Monthly Archive November 18, 2020

Key points of processing cam parts with computer gong

Research on key technology of design and manufacture of continuous fine blanking die for complex parts

The continuous fine blanking die for complex parts is the cutting-edge basic technology of fine blanking technology, which is taken as the leader to carry out the research, hoping to promote the whole fine blanking technology in China. Taking the synchronizer gear ring, clutch plate, longitudinal compound continuous fine blanking process and die as the breakthrough point, the key technology of fine blanking die design and manufacturing is studied, so as to realize the rapid improvement of fine blanking die technology in China and shorten the gap with advanced countries as soon as possible.

  1. Research on life improvement of fine blanking die and related key technologies

Die life is the comprehensive reflection of die material and supporting product level. Taking the fine blanking die life as the leader to carry out technical research can not only solve the problem that the service life of fine blanking die is too low, but also promote the technological development of die material, fine blanking process, supporting tooling and other auxiliary products.

  1. Research and development of composite technology of fine blanking and precision forging

Fine blanking and precision forging are two advanced manufacturing technologies developed in parallel. If the precision stamping part is too thick and needs precision forging, and if the precision forging piece is too thin, it must be fine blanking. The basic idea of developing the composite process of precision forging and fine blanking is to find the combination point of the two processes (such as gear parts with wheel hub and cam parts with short shaft). The precision forging in China has a long history and the level is very high. Therefore, it is a good way to improve the overall level of fine blanking technology in China.

CNC computer gongs machine tool debugging

Before the commissioning of CNC computer gong machining machine tool, the debugging method of CNC computer gong machining machine precision and function is as follows:

  1. Using precision level instrument and other detection tools, mainly by adjusting the pad iron way to fine adjust the level of the main bed of the computer gong processing machine tool, so that the geometric accuracy of the machine tool can reach the allowable tolerance range;
  2. For the automatic tool change device, adjust the position of the tool magazine, manipulator, travel parameters, etc., and then check the action with the command, which is required to be accurate;
  3. For the machine tool with APC automatic exchange table, after adjusting the relative position, carry out automatic load exchange;
  4. After the adjustment of the machine tool, carefully check whether the parameter setting values in the numerical control system and the programmable controller conform to the data specified in the random index, and then test the main operation functions, safety measures, execution of common instructions, etc.
  5. Check the auxiliary functions and accessories of the machine tool. CNC machining is the basis of modern manufacturing technology. This invention has epoch-making significance and far-reaching influence for the manufacturing industry.

CNC machining to prevent deformation of parts

Computer gong processing is an automatic numerical control machine,

Now many processing enterprises need this kind of mechanical equipment, but due to the fierce market competition, computer gongs processing chaos. The author suggests that before purchasing computer gong equipment, we must have a detailed understanding and investigation of the manufacturer.

Computer gong processing in the process of use will encounter some common faults, such as computer gongs can not return to zero, computer gongs positive and negative hard limit alarm, so what are the causes of these failures?

Cause analysis of computer gong can not return to zero

  1. The contact of origin switch is stuck and cannot act;
  2. The origin stop can not press the origin switch to the switch action position;
  3. The water in the origin switch causes the contact rust and poor contact;
  4. The line of origin switch is disconnected or the input signal source is faulty;
  5. PLC input point burned out.

Cause analysis of positive and negative hard limit alarm of computer gong

In this case, what is the cause of this normal situation?

  1. The contact of travel switch is pressed and stuck (over travel);
  2. The travel switch is damaged;
  3. There is open circuit, short circuit and no signal source in the travel switch circuit;
  4. The limit stop can not press the switch contact to the action position;
  5. PLC input point burned out.

Most of the time, due to the improper use of technical personnel, or work handover is not in place, computer gong processing will cause some problems.

Precision CNC machining criteria

CNC machining can change the shape and size of products, which plays a very important role.

Many friends do not understand the high-speed CNC machining process benchmark.

