July 2019 – Page 2 – CNC Machining & Turning, Milling, Metal parts

How to Maintain CNC Machining Machine

The key to preventive maintenance of CNC machine tools is to strengthen daily maintenance. The main maintenance work includes the following: daily inspection, weekly inspection, monthly inspection, quarterly inspection and half-year inspection. The preventive maintenance of CNC machine tools is as follows:

1. Daily Inspection of CNC Machining Machine Tools

Its main projects include hydraulic system, spindle lubrication system, guide rail lubrication system, cooling system, air pressure system. Daily inspection is based on the normal conditions of each system to be tested. For example, when testing the process of the spindle lubrication system, the power supply lamp should be on, the oil pressure pump should be running normally, and if the power supply lamp is not on, the spindle should be kept in a stop state and contacted with the mechanical engineer. Maintenance.

2. Weekly Inspection of CNC Machining Machine Tools

Its main items include machine tool parts, spindle lubrication system, which should be checked correctly every week, especially for machine tool parts to remove iron chips and carry out external debris cleaning.

3. Monthly Inspection of CNC Machining Machine Tools

Mainly check the power supply and air dryer. The power supply voltage is rated at 180V-220V under normal conditions and the frequency is 50Hz. If there is any abnormality, it should be measured and adjusted. The air dryer should be disassembled once a month and then cleaned and assembled.

4. Quarterly Inspection of CNC Machining Machine Tools

Quarterly inspection should be carried out mainly from three aspects: machine tool bed, hydraulic system and spindle lubrication system. For example, when inspecting the machine tool bed, it mainly depends on whether the accuracy of the machine tool and the level of the machine tool meet the requirements of the manual. If there are any problems, we should contact the mechanical engineer immediately. When inspecting the hydraulic system and the main shaft lubrication system, if there are any problems, the new oil 6oL and 20L should be replaced and cleaned separately.

5. CNC Machining CNC Machine Tool Half-year Inspection

Half a year later, the hydraulic system, spindle lubrication system and X-axis of the machine tool should be inspected. If there is a problem, the new oil should be replaced and then the cleaning work should be carried out. After knowing and mastering the knowledge of preventive maintenance in an all-round way, we must have a better understanding and necessary mastery of the causes and treatment of abnormal phenomena in oil pressure system. For example, when the phenomenon of oil pump not injecting oil, abnormal pressure, noise and so on occurs, we should know what the main reasons are and what the corresponding solutions are.

Development and Current Situation of Alloy Die Casting Industry

Many characteristics of pressure casting technology have shown great advantages in improving the accuracy, production efficiency and surface quality of non-ferrous metal alloy castings. With the development of automobile, motorcycle and other industries, as well as the realization of design requirements such as improving the quality of die castings, saving energy consumption and reducing pollution, the application scope of non-ferrous metal alloy die castings, especially light alloy (aluminum and magnesium alloy) die castings, is expanding rapidly. It has been shown that replacing iron and steel castings with aluminium alloy and magnesium alloy castings is becoming an important development trend in developed countries. At present, die casting has become one of the most widely used processes in automotive aluminum alloy forming process, accounting for 49% of all automotive forming processes.

Since the 1990s, China’s non-ferrous metal die-casting industry has become a new industry while achieving amazing development. There are about 3000 non-ferrous metal die-casting enterprises in China. The output of die-casting increased from 266,000 tons in 1995 to 870,000 tons in 2005, with an average annual increase rate of 12.58%. Aluminum alloy die-casting accounts for more than 3/4 of all die-casting production.

With the improvement of technology level and product development capability, the categories and application fields of aluminium alloy die casting products are expanding continuously, and the types of alloys, die casting equipment, die casting die and die casting process have undergone tremendous changes.

