Monthly Archive October 10, 2020

Generally speaking, the engraving machine is a kind of CNC milling machine with small cutting tools, high power and high-speed spindle motor. Foreign countries do not have the concept of precision carving machine. They mainly use machining centers (computer gongs) to mill molds. However, machining centers have their own shortcomings, especially when using small cutters to process small molds, and the cost is very high. At the beginning of China, there was only the concept of CNC engraving machine. The advantage of engraving machine is carving. If the hardness of processing material is relatively large, it will be unable to meet the requirements. The emergence of carving machine can be said to fill the gap between the two. The engraving machine can not only carve, but also mill. It is an efficient and high-precision CNC machine tool.

Shape and structure

The appearance and structure of the carving machine, engraving and milling machine and machining center (computer gong) are very similar. The following is a comparative analysis of the four:

Conceptually:

Processing center: Hong Kong, Taiwan, Guangdong area known as the computer gong, is a highly automated multi-functional CNC machine tool with tool magazine and automatic tool change device. The first machining center appeared in the United States in 1958. It can realize the centralized processing of milling, drilling, boring, reaming, tapping and other processes after the workpiece is clamped at one time, with special emphasis on “milling”.

Engraving machine: its spindle speed is high, suitable for small cutting tools processing, torque is relatively small, focusing on the “carving” function, such as wood (wood carving machine for special processing of wood), dual color board, acrylic plate and other plates with low hardness, which are not suitable for large workpieces with strong cutting. Dongguan Machinery parts processing at present, most of the products bearing the banner of engraving machine in the market are mainly for processing handicrafts with low cost. Due to the low precision, they are not suitable for mold development. However, there are also exceptions, such as wafer engraving machine.

Carving machine: as the name implies. On the basis of the engraving machine, the power of the spindle and servo motor is increased, and the bearing force of the bed is maintained. At the same time, the high speed of the spindle is maintained. More importantly, the precision is very high.

Engraving and milling machine: engraving and milling machine focus on carving and milling, which is a transitional model between the fine carving machine and the machining center. Compared with the precision carving machine, the advantages of computer gong processing are stronger machine rigidity, higher processing efficiency, high power, and suitable for fast and heavy cutting of soft metal. Compared with the machining center, the speed of processing soft metals such as copper and aluminum is faster, and the finishing speed and efficiency of steel mold are higher. Its disadvantages are not suitable for large-scale workpiece rough cutting, heavy cutting. Engraving and milling machine also to high-speed development, commonly known as high-speed machine, cutting ability is stronger, processing accuracy is very high, but also can directly process hardness above HRC60 materials, one-time molding.

In terms of appearance and volume:

The volume of the machining center is the largest, the volume of large-scale 1690 machine is 4 m * 3 m, and that of small-scale 850 type machine is 2.5 m * 2.5 m; the volume of fine carving machine is the second, and that of large-scale 750 type machine is 2.2 m * 2 m; the carving machine is the smallest.

In terms of mechanical structure:

Generally, the cantilever type is used in the machining center, and the gantry structure is commonly used in the carving machine and engraving machine. The gantry type is divided into the pillar type and the fixed beam type. At present, the fixed beam type is the main type of the fine carving machine.

In terms of index data:

The highest spindle speed (R / min): Machining Center 8000; engraving machine is the most common 240000, high-speed machine is the lowest 30000; engraving machine is generally the same as engraving and milling machine, the engraving machine used for high gloss processing can reach 80000, but the air bearing spindle is not the general electric spindle.

Spindle power: the machining center is the largest, ranging from several thousand watts to tens of kilowatts; the carving machine is the second, generally within ten kilowatts; the engraving machine is the smallest.

It is suitable for machining center, especially for rough machining.

Speed: due to the light weight of the engraving machine and engraving machine, their moving speed and feed speed are faster than that of the machining center, especially for the high-speed machine equipped with linear motor, the maximum moving speed is 120m / min

Accuracy: the accuracy of the three is similar.

