the stranger the shape, the less use it will have. Who calls a person too professional? Here are some typical introductions. Plastic hooks are seldom used in external systems, because during the travel process, things outside the package are easy to collide, and plastic things, no matter how hard they are, are also vulnerable to damage. Generally large hooks are often used on the backstrap of a waistbag or leisure schoolbag, and are used with D-rings on both sides of the bag. Small hooks are often used in bags to hang keys and other things. The hook on the left is strong enough to rotate and has metal spring openings, thus avoiding the disadvantage of easy breaking with plastic openings. Usually used for single shoulder bag strap and D ring connection. This strength of the hook is sometimes used on the outside of the load. The small hook is usually used to hang small bags, keys and other small items in the bag.
2.D-ring (DRing)
D-ring, named for its shape like the letter “D”. It has a wide range of uses. It is often used to fix pipes on the back strap or hang small objects (do many donkey friends often put towels in D-rings to wipe sweat on their faces when they are on the road?). There are not many kinds of D-rings. The arc is smooth and suitable for use with forefinger or thumb, so some bags will design the D-ring in place to support the force. For example, a larger travel bag has a D-ring in front of its right strap, which is designed to use the right hand to assist with the afterburner when the bag is too heavy. Sometimes the plug-in system uses a D-ring.
3. Square Loop
Like D-rings, square rings are named for their shape. Square rings are often used in plug-in systems. For example, a general mountaineering bag has four square rings on its cover, which can be used to hang things like sleeping bags. The square ring can be used in conjunction with an elliptical three-stop buckle and can be fastened like a button on a garment. It is easy to attach a small hanging bag to the backpack. It can also be used as a square buckle.
A. Metal well covers: cast iron, ductile iron, bronze well covers, etc.
B. High-strength steel fiber cement concrete well cover (cement-based composite material);
C. Recycled Resin Well Cover (Recycled Resin Matrix Composite);
D. Polymer Matrix Composite Material Inspection Well Cover, etc.
among
Composite material covers are divided into inorganic composite covers and organic composite covers.
The steel fiber reinforced concrete inspection covers are classified into four grades according to their bearing capacity: a, b, C and D.
Grade A steel fiber reinforced concrete inspection well cover is used for special roads and sites such as airports.
Grade B steel fiber reinforced concrete inspection covers are used for urban roads, highways and parking lots where motor vehicles are driving and parking.
Grade C steel fiber reinforced concrete inspection well cover is used for slow lane, passageway and sidewalk in residential area.
Grade D steel fiber reinforced concrete inspection well covers are used for green belts and roadways and sites where motor vehicles can not drive or park.
Rockwell hardness tester is used for hardness testing of metal stamping parts. Small stamping parts with complex shapes can be used to test the plane is very small and can not be tested on ordinary desktop Rockwell hardness tester.
Stamping process includes blanking, bending, drawing, forming, finishing and other processes. Stamping materials are mainly hot-rolled or cold-rolled (mainly cold-rolled) metal strip materials, such as carbon steel plate, alloy steel plate, spring steel plate, galvanized plate, tin plate, stainless steel plate, copper and copper alloy plate, aluminum and aluminum alloy plate, etc.
PHP series portable surface Rockwell hardness tester is very suitable for testing the hardness of these stamping parts. Alloy stamping parts are the most commonly used parts in the field of metal processing and mechanical manufacturing. Stamping parts processing is a method of separating or forming metal strips by means of dies. It has a wide range of applications.
The main purpose of hardness testing of stamping materials is to determine whether the annealing degree of the purchased metal sheet is suitable for the subsequent stamping process. Different kinds of stamping process require different hardness levels of sheet metal. Aluminum alloy sheet used for stamping can be tested by Wechsler hardness tester. When the thickness of material is more than 13mm, it can be changed to Barkholder hardness tester. Pure aluminium or low hardness aluminium alloy sheet should be used Barkholder hardness tester.