The broad meaning of benchmark is the meaning of “basis”. In mechanical manufacturing, the datum refers to the points, lines and surfaces used to determine the geometric relationship between geometric elements on the production object. According to the different functions and applications, the datum can be divided into two categories: design datum and process datum. Process datum can be divided into process datum, locating datum, measuring datum and assembling datum.

High speed CNC machining technology is the premise to ensure the production of high-quality parts.

On the lathe, the shape and size of the blank can be changed by the rotary motion of the workpiece and the linear or curvilinear motion of the cutter, so that it can be processed to meet the requirements of the drawing.

Ordinary machine tools are more and more difficult to meet the needs of machining precision parts,

At the same time, due to the improvement of production level, the price of CNC machine tools is falling from time to time. CNC precision parts processing mainly includes ultra precision turning, mirror grinding and grinding.

The primary premise of CNC precision parts processing is the accuracy of process datum. The datum on mechanical drawings are all represented by capital letters a, B, C, D, etc. with a specific ring datum symbol. When the datum symbols are aligned with the surface and the extension line of the surface or the dimension limit of the surface, the indication is based on the surface. When the datum symbol is aligned with the dimension line, it is indicated that it is based on the solid center line of the dimension. It is a more general statement that the accuracy of the technology mentioned above is mentioned for you.

Assembly benchmark refers to the accuracy of the position of parts in parts or products during assembly. Measurement benchmark refers to the specification for the size and position of the measured processing surface when the parts are inspected. Positioning reference, refers to the processing, the workpiece in the machine tool or fixture positioning with the reference.

Polishing and grinding of hardware electroplated parts

For hardware electroplated parts, grinding and polishing is a very important step. Polishing technology and polishing effect are directly related to the smoothness, roundness, porosity and brightness of electroplated coatings. Especially for the products with high surface finish, it has strict requirements for the proficiency of polishing machine, grinding wheel, polishing wax, polishing workers and inspectors.

There are polishing lines for plastic electroplated parts, copper parts and aluminum alloy parts. The polishing methods and process details of different electroplating products are very different. It needs to adopt different polishing methods for different product data, different polishing wheels, different polishing wax and wheel rotation speed, so as to obtain high plating product rate and plating layer quality.

Even if it is the same kind of material Hardware electroplating parts polishing, is not the same situation, not the same treatment. There are red copper parts, brass parts, bronze parts, stamping parts, copper casting parts and turning parts. Although they are all copper parts, their polishing methods are different.

For example, the material of the copper stamping parts is generally better, so it is better to polish the surface of the copper stamping parts, The earliest use of 320 mm or 400 mm abrasive belt grinding once, if it is a high demand mirror, then use 600 mm abrasive belt to play once, then use 25 mm hemp wheel to hit diamond white wax, and finally polish with polishing powder. Maybe use soft cloth wheel to hit Japanese white wax or green wax or OK, if it is the demand for high mirror surface, use wool wheel to hit Japanese white wax. Here, pay attention to the soft and hard hemp wheel will directly affect the oil skid of the product.

For the surface polishing of hardware electroplated parts, it is often divided into rough polishing, medium polishing, fine polishing, ultra precision polishing and super mirror polishing. In order to achieve the corresponding surface effect, what type of polishing wheel is selected? What are the characteristics of polishing wax? What kind of process parameters and process flow can be used to obtain the most useful electroplating effect with the lowest polishing cost, which is the main content of electroplated parts polishing technology.

There are many types of manual polishing machine and active polishing machine on the market. Active polishing machines such as disc polishing machine, reciprocating plane linear polishing machine, aluminum plate stainless steel plate double axis polishing machine, pipe polishing machine, etc. At present, there are more advanced active polishing equipment operated by manipulator and robot. In active polishing machine, liquid wax and special polishing wax are usually used for polishing.

The main data of the manual polishing machine are polishing wax and polishing wheel.