From the processing size: the worktable area can better reflect this. The smallest worktable area (unit mm, the same below) of domestic processing center (computer gong) is 830 * 500 (850 machines); the largest worktable area of fine carving machine is 700 * 620 (750 machines), and the minimum is 450 * 450 (400 machines); engraving machines generally do not exceed 450 * 450, and the common ones are 45 * 270 (250 machines).

From the perspective of application objects: the machining center is used to complete the processing equipment of large milling amount of workpieces, large molds and materials with hardness comparison, which are also suitable for the opening of common molds; the precision carving machine is used to finish the finishing of small molds with small milling amount, which is suitable for copper and graphite processing; the low-end engraving machines are inclined to those with low hardness such as wood, double color plate and acrylic plate Plate processing, high-end suitable for wafer, metal shell polishing and polishing.

It is generally believed that: Machining Center, carving machine can do both products and molds, engraving machine can only do products.

Model difference

Let’s first clarify the differences between the three models

1. CNC milling and machining center is used to complete the processing equipment of large milling amount of workpieces
2. CNC engraving machine is used to finish small milling amount or soft metal processing equipment
3. High speed cutting machine is used to finish medium milling amount and reduce grinding amount to the minimum

In depth analysis of the above equipment structure can help us make the right choice

1、 — from a mechanical point of view

The machine is divided into two parts, the moving part

The internal grinder is very common in mold factories and hardware processing plants, and has become the common equipment of the majority of mechanical industry technicians. The selection of abrasive is very important for large grinding machine processing in the operation of internal grinder.

Characteristics of CNC system for internal grinder

Portability: the functional software of the system is independent of the equipment, and various functional modules run in different control systems, that is, they can run on the hardware platforms provided by different suppliers;

Scalability: the function and scale of CNC system of internal grinder can be flexibly set and modified easily. The size of the control system (hardware or software modules) can be increased or decreased according to the specific application;

Expansibility: users or secondary developers of CNC system of internal grinder can effectively integrate their own software into the NC system to form their own special system. The increase or decrease of functions only requires the loading and unloading of function modules;

Interchangeability: through standardized interface, computer gong processing, mechanical parts processing, Dongguan CNC machining center, Dongguan high-speed computer gong processing communication and interaction mechanism, different functional modules can run on the system platform with standard application program interface, and obtain equal mutual operation ability and coordinate work.

Interchangeability: the selection of hardware modules and functional software constituting the system is not controlled by a single supplier, and can be replaced with each other according to the requirements of function, reliability and performance, without affecting the coordinated operation of the whole system;

The harder the grinding roller surface of the internal grinder is, the softer the hardness of the grinding wheel should be selected.

(1) If the grinding wheel is obviously blocked (hard) or dirty, the passivated sand particles are not easy to fall off, the grinding wheel is easy to adhere to the grinding debris, and the grinding roller surface appears burn and scuffing, it indicates that the selected grinding wheel is too hard, and the following measures can be taken to improve it:

A. Reduce the linear speed of grinding wheel;

B. Increase the roller speed.

If the grinding effect is not obvious after the above measures are taken, it means that the grinding wheel is too hard, so the soft grinding wheel should be selected.

1. Selection of bond for grinding wheel of internal grinder

Except resin bonded grinding wheel, ceramic grinding wheel is better for other grinding types of roller surface.

(2) If the grinding wheel is worn too fast, it means that the grinding wheel selected for the specific processing roll is too soft. The following improvement measures can be taken:

A. Increase the linear speed of grinding wheel;

B. The longitudinal feed rate of the carriage is increased to 2 / 3-3 / 4 of the width of the grinding wheel;

C. Reduce the roll speed.

If no obvious grinding effect has been obtained after the above measures are taken, it means that the grinding wheel is too soft and not suitable for use, and a harder grinding wheel should be selected.

