July 2019 – Page 19 – CNC Machining & Turning, Milling, Metal parts

Mold performance

1. Low density: The low density of plastics is of great significance for reducing the weight and energy saving of mechanical equipment, especially for vehicles, ships, aircraft, and spacecraft.

2. Specific strength and specific stiffness: The absolute strength of plastic is not as high as that of metal, but the density of plastic is small, so the specific strength (σb/ρ) and specific stiffness (E/ρ) are quite high. In particular, reinforced plastics made of various high-strength fibrous, flake and powdery metals or non-metal fillers have higher specific strength and specific stiffness than metals.
3. Good chemical stability: Most plastics have good acid, alkali, salt, water and gas properties. Under normal conditions, they do not chemically react with these substances.
4. Electrical insulation, heat insulation and sound insulation performance are good.
5. Good wear resistance and self-lubricating property: plastic has small friction coefficient, good wear resistance, good self-lubricating property, high specific strength and low transmission noise. It can be used in liquid medium, semi-dry or even dry friction. Work effectively under conditions. It can be made into machine parts such as bearings, gears, cams and pulleys, which is very suitable for occasions where the speed is not high and the load is not large.
6. Strong bonding ability.
7. Good molding and coloring performance.

Do you know what different tool holders are available in CNC machining centers

What does 7:24 in the BT holder mean?

What are the standards for BT, NT, JT, IT, and CAT?

CNC machine tools are now widely used in factories. These machines and tools come from all over the world and come in different models and standards. Talk to everyone today about the machining center tool holder.

The shank is the connection between the machine tool and the tool. The shank is a key link that affects the concentricity and dynamic balance. You should never treat it as a general part. The concentricity determines whether the cutting amount of each cutting edge portion is uniform when the tool rotates one revolution; the dynamic unbalance will produce periodic vibration when the spindle rotates.

1 according to the spindle cone hole divided into two categories

The taper of the tool hole according to the machining center spindle is usually divided into two categories:

SK universal shank with a taper of 7:24

HSK vacuum shank with a taper of 1:10

SK SK universal shank with a taper of 7:24

7:24 means that the taper of the shank is 7:24, which is a separate cone positioning, and the taper shank is longer. The cone surface also plays two important roles at the same time, namely the precise positioning of the shank relative to the spindle and the clamping of the shank.

ŸAdvantages: It can realize fast loading and unloading of tools without self-locking; the manufacturing of the tool holder can ensure the accuracy of the connection by processing the taper angle to high precision, so the cost of the tool holder is relatively low.

Disadvantages: At the high speed rotation, the taper hole at the front end of the spindle will expand. The amount of expansion increases with the increase of the radius of rotation and the rotation speed. The stiffness of the taper connection will decrease. Under the action of the tension of the tie rod, the axial displacement of the shank There will also be changes. The radial dimension of the shank changes after each tool change, and there is a problem that the repeat positioning accuracy is unstable.

Universal shanks with a 7:24 taper typically have five standards and specifications:

1. International Standard IS0 7388/1 (referred to as IV or IT)

2. Japanese Standard MAS BT (BT for short)

3. German standard DIN 2080 (referred to as NT or ST)

4. American Standard ANSI/ASME (CAT)

5. DIN 69871 (JT, DIN, DAT or DV for short)

Tightening method:

The NT type shank is used to tighten the shank by a tie rod on a conventional machine tool. It is also called ST in China. The other four shanks are used to tighten the shank on the machining center through the shank of the shank

Generality:

1) At present, the most used in the country are the DIN 69871 (ie JT) and Japan MAS BT type handles;

2) The shank of the DIN 69871 can also be mounted on a machine with an ANSI/ASME spindle taper;

3) The international standard IS0 7388/1 tool holder can also be mounted on the DIN 69871, ANSI/ASME spindle taper machine, so the ISO 7038/1 tool holder is the most versatile.

HS HSK vacuum shank with a taper of 1:10

The HSK vacuum shank is elastically deformed by the shank, not only the 1:10 taper surface of the shank is in contact with the 1:10 taper surface of the machine tool spindle hole, but also the flange surface of the shank is in close contact with the main shaft surface. The surface contact system is superior to the 7:24 universal tool holder for high speed machining, joint rigidity and coincidence accuracy.