According to the abrasives contained in polishing wax, they can be divided into four categories

1, diatomite 2, quartz powder 3, alumina 4, chromium oxide

According to the function of polishing wax, it can be divided into five types: coarse polishing wax, medium polishing wax, fine polishing wax, super polishing wax and super mirror polishing wax.

We also used to use color to distinguish polishing wax, also known as yellow wax, purple wax, green wax, small white wax, etc.

Because of the different sizes and colors, there are no uniform sizes and colors on the market.

For example, stainless steel polishing wax is used to: palmitic acid, stearic acid, rosin adhesive, plus abrasive feldspar powder, corundum, chromium oxide, iron red, etc., and then according to different matrix composition and requirements, different fineness and varieties are made.

Therefore, how to select the appropriate polishing wax is an important step in the polishing and polishing of metal electroplating parts.

In addition to the specifications and dimensions, such as internal and external diameter, thickness, number of layers, maximum speed and rotation direction, the polishing wheels can be divided into the following categories according to their data and shapes:

  1. Cloth wheel

It is made of cotton cloth, white cloth, denim, colored miscellaneous cloth, etc.

The structure shape of cloth wheel includes wave type, fold type, finger type, etc. In addition, there are wind cloth wheel, plane denim cloth wheel, plane color cloth wheel, button cloth wheel, bag cloth wheel and so on.

  1. Hemp wheel

The hemp wheel is made of linen.

Its structural shapes are: plain pure hemp wheel, twill hemp wheel, U-wave hemp wheel, wavy hemp wheel, folded hemp wheel, wind hemp wheel, finger hemp wheel, plane cloth folder hemp wheel, fiber hemp wheel, group nail hemp wheel, etc

  1. Hemp rope wheel

It’s made of hemp rope. There are hemp rope wheel, hemp rope wind wheel, steel core hemp rope wheel, etc.

  1. Nonwoven wheel

Not only cloth wheel is made of different abrasives, man-made fibers and adhesives, but also called nylon wheel. It has nylon wheel, nylon wind wheel, various special-shaped nylon wheel.

At present, there are more businesses using alumina, silicon carbide and other abrasives and a variety of special fibers made of non-woven cloth polishing wheel, this kind of polishing wheel is suitable for the polishing and polishing of various surfaces of objects.

Chip removal of computer gongs

It is said that the chip forming device with positive rake angle on the blade can reduce the cutting force and reduce the cutting power consumption by 15% – 25%. It can also guide the chip to leave the cutting area, so as to prevent the side of the machined part from being scratched by the chip. The chip is guided to flow inward (tool center) rather than outward (workpiece sidewall). The tool is equipped with two types of blades, one is used for slotting and the other is for cutting.

Tanglot milling cutter can be supplied as FDN flange type or SDN disc type cutter. The tool width can be adjusted according to the tool collet used and the blades with different widths. The range of tool diameter is 100-250mm, and the width of tool is 6.0-14.6mm. The new tool can be used for grooving and cutting of automobile bearing cover, steering knuckle and connecting rod, as well as other conventional slotting.

(2) Seco tools Inc. claims its new crown MF5 chip breaker has increased tool life by 67% in field cutting tests and improved chip control in 41% of tests. According to the company, MF5 chip breaker is optimized for semi finish machining related to near net machining. Its chip breaking groove can generate very small cutting force and allow the tool to carry out advanced cutting at a cutting depth of 0.5-2.7mm. MF5 chip breaker adopts crown shape with three sharp forks, chip guiding platform and cooling channel, which is conducive to small deep cutting and ultra-high pressure cooling. In addition, the open geometry angle can reduce the cutting force. The chip breaker has a ground island shaped protuberance, which can improve the positioning of the blade and is conducive to the heat dissipation of the workpiece and cutting edge.