Machinability includes formability and cutting property. Because the formability is related to the state, the strength range of various states should be considered after selecting the grade of aluminum alloy. Generally, the material with high strength is not easy to form. If bending, stretching, deep drawing and other forming processes are needed, the formability of the fully annealed material is the best, while the formability of the heat-treated state is the worst. The machinability of aluminum alloy is closely related to the alloy composition. Generally, the machinability of aluminum alloy with higher strength is better than that of aluminum alloy with low strength. The machinability of aluminum alloy is an important factor to be considered for the products that need to be machined, such as dies and mechanical parts.

Architectural aluminum is a kind of decorative structural materials. In order to improve its decorative effect, enhance its corrosion resistance and extend its service life, except for some cases, it has to go through surface treatment.

Many customers are very concerned about the hardness when buying aluminum products. The hardness is directly related to the chemical composition of the alloy. Secondly, different states also have great influence. In terms of the highest hardness that can be achieved, 7 series, 2 series, 4 series, 6 series, 5 series, 3 series and 1 Series decrease in turn. Therefore, surface treatment has become an essential and important process in the production of architectural aluminum profiles. There are many methods of surface treatment for computer gongs, and corresponding surface treatment methods can be adopted according to different uses of materials. The commonly used commercial surface treatment methods are: Anodizing coloring, electrostatic powder spraying, fluorocarbon spraying, electrophoretic painting, chemical coloring, water ripple treatment, etc.

Strength is an important factor that must be considered in product design, especially when aluminum alloy components are used as structural parts, appropriate alloy should be selected according to the pressure they bear. The strength of pure aluminum processed by computer gong processing, mechanical parts processing, Dongguan CNC machining center, Dongguan high-speed computer gong processing is the lowest, while the strength of 2-Series and 7-series heat-treated alloys is the highest. There is a positive correlation between hardness and strength.

Corrosion resistance includes chemical corrosion resistance, electrochemical corrosion resistance and stress corrosion resistance. Generally speaking, the corrosion resistance of 1 series pure aluminum is the best, 5 series is good, followed by 3 series and 6 series, and 2 series and 7 series are poor. The selection principle of corrosion resistance should be determined according to the application situation. When high strength alloy is used in corrosive environment, it is necessary to use various composite materials for corrosion protection.

Processing by material classification: aluminum alloy, hard aluminum, aluminum oxide, copper, brass, bronze, red copper, titanium, iron, aluminum parts, imported domestic carbon steel, manganese steel, alloy steel, tool steel, high speed steel, 303, 304, 316, 303, 400 stainless steel, saigang, ABS acrylic (PMMA), PC, POM Non standard precision machining of PVC, PP, nylon, bakelite, plastic, Teflon, epoxy board, plastic, etc

Over the past 30 years since the reform and opening up, the coating industry has made great progress in self-improvement and development in order to meet the development needs of various departments of the national economy. Products, quality, variety, quantity and technical equipment level have been greatly improved. In particular, through the introduction of technology and cooperation with foreign investors, the technical level and ability of the industry have been improved.

“2013-2017 China coating industry market demand forecast and strategic investment planning analysis report” shows that at present, the domestic coating industry in coating materials, coating technology and equipment, has basically met the needs of household appliances, machine tools, machinery, furniture, construction and other industries, and has made outstanding contributions to the development of the national economy, but the domestic coating technology is similar to the foreign advanced technology There is still a big gap between the two, which is mainly reflected in the industries with higher requirements for coating technology, such as car coating, which can not fully meet the requirements. At present, the domestic car coating technology and equipment are still mainly foreign technology and equipment.