HSK vacuum shank can improve the rigidity and stability of the system and the precision of the product during high-speed machining, and shorten the tool replacement time. It plays an important role in high-speed machining, and it adapts to the spindle speed of the machine to 60,000 rpm. HSK tool systems are being widely used in aerospace, automotive, precision mold and other manufacturing industries.

HSK holders are available in A, B, C, D, E, and F types, among which A, E, and F are commonly used in machining centers (automatic tool change).

The biggest difference between type A and type E:

1. Type A has a transmission slot and E does not. Therefore, the A-type transmission torque is relatively large, and relatively heavy cutting can be performed. The E-type transmission torque is relatively small, and only some light cutting can be performed.

2. In addition to the transmission groove, the A-type holder has manual fixing holes, direction grooves, etc., so the balance is relatively poor. The E type is not available, so the E type is more suitable for high speed machining. The E-type and F-type mechanisms are identical. The difference is that the E-type and F-type shanks (such as E63 and F63) are also called, and the taper of the F-type shank is smaller. That is to say, the flange diameters of E63 and F63 are both φ63, but the taper size of F63 is only the same as that of E50. So compared to the E63, the F63 will spin faster (small spindle bearings).

2 shank loading form

spring collet handle

It is mainly used for the clamping of straight shank tools and tools such as drills, milling cutters and taps. The elastic deformation of the circlip is 1mm, and the clamping range is 0.5~32mm.

Hydraulic chuck

A- locking screw, use an Allen key to tighten the locking screw;

B- lock the piston and press the hydraulic medium into the expansion chamber;

C- expansion chamber, compressed by liquid to generate pressure;

D- Thin expansion bushing that positions and evenly envelops the center of the tool holder during locking.

E- Special seals ensure an ideal seal and long service life.

Heating the handle

Inductive heating is used to heat the tool holder on the shank so that its diameter expands and the cold shank is placed in the hot shank. The heating shank has large clamping force and good dynamic balance, which is suitable for high speed machining. The repeating positioning accuracy is high, generally within 2μm, and the radial runout is within 5μm; the anti-fouling ability is good, and the anti-interference ability is good in processing. However, each type of tool holder is only suitable for a tool with a shank diameter and a heating device is required.

What are the design principles for CNC machine tool programming

CNC machining refers to a process for machining parts on CNC machine tools. The process specifications of CNC machine tools and traditional machine tools are generally the same. The difference is that CNC technology uses digital information to control the machining of parts and tool displacements. . It is an effective way to solve the problems of variable parts, small batch size, complex shape and high precision, and to achieve high efficiency and automatic processing. The following Yida Lurun Petrochemical briefly introduces the design principles of the CNC lathe programming to determine the processing plan:

Student training operation 1

First, determine the principle of the processing plan

The processing plan is also called the process plan. The machining plan of the CNC machine tool includes the formulation of the process, the work step and the route of the cutter. In the machining process of CNC machine tools, due to the complex and diverse processing objects, especially the shape and position of the contour curve, and the influence of various factors such as different materials and batches, specific analysis should be carried out when formulating the processing plan for specific parts. And treat differently and handle it flexibly. Only in this way can the processing plan formulated be reasonable, so as to achieve the objectives of superior quality, high efficiency and low cost.

The general principles for formulating a processing plan are: first coarse and then fine, first and then far, first inside and outside, the least program, the shortest route and special treatment.

Second, the steps of the CNC machining program

(1) first coarse and fine

In order to improve the production efficiency and ensure the finishing quality of the parts, the roughing process should be arranged during the cutting process. In a short period of time, a large amount of machining allowance before finishing is removed, and the allowance for finishing is as uniform as possible. Sexual requirements. When the roughing process is completed, the semi-finishing and finishing after the tool change should be arranged. The purpose of arranging the semi-finishing is to arrange the semi-finishing as a transitional process when the uniformity of the remaining amount after roughing can not meet the finishing requirements, so that the finishing allowance is small and uniform.

When arranging a finishing process that can be performed with one or more knives, the final contour of the part should be continuously machined from the last knive. At this time, the position of the advance and retraction of the machining tool should be considered properly. Try not to arrange the cutting and cutting or changing and stopping in the continuous contour to avoid the elastic deformation caused by the sudden change of the cutting force, resulting in a surface stroke on the smooth connecting contour. Rickets such as injuries, sudden changes in shape, or stagnant knife marks.