New Development of Die Casting Aluminum Alloys

Die-casting aluminium alloy has been commercialized since 1914. With the development of automobile industry and the invention of cold chamber die-casting machine, its alloy types have developed rapidly. Die-cast aluminium alloys can be divided into low strength (e.g. Y102 in China) and high strength (e.g. Y112 in China) according to their properties. At present, the main series of die-casting aluminium alloys used in industry are Al-51, Al-Mg, Al-Si-Cu, Al-Si-Mg, AI-Si-Cu-Mg, Al-Zn and so on. Main Die Casting Aluminum Alloy Series Used in Industrial Developed Countries

Characteristics of traction folding arm high altitude working platform

Characteristic of traction folding arm high altitude working platform:

1. The 360-degree rotation of the folding arm high-altitude working platform does not need external power supply. It can work over obstacles and lift smoothly and safely. The folding arm type lifting platform uses folding arm type working arm. The scope and space of the operation are not limited.

2. The folding arm hydraulic elevator adopts the full hydraulic elevator mechanism, which is operable in the platform bucket and the elevator body.

3. The working arm of the elevator can rotate around 360 degrees.

4. The hydraulic system is equipped with a safety explosion-proof valve to prevent the main arm cylinder tubing from bursting.

5. Hydraulic support legs are equipped with hydraulic locking installation to avoid the retraction of the leg cylinder.

6. Hydraulic system is equipped with platform overload automatic maintenance and installation, so as to ensure the safety of operators.

7. All the working arms of the platform are equipped with safety limit installation.

8. Seals of platform hydraulic system are well-known brands both at home and abroad.

What is the companys requirement for import and export? Seaborne price inquiry

At present, the requirements of the state for applying for import and export enterprises have been greatly reduced, as long as the applicant enterprises handle valid business licenses, tax registration certificates, organization code certificates and bank accounts according to law.

Import and export filing application process:

1. REPORT OF THE ECONOMIC AND FOREIGN COMMITTEE
2. Overseas filing
3. Foreign Exchange Registration
4. Inspection and Quarantine Record
5. Electronic Port Registration
6. Registration of Export Tax Rebate

Material required for import and export filing applications:

1. The original and photocopy of the company’s business license
2. Original and photocopy of organization code certificate
3. Original and photocopy of tax registration certificate

Minimum Registered Capital Regulations for Import and Export Companies
1. In the past, the minimum registered capital of import and export companies was RMB 1 million.
2. According to the new Company Law of the People’s Republic of China, the minimum registered capital is RMB 30,000.
3. One person registers an import and export company with a minimum registered capital of RMB 100,000.
4. The minimum registered capital of two or more import and export companies is RMB 30,000 or more.
5. If an import and export company applies for general taxpayer qualification, the minimum registered capital requirement is RMB 500,000 (no upper limit).

Xiaobian reminds you here: Import and export companies can only enjoy the export tax rebate policy if they have the general taxpayer qualification, otherwise, they will not enjoy the export tax rebate.
Provisions on the Period of Investment of Registered Capital of Import and Export Companies

1. When one person (one shareholder) registers an import and export company, the registered capital needs to be in place at one time and cannot be contributed by stages.
2. When two or more persons register an import and export company, the registered capital may be invested in batches. The first batch of registered capital shall not be less than 20% of the total registered capital. The remaining registered capital shall be in place within two years.

Seaborne Price Inquiry
Finder is an effective inquiry tool to help international freight forwarders find customers. Through the analysis and collation of the massive freight data of all import and export enterprises in China, the freight forwarding enterprises can accurately understand: the cargo route, the scale and the type of freight. It matches with the advantages of freight forwarding enterprises and makes use of big trade data to achieve precise marketing.

Life Analysis of Cast Iron Plate

Measurement of Scraping Depth and Scraping Contact Spot Area and Life Analysis of Plate

The results of wear investigation on 20 plates are as follows: 2 Hebei Botou cast iron plates, one of which has been used for more than five years, are still in normal use; the other conductor has been used for more than five years, and the corrosion caused by poor storage has been repaired. The remaining 18 cast iron slabs scraped and polished by other provinces and municipalities have been used for one year. After verification, 10 of them are seriously worn out and need to be repaired. Eight of them can still be used, but some of them have been spotted and patched. The average scraping depth is 37.36 micron for No. 1 plate and 9.06 micron for No. 2 plate. The difference between them is more than three times. According to the relationship between friction curve loss and friction time, the plate is always in the initial wear stage, the curve is linear, and the wear amount is proportional to the friction time. As a result of the investigation of plate wear, the service life of Hebei Botou plate is five times as long as that of Wafangdian plate. Obviously, the influence of scraping depth on the service life of flat plate can not be ignored. JJG 117-91 plate verification regulation does not stipulate scraping depth, which is undoubtedly a defect. From the above test results, it can be seen that the contact spots are approximately the same, but the contact areas measured are 20% and 10%, respectively. The difference is very large. From the point of view of use, the service life of the flat plate can be improved by increasing the contact area as much as possible without causing the workpiece to lap into the flat plate. JJG 117-91 Plate Verification Regulation also does not appropriately restrict this item.