In addition, domestic coating enterprises have made a lot of efforts in technical innovation, and have made great achievements. However, it still needs independent innovation. The direction and goal of the future development of the coating industry is to further meet the needs of the continuous development of the national economy, mainly to reduce pollution, energy conservation and emission reduction, improve the process, improve the decorative, protective and functional properties of coatings, as well as the generalization, serialization and automation of coating equipment. The so-called coating refers to covering metal and non-metallic surfaces with protective or decorative layers. With the development of industrial technology, it goes deep into many fields of national economy. The development of China’s coating production line has experienced the development process from manual production line to automatic production line. The painting process in China can be simply summarized as: pretreatment → spraying → drying or curing → three wastes treatment. China’s painting industry really originated after the introduction of Soviet technology in the 1950s. Since the 1960s, due to the development of light industry, there have been mechanized production lines and automatic production lines in the bicycle manufacturing industry, as well as the program-controlled assembly lines formed on the basis of the original trough production line and the program-controlled car, which are mainly in Shanghai and Tianjin. During this period, the main task of China’s coating industry was mainly anticorrosion. However, with the development of China’s economy and the development of foreign painting technology, through the introduction of technology and the exchange of foreign technology, China’s coating technology began to develop rapidly. In the aspect of coating automation production, the popularization and application of electrostatic spraying and electrophoretic painting technology, and the development and promotion of powder spraying technology, especially in China’s home appliance industry, household hardware, steel furniture, aluminum With the rapid development of components, electrical products, automobile industry and other fields, the coating industry has made obvious progress.

2、 Coating production spare parts – coating equipment:

1. Through shot blasting chamber

The through shot blasting chamber is composed of cleaning chamber body, shot blasting machine, shot circulation system, ventilation and dust removal system, bottom foundation and electrical control system. Non standard design of different sizes can be carried out according to different specifications of workpieces, and finalizing equipment can also be selected.

Through shot blasting chamber is suitable for cleaning and strengthening the surface of structural parts of construction machinery, forging and casting, and high-speed computer gong processing, so as to obtain a smooth surface with certain roughness, increase the adhesion of coating film and improve the anti-corrosion effect of workpiece. When the workpiece enters the shot blasting chamber, the shot blasting machine driven by the motor will throw high-speed projectiles centrifugally, which will strongly impact the rust and oxide scale on the surface of the workpiece. The surface quality of the workpiece can reach the standard of SA2 ～ Sa2.5.

1. Water spinning spray booth

Water spinning spray booth is also called hydraulic spinning spray booth. This chamber adopts the gas laminar flow suppression method to prevent the paint mist from spreading, and uses the hydraulic spinning pipe to filter the paint mist. It is a relatively complete paint spraying room in technology at present.

The water spinning spray painting room is composed of a chamber body, an electric door, a paint mist filtering device, an air conditioning air supply device and an exhaust device. The lighting device is installed on both sides of the room, and the illumination is above 500 lux, which can be controlled in groups. Combustible gas concentration detection and alarm devices are installed indoors. The paint mist filtering device is composed of washing plate, hydraulic spinning device, underground water tank and exhaust device. The results show that the removal rate of paint mist is more than 98%. The air supply device is the main component to make the gas form laminar flow. After being filtered and heated, the air sent into the air supply room is evenly sent to the room from the air supply ceiling, so that the indoor wind speed is even. When there is no workpiece, the vertical wind speed can reach (0.35 ~ 0.4) m · s – 1; The exhaust device uses a fan to filter the gas containing paint mist in the chamber through a hydraulic spinning pipe, and then discharges it from the sink and the washing plate.

1. Hot air drying room

The drying method is hot air circulation convection mode, its biggest advantage is that the baking is uniform, especially suitable for the construction machinery parts with large heat capacity. Heating heat sources include steam, electricity, light diesel, natural gas, liquefied petroleum gas, etc. If conditions permit, LPG shall be preferred. It is a kind of clean and efficient energy. The biggest advantage is that the cost of production and operation is only 35% – 40% of the cost of electricity.

1. Conveying system

For construction machinery components (structural parts), the use of self-propelled electric hoist is an effective choice.

The conveying system of self-propelled electric hoist is composed of gantry column, bearing rail, sliding conductor rail, collector, loading car, electric hoist and central control cabinet controlled by PC.

The system integrates mechanical, electronic, computer, automatic

(1) Selection of milling cutter type

According to the geometry of the parts to be processed, the types of cutting tools are selected as follows:

1) When machining curved surface parts, in order to ensure that the cutting edge of the cutter is tangent to the machining contour at the cutting point, the high-speed computer gong machining is used to avoid the interference between the cutting edge and the workpiece contour. Generally, ball end cutter is used for rough machining, and four edge milling cutter is used for semi finishing and finishing machining, as shown in Fig. 4.