(2) First and then far

The far and near here is based on the distance of the processing part relative to the tool point. In general, especially in roughing, it is usually arranged to process the part close to the tool point and process it from the far side of the tool point to shorten the tool moving distance and reduce the idle travel time. For turning, it is advantageous to maintain the rigidity of the blank or semi-finished part to improve the cutting conditions.

(3) First inside and outside

For parts that require both the inner surface and the outer surface, when formulating the machining plan, it is usually necessary to arrange the inner and inner cavities and the outer surface. This is because it is difficult to control the size and shape of the inner surface, the rigidity of the tool is correspondingly poor, the durability of the tip is easily reduced by the heat of cutting, and it is difficult to remove the chips during processing.

(4) The shortest route

The work focus of the pass route is determined, which is mainly used to determine the roughing and idle travel path, because the cutting path of the finishing cutting process is basically carried out along the order of its parts. The path of the tool generally refers to the path that the tool starts from the point of the tool point until it returns to the point and ends the machining process, including the path of the cutting process and the non-cutting idle path such as tool introduction and cutting. Under the premise of ensuring the processing quality, the machining program has the shortest path, which not only saves the execution time of the whole machining process, but also reduces unnecessary tool consumption and wear of the sliding parts of the machine feed mechanism.

Third, the choice of cutting tools
(1) Currently commonly used cutting materials are high speed steel and hard alloy. Because high speed steel can only maintain its cutting performance at lower temperatures, it is not suitable for high speed cutting. Cemented carbide has better heat resistance and wear resistance than high-speed steel, so carbide tools are more suitable for cutting.
(2) When processing high-viscosity and high-plastic parts, the tool is required to have high wear resistance and heat resistance, and can maintain excellent cutting and chip breaking performance at a higher temperature. On the premise of sufficient strength, a larger rake angle should be used to reduce the plastic deformation of the metal to be cut, reduce the cutting force and cutting temperature, and reduce the depth of the hardened layer.

(3) In the choice of tool coating, it is advisable to select coating materials with high hardness, good adhesion and toughness. The ultra-fine coating process improves the wear resistance of the blade, smoothes the surface of the coating, reduces friction and reduces the generation of built-up edge. It is suitable for high-speed semi-finishing and fine turning of stainless steel under good working conditions.

Fourth, the choice of cutting oil
Due to the poor processability of the high-speed cutting process, there are higher requirements for the cooling, lubrication, penetration and cleaning performance of the cutting oil. The commonly used cutting oil can form high melting point sulfide on the metal surface during the cutting process, and it is not easy to be high temperature. Destruction, good lubrication, and a certain cooling effect, generally used for high-hardness stainless steel cutting, drilling, reaming and tapping.

Bending machine structure

The bending machine is an important equipment for bending and forming the workpiece in the sheet metal industry. Its function is to press the steel plate into various shapes according to the process requirements. As shown in the figure, the hydraulic sheet bending machine is mainly composed of left and right columns, workbench and beam. The left and right cylinders are fixed on the column. The slider is connected with the piston of the cylinder and along the guide rail fixed on the column. Movement, the lower mold is fixed on the workbench, the upper mold is installed at the lower end of the slider, the hydraulic system provides power, and the electric system gives instructions. Under the action of the oil cylinder, the slider drives the upper mold to the lower mold and the lower mold to realize the folding of the sheet material. bend. The left and right columns, workbench and slider (hereinafter referred to as the three major parts) are the key parts of the bending machine. The sum of the weights of the three large parts accounts for 70%~80% of the total weight of a bending machine. Its strength and rigidity directly determine the running accuracy, service life of the machine and the accuracy of the workpiece.