In order to improve the service life of the plate and ensure its working accuracy, it is suggested that the scraping depth should be controlled at or above 0.02 mm, so as to ensure a longer service life and verification period of the plate. According to the introduction of scraping depth and the measured data of scraping depth, the processing requirements of this process can be achieved. For the control of contact speckle area, the UK Standard Specification for Plate and Platform stipulates that the proportion of supporting area for AA (equivalent to JJG 117-91 specification 0), A (equivalent to JJG 117-91 specification 1) and B (equivalent to JG 117-91 specification 2) is not less than 20% and 10% respectively. Highlights should be evenly distributed, and the proportion of supporting area should not be high enough to cause adhesion of the workpiece. This regulation not only guarantees the accuracy of the plate, but also takes into account the service life of the plate, which can be used for reference.

Notice in cast iron plate casting: The control of casting grinding process and the properties of moulding sand will directly affect the quality of measuring tool castings. Therefore, moulding sand should have good permeability, wet strength, fluidity, plasticity and yielding. Strictly according to the order of feeding: old sand – new sand – clay – coal powder – water. The mixing time is set at 6-7 minutes, and the mixing time is about 5 hours. After leveling, sieving, loosening and reusing can make the moulding sand loose, so as to improve the permeability and fluidity. Control of casting process. The casting water should be inoculated and slag removed before pouring. In the process of pouring, it is necessary to flow continuously and smoothly so as to avoid sand scouring and formation of sand holes. In order to reduce the defects of cold insulation and insufficient pouring, it is necessary to plug the part of lost casting water and make up for the casting water in time when running out of fire. The control of casting cleaning process is that the measuring tool castings are cleaned from the casting mould after cooling in order to obtain the surface defect-free measuring tool castings.

Reasonable process: Operators should operate strictly according to the process. Calculating the structure of the measuring tool castings can make the pattern manufacturing simple and convenient, make the number of parting surfaces less, have the inclination of drawing die, the number of sand cores less, have reasonable wall thickness, and have transition at the joint. Reasonable gating system is selected to solidify the measuring tool castings sequentially so as to obtain the measuring tool castings with uniform structure.

Closing the box: Closing the box is an important link that can not be ignored. The floating sand on the surface of the casting mould should be cleaned up, combined according to the seal, and pay attention to the wrong box quantity. It is an important means to reduce the bias box of measuring tools and castings.

Core setting: When core setting, it should be smooth and clear floating sand. The position of sand core should be well placed to prevent the deviation of core. Drying: For the drying process of the dry mould, the operation should be carried out according to the operating rules. The drying time is more than 8 hours, in order to prevent sand, stomata and other defects caused by the impermeability of drying. Attention should be paid to the EPC coating of cast iron slab.

(1): Coatings requirements: use water-based graphite paint, its Baume of 60-70, painting in the greenhouse, before drying, strictly prohibit removal, in order to prevent deformation.

(2) Brushing requirements: uniform mixing of paint, strict whiteness when brushing.

(3) Coating drying: Coatings should have enough strength after drying, drying for 24 hours at 50-60 C.

Key Points of Safety Valve Setting

The following points should be paid attention to when setting safety valve:

(1) When there are gas and liquid two-phase materials in the container, the safety valve should be installed in the gas phase part.

(2) When the safety valve is used to discharge flammable liquid, the outlet of the safety valve should be connected with the accident tank. When the discharged material is high temperature combustible, the receiving container should have corresponding protective facilities.