2) When milling large plane: in order to improve the production efficiency and surface roughness, insert type disc milling cutter is generally used, as shown in Fig. 5.

3) When milling small plane or step surface, general milling cutter is generally used, as shown in Fig. 6.

4) In order to ensure the accuracy of keyway milling, use the cutter as shown in Figure 7.

5) During hole processing, drill bit, boring cutter and other hole processing tools can be used

Milling cutter is generally composed of blade, positioning element, clamping element and cutter body. There are many kinds of positioning and clamping methods for the blade on the cutter body, and the structure of the positioning element of the blade has different types. Therefore, there are many kinds of structure forms and classification methods of milling cutter. When selecting, it can be mainly according to the arrangement of blades. The arrangement of blades can be divided into two categories: flat mounting structure and vertical mounting structure.

Flat structure (radial arrangement of blades)

The flat structure milling cutter (as shown in Fig. 9) has a good structure and is easy to process. It can also use a non hole blade (the blade price is low and can be reground). Due to the need for clamping elements, a part of the blade is covered, the chip holding space is small, and the cemented carbide section in the direction of cutting force is small, so the flat structure milling cutter is generally used for light and medium milling.

Vertical installation structure (blade tangential arrangement)

The blade of end mounted structure milling cutter (as shown in FIG. 10) is fixed on the cutter groove with only one screw, which is simple in structure and convenient in rotation. Although there are few tool parts, it is difficult to process the cutter body, so it is necessary to process it with five coordinate machining center. Since the blade is clamped by cutting force, the clamping force increases with the increase of cutting force, so the clamping element can be omitted and the chip holding space is increased. Because the blade is installed in tangential direction, the section of cemented carbide in the direction of cutting force is large, so it can be used for large cutting depth and large cutting distance. This kind of milling cutter is suitable for heavy and medium milling.

The angle of milling cutter includes front angle, back angle, main deflection angle, auxiliary deflection angle, edge inclination angle, etc. In order to meet the different processing needs, there are a variety of angle combination types. The main deflection angle and rake angle are the most important in the processing of high-speed computer gongs.

Main deflection angle KR

The main deflection angle is the angle between the cutting edge and the cutting plane, as shown in FIG. 11. The main deflection angles of milling cutter are 90 °, 88 °, 75 °, 70 °, 60 ° and 45 ° etc.

The main deflection angle has a great influence on the radial cutting force and cutting depth. The size of radial cutting force directly affects the cutting power and anti vibration performance of cutting tools. The smaller the main deflection angle of the milling cutter is, the smaller the radial cutting force is, the better the vibration resistance is, but the cutting depth is also reduced.

The main deflection angle of 90 ° is selected when milling the plane with shoulder, but it is not used for pure plane machining. This kind of tool has good versatility (not only can process step surface, but also can process plane), so it can be selected in single piece and small batch processing. Because the radial cutting force of this kind of cutting tool is equal to the cutting force, the feed resistance is large, and it is easy to vibrate. When machining the plane with shoulder, the milling cutter with 88 ° main deflection angle can also be selected. Compared with the milling cutter with 90 ° main deflection angle, its cutting performance is improved to some extent.

The main deflection angle of 60 ° to 75 ° is suitable for rough machining of plane milling. Due to the obvious reduction of radial cutting force (especially at 60 degrees), its vibration resistance is greatly improved, and the cutting is smooth and light. Therefore, it should be preferred in plane machining. 75 ° main deflection angle milling cutter is a general-purpose tool with wide application range; 60 ° main deflection angle milling cutter is mainly used for rough milling and semi finishing milling on boring and milling machines and machining centers.

The radial cutting force of this kind of milling cutter with 45 ° main deflection angle is greatly reduced, which is approximately equal to the axial cutting force. The cutting load is distributed on the longer cutting edge, and has good vibration resistance. It is suitable for the machining occasions with longer spindle overhang of boring and milling machine. When machining plane with this kind of cutting tool, the damage rate of blade is low and the durability is high; when machining iron castings, the edge of the workpiece is not easy to break.