In the stamping industry, stamping is sometimes called sheet metal forming, but it is slightly different. The so-called sheet metal forming refers to the forming method of using sheet metal, thin-walled tube, thin section as raw materials for plastic processing, which is collectively called sheet metal forming. At this time, the deformation in the direction of thick plate is generally not taken into account.
1. Lightweight and high rigidity: The base made of extruded aluminium alloy profiles is combined with linear guides to achieve lightweight and high rigidity. High rigidity, high precision, low price, small size, light weight, aluminium alloy structure, modular design, sliding table and base are loaded into linear guide rail after passing through the anode. The base is matched with sliding table to achieve high rigidity and load capacity. The small displacement of load can also maintain high stability for the quality of load or the use of external load changes.
2. Corrosion resistance: Aluminum alloy base and sliding base can be selected. Its surface can be passivated by high corrosion resistance and wear resistance aluminum alloy (natural anodic oxidation treatment). In addition, stainless steel linear guide rail and installation screw are all made of nickel plated material with special treatment, so it has sufficient corrosion resistance.
3. Structure and specialty: Pneumatic sliding table is a single-axis intelligent combination unit which can be installed with LM linear guide rail and aluminum alloy base and combined with cylinder drive. Transportation is its main use.
4. Component standardization: realizing modular component standardization of pneumatic equipment. Horizontal and vertical directions can be used in handling, transmission and conveying operations. The pneumatic sliding table module can replace the cylinder and has the advantages of low price, long service life and easy maintenance.
Technological Characteristics and Quality Factors of Metal Cutting
With the continuous development of machine tools and cutting tools, the accuracy, efficiency and automation of cutting process are constantly improving, and the application scope is also expanding, which greatly promotes the development of modern machinery manufacturing industry. There are many classifications for metal cutting. There are three common classifications: according to process characteristics, according to material removal rate and processing accuracy, and according to surface forming method. The main factors affecting the quality of cutting are machine tools, tools, fixtures, workpiece blanks, cutting oil, process methods and processing environment. Following is a brief introduction of the common types of metal cutting technology and methods to improve quality. I. Characteristics of Cutting Technology
(1) Large-scale
With the increasing size of parts and the high efficiency of parts, a multi cavity mold is required, which makes the mold more and more large-scale, requiring large operation, large shaft stroke, heavy bearing, high rigidity and high consistency.
(2) Complexity
With the complexity of the shape of die parts, it is necessary to improve the design and manufacturing level of the die. The multi-functional composite die with various grooves and materials forming or assembling components in a set of dies requires a large amount of process programming, high comprehensive cutting ability and high stability of deep hole cavity, and improves the processing difficulty.
(3) Precision
The refinement of die processing makes the compounding and high efficiency of processing equipment more stringent. High-speed milling has many advantages, such as Machinable high-hard materials, stable processing, small cutting force, small workpiece warming deformation and so on. Die and mould enterprises pay more and more attention to high-speed milling
Types of Cutting Technology
(1) Classification by process characteristics
The technological characteristics of cutting depend on the structure of cutting tool and the relative motion form of cutting tool and workpiece. Generally, it can be divided into turning, milling, drilling, boring, reaming, planer, slotting, broaching, sawing, grinding, grinding, honing, ultra-precision processing, polishing, gear processing, worm wheel processing, thread processing, ultra-precision processing, fitter and scraping.
(2) Classification by process accuracy
According to material removal rate and machining accuracy, cutting can be divided into rough processing, semi-finish processing, finish processing, finishing processing, decoration processing, ultra-precision processing, etc.
(3) Classification by surface forming
In cutting, the machined surface of the workpiece is obtained by the relative movement of the cutting tool and the workpiece. According to the surface forming method, cutting can be divided into three categories: tool path method, forming tool method and generating method.
3. Ways to Improve Quality
Cutting quality mainly refers to the machining accuracy and surface quality of the workpiece. The main factors affecting the cutting quality are machine tools, tools, fixtures, workpiece blanks, process methods and processing environment. In order to improve the cutting quality, appropriate measures must be taken in the above aspects, such as reducing the working error of machine tools, selecting cutting tools correctly, improving the quality of blanks, arranging the process rationally and improving the environmental conditions.