(3) General safety valves can be vented in situ. The vent should be higher than 1 m (m) of the operator and should not be directed towards the open flame location, spark emission location and high temperature equipment within 15 m (m). The safety valve vent of indoor equipment and containers should lead out the roof and be over 2 meters (m) above the roof.

(4) When there is a partition valve at the entrance of the relief valve, the partition valve should be in a normal open state and be sealed with lead to avoid mistakes. 4h

Anodic oxidation of die-cast aluminium alloy products

Die-cast aluminium can not make the texture of the iPhone 6 by anodizing.

The process of making Ip6 aluminium alloy fuselage is briefly described as follows:

Aluminum extrusion – CNC blank – T treatment – Nano injection molding – grinding – sandblasting – anodic oxidation – CNC bright edge. The main reason why die-casting aluminium blank is cheap is that the processing time of CNC blank after aluminium extrusion is saved.

But there is a big defect in die-casting aluminium: it is easy to produce pore and impurity. In CNC process, the defect becomes obvious when it meets the position of air hole, and there will be “small pits” on the surface, commonly known as sand holes; after anodic oxidation, because of the influence of impurity silicon, the surface will produce black spots and black lines; because the density of die-casting aluminum is not as high as that of aluminium extrusion, after anodic oxidation, the surface grain pattern will be more obvious.

So the surface effect of die-casting aluminium produced by conventional process is very poor.
Can you do it? It can also be done.

Mould exhaust holes should be improved to minimize the amount of internal bubbles; polishing and polishing before sand blasting has little effect, but there are some effects; spraying coarse sand, such as glass sand, to cover the sand holes; selecting aluminium material without silicon to avoid black spots; deep anodic oxidation color, such as black, covering defects; making small appearance parts. In order to improve the yield.

What factors affect the quality of metal stamping parts

Stamping process can be roughly divided into separation process and forming process (also divided into bending, deep drawing, forming) two categories. Separation process is to separate stamping parts and blanks along a certain contour line in the stamping process, while the quality of the separated section of stamping parts must meet certain requirements; forming process is to make the blanks plastic deformation without destroying, and transform into the required finished product shape, but also to meet the requirements of dimension tolerance. What factors will affect the quality of stamping parts are briefly introduced below by Baida Borun Petrochemical Company.

I. Impact of Stamping Technology on Workpiece Quality

According to the temperature of stamping, there are two ways: cold stamping and hot stamping. This depends on the strength, plasticity, thickness, degree of deformation and equipment capacity of the material, and the original heat treatment state and final service conditions of the material should be taken into account.

(1) Cold stamping metal processing at room temperature is generally suitable for blanks with thickness less than 4 mm. The utility model has the advantages of no heating, no oxide skin, good surface quality, convenient operation and low cost. The disadvantage is work hardening, which makes the metal lose the ability of further deformation. Cold stamping requires uniform blank thickness and small fluctuation range, smooth surface, no spot, no scratch and so on.

(2) Hot stamping is a kind of stamping method which heats metal to a certain temperature range. The advantages are that internal stress can be eliminated, work hardening can be avoided, plasticity of materials can be increased, deformation resistance can be reduced and power consumption of equipment can be reduced.

2. The Effect of Stamping Material on Workpiece Quality

There are three main stamping processes: blanking, bending and stretching. Different processes have different requirements for sheet metal. The selection of sheet metal should also be considered according to the general shape of the product and the processing technology.

(1) The influence of material on blanking

Blanking requires that the sheet should have enough plasticity to ensure that the sheet does not crack during blanking. Soft materials can be blanked to obtain smooth cross-section and small inclination of the parts; hard materials have large cross-section roughness after blanking, especially for thick sheet materials, which are especially serious brittle materials, and tear easily occurs after blanking.

(2) The influence of material on bending

The sheet which needs bending forming should have enough plasticity and lower yield limit. Plates with high plasticity are not easy to crack when bending; sheets with lower yield limit and lower elastic modulus have smaller springback deformation after bending, and are easy to get accurate bending shape. The material with larger brittleness must have larger relative bending radius when bending, otherwise it is easy to crack in the bending process.