MF5 chip breaker is used in 8 kinds of positive C-type and standard W-type blades (brand numbers are TK1000, tk2000, tp1000, tp3000 and duratomic tp2500). When roughing the steel rock bit (hardness hrc42 ~ 45), the tool life of TK1000 made of MF5 chip breaker is 5 times longer than that of a competitive chip breaker. In the similar cutting experiment with MF5 tp2500 blade, compared with tp2000 blade with M5 chip breaker, the productivity is increased by 55% and the tool life is increased by 360%.

(3) Sandvik Coromant’s new LC blade geometry prevents chip clogging that often occurs when cutting difficult to machine materials. Because of the edge shape design of LC blade, the risk of chip accumulation in machining low carbon steel workpiece is reduced, so the tool life and machining surface finish are improved. The scraping edge can increase the feed rate. The company provides LC turning blade grades for low carbon steel machining, including gc4225, gc1525 and gc2025.

(4) It is designed by guhring-48, Inc., which is easy to produce fine cutting chips. The 3365 series allows slotting and rough milling of steel parts at high cutting speeds and feed rates, while achieving maximum metal removal with minimum torque horsepower, the company said. The milling cutter is also suitable for machining titanium and titanium alloy aviation materials and nickel base alloy.

Cobalt collar has also launched 3376 series aluitech LR and 3364 series roughtech Alu three groove carbide end mills for processing aluminum and aluminum alloys. The above three kinds of end milling cutter series are supplied according to the standard specifications, and the cutter diameter ranges from 6.0 mm to 20.0 mm.

Mainly engaged in a variety of plastic mold design, manufacturing and plastic products injection, injection, pad printing and other processing services. The company produces a wide range of mold types, including various household appliances, computer weekly products, communication products, power tools and CD, DVD, MP3, MP4 categories, etc., which can be used to make rapid template mold and two-color molding mold. It can take into account large, medium and small die. The largest mold size is 2 m * 1 m, and the maximum weight can reach 8 tons.

Reasons for uneven machining of CNC parts

In the process of using computer gong machining center, the tool imbalance may appear. If not adjusted in time, it will affect the processing effect. Therefore, we should always pay attention to the tool balance of the computer gong machining center. What are the main reasons for the imbalance of the handle?

The main reasons are that the design of the tool is asymmetric, there are defects in the tool body, and all the adjustments on the tool. The correct balance of the tool can significantly reduce noise and vibration, which increases the tool life and improves the accuracy consistency of parts.

The centrifugal force of computer gong machining center magnifies the vibration caused by unbalance in proportion to the square of velocity. The vibration increase of CNC machining center caused by the machining center minimizes the service life of bearing bush, bearing, shaft, spindle and gear.

It is necessary to measure the magnitude of the unbalance and the angle position of each selected correction plane before balancing the tool on the computer gong machining center. These variables are measured on two general types of balancing machines: non rotating or gravity machines are used to measure single plane unbalance, while rotary or centrifuge is used to measure single plane or two plane unbalance.

After measuring the magnitude and angle of the unbalance in the correct plane, you can correct it by adding or removing material from the workpiece. For the components which are not tools, the most widely used material adding method of drilling center is welding counterweight on the components.

For components with slight unbalance, other methods include adding solder on the assembly body or increasing weight in pre drilling. For tools, when you determine that the unbalance must be removed in order to get the correct balance, the easiest and most effective method is drilling.

  1. Check the condition of lubrication system and pressure gauge, clean the filter screen of lubrication system, change lubricating oil and dredge oil circuit. machining center
  2. Check the gas system, clean the air filter screen and eliminate the leakage of pressure gas.
  3. Check the fluid system, clean the filter, clean the oil tank, replace or filter the oil. If possible, replace the seal.
  4. Fasten the transmission parts and replace the defective standard parts.
  5. Grease lubrication parts, according to the requirements, add grease
  6. Clean and clean all driving surfaces,
  7. Check the status of tool magazine and manipulator for computer gong processing, analyze the wear status of manipulator, and propose replacement suggestions to customers.
  8. Repair and repair the damaged parts of external components.
  9. Check the condition of the protective cover.