1. Slider part: hydraulic drive is adopted, and the slider part is composed of slider, oil cylinder and mechanical stop fine adjustment structure. The left and right cylinders are fixed on the frame, and the piston (rod) is driven by the hydraulic pressure to move the slider up and down, and the mechanical stop is controlled by the numerical control system to adjust the value;
2, the workbench part: operated by the button box, so that the motor drives the material rack to move back and forth, and the distance controlled by the numerical control system is controlled, the minimum reading is 0.01 mm (the front and rear positions have the limit of the travel switch);
3. Synchronous system: The machine consists of a mechanical synchronizing mechanism consisting of a torsion shaft, a swing arm and a joint bearing. The structure is simple, the performance is stable and reliable, and the synchronization precision is high. The mechanical stop is regulated by the motor and the numerical control system controls the value;
4, the material blocking mechanism: the material is driven by the motor, and the two screw rods move synchronously through the chain operation, and the numerical control system controls the size of the material.

Wrench classification

Wrenches are basically divided into two types, dead wrenches and adjustable wrenches.
Wrench
. The former refers to a wrench that has a fixed number written on it, and the latter is an adjustable wrench. 1. Wrench: One or both ends are provided with fixed-size openings for screwing nuts or bolts of a certain size. 2. Torx wrench: The working end with hexagonal hole or twelve-corner hole at both ends is suitable for occasions where the working space is small and ordinary wrench cannot be used. 3. Combination wrench: One end is the same as the single wrench, the other end is the same as the wrench, and the bolts or nuts of the same specification are screwed at both ends. 4. Adjustable wrench: The width of the opening can be adjusted within a certain size range, and the bolts or nuts of different specifications can be twisted. The structural feature of the wrench is that the fixed jaw is made into a flat jaw with a fine tooth; the movable jaw is made at one end with a flat jaw; the other end is made with a concave jaw with a fine tooth; the worm is pressed downward, the activity The jaws can be removed quickly and the jaws can be replaced. 5. Hook wrench: Also known as a crescent wrench, used to twist flat nuts with limited thickness. 6. Socket wrench: It is composed of a plurality of sleeves with hexagonal holes or twelve-corner holes and is equipped with various accessories such as handles and posts. It is especially suitable for bolts with very narrow position or deep depression. Or nut. 7. Allen key: An L-shaped hexagonal bar wrench designed to screw the hexagon socket head cap screws. The model of the Allen key is in accordance with the size of the opposite side of the hexagon. The size of the bolt has the national standard. Uses: Specially used for fastening or disassembling round nuts on machine tools, vehicles and machinery. 8. Torque wrench: It can show the applied torque when the bolt or nut is turned; or when the applied torque reaches the specified value, it will emit a light or sound signal. Torque wrenches are suitable for installations where the torque is clearly specified. cnc machining

How to choose a planetary reducer to select a gear

The choice of planetary reducer is very important for the motor. When selecting a planetary reducer, the selection of the reducer gear is a very important part. Because the gears are not matched and unreasonable, the reducer will not operate normally. How to choose the planetary reducer to select the gear?

1. When selecting a gear, the planetary reducer should pay attention to the hardness of the working tooth surface of the pinion gear is slightly higher than the working tooth surface hardness of the large gear.

2, the use of a smaller pressure angle can reduce the running noise, comprehensively consider the impact of strength, usually take the standard value of 20 ° C. When the structure allows, the use of helical gears should be given priority, and the vibration and noise are greatly reduced compared with the spur gears. Generally, the helix angle is selected between 8 ° C and 20 ° C.

3. Under the economic ability that the user can withstand, the accuracy level of the gear should be improved as much as possible. High-precision grade gears produce much less noise than low-precision grade gears.

4. Under the premise of satisfying the bending fatigue strength, when the center distance of the planetary reducer is constant, more teeth should be selected, which can improve the coincidence degree, make the transmission smooth and reduce noise. Under the premise of meeting the transmission requirements, the number of teeth of the large and small gears should be made as large as possible, so as to disperse and eliminate the influence of the gear manufacturing error on the transmission, and also avoid the teeth of the large and small gears periodically meshing with each other, so that the transmission is stable. Reduce noise.

The above is the method of selecting the planetary reducer gear. What we can see is that the use of the planetary reducer is an aspect that must be paid attention to for the choice of gears. I hope that the introduction of Dongguan Ji Chuang Xiaobian can help everyone.

How to replace all kinds of filter elements? Collect this article, get it all

Replace or clean the air filter at least every 2000 hours or when the warning light is on. The outer filter can be cleaned up to 6 times and must be replaced. The inner filter is a disposable product that cannot be cleaned and replaced directly. If the filter is damaged, it must also be replaced.