Anterior angle γ

The rake angle of milling cutter can be divided into radial rake angle γ F and axial rake angle γ P. the radial rake angle γ f mainly affects the cutting power; the axial rake angle γ P affects the chip formation and the direction of axial force. When γ P is positive, the chip will fly away from the machining surface. The discrimination between the positive and negative radial forward angle γ F and the axial forward angle γ P is shown in FIG. 12.

The common combination forms of front angle are as follows:

The milling cutter with double negative rake angle and double negative rake angle usually adopts square (or rectangular) blade without back angle. The cutter has many cutting edges (generally 8), high strength and good impact resistance, which is suitable for rough machining of cast steel and cast iron. Because the chip shrinkage ratio is large, it needs a large cutting force, so the machine tool has higher power and higher rigidity. Because the forward angle of the shaft is negative, the chip can not flow out automatically. When cutting ductile materials, chip accretion and tool vibration are easy to occur.

It is suggested that the double negative rake angle milling cutter should be preferred in order to make full use of and save the blade. When double positive rake angle milling cutter is used to produce chipping edge (i.e. large impact load), the double negative rake angle milling cutter should also be preferred when the machine tool allows.

The milling cutter with double positive rake angle and double positive rake angle adopts a blade with back angle. The wedge angle of the cutter is small

1. The mold industry is the mother of industry. In terms of this year’s financial crisis, the mold industry is one of the earliest industries to recover. Therefore, it is very important to learn the mold well. However, due to the variability and uncertainty of mold materials and shapes, it is very difficult for us to learn mold well. Therefore, I will collect and sort out this 10 It’s classic. It’s worth collecting and reading. I’m sure you’ll appreciate my recommendation. I don’t need to communicate with UG, but you are welcome to communicate with me in the industry..
2. Common shrinkage rate of plastic materials?

A: (see plastic materials) Click for information

1. Common defects in plastic parts?

Answer: lack of glue, Cape, bubble, shrinkage, weld mark, black spot, bubble, stripe, warpage, delamination, peeling, etc

1. Common plastic mold steel?

A: (see die steel)

1. What kind of steel is used for high mirror polishing?

Answer: commonly used high hardness heat treatment steel, such as SKD61, 8407, S136 and so on!

1. The role of mapping key?

Answer: simplify operation steps, reduce labor intensity, improve work efficiency!

1. What’s the difference between mirror and mirror?

A: mirror body refers to the whole mirror image, and the mirror feature refers to local mirror image or single feature image!

1. How to hide each other in UG?

Answer: Ctrl + B and Ctrl + Shift + B

1. Is there a local bias function in UG?

A: Yes

1. Does UG have symmetrical constraint function in sketching?

A: none

1. What is 2D? What is 3D?

A: D is the prefix of dimension, 2D refers to two-dimensional plane, and 3D refers to three-dimensional space. In the mold part, 2D usually refers to plan drawing, i.e. CAD drawing; 3D usually refers to solid drawing, i.e. Pro / E, UG or other 3D software drawing files.

1. What is the default accuracy of Pro / E? What is the default accuracy of UG?

A: the default accuracy of Pro / E is 0.0012mm, and that of UG is 0.0254mm

1. What is the default word height of CAD?

Answer: the default word height of CAD is 2.5mm.

1. Where is the text file of CAD?

Answer: the text file of CAD is placed in the fonts folder under the root directory of CAD.

1. Does Pro / E have auto save function like CAD?

A: Pro / E has no auto save function

1. What is touch through? What is penetration?

A: the joint surface of male and female mold parallel to pl surface is called impact through surface; the joint surface of male and female mold that is not parallel to pl surface is called interpenetrating surface!

1. The relationship between sliver and silk?

A: both sliver and silk are units of length. In Taiwan, 1 = 0.01mm; in Hong Kong, 1 = 0.01mm, so 1 = 1

1. What is pillow position?

Answer: the edge of shell plastic parts often has a gap, which is used to install various accessories

1. What is a crater?

A: the mold crater is the shape similar to the volcano eruption reflected on the mold of the root of boos column.