(3) Effect of Material on Tensile Processing

The drawing process of sheet metal requires not only the drawing depth as small as possible, the shape as simple as possible and smooth transition, but also the material has better plasticity. Otherwise, it is very easy to cause the whole distortion, local wrinkling and even the tension part cracking.

3. Impact of Stamping Oil Products on Workpiece Quality

Stamping oil plays a key role in the stamping process. Good cooling performance and extreme pressure and anti-wear performance have made a qualitative leap in improving the service life of the die and the accuracy of the workpiece. According to the different material of the workpiece, the emphasis of the performance of stamping oil is also different when it is used.

(1) Silicon steel sheet is a relatively easy punching material. In order to clean the workpiece, low-viscosity punching oil will be selected on the premise of preventing punching burr.

(2) When choosing punching oil for carbon steel sheet, the better viscosity should be determined according to the difficulty of process and the method of drawing oil and degreasing.

(3) Galvanized steel sheet and chlorine additives will react chemically, so when choosing stamping oil for galvanized steel sheet, attention should be paid to the possibility of white rust in chlorine stamping oil, while using Yida Borun sulfur stamping oil can avoid rust, but degreasing should be done as soon as possible after stamping.

(4) Stainless steel sheets are easy to harden. It is required to use oil film with high strength and sintering resistance. Pressing oil containing sulfur-chlorine compound additives is generally used to ensure extreme pressure performance and avoid burrs and cracks on the workpiece.

Effect of Chromium on Stainless Steel

Chromium is the most important alloy element in austenitic stainless steel. The main reason for obtaining the stainless and corrosion resistance of austenitic stainless steel is that chromium promotes the passivation of steel and keeps the steel stable and passive under the action of mass transfer. Effect of Chromium on Microstructure: In austenitic stainless steel, chromium is an element that strongly forms and stabilizes ferrite, reducing austenitic zone. With the increase of steel content, ferrite (delta) structure can appear in austenitic stainless steel. The research shows that in chromium-nickel austenitic stainless steel, when carbon content is 0.1% and chromium content is 18%, the required nickel content for obtaining stable single austenitic structure. In this regard, the commonly used 18Cr-8Ni austenitic stainless steel with chromium content is the most suitable one. In austenitic stainless steel, with the increase of chromium content, the formation tendency of some intermetallic phases (e.g. Delta phase) increases. When molybdenum is contained in steel, the chromium content will increase and the formation of_equivalence will also occur. As mentioned earlier, the precipitation of_and_phase not only significantly reduces the plasticity and toughness of steel, but also reduces the corrosion resistance of steel under some conditions, and the extraction of chromium content in austenitic stainless steel. High martensitic hydrocarbon transfer temperature (Ms) decreases, which improves the stability of austenite matrix. Therefore, it is difficult to obtain martensite structure of austenitic stainless steel with high chromium (for example, more than 20%) even after cold working and low temperature treatment.

Chromium is a strong carbide forming element, and it is no exception in austenitic stainless steel. Cr23C6 is a common chromium carbide in austenitic stainless steel. When molybdenum or chromium is contained in steel, carbides such as Cr6C can also be seen. Their formation will have an important impact on the properties of steel under certain conditions. In general, as long as austenitic stainless steel retains complete austenitic structure without formation of delta ferrite, only increasing chromium content in steel will not have significant effect on mechanical properties. The greatest effect of chromium on the properties of austenitic stainless steel is corrosion resistance, which is mainly manifested as follows: chromium improves the properties of oxidation resistance medium and acid chloride medium of steel; Under the combined action of molybdenum and copper, chromium improves the resistance of steel to some reducing medium, organic acid, urea and alkali medium, and chromium also improves the resistance of steel to local corrosion, such as intergranular corrosion. Point corrosion, crevice corrosion and stress corrosion properties under certain conditions. The most important factor affecting the susceptibility to intercrystalline corrosion of austenitic stainless steel is the carbon content in the steel. The effect of other elements on Intercrystalline Corrosion depends mainly on the dissolution and precipitation behavior of carbides. In austenitic stainless steel, chromium can increase the solubility of carbon and reduce the dilution of chromium. Therefore, increasing the chromium content is beneficial to the intercrystalline corrosion resistance of austenitic stainless steel. Effectively improve the pit corrosion resistance and crevice corrosion resistance of austenitic stainless steel. When molybdenum or molybdenum and nitrogen exist in the steel at the same time, the effectiveness of chromium is greatly enhanced. Although the resistance of molybdenum to pit corrosion and crevice corrosion is about 3 times of chromium and 30 times of chromium according to the research, a lot of studies have shown that if there is no chromium or low chromium content in austenitic stainless steel, the resistance of molyb Point corrosion and crevice corrosion will be lost or not significant enough.