Clean the compressed air with a maximum pressure of 5 BAR using air compressed gas. Do not place the nozzle close to 3 – 5 cm. Blow the filter from the inside along the folds.

Air conditioning filter replacement

The air conditioning filter replaces the air conditioning filter every 1000 hours or 5 months. If the air conditioning filter is clogged, the amount of air intake will decrease and the cooling/heating capacity will decrease. Therefore, it is necessary to clean or replace it regularly (there is a part of the brand air-conditioning filter in the rear position of the cab).

Hydraulic oil line filter replacement

The hydraulic oil line filter is replaced every 500 hours. Pay attention to when disassembling and replacing:

1. When replacing the pipe filter, use a filter wrench to turn the filter counterclockwise to remove it.

2. Apply hydraulic oil to the new filter element and apply a layer of hydraulic oil to the O-ring seal.

Fuel filter replacement

The engine fuel filter is replaced every 1000 hours. Pay attention to when disassembling and replacing:

1. Turn off the fuel line switch when replacing the fuel filter to prevent oil from being discharged all the time.

2. Use a filter wrench to turn the filter counterclockwise to disassemble it.

3. Install a layer of fuel on the new filter O-ring and install it (do not fill the fuel filter with fuel, because unfiltered fuel will damage the fuel components).

Hydraulic oil return filter replacement

The hydraulic oil return filter is replaced every 1000 hours. Pay attention to when disassembling and replacing:

1. First release the internal pressure of the hydraulic tank.

2. Unscrew the hydraulic oil return oil end cap.

3. Remove the springs in sequence, bypass the valve assembly, and finally remove the return oil filter.

4. Install the oil return filter according to the disassembly procedure.

Hydraulic oil filter (51).jpg

Pilot filter replacement

The pilot filter is replaced every 1000 hours. Pay attention to when disassembling and replacing:

1. Use a wrench to remove the pilot filter and remove the filter bowl and filter.

2. First install the pilot filter element onto the pilot filter holder.

3. Install a layer of lubricating oil on the new pilot filter O-ring seal.

Hydraulic oil suction filter replacement

The hydraulic oil suction filter is replaced every 2,000 hours. Pay attention to when disassembling and replacing:

1. Press down the air ventilator to release the internal pressure of the hydraulic tank.

2. Remove the oil-absorbing filter end cap and pull out the oil-absorbing filter.

3. Clean or replace the oil suction filter according to the hours of operation.

Type of CNC blade

2018/10/12 9:40:09 Viewers:6

There are many kinds of CNC blades and they are widely used. Nowadays, CNC blades are mainly the following types of blades:

1. Monolithic: Grinded from a single piece of material, the cutting part can be ground to the desired shape according to different purposes.

2, mosaic: it is divided into welding and machine clamp. The machine clamp type is different according to the structure of the cutter body. Can be divided into non-transposition and indexable

3. Damping type: When the length and diameter ratio of the working arm of the tool is greater than 4, in order to reduce the vibration of the tool and improve the machining accuracy, a special structure tool is used. Mainly used for pupils.

4. The cutting coolant of the internal cooling type is transmitted to the inside of the cutter body through the machine spindle or the cutter head and is sprayed from the injection hole to the cutting edge.

5, special types: including strong clamping, reversible tapping, composite tools, etc. At present, CNC Machining tool tools mainly use machine clamp indexable tools.

Mold process performance

Mold manufacturing generally involves several processes such as forging, cutting, and heat treatment. In order to ensure the quality of the mold and reduce the production cost, the material should have good forgeability, machinability, hardenability, hardenability and grindability; it should also have small oxidation, decarburization sensitivity and quenching. Deformation cracking tendency.