1. What do you mean?

A: ah, it’s Mo Ren, a Hong Kong idiom

1. What is tiger mouth?

A: Tiger mouth, also known as tube position, is used to limit the part.

1. What is ranking?

Answer: the product layout on the mold is called placement.

1. What is glue position?

Answer: the cavity of the product on the mold is called glue position.

1. What is bone position?

A: the tendon on the product is called bone position.

1. What is column position?

Answer: boss column on the product is called column position.

1. What is virtual position?

Answer: the gap on the mold is called virtual position.

1. What is buckle?

Answer: the hook used for product connection is called buckle position.

1. What is spark pattern?

After the spark machining is called spark striation.

1. What is PL plane?

Answer: PL is the abbreviation of parting panel. PL is also called parting surface, which refers to the part of male mold and female mold in contact when the mold is closed.

1. What is a computer gong?

Answer: general name of CNC milling machine and machining center

1. What is a copper worker?

Answer: EDM usually uses copper material which is easy to process as discharge electrode, which is called copper work, also known as electrode. Copper workers are generally divided into roughs, roughers and young workers. Young workers are also called Seiko

1. What is EDM?

A: an electric spark is a self-excited discharge. There is a high voltage between the two electrodes before discharge. When the two electrodes are close, the dielectric between them is broken down, and then spark discharge occurs. With the breakdown process of Dongguan high-speed computer gong machining, the resistance between the two electrodes decreases sharply, and the voltage between the two poles also decreases sharply. The spark channel must be extinguished in time after a short time (usually 10-7-10-3s), so that the machining of mechanical parts can maintain the “cold pole” characteristics of spark discharge (that is, the heat energy converted by the channel energy can not be transmitted to the depth of the electrode), so that the channel energy can act on a very small range. Due to the effect of channel energy, the electrode can be corroded locally. Using the corrosion phenomenon produced by spark discharge to process the size of materials is called EDM.

1. What is the spark bit?

A: in the process of discharge, the discharge gap between copper and steel is called spark position. The spark position of rougher is generally 10 to 50, and that of young worker is 5 to 15

1. What is the material level?

A: the wall thickness of plastic products is also called meat thickness.

1. What is the original stay?

Answer: willing body retention is relative to cutting and inserting parts. Original body retention refers to a whole piece of steel material for processing embryo, which is processed together when processing

1. What are weld lines?

A: the line formed by the meeting of two strands of plastic is called weld line.

1. What is a jet?

A: the plastic from the inlet into the cavity after the formation of bending fold snake like flow marks, known as jet flow.

1. What is LKM

Gear processing should adopt different technology according to different structure and precision. In view of the large equipment investment, the selection of process mode (as shown in Table 1) usually takes full account of the existing resources. The control of micro deformation and process stability in the process of high-speed computer gong machining gear is relatively complex. Isothermal normalizing is usually used after blank forging in order to obtain good processing performance and uniform microstructure with trend deformation. For low-speed cylindrical gear with low accuracy requirements, gear shaving can be done before hot rolling, and no processing is required after hot rolling. There are many teeth in hot post processing of cylindrical gear according to the conditions Different from gear grinding, the cost of tooth cleaning is low, but the ability of tooth profile correction is weak, and the precision of gear grinding is high but the cost is high. The technology of edge dressing and drum tooth modification can significantly reduce the gear meshing noise and improve the transmission performance, which are widely used at present.

The straight bevel gear is mainly used in the differential. Due to the low speed and relatively low precision requirement, precision forging gear is recommended. The complicated and time-consuming manual operation of spiral bevel gear processing and machine tool adjustment has been replaced by modern special software and computer program. The introduction of finite element analysis makes the process parameter design more reliable and convenient. There are mainly two kinds of gear grinding: grinding and grinding. Due to the high cost, low efficiency and limitation of gear grinding, gear lapping is mostly used at present Recently, a large marine gear with world advanced level and equipped with adjustable propeller [gear: gear is a mechanical element with teeth on the rim that can continuously mesh and transmit motion and power. The meshing of teeth in mechanical parts has been used for a long time. Box was born in hangchi group. This product belongs to the transmission device of marine power propulsion system. It not only has the functions of deceleration, clutch and bearing propeller thrust, but also has the function of auxiliary power output and auxiliary power input, which can meet the requirements of French bv ship inspection unmanned engine room.