The effect of chromium on stress corrosion resistance of austenitic stainless steel varies with the experimental medium conditions and the actual use environment. In MgCl2 boiling solution, the effect of chromium is generally harmful. However, under the conditions of stress corrosion with Cl-and oxygen-containing water, high temperature and high pressure water and pitting corrosion as its origin, increasing the content of chromium in steel is beneficial to stress corrosion resistance, and at the same time, chromium can be prevented. The tendency of intergranular stress corrosion in austenitic stainless steels and alloys is prone to occur due to the increase of nickel content, which is also beneficial to the stress corrosion of cracking (NaOH) and the effect of chromium. In addition to the important influence of chromium on the corrosion resistance of austenitic stainless steels, it can also significantly improve the anti-oxidation, anti-sulfuration and anti-molten salt corrosion properties of such steels.

Operating Rules of CNC Machining Center

A. Machine Tool Maintenance

1. Clean up and maintain the machine tool half an hour before work every day. If air gun or oil gun is used to clean chips, the spindle must have a knife.

It is forbidden to blow spindle cone holes with air gun or oil gun, so as to avoid small particles such as chips being blown into the spindle holes, which will affect the cleanliness of the spindle.

2. Check whether the lubricating machine is working properly and whether the lubricating oil is sufficient. Start the machine in the normal order.

3. Start the spindle (the speed is 501R/M) to preheat the spindle before the machine is working properly.

B. Machine Tool Operation

1. Confirm the type, dimension and allowance of the blank before going on the machine and sanding the blank.

2. Confirm the placement of the workpiece and the processing sequence after the machine is installed, and complete the table action.

3. The speed of the computer gong processing depends on the cutting tool if the “dividing the middle bar” is needed. In order to ensure the accuracy of the dividing, the “G0 G54 X0 Y0” can be used for inspection after the dividing.

4. Check again before formal processing to confirm the position of the workpiece and whether the number is correct.

C. Processing Notes

1. Before each procedure is processed, it is necessary to strictly confirm whether the tool is in accordance with the procedure.

2. The length of the cutter and the suitable clamping tool head should be confirmed when loading the cutter.

3. Keep the same area for each tool alignment in the same workpiece to ensure the accuracy of tool alignment.

4. Blow with air as far as possible in the roughening procedure and inject oil in the light knife procedure.

5. Clean up the aluminium residue in the machine tool before spraying oil with a light knife to prevent the aluminium residue from absorbing oil.

6. Dongguan Machinery Parts Processing Operators shall not leave the machine tool or regularly check the operation status of the machine tool while the machine tool is running on its own. If they need to leave halfway, they must designate relevant personnel to check.

7. If excessive machining allowance is found in the process of processing, the X, Y and Z values must be cleared by “single segment” or “pause” and then manually milling them off and then shaking them back to “zero” to allow them to run on their own.

8. In the process of Dongguan high-speed computer gong processing, if a knife collision is found, the operator must stop immediately, such as pressing the “emergency stop” button or the “reset” button or setting the “feed rate” to zero, etc.

9. Do not turn on the door to avoid flying knife or workpiece while the machine is running.

10. Workpiece must be deburred in time after it is off the machine.

11. At the end of work, CNC processing operators must make timely and accurate handover to ensure that follow-up processing can proceed normally.

12. Make sure the tool library is in the original position before shutdown, and the XYZ axis is in the middle position. Turn off the power supply and the total power supply on the machine tool operation panel in turn.

13. In case of heavy thunderstorm, the power supply must be cut off immediately.