Honing of parts processing

Honing is a machining method that uses a group of diamond (or cubic boron nitride) honing heads with different diameters according to the size order, and each grinding head only makes one reciprocating cutting action in turn. After all the honing heads are machined, the final part requirements are met. The sequential honing technology is developed on the basis of traditional honing, which combines honing method with reaming method, so it is also called honing; in addition, sequential honing generally only has one reciprocating action, so it is also called single stroke honing

The characteristics of sequential honing mainly lie in its sequential honing head and actual honing process. Compared with the traditional honing process, the honing head of sequential honing has been set to the final machining size required by the workpiece in advance. Therefore, the cutting process of sequential honing only needs 1-3 reciprocating strokes. The thickness of metal layer removed by each honing head is 2-20 μ M. The shape and dimension accuracy of the hole can be improved by one level after the sequential honing, and the surface roughness value can reach Ra0.2. This processing method does not need tool feed, the processing time is fast, and also can improve the position accuracy of the hole to a certain extent.

Compared with ordinary honing machine, sequential honing machine has some advantages in processing beat, dimensional stability, shape and position accuracy. However, the domestic users of this honing machine tool used to rely entirely on imports. Because of the high price of machine tools, machine accessories and after-sales service, many users are deterred from importing sequential honing machines. The users who have the ability to purchase imported sequential honing machines also affect their production due to the lack of timely technical support from imported machine tools. Until the beginning of 2008, the third machine tool branch of Beijing No. Compared with foreign manufacturers which have developed for many years, they started later, but started higher. The sequential honing machine tools produced by them have been favored by many users as soon as they come into being, and have achieved multiple sales.

The machine tools they produce adopt German Siemens Servo motor and 810D numerical control system to realize the flexible adjustment of reciprocating speed and position, realize the real-time detection of processing torque of each processing shaft and set overload alarm; adopt German fibro rotary table, which has accurate positioning and fast speed, and the transposition time of each station reaches 0.69s; the rolling guide rail and ball screw of Japan THK can realize this At present, the spindle box is stable and accurate reciprocating; the honing tool, tool extension rod and workpiece fixture are all of full floating structure, which can ensure high honing accuracy: roundness: 0.001 mm, cylindricity: 0.002 mm, roughness: Ra0.2 μ m; processing beat is 9s / piece. Their machine tool also adopts modular design, and the number of spindles and turntable stations can provide users with the best processing scheme according to the process requirements of users and their parts. In recent years, with the batch launch of domestic medium-sized CNC machine tools, some high-end CNC machine tools began to enter the core manufacturing field of key industries, and were initially applied.

At the high-level forum of CNC machine tool exhibition, the equipment utilization rate of similar imported machine tools was 89.5%, and the domestic equipment was basically close to the same level of foreign equipment. “

As the user side of domestic CNC machine tools, the main problems of domestic CNC machine tools are the lack of design and innovation ability, slow response speed, no serial and high maturity CNC system, the quality of accessories needs to be improved, and the overall service awareness is weak.

According to the special plan for high-end CNC machine tools and basic manufacturing equipment, by 2020, about 80% of the high-end CNC machine tools and basic manufacturing equipment required by aerospace, shipbuilding, automobile and power generation equipment manufacturing will be based in China, which requires the industry to focus on the automobile, machinery manufacturing, military and other key downstream industries.

Experts suggest that the machine tool industry in the “Twelfth Five Year Plan” period should develop high-end market segments, focus on the product and process requirements of high-end customers and major customers, and provide personalized services according to the needs of customers. At the same time, we should closely track the development of strategic emerging industries and provide them with advanced and applicable machine tools and equipment.