This product is designed and manufactured by hangchi technicians according to the order requirements of foreign customers. High speed computer gong processing synchronous belt wheel is specially equipped with adjustable paddle for transportation and ocean fishing vessels. The product is controlled by electricity and hydraulic pressure. It has clutch system and gear transmission system with clutch and deceleration functions. For the first time, the PTO / PTI function is realized on the gearbox at the same time, which can make the propeller obtain the best propulsion efficiency and realize the automatic control of ship forward and backward. The auxiliary power input can realize the function of ship emergency return when the main engine fails, and the auxiliary power output can generate power for the ship when necessary. This kind of function can be used not only as generator but also as engine, which can greatly meet the needs of users.

The product has large speed ratio and wide application range. Hangchi installed the liquid level alarm for the first time in this product. All controllers and transmitters of synchronous belt pulley are imported brands. Make its performance more safe and reliable. The gearbox adopts double pump, which simplifies the design of hydraulic system and reduces the possibility of failure.

1. The tightness of the sprocket should be appropriate. If it is too tight, the power consumption will be increased, and the bearing is easy to wear; if the sprocket is too loose, it is easy to jump and fall off the chain. The tightness of the chain wheel is: lift or press down from the middle of the chain wheel, which is about 2% – 3% of the center distance between the two chain wheels.
2. There should be no swing and skew when the sprocket is installed on the shaft. In the same transmission component, the end faces of two sprockets should be in the same plane. When the center distance of sprocket is less than 0.5 m, the deviation can be 1 mm; when the center distance of sprocket is more than 0.5 m, the deviation can be 2 mm. However, there should be no friction on the side of sprocket teeth. If the offset of two wheels is too large, it is easy to cause chain shedding and accelerated wear. Pay attention to check and adjust the offset when replacing the sprocket.
3. When the sprocket is seriously worn, the new sprocket and new sprocket should be replaced at the same time to ensure good meshing. Do not replace new sprocket or new sprocket separately. Otherwise, it will cause bad meshing and accelerate the wear of new sprocket or new sprocket. When the tooth surface of the sprocket is worn to a certain extent, it should be turned over in time to extend the service time.
4. If the new sprocket is too long or elongated after use, it is difficult to adjust. The chain link can be removed according to the situation, but it must be even. The chain link shall pass through the back of the chain wheel, the locking plate shall be inserted outside, and the opening of the locking plate shall face the opposite direction of rotation.
5. The sprocket should be filled with lubricating oil in time. Lubricating oil must enter the clearance between roller and inner sleeve to improve working conditions and reduce wear.
6. The old chain wheel can not be mixed with some new ones, otherwise it will cause impact in the transmission and break the chain wheel.
7. When the machine is stored for a long time, the sprocket wheel should be removed and cleaned with kerosene or diesel oil, and then coated with oil or grease and stored in a dry place.

2、 The structural design of the sprocket:

1. Tooth profile of sprocket

The tooth shape of the chain wheel must ensure that the chain can enter and exit the meshing smoothly and smoothly, reduce the impact and contact stress of the chain link during meshing as far as possible, and it should be easy to process.

The common tooth profile of sprocket end face is composed of three arc AA, AB, CD and a straight line BC, which is called three arc straight line profile for short. The tooth profile is processed with standard cutter. It is not necessary to draw the end face tooth profile on the sprocket working drawing. It is only necessary to mark “the tooth profile is manufactured according to the provisions of 3rgb1244-85” on the drawing. However, the axial tooth profile of the sprocket shall be drawn, as shown in Fig. 2, and the dimension shall refer to the relevant design manual. ginseng