1. Forgeability
It has low hot forging deformation resistance, good plasticity, wide forging temperature range, low tendency for forging cracking and precipitation of reticulated carbides.
2. Annealing process
The spheroidizing annealing temperature range is wide, the annealing hardness is low, the fluctuation range is small, and the spheroidization rate is high.
3. Machinability
Large cutting amount, low tool loss and low surface roughness.
4. Oxidation and decarburization sensitivity
When heated at high temperature, the anti-oxidation energy is good, the decarburization speed is slow, and it is not sensitive to the heating medium, and the tendency to produce pitting is small.
5. Hardenability
Uniform and high surface hardness after quenching.
6. Hardenability
After quenching, a deep hardened layer can be obtained, which can be hardened with a mild quenching medium.
7. Quenching deformation cracking tendency
The conventional quenching volume change is small, the shape is warped, the distortion is slight, and the abnormal deformation tendency is low. Conventional quenching cracking has low sensitivity and is not sensitive to quenching temperature and workpiece shape.
8. Grindability
The relative loss of the grinding wheel is small, the amount of grinding without the limit of grinding is large, and it is not sensitive to the quality of the grinding wheel and the cooling condition, and it is not easy to cause abrasion and grinding crack.

What materials and methods of using titanium plating

In the electroplating process, the titanium hanger mainly functions as a conductive, supporting and fixing part, so that the part can obtain a uniform current in the plating tank as much as possible. Therefore, designing and making reasonable hangers is of great significance for ensuring product quality, improving production efficiency and reducing costs. The following principles must be mastered when designing and selecting hangers: First, the selection of titanium hanger materials and insulation materials should be reasonable, and the structure should ensure the uniformity of coating thickness; second, it must have good electrical conductivity and meet the process requirements. Third, it is convenient to operate between the titanium hanger and the parts, which is beneficial to increase productivity. For more information, please click “How to Reduce Corrosion Methods for Titanium Hangers”.

(1) Forms of general titanium hangers and materials used

The form and structure of the universally-plated titanium hanger should be determined according to the geometry of the plating, the technical requirements of the coating, the process and the size of the equipment. For example, the sheet-like plated member may float with the resistance of the plating solution between the upper and lower processes, and the plated member is clamped or tied with a copper wire when the hanger is selected. If the plated part is heavy and has holes, a hook-shaped hanger can be used. For example, the bicycle rim is round, and as long as the inside is plated, a larger clamp is used to clamp the outside of the rim.

Common fixtures are mostly used for plating that is not too thick, allows parts to sway in the plating tank, and has a low current density, such as galvanizing, cadmium, tin, copper, nickel, and the like. Universal hangers are generally composed of five parts. These five parts can be welded into a fixed type, and the hooks and struts can be made into an adjustable assembly. The effects of free space and power lines should be considered between parts and parts during plating. To make the coating uniform, a certain distance must be maintained. If the form and structure of the titanium hanger is not properly selected, it will affect the quality of the coating.

In short, the form of the titanium hanger must depend on the shape of the plated part and the surface to be plated. Whether the selection of the form and structure of the titanium hanger is reasonable in electroplating, and whether the use of the material is appropriate will directly affect the product quality and production efficiency.

(2) Calculation of the cross-sectional area of titanium hangers

The size of the cross-sectional area of the titanium hanger is very important. If the cross-sectional area of the titanium hanger is too small, it takes a long time to make the thickness of the coating meet the requirements. If the cross-sectional area is too large, it will result in waste of materials, so the calculation of the cross-sectional area of the titanium hanger should be reasonable.

(3) The use of titanium hangers requires good contact between the hanger and the cathode rod, which is critical to the quality of the plating, especially in the case of high-current hard chrome plating and decorative plating using cathode moving agitation, often due to poor contact. The contact resistance is generated to make the current not smooth. Therefore, intermittent power failure occurs, causing poor bonding strength of the plating layer, and also affecting the thickness of the plating layer, resulting in a decrease in corrosion resistance. It is therefore required to maintain a clean and good contact of the contact points between the titanium hanger and the cathode rod during processing of the hanger and the use. The cross section of the guide rod is usually round and rectangular, and the suspension method is required to design the hook.

(4) Insulation of titanium hangers, cnc machining

The main and struts of the titanium hanger are immersed in the plating solution during electroplating. During the electroplating, the titanium hanger and the plated part are subjected to the same process of electroplating. If the titanium hanger and the plating solution are not insulated, the plating area will be enlarged, thereby reducing the current density, prolonging the plating time, wasting energy and metal materials, and increasing the plating cost. Therefore, the insulation of the titanium hanger is very important. It is required that the insulating material can withstand high temperature during electroplating, does not affect the composition of the plating solution, and is not damaged for a certain period of time.