(1) Selection of process methods
Each kind of surface has a variety of processing methods, and the specific selection should be based on the Parts’processing accuracy, surface roughness, material, structural shape, size and production type, select the appropriate processing methods and processing programs.
(2) Determination of process steps
The general principle of working procedure arrangement is to process the datum first, then other surfaces, first roughing and then finishing, roughing and finishing independently. Two important factors should also be considered in the specific operation to minimize the clamping times so as to improve efficiency and ensure accuracy.
(3) Measures to ensure accuracy
The process assurance measures of key dimensions and technical requirements are very important for the design of process plans, so as to avoid the factors such as clamping deformation, thermal deformation, and processing ripple caused by workpiece vibration affecting the processing quality of parts.
(4) Use of cutting oil Cutting oil is a kind of medium which must be used in metal cutting process. It mainly plays the roles of lubrication, cooling and cleaning in the process of processing. Special cutting oil contains vulcanized extreme pressure and anti-wear additives, which can effectively protect cutting tools and greatly improve process accuracy.
Many people don’t know the use of bimetal band saw blades. How did they lose their teeth? Or is it called teeth beating or broken teeth? Next, we summarize the following reasons for users by synthesizing years of experience:
1. The sawing machine is shaken by the surrounding forging equipment.
2. The sawing machine is unstable and trembling.
3. Workpiece is not tightened and loosened during sawing.
4. Anti-alignment of saw band teeth.
5. Inappropriate selection of tooth shape, too large or too small pitch.
6. Saw frame descends too fast and improper operation causes tooth tip to impact workpiece.
7. The new belt does not run in.
8. The clamped workpiece has slag inclusion and hard point.
9. The top guide block is damaged. When sawing, the saw band rises and the serrated teeth collide with the side guide block.
10. When the lifting cylinder enters the air, the oil quality is not good, the cylinder is worn out, and the control valve is out of control, all of these make the sawing frame unable to descend uniformly, resulting in teeth beating.
Please pay attention to the above ten points, which will greatly reduce the probability of bimetal band saw blade teeth.
(1) stamping in automobile industry. Deep drawing is the main method. In our country, this part is mainly concentrated in automobile factory, tractor factory, aircraft manufacturer and other large factories, and there are few independent large-scale stamping and drawing plants.
(2) stamping of parts and components in automobile and other industries. It is mainly formed by punching and shearing. Many enterprises in this sector belong to scale parts factories, and some independent stamping factories. At present, there are many such small factories near some automobile factories or tractor factories.
(3) Electrical parts stamping plant. This kind of factory is a new industry, which develops with the development of electrical appliances. It mainly concentrates in the south.
(4) Stamping plant for daily necessities. Make some crafts, tableware, etc. These factories have also made great progress in recent years.
(5) Stamping Plant for Household Appliance Parts. These factories are in our country after the development of household appliances, most of them are distributed in household appliances enterprises.
(6) Special stamping enterprises. For example, stamping of aviation parts belongs to this kind of enterprise, but these craft factories also belong to some large factories.
Analysis of the Common Defects in Zinc Alloy Die Castings
Zinc alloy die castings are widely used in various decorative fields, such as furniture accessories, architectural decoration, bathroom accessories, lighting parts, toys, tie clips, belt buckles, bags, various metal decorative buckles, etc. Therefore, the surface quality of the castings is required to be high, and good surface treatment performance is required. The most common defect of zinc alloy die castings is surface blistering.
Defect characterization: There are protuberant bubbles on the surface of die castings, which are found after die casting, exposed after polishing or processing, and appearing after oil spraying or electroplating.
Causes: 1. Cavitation: mainly stomata and contraction mechanism, stomata are often round, and contraction is mostly irregular.
(1) Causes of pore formation: In the process of filling and solidification of liquid metal a, the gas intrusion leads to the formation of holes on the surface or inside of castings. B. Invasion of vaporized gas from paint. C alloy liquid contains too much gas and precipitates during solidification.