Methods of quality inspection

Seven new methods of QC

① Relation graph method (association graph method);

② KJ method (affinity graph method, card method);

③ System diagram method (tree diagram method);

④ Matrix diagram method;

⑤ Matrix data analysis method;

⑥ Process decision program chart (PDPC)

Or major accident prediction chart method;

⑦ Network graph method (also known as network planning technology < PERT > method or vector diagram is also called critical path

Line method)

Five core manuals of ISO / TS16949

① FMEA (potential failure mode and effect analysis)

mode and effects Analysis);

② MSA (measurement system analysis);

③ SPC (statistical process control);

④ APQP (advanced product quality planning and control plan)

Product Quality Planning (APQP) and Control Plan);

⑤ PPAP (production part approval process)

The most important of the five manuals is APQP

10s / five constant method

(1) 10s from 5S

1s: finishing (Seiri)

2S: Seiton

3S: cleaning (seis0),

4S: cleaning (seiketsi)

5S: accomplishment (shitsijke)

6S: Safety

7S: saving / speed

8s: Service (servlce)

9s: satisficatl0n

10s: persistence

Five regular methods

The five constant method is a technology used to maintain the quality environment, which is called 5S in western countries. Hong Kong is known as the “five constant laws”. Due to the language needs, it has translated five English words, namely, structure, systematise, sanitise, standardization and self discipline. The implementation of the five standing laws in Hong Kong naturally requires the cooperation of five Chinese characters. It is also what we usually say: sorting out, rectifying, cleaning, and self-cultivation.

Chinese * English (5-s) * 50 points * court example*

① Often organize structurise 10 to throw away or return unnecessary items

② The file can be found in 30 seconds after regular systematise rectification

③ 5 people should be aware of hygiene responsibility

④ Storage transparency of standard 15;

⑤ Self discipline 10 daily use of five

Dry, semi dry and low temperature cold air cutting technology

In the process of cutting, elastic deformation, plastic deformation and friction deformation occur in the three deformation zones, 99.5% of the cutting power is transformed into shear slip deformation (the first deformation zone), the friction deformation of the rake face (the second deformation zone), and the energy consumed by extrusion, excess deformation and friction deformation of the back face (the third deformation zone), and it is transformed into heat energy in an instant, resulting in the temperature rise of chip, cutting edge area and workpiece surface.

Cutting heat is an inevitable physical phenomenon in the process of metal cutting, which has a significant impact on the quality of workpiece and tool life. In low-speed cutting, mechanical wear is the main reason for tool wear; while in high-speed cutting, high-temperature induced tool wear changes from mechanical wear to diffusion wear, phase change wear and carbonization wear, and leads to adhesive wear on the tool surface. Cutting heat also causes the thermal expansion of cutting tools and workpieces, aggravates the friction and wear of the flank of the cutting tool, and causes the surface roughness of the workpiece to rise. Therefore, the ultra precision machining process emphasizes that the conduction of cutting heat in the workpiece and tool must be controlled timely and effectively. It is also very important to control the temperature rise of tool and workpiece for NC machining.

The cutting heat of metal originates from the strength, hardness, toughness, plasticity and elasticity of materials. The research also shows that the temperature rise of cutting tool and workpiece is closely related to the contact area, heat transfer coefficient, temperature difference, contact time and so on. Generally speaking, reducing the cutting rate can reduce the contact area between the tool and the heat source; increasing the flow rate and flow rate of the cooling medium is to increase the heat transfer coefficient; reducing the temperature of the cooling medium can increase the heat capacity and temperature difference effect of the cutting tool and workpiece; and increasing the machine speed and cutting speed actually shortens the heat conduction time of cutting.

It can be seen that in order to control the cutting heat of metal and the temperature rise of cutting tools and workpieces, various factors must be considered comprehensively. In addition to the reasonable selection of cutting tools and cutting process parameters according to the characteristics of metal materials and machining technical indicators, the most direct measure is to use various cooling media to quickly take away the cutting heat on the tool and workpiece and reduce the temperature.