When the gas in the cavity, the volatile gas from the coating and the gas from the alloy solidification are not exhausted properly in the die, the air holes formed in the castings will be left at last.
(2) Causes of shrinkage: during the solidification of liquid metal, shrinkage occurs because of shrinkage of volume or lack of liquid metal feeding at the final solidification part. B. Local overheating of uneven thickness castings or castings results in slow solidification at a certain part and concave surface formation during volume shrinkage. Because of the existence of air holes and shrinkage holes, the holes may enter into water during surface treatment of die castings. When spraying paint and baking after electroplating, the gas in the holes will expand by heat; or the water in the holes will change into vapor and volume expansion, which will cause foaming on the surface of castings.
2. Intergranular corrosion causes:
Harmful impurities in zinc alloy composition: lead, cadmium and tin will gather at the grain boundary and lead to intergranular corrosion. Metal matrix will be broken by intergranular corrosion. Electroplating accelerates this disadvantage. The parts affected by intergranular corrosion will expand and the coating will be jacked up, resulting in foaming on the surface of castings. Especially in wet environment, intergranular corrosion will cause casting deformation, cracking, and even breakage.
3. Cracks: water marks, cold isolation marks and hot cracks.
Watermark and cold barrier: In the filling process of liquid metal, the contact wall of liquid metal first solidified too early, and then the liquid metal can not be fused with the solidified metal layer, forming overlapping lines at the butt of the casting surface, resulting in strip defects. Water marks are usually on the shallow surface of castings, while cold barrier marks may penetrate into the inner part of castings.
Hot crack: a when the thickness of the casting is uneven, the solidification process produces stress; B is premature ejection, metal strength is not enough; C is uneven ejection, D is too high die temperature to make the grain coarser; e is harmful impurities.
All the above factors may cause cracks.
When there are water marks, cold barrier lines and hot cracks in die castings, the solution will infiltrate into the cracks during electroplating, and turn into steam when baking, and the plating layer will be bubbled by air pressure.
Solutions to defects:
The key to control the production of gas holes is to reduce the amount of gas mixed into the casting. The ideal metal flow should be accelerated from the nozzle through the diversion cone and runner into the cavity to form a smooth and uniform metal flow. The conical runner design means that the flow should be gradually reduced from the nozzle to the inner runner, which can achieve this goal. In the filling system, the gas mixing is due to the mixing of turbulence and liquid metal to form pore. From the study of the simulation die casting process of liquid metal entering the cavity from the casting system, it is obvious that the sharp transition position and increasing cross-section area of the runner will cause turbulence and entrainment of the liquid metal flow. Only a smooth liquid metal can facilitate the gas entering the overflow slot from the runner and the cavity. And exhaust groove, discharge out of the die.
For shrinkage: to make all parts of the die casting solidification process as uniform as possible heat dissipation, and solidification at the same time. Shrinkage can be avoided by reasonable nozzle design, thickness and location of inner nozzle, die design, temperature control and cooling. For the phenomenon of intergranular corrosion, it is mainly to control the content of harmful impurities in alloy raw materials, especially lead < 0.003%. Pay attention to the impurities brought by waste.
For water marks and cold partition marks, the appearance of cold partition marks can be reduced by increasing the temperature of the die, increasing the speed of the inner gate, or increasing the overflow groove in the cold partition area.
For hot cracks: the thickness of die castings should not change sharply to reduce stress generation; the relevant die casting process parameters should be adjusted; and the die temperature should be lowered.
1. Vertical and horizontal drainage on the back and side ditches of various retaining walls of expressway;
2. Drainage of tunnels and underground tunnels;
3. Water supply and drainage of municipal works, water purification plants, sewage plants, garbage dumps, etc.
4. Drainage of golf courses, stadiums, parks and other recreational green spaces;
5. Developing slope soil and water conservation on hillside;
6. Underground drainage of land preparation works;
Cast iron drain pipe is suitable for pavement structure with waterproof layer. The lower end of the pipe should extend at least 0.15-0.20 m below the bottom of the lane board to prevent seepage on the rib surface of the main girder.
